MXPA00007259A - Water purification apparatus - Google Patents

Water purification apparatus

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Publication number
MXPA00007259A
MXPA00007259A MXPA/A/2000/007259A MXPA00007259A MXPA00007259A MX PA00007259 A MXPA00007259 A MX PA00007259A MX PA00007259 A MXPA00007259 A MX PA00007259A MX PA00007259 A MXPA00007259 A MX PA00007259A
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MX
Mexico
Prior art keywords
water
membrane
hydrophilic
contaminants
dissolved solids
Prior art date
Application number
MXPA/A/2000/007259A
Other languages
Spanish (es)
Inventor
Mark Christopher Tonkin
Mark Andrew Young
Olaf Norbert Kirchner
Original Assignee
Design Technology & Innovation Limited
Ei Du Pont De Nemours And Company
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Publication date
Application filed by Design Technology & Innovation Limited, Ei Du Pont De Nemours And Company filed Critical Design Technology & Innovation Limited
Publication of MXPA00007259A publication Critical patent/MXPA00007259A/en

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Abstract

The present invention relates to the use of a hydrophilic membrane to provide by the process of vaporation through the membrane water suitable for agricultural irrigation, industrial use, hydrating or rehydrating of food or agricultural or pharmaceutical compositions. The present invention also relates to a waterpurification apparatus which includes the hydrophilic membrane, comprising one or more layers of hydrophilic polymers, to purify water which may contain suspended or dissolved impurities and solids, including but not limited to seawater, brackish water and other kinds of polluted water.

Description

APPARATUS FOR WATER PURIFICATION 1. Field of the Invention This invention concerns the purification and controlled release of water by perevaporation, and specifically concerns the use of a hydrophilic membrane in an apparatus that allows the direct use of pure or impure water for irrigation, rehydration or drinking. 2. Description of the matter.
There are known processes for purifying water, and the type of process used depends on the nature and amount of the impurities in the water. For example, impurities in the form of particles and in solution may both need to be removed from the water. The purpose is to purify the water so that it contains sufficiently low amounts of suspended particles, suspended microbes and dissolved salts to meet the water quality requirements for drinking, for the production of food and beverages, for agricultural irrigation and for industrial use. REF.121286 / Processes for water purification are usually classified as filtration, distillation or reverse osmosis. In conventional particulate filtration processes, impurities in the form of particles, such as suspended inorganic particles, are removed using porous constructions such as woven or nonwoven fabrics. In cases where very small particles must be filtered, polymer membranes are used which are microporous, that is, the membranes have very small holes through which the particles to be filtered can not pass.
Aqueous solutions containing dissolved salts are usually purified by reverse osmosis or distillation. When the aqueous solution is in the form of seawater or brackish water, these processes are generally known as desalination. The reverse osmosis process concerns the application of pressure to ion solutions through a semipermeable membrane. If the applied pressure is greater than the osmotic pressure "of the solution, purified water is collected from the side of the membrane not in contact with the solution. Reverse osmosis membranes let water pass through them but reject the passage of ions from In fact, a small percentage, that is to say 1%, of sea salts pass through the membranes US Pat. No. 5,547586 discloses a method for desalinating saline water and brackish water using a membrane supported by an enzyme. As opposed to reverse osmosis, distillation methods using seawater or brackish water can produce water with a very small amount of suspended particles and dissolved solids, however, the high latent heat of water evaporation means that the distillation process it requires a high power supply and therefore generally operate at a higher cost compared to reverse osmosis processes.
It has been known from US Patent no. No. 4,725,481 that a copolyether ester elastomer can be used, as one's own or as a part of a two-component film of a hydrophobic layer and a hydrophilic layer of elastomers copolyether esters bonded together, to allow differential transfer of water vapor to prevent moisture buildup such as in a surgical blanket or a waterproof constructed equipment.
BRIEF DESCRIPTION OF THE INVENTION The present invention generally concerns a method and apparatus for the purification and / or controlled release of water by evaporation, by passage of water vapor contained in the air, or liquid water which may contain suspended or dissolved impurities, including but not limited to it is limited to saline water, brackish water or another type of contaminated water, through one or more layers of hydrophilic membranes to remove impurities from the water.
The layer or layers of hydrophilic membranes can be present either in the form of a structure without support or coated on or adhered to a support material, in the present the layer of the hydrophilic membrane can be a copolyether ester elastomer, a polyether block - polyamide, a polyether urethane, homopolymers or copolymers of polyvinyl alcohol, or mixtures thereof.
A preferred hydrophilic membrane layer is made of a hydrophilic polymer having a water vapor transmission rate in accordance with ASTM E96-95 (Method BW) of at least 400 g / m2 / 24h, "measured using air at 23 ° C. and 50% relative humidity at a speed of 3 m / s on a film with a total thickness of 25 microns A more preferred hydrophilic membrane layer is made of a hydrophilic polymer having a water vapor transmission rate in accordance with. ASTM E96-95 (Procedure BW) of at least 3500 g / m2 / 24h, measured using air at 23 ° C and 50% relative humidity at a speed of 3 m / s on a film with a total thickness of 25 microns.
BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 and 2 are drawings showing the growth of plants in "Culture bags" and irrigated conventionally or using the irrigation bags of examples 11-14.
Figure 3 is a drawing that explores the growth of plants in open containers representative of Experiments 10 and 12 of Example 17.
Figure 4 is a drawing showing the growth of plants in the open container representative of Experiment 17 of Example 19.
DETAILED DESCRIPTION The present invention generally concerns a method for the purification and / or controlled release of water by evaporation, by passage of water vapor contained in the air, or liquid water which may contain suspended or dissolved impurities, including but not limited to to saline water, brackish water or other contaminated water, through one or more layers of hydrophilic membrane to remove impurities from the water. The layer or layers of hydrophilic membrane can be represented either in the form of a structure without support or coated on or adhered to a support material.
Perevaporation is the process in which a given solvent penetrates a porous or coated membrane, is transported through the membrane and is subsequently released from the opposite face of the membrane or coating in the form of vapor. Perevaporation is however different from the known filtration, distillation or reverse osmosis processes in which the product is a vapor and not a liquid. If the solvent is water, non-porous hydrophilic membranes are suitable for evaporation, because water is easily absorbed by, transported through and released from such a membrane. This water vapor can then be used to apply so as to provide moisture to a plant culture medium or to the air space of a culture chamber, to hydrate the dry matter or rehydrate the dehydrated matter, or else it can be Condensate for additional use as liquid water.
Hydrophilic membranes "Hydrophilic membranes" means non-porous membranes that absorb water, for example, that allow water to pass through. If there is a moisture gradient across the hydrophilic membrane, this absorbed water can diffuse through the thickness of the membrane and can be emitted from its opposite face. The hydrophilic or coated membranes, hereinafter collectively referred to as membranes in this disclosure, feature of sufficiently high rate of water vapor transmission, as defined below, so that water that has passed through the membrane can be used directly in applications that include but are not limited to plant watering and rehydration of foods, beverages, drugs and the like. Such membranes may comprise one or more individual layers made of materials including but not limited to the same or different hydrophilic polymers. While the water vapor permeability ratio of the membrane in total is sufficiently high, this water may be provided at a rate consistent with its use in a practical application as described. The non-porous nature of the membranes disclosed herein serves to exclude any impurities in particles from the passage through such a membrane, including microbes such as bacteria and viruses. Furthermore, it has been discovered that membranes made from the hydrophilic polymers described in the present invention reduce or significantly prevent the passage of dissolved salts. However, the ability to use not only fresh water, but also water that may contain suspended or dissolved impurities, to produce desired amounts of purified water by evaporation allows saline water, which includes but is not limited to seawater or brackish water , after processing through the apparatus disclosed in the present invention, to be used in irrigation of agricultural lands and sustains the growth of the plants, and for the controlled release of water in an environment.
The proportion at which the pre-evaporated water passes through the membrane made of hydrophilic polymers depends, among other factors, on the moisture content on the waterless side. However, irrigation systems based on the membranes of the present invention are self-regulating and can be "passive" in nature, providing more water to plants under dry conditions and less under wet conditions.
In a manner similar to that described for the above agricultural irrigation application, the water permeation through the membrane according to the present invention is sufficient to rehydrate dry foods, pharmaceuticals and the like, regardless of whether the water in the The opposite face of the membrane is fresh water or water that may contain suspended or dissolved impurities. If water is required in liquid form, such as for applications that include but are not limited to the production of water for drinking or for use in industry, water vapor produced by evaporation through the membrane can be condensed to water liquid Water Vapor Transmission Characteristics The standard test to measure the proportion in which a given membrane transmits water is ASTM E-96-95-BW Procedure, previously known and referred to as .ASTM E-96-66- BW Procedure, which is used to determine the proportion of water vapor transmission (WVTR) of a membrane. For this test an assembly based on a waterproof cup is used, also called "Thwing-Albert Steam Meter". This cup contains water up to about ± inch (19 ± 6 mm) from the top edge. The opening of the cup is hermetically sealed to the water with a water permeable membrane of the test material to be measured, leaving an air gap between the surface of the water and the membrane. In Procedure BW, the cup is then inverted, so that the water is in direct contact with the membrane. The apparatus is placed in a test chamber at a controlled temperature and humidity, and the air is then blown through the outside of the membrane at a specified rate. The experiments are run in duplicate. The weights of the cup, water and membrane as a whole are measured over several days and the results are averaged. The proportion in which water penetrates through the membrane is quoted as the "Water Vapor Transmission Rate", measured as the average weight loss of the set at a given thickness, temperature, humidity and membrane air velocity. , expressed as loss of mass per unit of membrane surface area and time. WVTR of membranes or films conforming to .ASTM E96-95 Method BW is typically measured on a film thickness of 25 microns and at an air flow rate of 3 m / s, air temperature of 23 ° C and 50% RH.
