MXPA00003318A - Deionization apparatus having non-sacrificial electrodes of different types - Google Patents

Abstract

An apparatus having deionization cells (80), each cell having two different electrodes (20, 22), is disclosed. The first electrode (22) is formed from a high surface are a absorptive material ("HSAAM") made from resorcinol, formaldehyde, a carbon reinforcing agent, catalyst and reaction products thereof, in carbonized form. The second electrode (20) is formed of non-HSAAM material, such as carbon cloth or carbon felt. Each deionization cell (80) has a single HSAAM electrode (22) bordered on either side by a non-HSAAM electrode (20), and adjacent cells do not share any electrodes of either type. A method of making the HSAAM electrodes (22) by setting a polymerized mixture of resorcinol, formaldehyde and carbon reinforcing agent supplied in the form of carbon fibers, carbon felt or cellulose under controlled temperature and time constraints, and subsequently firing the resulting product to carbonize the electrode is disclosed.

Description

DEVOLUTION DEVICE THAT HAS NON-SACRIFICATORY ELECTRODES OF DIFFERENT TYPES • BACKGROUND OF THE INVENTION The present invention relates to carbon aerogels, electrochemical cells and systems for the deionization and purification of aqueous effluents. Resorcinoi is a well-known material commonly used in resins, dyes, adhesives, pharmaceutical agents and other applications. It can be obtained in various grades and forms, such as crystals, flakes, pellets, and the like. Resorcinoi, in its various forms, is soluble in water, alcohol, ether, benzene, glycerol and formaldehyde. In accordance with that indicated in USP 5,425,858 to Farmer, resorcinol can be used to synthesize carbon aerogels. Specifically, a carbon airgel can be produced by polycondensation of resorcinol and formaldehyde in a slightly basic medium, followed by supercritical drying and pyrolysis in an inert atmosphere. Thin electrodes formed from such carbon aerogoles can be used in capacitive deionization applications, in accordance with that indicated in this reference, the contents of which are hereby incorporated by reference in their entirety. The thin electrode plate (thickness of about 0.25 mm) formed by this method nevertheless has numerous drawbacks. First, such plates are excessively expensive to be used on a commercial scale, at a cost of US $ 1000 per square inch of surface area. Second, a device that employs these electrodes has been activated effectively only at voltages and currents less than the levels at which the water is electrolyzed. Likewise, the thin nature of the plates limits the capacity for deionization. Thin plates are not self-supporting and it is difficult to make a direct reliable electrical connection with them. Finally, these electrodes are glued on a titanium plate and consequently one side of said plates is not available for use as a deionization surface. SUMMARY OF THE INVENTION The present invention is directed to a deionization apparatus comprising a tank having a plurality of deionization cells. Each deionization cell comprises three non-sacrificial electrodes of two different types. An electrode comprises a high surface area absorption material ("HSAAM electrode") formed as a plate having two sides facing in opposite directions. The HSAAM electrode removes ions from the liquid in the process of deionization. This HSAAM electrode is located between two electrodes, one on each side, that do not remove ions from the liquid in the process of deionization. The bottom of the tank can have a network of pipes to conduct air, each pipe having small holes through which the air can exit. The air pumped through these pipes agitates and mixes the liquid in the process of deionization, thus promoting contact and ion capture in the HSAAM electrodes. The non-HSAAM electrodes in the present invention are in the form of carbon cloth (CC) electrodes or graphite plate fixed on both sides of a flat, non-conductive structural support member. The non-HSAAM electrode on one side of the structural support member is electrically isolated from the non-HSAAM electrode on the other side of the structural support member. Thus, each non-HSAAM electrode is associated with a different HSAAM electrode. This results in the formation of a deionization cell comprising a first non-HSAAM electrode and a second non-HSAAM electrode, each mounted on a different structural support member, but facing the same HSAAM electrode sandwiched between them. The HSAAM electrodes used in the deionization cells are produced by first dissolving resorcinol in formaldehyde to form an initial liquor. A catalyst is added to promote the polymerization and to create the final structure of HSAAM. A certain amount of a non-sacrificial material is introduced into the liquor as reinforcement material. Sufficient heat is added by heating the mixture to a sufficient temperature or for a sufficient time such that a controlled polymerization is carried out and the mixture reaches a sufficient consistency to support the reinforcing material. The resulting viscous liquid can then follow the polymerization in order to form a solid in a mold. The resulting brick is then calcined in an oven until its carbonization after which it is machined for subsequent use in the apparatus. BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics, aspects and advantages of the present invention can be seen in the drawings in which: Figure 1 is a perspective view of an apparatus formed in accordance with the present invention; Figure 2A is a view of the tank employed in the apparatus of the present invention. Figures 2B and 2C show two arrangements for immobilizing the HSAAM plates inside the tank; Figure 3 is a top view of the apparatus of Figure 1 arranged for a serpentine flow; Figures 4a and 4b show a deionization cell formed from neighboring electrodes; Figure 5 shows an apparatus with three devices connected in series; Figures 6A and 6B show different alternatives of having all the electrodes parallel to each other; Figure 7 shows a top view of a tank having ion outlet holes formed there; Figure 8 shows an experimental apparatus constructed in accordance with that illustrated in Figure 5; Figures 9A-9E present batch processing results using the apparatus of Figure 8; Figure 10 shows a block diagram for an automated deionization apparatus. DESCRIPTION OF THE PREFERRED MODALITY Figure 1 an apparatus 18 made in accordance with the present invention. The apparatus comprises several electrodes 20, 22, upright, arranged in parallel. As will be discussed below, two different types of electrodes are provided, and alternately. The electrodes of the apparatus are mounted across the width in a substantially rectangular chamber or tank 24. The tank itself comprises a pair of side walls 26, 28, a pair of end walls 30, 32, and a flat bottom 34. The walls of the tank are preferably formed of glass, plastic, plexiglass, or another impermeable, electrically insulating material.