Under the conditions of the plant growth experiments modalized in the invention, a selection of which are detailed in Examples 15-19 below, irrigation bags made from the membrane were used to provide water for plant growth. In the experiments carried out to date, a water transfer rate of 10 g / 24h (equivalent to 70 g / m3 / 24h) through a watering bag was found to be sufficient to sustain the growth of one or more plants. This proportion of water transfer needed to sustain the growth of plants can be expressed as the proportion at which water passes through the unit of surface area of the membrane used in the experiment per unit of time, which is reported as the "Average Water Transfer Rate" for the purposes of this exhibit. Under the conditions of plant growth experiments modalized in the invention, a selection of which are detailed in Examples 15-19, an average water transfer rate of 70 g / m2 / 24h or more was found to be sufficient for sustain the growth of a plant, as shown in Tables 2-6.
In these experiments, the conditions under which water was transferred from the interior of the irrigation bags through the membrane to the plant's growing medium and to the roots of the plant were from the irrigation bags entering the culture medium. , in the absence of air movement on the surface of the irrigation bags. Under these conditions, the water vapor moved from the inside of the irrigation bags through the membrane and into the culture medium only by diffusion.
Hydrophilic Polymers In the context of this disclosure, the hydrophilic membranes for use with the modalized apparatus in the invention are made of hydrophilic polymers. "Hydrophilic polymers" means polymers that absorb water when in contact with liquid water at room temperature in accordance with the specifications of the International Standards Organization ISO 62 (equivalent to the American Society for Testing and Specification of Materials ASTM D 570).
The hydrophilic polymer may be one or a mixture of several polymers, for example, the hydrophilic polymer may be a copolyether ester elastomer or a mixture of two or more copolyether ester elastomers as described below, such as polymers available from E. I. Du Pont de Nemours & Company under the trademark Hytrel®; or a block polyether polyamide or a mixture of two or more block polyether polyamides, such as polymers available from ElfAtochem Company of Paris, France, under the trademark of PEBAX; or a polyether urethane or a mixture of polyether urethanes; or polyvinyl alcohol homopolymers or copolymers or a mixture of polyvinyl alcohol homopolymers or copolymers.
A particularly preferred polymer for water vapor transmission in this invention is a copolyether ester elastomer or mixture of two or more copolyether ester elastomers having a multiplicity of recurring units of long chain ester and short chain ester units together head to tail through the ester links, in which the long chain ester units are represented by the formula: o o -OGO-C-R-C-: D and said short chain ester units are represented by the formula: O O -ODO-C-R-C- (II) where: a) G is a divalent radical that remains after the removal of the terminal hydroxyl groups of a poly (alkylene oxide) glycol having an average number of molecular weight of about 400-4000; b) R is a divalent radical that remains after the removal of the carboxyl groups of a dicarboxylic acid having a molecular weight of less than 300; c) D is a divalent radical that remains after the removal of the hydroxyl groups of a diol having a molecular weight of less than 250; optionally d) the copolyether ester contains 0-68 weight percent based on the total weight of the copolyetherester, ethylene oxide groups incorporated in the long chain ester unit of copolyether ester; and e) the copolyetherester contains about 25-80 weight percent short chain units.
This preferred polymer is suitable for making thin but resistant membranes, films or coated membranes. The preferred polymer, polyether ester elastomer, and methods of making are known in the art, such as those set forth in US Patent No. 4,725,481 for a polyether ester elastomer with WVTR of 3500 g / m2 / 24hr, or US Patent No. 4,769,273 for a copolyester ester elastomer with a WVTR of 400- 2500 g / m2 / 24hr. Both are incorporated herein by reference.
The polymer may be composed of antioxidant stabilizers, UV stabilizers, hydrolysis stabilizers, dyes or pigments, fillers, antimicrobial reagents and the like.
The use of commercially available hydrophilic polymers as membranes is possible in the context of the present invention, although it is more preferable to use copolyester ether elastomers having WVTR of more than 400 g / m2 / 24 hr measured on a 25 micron thick film using air at 23 ° C and 50% relative humidity at a speed of 3 m / s. More preferred is the use of membranes made of commercially available copolyetherester elastomers having a WVTR of more than 3500 g / m2 / 24 h, measured on a 25 micron thick film using air at 23 ° C and 50% relative humidity at a speed of 3 m / s.
Methods • To Prepare Polymer Membranes Hydrophilic Hydrophilic polymers can be manufactured to membranes of any thickness by a number of processes. A useful and well-established way to make membranes in the form of films is by melt extrusion of the polymer on a commercial extrusion line. Briefly, this involves heating the polymer to a temperature above the melting point, extruding through a flat or annular bead and then molding a film using a roller system or blowing a film from the melt.
Useful support materials include woven or non-woven or bonded papers, fabrics and water vapor permeable fiberglass gratings, including those constructed of moisture-stable organic and inorganic polymer fibers such as polyethylene, polypropylene, glass fiber and the like . The support material increases both the resistance and protects the membrane. The support material may be disposed on only one side, the support material may be in contact with or remote from the water source. Typically the support material is disposed on the outside of the container formed by the hydrophilic polymer membrane to better protect the membrane from physical damage and / or degradation by light.
The water purification apparatuses of the present invention employ hydrophilic polymer membranes, is not limited to any particular shape or profile, and may be by way of illustration, a bag, a film, a tube or the like.
Applications of the Invention Without being bound to any particular theory, it is believed that the purifying effect identified as the main inventive concept of the hydrophilic membrane, performed either in the form of a coating or a membrane without support, when in contact with water it may contain impurities and suspended or dissolved solids, occurs because highly dipolar molecules such as water are preferentially absorbed and transported through the membrane or coated, compared to ions such as sodium or chlorine. When, in addition, a moisture gradient exists through the membrane, water is released from the side that is not in contact with the water source, and can be absorbed by the roots of the plants or by an article to be hydrated or rehydrated. Alternatively, water vapor can be condensed to provide potable water and water for agricultural, horticultural, industrial and other uses.
Agricultural / Horticultural Applications When used to provide moisture to a culture medium for the growth of plants or crops, the membranes control the moisture content, which can be carried away by water vapor or water absorbed, from the culture medium regardless of the type of source. of water passed through the membrane.
The gradient of moisture content between the water source and the culture medium always tends towards equilibrium, so under conditions where the culture medium is dry, there is a relatively rapid proportion of water transport through the membrane to provide water to the culture medium. Under conditions in which the culture medium already has a high moisture content, the gradient across the membrane between the water source and the culture medium is close to equilibrium, thus the rate of water transfer through the membrane towards the culture medium is low, and can be equal to zero if equilibrium is reached.
Due to the nature of the hydrophilic membranes, water is passed over the entire surface of the membrane as determined by the moisture content of the soil, which can be infinitely variable along the surface of the membrane. The proportion at which water passes through the membrane and the equilibrium conditions can be adjusted for specific growth requirements, for example by increasing or reducing the temperature of the water source, by varying the thickness of the membrane or by modification of the polymer composition of one or more of the layers.
The apparatus coated with a layer of the hydrophilic membrane acts in the same manner as the apparatus having an unsupported hydrophilic membrane in which both are "self-regulating systems of water release which provide water for a culture medium as necessary. , depending on the moisture content of the culture medium.
In the context of this exhibition, a "culture medium" is a medium in which the roots of plants grow. However, "culture medium" naturally includes soils as naturally occurring or adapted artificially used but not limited to agriculture, horticulture and hydroponics. These soils include varying the amounts of sand, silt, clay and humus. "Growth medium" also includes but is not limited to other materials used for plant growth, such as vermiculite, perlite, peat moss, truncated fern tree trunks, crushed or crushed tree bark and crushed coconut bagasse. As the membrane provides moisture in the form of water vapor to the culture medium, the materials of the culture medium having hygroscopic properties more effectively bind and store the water vapor and may work better with this invention.
To provide moisture more effectively to the culture medium in agricultural or horticultural irrigation, the membrane should be as close as possible to the culture medium. Typically, the membrane is completely covered by the culture medium to maximize contact and protect the polymer from degradation by sunlight. The membrane also needs to be placed sufficiently close to the root zone in the culture medium to provide moisture to the plants.
The membrane can be without support or coated on a support material to increase strength and durability. The apparatus typically has at least one opening for filling with water. To provide moisture for an extended period, the apparatus is conveniently in the form of a bag, duct or tube, which allows the water to be continuously or periodically released to prevent the increase of salts or other contaminants. Water vapor preferentially passes through the membranes, leaving behind dissolved salts and other materials as well as suspended particles such as organic or inorganic matter, which includes microbes such as bacteria, viruses and the like.
Agriculturally concerns embodiments of this invention which include providing moisture for plant growth, germination of seeds while excluding not only harmful salts but also pathogens such as fungi, bacteria and viruses harmful to seeds and plants. This can be achieved by placing the root of the plant or seeds on a layer of the membrane in contact with water on the opposite side of the roots or seeds.
Alternatively, for seed germination, the seeds may be enclosed in the hydrophilic membrane, such as in a sealed container, and the container placed in contact with water or moistened medium. This allows the seeds to germinate in a sterile environment, preventing the loss of seeds due to pathogen attacks.
. Horticultural Applications / Humidification. In addition to providing moisture to seeds, plants, or growth media in agricultural applications, the apparatus of the present invention can also be used to maintain or increase the humidity of closed chambers. An example is in agricultural applications to provide moisture to the surrounding air of plants in culture chambers.
When plants are grown in a closed culture chamber, such as a greenhouse, the increase in moisture can have a significant and beneficial effect. In addition, the membranes of this invention may be partially or completely exposed to the airspace, to increase humidity through the process of evaporation. The membranes of the apparatus that releases water may be partially or completely in contact with the airspace. To protect the hydrophilic polymer from degradation, the membrane can be covered by a layer of support material to block the light or preferably the apparatus is placed under shade or in a dark enclosure.
As an application. agricultural, the apparatus typically has at least one opening to fill with water, and to provide moisture for an extended period, the apparatus is conveniently in the form of a bag, pipe or tube, allowing the water to exit continuously or periodically to prevent the increase of salts or other contaminants.
Hydration or Rehydration. The method of membrane permeation and the water purification apparatus of the present invention can be used to hydrate or rehydrate materials such as food or pharmaceutical or agricultural compositions.
The dry or dehydrated materials may be carried in sealed bags comprising the hydrophilic membrane of the invention, and then hydrated or rehydrated using water vapor contained in the air, or liquid water which may contain suspended or dissolved impurities, including but not limited to they limit to saline water, brackish water or other kinds of contaminated water.
Desalination An important feature of this invention is that the membranes selectively disperse not only against particles, but also against contaminants that are dissolved in water, including but not limited to salts, as well as against contaminants that are present in the form of a emulsion in water, which include but are not limited to fatty oils and the like. The membranes may also function to purify gaseous vapor from contaminated water and / or liquid mixtures. This process of selective discrimination takes place at room temperature and constantly without pressure applied across the membrane. Accordingly, the invention allows water vapor contained in the air, or liquid water containing a level of residual salts that is low enough to direct the use to agriculture, starting from seawater, brackish water or other sources of contaminated water to be used, using the apparatus that can be operated at a very low cost than conventional desalinations such as reverse osmosis systems for seawater, reverse osmosis for brackish water, reverse electrodialysis, multiple effect distillation, vapor compression systems Mechanical and instantaneous in multiple stages.
In summary, the pervaporation by means of the purification apparatus of the present invention can therefore be used to purify water for irrigation of agricultural lands, to provide a means of providing self-regulated water for a culture medium, to moisten the airspace of chambers of cultivation such as greenhouses, to provide drinking water and to hydrate or rehydrate food, dry pharmaceuticals and the like.
The present invention can be operated at a low cost and with less infrastructure in equipment, compared to the previous systems in the matter. Because the apparatus for providing moisture to a culture medium or to the air space of a closed chamber emits water in the form of water vapor preferably to that of liquid water, the impure water pressure applied to the membrane layer of the apparatus may be much less than 2500 kPa typically required for seawater purification using reverse osmosis. The pressure is also lower than the lower pressures required for reverse osmosis of less saline brines. Generally, the differential pressure applied to the ambient atmospheric pressure is less than about 1000 kPa. Although high pressures can increase the rate at which the membrane layer emits water vapor, excessive pressure can shift the equilibrium that self-regulates to cause the culture medium to become moist as well. In addition, high pressures require thick membranes or preferably materials that withstand the force to contain the pressure.
Accordingly, the applied pressure is typically less than about 250 kPa, and very often less than about 100 kPa. More often the applied pressure is little or no more than that provided by the weight of the water itself, or the pressure needed to discharge impure water through the water purifying apparatus, so that this allows the use of thin hydrophilic membranes or films of the hydrophilic polymer.
Examples In the following examples, Copolyether ester A is a polymer made according to the method set forth in Patent US Pat. No. 4,725,481 starting from 30 parts of dimethyl terephthalate, 57 parts of a poly (alkylene) glycol, the alkylene content of which comprises 65% ethylene and 35% propylene, 9 parts of dimethyl isophthalate, 16 parts of butanediol (stoichiometric amount) and 0.7 parts trimethyl trimellitate. The copolyether ester A contains about 37% by weight of poly (ethylene oxide) glycol, and the membranes made from the Copolyether ester A characterize a water increase of 54% by weight at room temperature and a WVTR of at least 10,000 g. / m2 / 24h, measured on a 25 micron thick film using air at 23 ° C and 50% relative humidity at a speed of 3 m / s.
Copolyether ester B is a polymer made according to the method set forth in US Pat. No. 4,725,481 starting from 44 parts of dimethyl terephthalate, 51 parts of a poly (alkylene) glycol, the alkylene content of which comprises 65% ethylene and 35% propylene. , 19 parts of butanediol (stoichiometric amount) and 0.4 parts of trimethyl trimethylate. The Copolyether ester B contains approximately 33% by weight of poly (ethylene oxide) glycol, and the elaborated membrane of Copolyether ester B features an increase in water of about 30% by weight at room temperature and a WVTR of at least 10,000 g. / m2 / 24 h, measured on a 25 micron thick film using air at 23 ° C and 50% relative humidity at a speed of 3 m / s.
Copolyether ester C is a polymer made according to the method set forth in US Pat. No. 4,725,481 starting from 50 parts of dimethyl terephthalate, 44 parts of a poly (alkylene) glycol, the alkylene content of which comprises 85% propylene and 15% ethylene, 21 parts of butanediol (stoichiometric amount) and 0.3 parts of trimethyl trimellitate. The membranes made of Copiesterther C characterize a water increase of around 5% by weight at room temperature and a WVTR of 2,200 g / m2 / 24. h, measured on a 25 micron thick film using air at 23 ° C and 50% relative humidity at a speed of 3 m / s.
EXAMPLES 1- 10 The first group of examples, Examples 1 to 10, show that water vapor passes through the hydrophilic membranes of the water purification apparatus, and that the hydrophilic membranes cause water to pass through them but reject the passage of water. the salt ions. In the examples, five hydrophilic membrane bags made from an extruded film of hydrophilic polymer Copolyether ester A were filled with seawater, and five bags of hydrophilic membrane were made from an extruded film of another hydrophilic polymer. Copiester B were filled with tap water . A heat sealer was used to seal the bags of closed hydrophilic membranes. The bags had a maximum effective surface area calculated as 0.1 m2.
The bags were placed in a room at room temperature and uncontrolled humidity. Samples 2, 3, 5, 7 and 8 were placed directly on the metal shelf.
Samples 1 and 10 were placed on fine paper on the shelf and samples 4 and 6 were placed on nylon mesh to indicate possible effects of air flow or "wicking effect", which could affect the proportion at which the steam of water was removed from the surface. As soon as the bags were filled, the surface of the bags became wet to the touch. The bags were weighed and inspected visually each day for a period of one week, and the measurement of the weight decreased daily until between 5 and 7 days all the bags were empty of water. In this first case, as the test was an empirical indicator, it was difficult to take into account all the factors such as original water mass, water type, surface area, water contact area and film thickness. However, taking all these considerations into account, there was no apparent difference in the proportion of "lost water" for a similar surface.
The empty bags that had originally contained seawater were found to have a white saline deposit inside, visible as large crystals. The bag of example 5, for example, contained in excess of 20 g of solids. Under pressure and room temperature, in excess of 2 liters of water per square meter per day per day through the bags. Other measures suggested that the Copiester ester A was able to pass more than one liter of water per square meter per hour, gave a sufficiently rapid flow of air through the surface of the hydrophilic membrane to remove the water vapor as it was emitted from the bag by perevaporation.
It is believed that the rate of natural evaporation was the limiting factor in the flow of water through the bag. The samples of the hydrophilic membrane bags 1 and 10, which were placed on fine paper, and the samples of the hydrophilic membrane bags 4 and 6, which were placed on nylon mesh, did not release any water faster than the bags. hydrophilic membrane that have been placed directly on a metal shelf. There was also no noticeable difference between the thickness or thinness of the polymer films.
The results of the examples are summarized in Table 1 that follows.
TABLE 1 Perevaporación OF water through Sealed Hydrophilic Membrane Bags Ex em- Type Pipe Mass Thickness Membrane Water Initial Polymer (microns) (g) Copolieteréstér B 100 Mar 493 Copolyetherester B 100 Mar 418 T BLA 1 (continued) Perevaporación OF water through Sealed Hydrophilic Membrane Bags Example - Thickness of Source of mass Peep Membrane Initial water Polymer (microns) (g) Copolyetherester B 100 tap 488 Copolyether ester A 100 Mar 509 Copolyetherster A 100 Mar 551 Copolyether ester A 100 tap 441 Copolyetherster A 50 Mar 260 Copolyetherester A 50 tap 515 Copolyether B 50 tap 338 Copolyether B 50 tap 380 EXAMPLES 11 - 14 In the next group of examples, Examples 11-14, the feasibility of using hydrophilic membranes made of hydrophilic polymer in a desalination apparatus was validated. Examples 11 and 14, 12 and 13 are illustrated in Figures 1 and 2 respectively.
In these examples, culture containers called "culture bags" were used.
The "culture bags" are commercially available, sealed polyethylene bags of approximate dimensions 100 X 50 X 15 cm, which contain a mixture of moist soil suitable for the growth of plants such as outdoor tomatoes. When "culture bags" were used, it is normal practice to place them on the earth with its wider horizontal face, so that it acts simulating beds for miniature plants of area 100 X 50 cm and height of 15 cm. "Three small slits were cut in the upper part and three tomato sprouts were planted in the soil of the" crop bags "with their buds and leaves protruding from the top of the bag.The polyethylene material of the" culture bag " "It served to retain the soil around the roots of the plant, as well as prevent excessive moisture evaporation.The tomato plants were selected because they have a short but active growing season and have a substantial area leaf that could serve as a convenient indicator of the health of the plant.
All twelve tomato plants were watered with clean water for two weeks to confirm that they were all healthy and put back into the "culture bags." The environment was an open greenhouse that was covered, but not heated, and totally ventilated to represent growth on the outside without rain. During the experiments, all plants were maintained to grow completely naturally without pruning or orientation and without additional assistance. Each "culture bag" containing three plants each was watered by a different method as follows: Example 11: Well-cleaned water. Managed through a static hose perforated with a row of holes to ensure constant watering.
Example 12: Well-cleaned water, administered in a tubular hydrophilic membrane irrigation bag of 20 cm diameter and approximately 40 cm length, made from a film of Copolyether ester A. The irrigation bag was then placed in the "culture bag" "along a 50 cm long sheet in the space between the top and the floor and the polyethylene material of the" culture bag ".
Example 13: seawater administered in a 20 cm tubular hydrophilic membrane irrigation bag. Of diameter and approximately 40 cm in length, made from a film of Copolyester ester A. As in Example 13, the irrigation bag was placed in the "culture bag" along a 50 cm sheet in the space between upper part of the soil and the polyethylene material of the "culture bag".
Example 14: sea water, administered through a perforated static hose as for Example 11.
The surface area of the hydrophilic membrane irrigation bags was estimated at 0.25 m2. This surface area provided the moisture that maintained the growth of the three tomato plants of Examples 12 and 13.
On day 1, irrigation started using the previous system. All the plants were green, healthy and indistinctly in advantage. The plants of Example 11 were watered daily, enough to keep the plants healthy. The plants of Example 14 received the same measured amount of water as in Example 11. The reservoirs that filled the irrigation bags of the membrane were made of the elastomer copolyether ester were kept full at daily intervals, also the irrigation bags were always full. , Example 12 with clean tap water and Example 13 with seawater.
By day 4, all the plants of Example 14 that had been irrigated daily with sea water showed yellow spots on the stems and leaves. There was no discernible difference between Examples 11 and 12 with tap water, and Example 13 with seawater. All the plants in Examples 11, 12 and 13 were healthy.
On day 21, the plants of Example 14 were yellow and flaccid in appearance. The plants of Examples 11, 12 and 13 had no spots or defects.
As the plants matured until day 60, fruits were produced in the plants of Examples 11, 12 and 13. The plants had a regular shape and good color level. The plants of Example 14 were stained and produced very small impoverished fruits. The plants of Examples 11, 12 and 13 produced good fruits, including Example 13 which was irrigated with sea water through the membrane of the plant. present invention made of copolyether ester elastomer. There was no discernible difference between the quantity or the quality of the fruits of the plants of Examples 11, 12 or 13. The fruit of Example 14 showed brown and yellow spots, contrasting to the fruit of the other plants.
Significantly, the amount of water required up to "the top" of the hydrophilic membrane irrigation bags made of copolyether ester elastomers in Examples 12 and 13 varied depending on the weather. On a hot day, the hydrophilic membrane watering bags made of copolyester ester elastomer required an additional half liter of water, on wet and cold days, the irrigation bags needed very little to fill. This showed that the water evaporation through the membrane was self-regulated, and was dependent on the moisture content and temperature of the air and soil in contact with the hydrophilic membrane. In Examples 12 and 13, the membrane bags made of copolyether elastomer provided moisture to the plants through the soil and also moistened the air in the vicinity of the plants.
It was believed that there was an increase in contamination and salinity in the membrane irrigation bag made of copolyester ester elastomer that "watered" the plants of Example 13, because only water (with a quantity of dissolved salts that was not measured, but that clearly not at a level that was harmful to the plant) it was possible to evaporate through the hydrophilic membrane, allowing the concentration of salts to continuously increase in the remaining seawater in the hydrophilic membrane irrigation bag. This suggests that the hydrophilic membrane watering bag made of copolyester ester elastomer can maintain plant growth for longer periods like the experimental "station" used in experiment 11-14, if any saline water that was used was spilled intermittently. or circulated continuously from a large source, thus limiting the increase of salts in the water source.
On the open cuts in the "culture bags" after the experiments of the Examples 11-14 was concluded, the content of the "culture bags" of Example 14, which was irrigated directly with seawater, was still wet at the touch. This was also evident by the dark color of the culture medium, which was an indicator of the high salt content of the soil after watering directly with seawater. The contents of the other "culture bags" of Examples 11-13 were all dry to the touch and light in color, which includes the soil in the "culture bag" of Example 13 that has been watered with sea water through of the hydrophilic membrane of elastomer copolyether ester.
EXAMPLES 15-19 Additional experiments were carried out to explore the growth potential of a number of plants irrigated through the membranes of the present invention under severe conditions of water availability for the plants in question. The results clearly demonstrated the viability of a hydrophilic membrane that self-regulates vapor penetration according to one of the embodiments of the present invention, even though very severe growth conditions were employed.
The plants that were grown included tomatoes, radishes, corn and sorghum. In these experiments, cultivation containers made of terra-cotta polypropylene plastic and compressed wood of different sizes and porosities were used. Representative experiments are illustrated in Figures 3 and 4. The upper floor used in Examples 15-19 was dried to a maximum of 15% moisture by weight, and the sand used was completely dried.
Containers "of porous cultivation made of terra-cota or compressed wood were used in most of the experiments, with culture containers made of polypropylene plastic that is used as references.The porous culture containers served to allow the steam to escape to through the walls of the culture container to simulate the lateral loss of water typically found in a field In all experiments, except Experiment 15 of Example 18, the tops of the culture containers were opened to the atmosphere, way that water vapor could escape from the top of the soil.The temperatures of the plants experimented around 30 ° C in the greenhouse environment for most of their growth periods of around 80 days.
These severe conditions were in contrast to the moderate conditions under which the experiments set forth in Examples 11-14 were carried out. In Examples 11-14, the containers of the "culture bags" had wet top soil and the containers had sealed polyethylene bags. The polyethylene materials from which the "growth sheets" were made prevented the loss of water vapor through the walls of these culture containers, as opposed to the more porous containers made of compressed wood and terracotta that were used in Examples 15-19.
Unless indicated otherwise, the hydrophilic membrane watering bags used in Examples 15-19 were horizontal, water-tight flat bags prepared from 50 micron thick films of Copolyether B-type. All hydrophilic membrane watering bags they were provided with a flexible tube sealed on the side, so that the bags could be filled to a given level from an external reservoir of the culture container. Hydrophilic membrane irrigation bags were buried in dry fertilized sand or fertilized agricultural soil dried maximum moisture content 15% by weight) to a depth of about 10 cm, unless noted otherwise. In different experiments, hydrophilic membrane watering bags variably contained deionized water, brackish water or seawater.
In all cases, the hydrophilic membrane irrigation bags were kept filled to a given level with deionized water from an external reservoir through the flexible tube.
The plants were either geminated in situ in the culture container with a small amount of water; or other of them were transplanted in culture containers as sprouts. The experiments were carried out under greenhouse conditions.
At the end of the tests, the plants were removed from the culture containers, cleared of culture medium and dried. Roots, roots and nuts were weighed separately.
The growth experiments of Examples 15-119 were discontinued after about 80 days. The proportion of water transfer through the hydrophilic polymer membranes of each experiment was determined by measuring the daily amount of water needed to fill each reservoir.
Once the plants had achieved maturity and the proportion of water loss by evaporation to "through the hydrophilic membrane irrigation bag had stabilized, the average water transfer rate per unit area of hydrophilic polymer membrane was calculated .
Example 15: In this example, corn plants were grown in dry fertilized sand or agricultural soil in four culture containers identified as Experiments 1, 2, 3 and 4, with hydrophilic membrane watering bags made of C-polyester ether B buried under the soil at a depth of about 10 cm. The containers were made from terra-cota (Experiments 1 and 3) or polypropylene plastic (Experiments 2 and 4). The hydrophilic membrane irrigation bag extended approximately halfway along the bottom of each growth container. Three plants were grown in each container, so that Plant A was placed directly on top of the hydrophilic membrane irrigation bag, Plant B was placed on the leaf of the irrigation bag and Plant C was placed away from the irrigation bag at the other end of the culture container. The results are shown in Table 2.
Table 2 Pests of dried stems and roots of corn plants and Average Rate of Water Transfer through the Hydrophilic Membrane Watering Bag Proportion bag of B C Transieren Example Weight Weight Weight Weight Weight Weight of Pio of de of de of water Pro vasta roots vasta roots dried dry g dried dried dry dried fruits of the (g) (g) ( g) (g) (g) (g) membrane (g / m2 / 24h) 1 5.45 2.86 1.42 1.85 1.13 1.60 750 4. 68 2.3Í 2.90 2.00 3.26 3.21 450 0. 44 1.60 0.26 0.66 0.25 0.50 200 1. 84 1.01 4.26 3.30 0.59 0.54 200 The weights of stem and root illustrate the best moisture retention for polypropylene plastic containers (Experiments 2 and 4), compared to the more porous terra-cota containers (Experiments 1 and 3). Plants grown on farm land (Experiments 1 and 2) grew to extend larger than plants grown on sand (Experiments- 3 and 4).
Plant A, which was placed closer to the hydrophobic membrane irrigation bag and therefore closer to the water source, grew to extend more than plant C, which was the most distant from the irrigation bag. This illustrates that the evaporation of water through the hydrophilic membrane irrigation bag sustained the growth of the plant.
Example 16: In four culture containers, identified as Experiments 5, 6, 7 and 8, germinated sorghum seedlings previously of about 7-10 cm height were transplanted and cultivated in fertilized sand or dry cultivated land, with bags Hydrophilic membrane watering systems made of Copolyether B, buried under the ground at a depth of about 10 cm, in terra-cota containers (Experiments 5 and 7) or polypropylene plastic (Experiments 6 and 8). The irrigation bag extended approximately halfway along the bottom of each culture container.
Three plants were grown in each container, so that plant A was placed directly on top of the irrigation bag, Plant B was placed on the leaf of the irrigation bag and Plant C was placed away from the irrigation bag in the other end of the culture container. As in Example 15 above, the weights of rods and roots and the Average Proportions of water transfer in the Table 3 clearly illustrate that the growth of the sorghum plant in agricultural soil (Experiments 5 and 6) grew better than the plants that grew in sand (Experiment 7 and 8). Plant A grew to the greatest extent and plant C to at least reflect its proximity to the water source of the hydrophilic membrane irrigation bag.
Table 3 Weights of dried stems and roots of sorghum plants and Average Rate of Water Transfer through the Hydrophilic Membrane Watering Bag Proportion bag of B C Transieren Example Weight Weight Weight Weight Weight Weight of Pio of de of de of water Pro vasta roots vasta roots dried dry g dried dried dried dry vegetables of the (g) (g) ( g) (g) (g) (g) membrane (g / m2 / 24h) 4. 71 5.85 4.33 0.70 0.75 0.23 1130 4. 30 5.40 3.74 1.18 2.88 0.65 1130 0. 25 0.18 0.28 0.26 0.07 0.10 200 8 0.53 0.43 0.16 0.13 0.09 0.08 200 Example 17. In four culture containers, identified as Experiments 9, 10, 11 and 12, previously germinated corn seedlings of about 7-10 cm height were transplanted and cultivated in dry fertilized agricultural soil. , with hydrophilic membrane irrigation bags buried under the ground at a depth of about 10 cm in terra-cota containers. Two different materials were used for the hydrophilic membrane watering bags Copiesterstress A for Experiment 11 and Copolyether B for Experiments 9, 10 and 12. Copolyether ester A absorbs more than 50% of water by volume, compared to 30% absorbed by Copolyether ester B. Consequently, characteristics of Copolyether ester A with higher water vapor permeability than Copiester ester B.
Hydrophilic membrane irrigation bags extended approximately halfway along the bottom of the culture containers used in Experiments 9 and 11, but extended along the total bottom of the culture containers used in Experiments 10 and 12. Three plants were grown in each container, so Plant A was placed directly above the irrigation bag, Plant B was placed on the leaf of the hydrophilic membrane irrigation bag and Plant C was placed far away. of the irrigation bag at the other end of the culture container of Experiments 9 and 11. All the plants were placed directly on top of the hydrophilic membrane irrigation bags used in Experiments 10 and 12.
Compared to Experiment 9, the effect of increasing the surface area of the hydrophilic membrane irrigation bag is illustrated for Experiment 10, and the effect of using a material with increased water vapor permeability is illustrated by Experiment 11 Finally, Experiment 12 demonstrates the effect of using seawater rather than fresh water, on the hydrophilic membrane irrigation bag of greater surface area, as used in Experiment 10.
The weights of the rods and roots and the Average Water Transfer Rate in the corn plants of these experiments are shown in Table 4. The data illustrate that the greatest improvement in growth conditions was achieved by the use of a hydrophilic membrane watering bag with a greater surface area (Experiment 1110). Using the more permeable Copolyether ester A for the irrigation bag (Experiment 11) instead of the standard Copolyether ester B (Experiment 9) also had the fastest growing plant. Experiment 12 illustrates that maize plants could be successively cultivated still watered through a bag containing seawater.
Table 4 Pests of dried stems and roots of corn plants and Average Rate of Water Transfer through the Hydrophilic Membrane Watering Bag Stock Proportion of A. B C Transieren Ejem- Weight Weight Weight Weight Weight Weight of Pio de de de de agua Pro vasta roots vasta roots dried dry g dried dried dry g of the (g) (g) (g) (g) (g) (g) ) membrane (g / m2 / 24h) 9 2.24 0.89 1.62 0.88 0.11 0.15 380 6.68 1.47 7.64 2.76 8.25 3.47 830 11 3.30 3.59 '3.54 1.07 3.71 1.05 750 12 1.03 0.95 1.44 1.22 1.13 0.91 170 Example 18: in three terra-cota cultivation containers, identified as Experiments 13, 14 and 15, previously germinated corn seedlings of about 15 cm in height were cultivated in membrane irrigation bags hydrophilic made of Copolyether B and buried under the soil at a depth of about 15 cm. In a fourth container of terra-cota cultivation, identified as Experiment 16, a Celebri tomato seedling was cultivated, also using hydrophilic membrane irrigation bags as described for Experiments 13, 14 and 15. The extended irrigation bags along the entire bottom of each culture container. One plant was cultivated in each container located directly above the hydrophilic membrane irrigation bag. Compared to the examples described in Examples 15, 16 and 17 (dimensions 15 X 15 X 60 cm) above, the containers used for Experiments 13, 14, 15 and 16 were larger (50 X 50 X 50 cm). All the irrigation bags were of the same size and extended along the entire bottom of the culture containers, so that about 1,450 cm2 of membrane surface area were available for the only plant used in these Experiments 13, 14, 15 and 16, compared to an area of 265 cm or 600 cm available for three plants used in the Experiments of Examples 15, 16 and 17.
In the reference to Experiment 13, a corn seedling was cultivated on dried fertilized agricultural land, irrigated through an irrigation bag containing fresh water. In Experiment 14, seawater was used as a source of water in the irrigation bag. In Experiment 15, dry fertilized sand was used instead of agricultural land as a growing medium for the corn plant, and the culture container was covered with a black polyethylene plastic sheet to retard the evaporation of water from the surface of the soil. floor. A Celebrity tomato plant instead of corn was used in experiment 16, which was irrigated using seawater as a water source in the hydrophilic membrane irrigation bag, with other factors remaining the same as in Reference Experiment 13.
The weights of dried stems and roots and the Average Water Transfer Rate are shown in Table 5.
Table 5 Weights of rods and roots of corn and tomato plants and Average Rate of Water Transfer through the Hydrophilic Membrane Watering Bag Experiment Plant Weight of Weight of Proportions Roots roots Average of dried dry Transfer (g) (g) of water through the membrane '(g / m2 / 24 h) corn 18.89 6.92 280 corn 6.65 3.81 70 corn 5.67 7.45 210 tomato 5.25 1.85 70 Example 19: Compressed wood culture containers (60 X 60 X 200 cm) were used in Experiments 17 and 18. Celebri and Rutgers tomato seedlings were transplanted and grown in dry fertilized agricultural soil. The Celebrity tomato plants were transplanted as tall seedlings of around 20 cm, while the Rutgers tomato plants were transplanted as tall sprouts of around 10 cm. These two different types of tomato were used to compare their growing behavior. Celebrity tomatoes grew to larger plants and are a certain variety, while Rutgers tomatoes grew to a more limited size and are an indeterminate variety.
In Experiment 17, hydrophilic membrane irrigation bags made of Copolyether B were buried under the soil to an initial depth just below the surface at one of the 60 cm wide ends of each culture container and progressively descending into a linear slope along the length of 200 cm from the bottom of the culture container to the other end of 60 cm in width. The placement of Plants A, B and C formed a straight line, so Plant A was located near the shallow end where the irrigation bag was just below the surface, and Plant C was placed near the end. deep where the irrigation bag reached the bottom of the culture container. Similarly, the location of Plants W, X and Y formed a straight line parallel to that formed by Plants A, B and C, so that Plant W was placed near the shallow end and Plant Y was placed near the end. deep of the culture container. Plants W, X and Y were staggered in relation to Plants A, B and C in order to achieve the recommended space of at least 50 cm between plants.
In Experiment 18, the plants were individually irrigated with deionized water from an irrigation distributor, without using an irrigation bag. An amount of water sufficient for the normal growth of each plant was used in this reference experiment.
The relative weights of the stems and roots of the plants grown in Experiment 17 showed that Plants A, B and W, relatively close to the irrigation bag, grew better than Plants C, X and And, further away from this water source.
The weights of stems and roots weights of Experiments 17 and 18 and the Average Water Transfer Rate of Experiment 17 are shown in Table 6 Table 6 Weights on dry basis of stems and roots of tomato plants and. Average Rate of Water Transfer through the Hydrophilic Membrane Watering Bag.
Experiment 17 Root Roots Fruits (watered with inclined bag) Plant A (tomato Celebrity) 91.32 9.34 22.24 Plant B (Celebrity tomato) 73.80 7.66 30.51 Plant C (Tomato Celebrity) 12.28 3.18 3.64 Plant W (tomato Rutgers) 9.81 1.43 Plant X (Rutgers tomato) 2.01 0.53 Table 6 (continued) Experiment 17 Root Roots Fruits (watered with inclined bag) Y Plant (tomato Rutgers) 3.89 0.69 Plant A (tomato celebrity) 43. 03 5. 35 28 .24 Plant B (tomato celebrity) 55 .22 4. 44 17. 91 Plant C (tomato celebrity) 72.72 7.67 12.58 Plant D (tomato celebrity) 55.71 6.34 30.60 Plant W (Tomato Rutgers) 19.60 1.85 EXAMPLES 20 AND 21 This Group of examples 20 and 21 were to demonstrate the application of the humidification of the present invention. In example 20, a water-tight bag containing tap water was made from a 50 micron thick copolyestertherm film and was placed on the upper section at room temperature. A paper towel was placed over the top of the hydrophilic membrane bag, in contact with the surface of the membrane, and seeds of radish plants, lettuce, turnip, brussel sprouts, spinach, cabbage and viola were placed on the towel of paper and other paper towels were placed on top of the seeds and the whole was kept in the dark. After five days, the seeds of all the previous plant species had germinated, using only the moisture from the inside of the bag.
Example 21. Using conventional heat sealing equipment, a soybean seed was sealed between two layers of 50 micron thick hydrophilic membrane made of Copolyether B, giving a translucent air-tight square pouch of 2 X 2 cm dimensions, with air trapped around the seed. The hydrophilic membrane pouch was then floated on tap water in a beaker and stored in the dark at room temperature. After two weeks, it was observed that the soybean seed had germinated in the sachet, from the water that had been pre-evaporated in the sachet through the hydrophilic membrane.
EXAMPLE 22 This Example was to demonstrate the feasibility of the present invention in a desalination application.
In this Example, two bags of hydrophilic membrane made of Copolyether ester A were filled with approximately 0.5 L each of sea water, sealed and stored in a warm chamber with free passage of air around the bags. Before the experiment, the weight of each bag was recorded. In three days, both bags were empty of water, leaving a brackish deposit. The bags were then weighed again, and the weight of the solids was calculated to be in excess of 3.7% by weight based on their original weight. ' The bags were thoroughly washed to remove any soluble impurities such as salts on the surface of the membrane. The bags were dried and weighed again. A control sample of water of the same initial weight was also evaporated using conventional techniques and the weight of the deposit was recorded. Both samples produced between 3.7 and 3.8% by weight of solids, which indicates that in excess of 95% of the solid (dissolved and in particle) contained in the water was filtered by the hydrophilic membrane.
EXAMPLE 23 Example 23 demonstrates an application in rehydration. In this Example, dehydrated solids were rehydrated. Two samples each of milk for dry baby, sugar (sucrose) or table salt (sodium chloride) were placed in sealed hydrophilic membrane bags separately prepared from Copolyetherester A. The pouches were placed under water, one sample of each under fresh water and a sample of each one under seawater. The contents were observed to rehydrate rapidly. The rate of rehydration varied, depending on the different amounts of? Igroscopicity of the powders. The specific benefit of providing dehydrated solids in sachets from the hydrophilic invective membranes is that the user does not carry drinking water, since the food can be rehydrated from impure water sources.
EXAMPLE 24 Example 24 modalizes another application where plants were cultivated from seeds using pre-evaporated water through a hydrophilic membrane. An open plastic channel of dimensions 60 X 45 X 3 cm was placed with the widest horizontal area and filled with fresh water to a depth of 2 cm. A 25 micron thick hydrophilic membrane made of Copolyether ester C was placed through the upper part of the channel so that it floated on the surface of the water, hanging over the leaves of the channel. Grass seeds from a commercial garden mix were distributed over the top of the hydrophilic membrane and covered with about 3 mm of peat moss containing crystals of a slow release solid fertilizer. The experiment was covered with a clear plastic lid that allowed light inside the container.
After a week, the inside of the clear plastic lid was covered with droplets of condensed water, and some grass seeds had germinated along the hydrophilic membrane sheet, where this condensation had impregnated the peat moss. A few seeds had also germinated through the middle of the hydrophilic membrane, away from the condensed water. In order to prevent additional moisture from the condensation of the lid and running on the peat moss, the lid was removed at this time. Since then, water from the bottom of the hydrophilic membrane was progressively filled with seawater from the English Channel once every two or three days, replacing the water that had pre-evaporated through the membrane and into the peat moss.
After two weeks, the grass appeared to grow from the seed through the entire surface of the hydrophilic membrane. Additional grass seeds were found germinated during the remainder of the experiment.
The experiment was finished after fourteen weeks. In this time, the grass formed a very dense mass of roots. Green, healthy leaves of grass in excess of 18 cm in length were cultivated normally.
This experiment demonstrates that the grass can be cultivated using water perevpaorada through the membrane of the present invention using a source of brackish water.
It will be appreciated by those skilled in the art that the term purification is somewhat dependent on the use to which the purified water is directed. For example, water to be used for growing plants may be less pure than that required for human consumption. Of course, it will be appreciated that the purification process can be repeated in successive steps to improve the purity, for example, allowing the contaminating water to pass through one or more thicknesses of hydrophilic membrane layer (or likewise through a system of additional filtration). In addition, purity can refer to different components that depend on the context of use. For example, in water for plant cultivation generally only the content and salts will be relevant, while in water for human consumption, the content of active microbes will be more relevant, and in water for (re) hydrating drugs for intravenous injection, the Total biological load and the content of salts will be highly relevant. Thus, the purification could be understood as referring to the process of preparing water of sufficient quality for the intended use. Generally, in the context of the invention, purified water released from the membrane will contain approximately less than 1% (preferably less than 0.1% and less) of dissolved or suspended solids and particulate matter. In relation to the dissolved salts, these are generally retained in and on the membrane, with purified vapor released from the membrane having a purity of less than 1% (and typically lower) in relation to the dissolved solids.
It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.
Having described the invention as above, it is claimed as property in the following:

Claims (56)

1. An apparatus for purifying water capable of providing water, of which at least one of suspended solids, dissolved solids, contaminants, salts and biological materials are removed from water, which is characterized in that it comprises: one or more layers of hydrophilic membrane to separate at least one of suspended solids, dissolved solids, contaminants, salts and biological materials from said water and retain at least one of suspended solids, dissolved solids, contaminants, salts and biological materials on one side, of said layer and allow a differential of water transfer through said layer with a proportion of at least 70 g / m2 / 24h,, where said water transfer rate is defined as the amount of water loss of the water purifying apparatus per unit surface area of the hydrophilic membrane for one unit of time.
2. The water purification apparatus of claim 1, characterized in that said hydrophilic membrane layer has a water vapor transmission rate according to .ASTM E96-95 (BW process) of at least 400 g / m2 / 24h, measured using air at 23 ° C and 50% relative humidity at a speed of 3 m / s on a film of 25 microns in total thickness, this thickness being the total thickness of said hydrophilic membrane layer.
3. The water purification apparatus of claim 1, characterized in that said hydrophilic membrane layer has a water vapor transmission rate in accordance with ASTM E 96-95. (Procedure BW) of at least 3500 g / m2 / 24h, measured using air at 23 ° C and 50% relative humidity at a speed of 3 m / s on a film of 25 microns in total thickness, this thickness being the total thickness of said hydrophilic membrane layer.
4. The water purification apparatus of claim 1, characterized in that said hydrophilic membrane comprises a polymer selected from the group comprising at least one of the copolyether ester elastomers, polyamide-polyether block, polyether urethanes, polyvinyl alcohol homopolymers and copolymers , and mixtures of these.
5. The water purification apparatus of claim 1, characterized in that the hydrophilic membrane comprises one or more copolyether ester elastomers having a multiplicity of resorting to long chain ester units and short chain ester units together head to tail through joints called long chain ester units that are represented by the formula: O O -OGO-C-R-C- (I) and said short chain ester unit which is represented by the formula: O O -ODO-C-R-C- '(II) wherein G is a divalent radical that remains after the removal of the terminal hydroxyl groups of a poly (alkylene oxide) glycol having an average number of molecular weight of about 400-4000; R, is a divalent radical that remains after the removal of carboxyl groups from a dicarboxylic acid having a molecular weight of less than 300; D, is a divalent radical that remains after the removal of hydroxyl groups from a diol having a molecular weight of less than 250; the copolyether ester contains 0-68 weight percent based on the total weight of the copolyether ester ethylene oxide groups incorporated in the long chain ester unit of the copolyether ester; Y the copolyetherester contains about 25-80 weight percent short chain ester units.
6. A water purification equipment which is characterized in that it includes a hydrophilic membrane layer comprising one or more layers of polymers having a water vapor transmission rate in accordance with .ASTM E96-95 (BW method) of at least 400 g / m2 / 24 h), measured on a film of 25 microns of total thickness using air at 23 ° C and 50% relative humidity at a speed of 3 m / s, this thickness is made of one or more layers of polymers , to remove at least one of suspended solids, dissolved solids, contaminants, salts and biological materials from a water source, wherein said polymer is selected from the group comprising at least one of the copolyether ester elastomers, block polyamides with polyether, polyether urethanes, polyvinyl alcohol homopolymers and copolymers, and mixtures thereof.
7. A water releasing apparatus for controlling moisture in a culture medium, which is characterized in that it includes a hydrophilic membrane layer comprising one or more layers of polymers having a water vapor transmission rate in accordance with .ASTM E96-95 ( Procedure BW) of at least 400 g / m2 / 24h, measured on a film of 25 microns of total thickness using air at 23 ° C and 50% relative humidity at a speed of 3 m / s, this thickness being formed of one or more layers of polymer, to remove at least one of suspended solids, dissolved solids, contaminants, salts and biological materials from a water source, wherein said polymer is selected from the group comprising copolyether ester elastomers, block polyamides with polyether, polyether urethanes, polyvinyl alcohol homopolymers and copolymers, and mixtures thereof.
8. The water releasing apparatus of claim 7 which is characterized in that the hydrophilic polymer comprises one or more copolyether ester elastomers or a mixture of two or more copolyether ester elastomers having a multiplicity of resorting to long chain ester units and short chain ester units attached head with tail through ester bonds said long chain ester units which are represented by the formula: O O -OGO-C-R-C- (I) and said short chain ester unit which is represented by the formula: 0 0 -ODO-C-R-C- (II) wherein G is a divalent radical that remains after the removal of the terminal hydroxyl groups of a poly (alkylene oxide) glycol having an average number of molecular weight of about 400-4000; R, is a divalent radical that remains after the removal of carboxyl groups from a dicarboxylic acid having a molecular weight of less than 300; D, is a divalent radical that remains after the removal of hydroxyl groups from a diol having a molecular weight of less than 250; the copolyether ester contains 0-68 by weight percent based on the total weight of the copolyether ester, ethylene oxide groups incorporated in the long chain ester unit of the copolyether ester; Y the copolyetherester contains about 25-80 weight percent short chain ester units.
9. An apparatus that is characterized in that it increases humidity to provide moisture in the air space of a closed chamber, said apparatus comprises a water source and a hydrophilic membrane comprising one or more layers of hydrophilic polymers to remove at least one of suspended solids, Dissolved solids, contaminants, salts, and biological materials from the water and emits water vapor into the airspace, where: the hydrophilic polymer is selected from the group comprising at least one of copolyether ester elastomers, block polyamides with polyether, polyether urethanes, homopolymers and copolymers of polyvinyl alcohols, and mixtures thereof; the hydrophilic polymer has a water vapor transmission rate in accordance with .ASTM test E96-95 (BW method) of at least 400 g / m / 24 h, measured on a 25 micron thick film using air at 23 ° C and 50% relative humidity at a speed of 3 m / s.
10. A water releasing apparatus for controlling the moisture content in a culture medium, which is characterized in that it includes a water source and a water release means, said means comprising: a hydrophilic membrane comprising one or more layers of polymers having a water vapor transmission rate according to .ASTM E96-95 (Procedure BW) of at least 400 g / m2 / 24 h, measured on a 25 micron film Thickness using air at 23 ° C and 50% relative humidity at a speed of 3 m / s, this thickness that is made up of one or more layers of polymer, to remove at least one of suspended solids, dissolved solids, contaminants, and biological materials of the water source, said polymer is selected from the group comprising copolyether ester elastomers, block polyamides with polyether, polyether urethanes, polyvinyl alcohol homopolymers and copolymers, and mixtures thereof.
11. A process for removing at least one of suspended solids, dissolved solids, contaminants, and biological materials from impure water, which is characterized in that it comprises the steps of: provide a source of water that contains at least one of suspended solids, dissolved solids, contaminants, salts, and biological materials in the water, providing a water purification apparatus comprising a hydrophilic membrane layer for separating at least one of suspended solids, dissolved solids, contaminants, salts, and biological materials from the water and retaining at least one of suspended solids, dissolved solids, contaminants, and biological materials on one side of said layer and allow a differential of water vapor transfer through said layer in a proportion of at least 70 g / m2 / 24h, wherein said transfer ratio is defined to der the amount of loss of water from the purifying apparatus per unit surface area of the hydrophilic membrane for one unit of time, and passing water through said water purification apparatus to remove at least one of suspended solids, dissolved solids, contaminants, salts, and materials biological of water.
12. A process for increasing the moisture content in a dehydrated material which is characterized in that it comprises the steps of: provide a source of water that contains at least one of suspended solids, dissolved solids, contaminants, and biological materials in the water, provide a water releasing system comprising a hydrophilic membrane layer to remove at least one of suspended solids, dissolved solids, contaminants, salts, and biological materials from the water and retain at least one of suspended solids, dissolved solids, contaminants, salts, and biological materials on one side of said layer and allow a differential transfer of water vapor through said layer at a rate of at least 70 g / m / 24 h, wherein said rate of water transfer is defined to be the amount of water loss of the water purifying apparatus per unit area of the hydrophilic membrane for one unit of time, and placing said dehydrated matter in contact with said water releasing system.
13. A process for germinating plant seeds and cultivating a seedling from a germinated seed of such plant, which is characterized in that it comprises the steps of: provide a source of water that contains at least one of suspended solids, dissolved solids, contaminants, salts and biological materials in the water, providing a water release system comprising a hydrophilic membrane layer to separate at least one of suspended solids, dissolved solids, contaminants, salts, and biological material from the water and retain at least one of the suspended solids, dissolved solids, contaminants, and biological materials on one side of said layer and allow a differential transfer of water vapor through said layer in a proportion of at least 70 g / m2 / 24 h, wherein said rate of water transfer is defined being the amount of water loss of the water purification apparatus per unit surface area of the hydrophilic membrane for one unit of time, and introducing the water into the water release system in which the water passes through the hydrophilic membrane into the culture medium which depends on the moisture content of the culture medium. provide a source of water that contains at least one of the suspended solids, dissolved solids, contaminants, salts, and biological materials in the water, provide a water release system comprising a hydrophilic membrane layer to separate at least one of the suspended solids, dissolved solids, contaminants, salts, and biological materials from said water and retain at least one of the suspended solids, dissolved solids, contaminants, salts and biological materials on one side of said layer and allow a differential transfer of water vapor to through said layer in a proportion of 70 g / m2 / 24 h, wherein said rate of water transfer is defined, the amount of water loss being from the water purification apparatus per unit area of the hydrophilic membrane during a unit of time, and . introduce the water into the water releasing system in which the water passes through the hydrophilic membrane towards the dehydrated matter depending on the moisture content of the dehydrated matter.
14. A process for increasing the moisture content in a dehydrated matter, said process which is characterized in that it comprises: provide a water release system comprising a hydrophilic membrane layer to separate at least one of the suspended solids, dissolved solids, contaminants, salts, and biological materials from said water and retain at least one of the suspended solids, dissolved solids , contaminants, salts, and biological materials on one side of said layer and allow a differential transfer of water vapor through said layer in a proportion of at least 70 g / m2 / 24 h, wherein said proportion of vapor transfer of water is defined, the amount of water loss of the water purification device per unit area of the hydrophilic membrane being for a unit of time, and introduce the water to the water releasing system in which the water passes through the hydrophilic membrane to the dehydrated matter depending on the moisture content of the dehydrated matter.
15. A process for controlling the humidity of the air space in a closed chamber, which is characterized in that it comprises the steps of: providing a water release system to said chamber, said system comprising a hydrophilic membrane layer for substantially removing any suspended particles and dissolved solids from said water and retaining suspended particles and dissolved solids on one side of said layer and allowing a differential transfer of water vapor through said layer in a proportion of at least 70 g / m2 / 24 h, wherein said rate of water transfer is defined, the amount of water loss being from the purification device per unit surface area of the hydrophilic membrane for one unit of time, and introduce water to the water release system where the water passes through the hydrophilic membrane to the closed chamber depending on the humidity of the chamber.
16. Using a membrane in water purification, the membrane is characterized in that it comprises a hydrophilic polymer.
17. Use of a membrane according to claim 16, characterized in that the membrane increases humidity in a vicinity of the membrane.
18. Use of the membrane according to claim 16 or 17, characterized in that the membrane comprises a polymer selected from: elastomers copolyether esters, block polyamides with polyether, polyether urethanes, homopolymers and copolymers of polyvinyl alcohols, and mixtures thereof.
19. Use of the membrane according to any of claims 16 to 18, characterized in that the membrane comprises at least one copolyetherester elastomer having a multiplicity of resorting to long chain ester units and short chain ester units together head to tail through of ester bonds of said long chain ester units which are represented by the formula: O o -OGO-C-R-C- (I) and said short chain ester units that are represented by the formula: O O -ODO-C-R-C- (II) wherein G is a divalent radical that remains after the removal of the terminal hydroxyl groups of a poly (alkylene oxide) glycol having an average number of molecular weight of about 400-4000; R, is a divalent radical that remains after the removal of carboxyl groups from a dicarboxylic acid having a molecular weight of less than 300; D, is a divalent radical that remains after the removal of hydroxyl groups from a diol having a molecular weight of less than 250; the copolyether ester contains 0-68 by weight percent based on the total weight of the copolyether ester, ethylene oxide groups incorporated in the long chain ester units of the copolyether ester; Y the copolyetherester contains about 25-80 weight percent of short chain ester units.
20. A method of purifying a water source containing at least one of the suspended solids, dissolved solids, contaminants, salts, and biological materials, the method is characterized in that it comprises the steps of: providing a hydrophilic membrane, the membrane having a first surface adjacent a first volume and a second surface adjacent a second volume; place the water source in contact with the first surface; Ensure that the humidity differential exists between the first volume and the second volume such that water penetrates through the membrane from the first surface to the second surface and into the second volume in the form of vapor, and where At least one of the suspended solids, dissolved solids, contaminants, salts and biological materials is retained by the membrane.
21. The method of purifying the water source according to claim 20, characterized in that it additionally comprises the step of: Periodically re-level through the first volume with water that requires purification.
22. The method of purifying the water source according to claim 20, characterized in that it additionally comprises the step of: continuously re-level through the first volume with water that requires purification.
23. The method of purifying the water source according to claim 20, characterized in that the water source is in a vapor state.
24. The method of purifying the water source according to any one of claims 20 to 23, characterized in that it additionally comprises the step of: provide a differential pressure across the membrane.
25. The method of purifying the water source according to any one of claims 20 to 24, which is "characterized in that it additionally comprises the step of: using the water vapor present in the second surface to increase humidity in the second volume.
26. The method of purifying the water source according to any one of claims 20 to 25, characterized in that it additionally comprises the step of: condensing the water vapor present in the second surface in the second volume.
27. The method of purifying the water source according to any one of claims 20 to 26, characterized in that the second volume is a closed chamber.
28. A method for hydrating at least one of the provisions and a drug contained in a container, at least part of the container comprises a hydrophilic membrane, the method which is characterized in that it comprises the step of: placing the membrane in contact with a source of water containing at least one of the suspended solids, dissolved solids, contaminants, and biological materials, so that the membrane acts to purify the water passed through, to hydrate the aforementioned one of the aforementioned provisions and drugs.
29. An article of at least one provision and a drug contained in a container, characterized in that at least part of the article is comprised of a hydrophilic membrane.
30. A water purification system which is characterized in that it comprises. A source of water supply that contains at least one of suspended solids, dissolved solids, contaminants, salts, and biological materials; Y A membrane in contact with the water source, the membrane comprising a hydrophilic polymer.
31. The water purification system of claim 30 which is characterized in that: the membrane has a first surface adjacent to a first volume and a second surface adjacent to a second volume and the source of water supply contacts the first surface, the system comprises at least one humidity differential between the first volume and the second volume so that water penetrates through the membrane from the first surface to the second surface and the second volume, and wherein at least one of the suspended solids, dissolved solids, contaminants, salts and biological materials is retained in the first volume.
32. The water purification system of claim 30 or 31, which is characterized in that it additionally comprises: means to re-level periodically through the first volume with water that requires purification.
33. The water purification system of claim 30 'or 31, which is characterized in that it additionally comprises: means for continuously releveling through the first volume with water that requires purification.
34. The water purification system of any one of claims 30 to 31, characterized in that it additionally comprises: means for providing a differential pressure across the membrane.
35. The water purification of claim 31 or claims 32 to 34 as they depend on claim 31, which is characterized in that the second volume is a closed chamber.
36. The water purification of claim 35, which is characterized in that the purified water present in the second surface increases the humidity in the second volume.
37. The water purification of claim 35 or 36, which is characterized in that it additionally comprises: means for condensing water vapor extruded from the second surface to the second volume.
38. The water purification of any one of claims 30 to 37, characterized in that the membrane comprises at least one layer of hydrophilic polymer.
39. The water purification of any one of claims 30 to 38, characterized in that the membrane includes a support substrate.
40. The water purification of any one of claims 30 to 39, characterized in that the system provides purified water in at least one of, a liquid form and a vapor form to an environment that supports at least one of, germination, propagation , and plant cultivation.
41. The water purification of the claim 40, which is characterized in that the purified water is supplied to a culture medium.
42. The ale of claim 29 or the water purification system of any one of claims 30 to 41, which is characterized in that the membrane has a water vapor transmission rate in accordance with ASTM test E96-95 (Method BW) of at least 400 g / m2 / 24 h, measured on a 25 micron thick film using air at 23 ° C and 50% relative humidity at a speed of 3 m / s.
43. The ale of claim 29 or the water purification system of any one of claims 30 to 41, which are characterized in that the membrane has a water vapor transmission rate in accordance with .ASTM test E96-95 (Procedure BW) of at least 3500 g / m2 / 24 h, measured on a 25 micron film using air at 23 ° C and 50% relative humidity at a speed of 3 m / s.
44. The ale of claim 29 or the water purification system of any one of claims 30 to 41, characterized in that the membrane comprises a polymer selected from 'copolyether ester elastomers, block polyamides with polyether, polyether urethanes, homopolymers and copolymers of polyvinyl alcohol, and mixtures of these.
45. The ale of claim 29 or the water purification system of any one of claims 30 to 41, characterized in that the membrane comprises at least one copolyetherester elastomer having a multiplicity of resog to long chain ester units and units. of short chain esters together head to tail through stellar junctions said long chain esters units which are represented by the formula: O 0 -OGO-C-R-C- (I) and said short chain ester units that are represented by the formula: 0 O -ODO-C-R-C-:? I) wherein G is a divalent radical which remains after the removal of the terminal hydroxyl groups of a poly (alkylene oxide) glycol having an average number of molecular weight of about 400,000; R, is a divalent radical that remains after the removal of carboxyl groups from a dicarboxylic acid having a molecular weight of less than 300; D, is a divalent radical that remains after the removal of hydroxyl groups from a diol having a molecular weight of less than 250; the copolyether ester contains 0-68 by weight percent based on the total weight of the copolyether ester, ethylene oxide groups incorporated in the long chain ester units of the copolyether ester; Y the copolyetherester contains about 25-80 weight percent of short chain ester units.
46. The article of claim 29 or the water purification system of any one of claims 30 to 41, characterized in that the membrane allows a differential transfer of water vapor through said membrane in a proportion of at least 70 g. / m2 / 24h, and wherein said rate of water transfer is defined, the amount of water loss of the water purification device per unit of surface area of the membrane being for one unit of time.
47. Use of a membrane in the water purification according to claim 16 or 17, which is characterized in that the membrane substantially separates all suspended particles and dissolved solids from said water and retains suspended particles and dissolved solids on one side of said membrane and allows a differential transfer of water vapor through said membrane in a proportion of at least 70 g / m2 / 24 h, and wherein said rate of water transfer is defined, the amount of water loss being from the purification apparatus of water per unit surface area of the membrane for one unit of time.
48. Use of the membrane according to any one of claims 16 to 18, characterized in that the membrane has a water vapor transmission rate according to .ASTM E96-95 (Method BW) of at least 400 g / m2 / 24 h, measured using air at 23 ° C and 50% relative humidity at a speed of 3 m / s on a film of 25 microns in total thickness.
49. Use of the membrane according to any one of claims 16 to 18, which is characterized in that the membrane has a water vapor transmission rate according to ASTM E96-95 (Procedure BW) of at least 3500 g / m2 / 24 h , measured using air at 23 ° C and 50% relative humidity at a speed of 3 m / s on a film of 25 microns in total thickness.
50. The method of purifying the water source according to claim 20, characterized in that the water source is a mixture of liquid and vapor.
51. The method of purifying the water source according to claim 20, characterized in that the water source is a mixture of liquid and vapor.
52. The method of purifying the water source according to claim 20, characterized in that the water source is an emulsion containing at least water.
53. The method of purifying the water source according to claim 27, characterized in that it additionally comprises the step of: using the water present in the closed chamber to germinate at least one plant seed or a seedling placed in said closed chamber.
54. A method for controlling the moisture content in a culture medium, the method which is characterized in that it comprises the steps of: placing the membrane in contact with a source of water containing at least one of the suspended solids, dissolved solids, contaminants, and biological materials, so that the membrane acts to purify the water passed through to wet said culture medium.
55. An article comprising at least one seed and a seedling contained in a container, characterized in that at least part of the container comprises a hydrophilic membrane.
56. The water purification system of claim 30, characterized in that the membrane separates at least one of the suspended solids, dissolved solids, contaminants, salts and biological materials from said water, and retains at least one of said suspended solids, dissolved solids, contaminants, salts and biological materials on one side of said membrane and allows a differential transfer of water vapor through said membrane in a proportion of at least 70 g / m2 / 24 h, and wherein said transfer ratio it is defined, the amount of water loss of the purification device per unit of surface area of the membrane being one unit of time.
MXPA/A/2000/007259A 1998-02-05 2000-07-25 Water purification apparatus MXPA00007259A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US09/019,287 1998-02-05

Publications (1)

Publication Number Publication Date
MXPA00007259A true MXPA00007259A (en) 2002-07-25

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