An inlet 36 formed in the bottom and an outlet 38 in a first end wall provide the inlet and outlet of a liquid that is deionized while in the tank. • tank. Alternatively, the inlet may be formed in the second end wall when a serpentine flow is desired, as represented by the path in dashed lines in Figure 3. Likewise, several inlets and outlets, spaced apart therebetween in the bottom or sides, can be provided when a single tank is used to deionize liquids from different sources, each liquid having ions of different polarities and sizes to be removed. At the base of the tank there is an air diffuser 42 through which air is introduced. As shown in Figure 2A, the air diffuser comprises several pipes arranged in parallel 44 formed of styrene or the like and have small openings formed therein. The pipes 44 extend across the width of the tank and, in the preferred embodiment, are placed between electrodes face to face. 20 When the apparatus is operational, air is pumped through these pipes to aerate and agitate the liquid in the tank. This promotes deionization by mixing the liquid inside the tank and agitating the ions between oppositely charged electrodes. It will be apparent to one skilled in the art that equivalent aeration devices can be employed in place of the pipe network in parallel with openings. For example, a false floor can be provided and the air, pumped between the bottom of the tank and the false floor could seep through openings formed in the latter. Another alternative is to place a substantially flat plastic bag at the bottom of the tank and the air, once pumped into the bag, could penetrate the liquid through openings in an upper side. The side walls 26, 28 of the tank are equipped with a row of mounting clips, also molded of styrene or other plastic, on their faces facing inwards. The mounting clips 46, 48, as illustrated in Figure 2a, serve to align and retain electrodes inserted into the tank. The mounting clips 46 and 48 may differ in size, shape and materials, depending on the physical and chemical properties of the electrodes 20, 22, which they must accommodate. An electrode can be inserted, on each side edge, directly into the opposite mounting clips. In this case, the electrode can be formed with an opening 50, as shown in Figure 3, adjacent to the place where it is inserted into the mounting clip. This opening 50 serves as a passage through which the liquid can pass as it travels through the tank.

Alternatively, an electrode can be maintained indirectly by means of a mounting clamp through an acrylic spacer 52 at one or both of its ends, the acrylic spacer being fixed on the electrode by means of a connecting clamp 54. In this case , an opening 56 can be formed in the acrylic spacer itself to allow the liquid to pass through. This arrangement is especially helpful when the opening can not be formed in the electrode itself, for structural, electrical or other reasons. In addition, the bottom 34 of the tank can be equipped with plastic protection members 57, as seen in Figure 2B, or slot 58, as can be seen in Figure 2C that extend across the width of the tank. Such protection members and grooves allow selectively adjusting, in a sliding manner, the electrodes towards one side wall or towards the other. This is especially advantageous when it is desired to have a serpentine flow of the liquid past each face of each electrode, from the entrance in an end wall of the tank to the outlet formed in the opposite end wall. As an alternative to a protection member or a groove along which an electrode can slide, a central portion of the bottom wall may be equipped with slits in which erect bottom pliers or spring-loaded retainers are inserted. The bottom edge of an electrode can then be inserted into these bottom clips or retainers at any desired distance from any side wall. As described above, acrylic spar bars can be used to bridge the gap between the free edge of the electrode and the mounting clamp. A busbar 60 can be provided in the external side walls of the tank. Each busbar is equipped with several terminals 62 thermally insulated therebetween, each arranged to connect to an associated electrode. This allows to individually control the voltage, and the current, that are applied to each electrode. The individual terminals may be electrically connected to their electrodes associated with conventional electrical connectors such as forceps or equivalent connection means. More preferably, however, the individual terminals can be connected by means of a copper wire 64 connected through a non-sacrificial graphite rod with any of the corresponding mounting clips or, when employed, the corresponding connection clamp. . The electrode then makes contact with the graphite rod when the electrode is inserted into the mounting or connecting clamp. To facilitate this electrical contact, a leaf spring or the like can be fixed on the end of the conductive band, in a known manner. The leaf spring can then be fixed on the clip channel where the edge of the electrode is inserted. As stated above, two types of conductive, non-sacrificial electrodes are employed in an apparatus formed in accordance with the present invention. In the preferred embodiment, a first type of electrode, formed as a flat plate has on both sides a second type of electrode. Together, the three electrodes form a deionization cell. During operation, a substantially similar voltage potential is normally established between an electrode of the first type and each of the electrodes of the second type. This is achieved by connecting a conductor of a voltage source to the electrode of the first type and a pair of common conductors from said same voltage source to each of the two electrodes of the second type. The common conductors ensure that a substantially similar potential is maintained between the electrode of the first type and each of the electrodes of the second type that are on both sides of the electrode of the first type. The first type of electrode (22) is formed of an absorption material of high surface area ("HSAAM electrode") based on carbon. This electrode removes and retains ions from an aqueous solution when an electric current is applied. In the preferred mode, the HSAAM electrode is formed of resorcinol, formaldehyde, at least one of the following: carbon fiber, carbon and cellulose felt, a catalyst, and reaction products thereof, in a carbonized form. The process for forming an HSAAM electrode is described in more detail below. The second type of electrode (20), even when formed of a conductive material, does not remove or retain ions when an electric current is applied and therefore is not an absorption ("non-HSAAM electrode"). This property is common to electrodes formed from carbon cloth, graphite, gold, platinum and other conductive materials that do not degrade in an electric field in an aqueous solution. In the preferred embodiment, the non-HSAAM carbon electrode is formed of either graphite, more preferably carbon cloth, such as for example the PANEX part number 30 woven fibers available in Zolte. As shown in Figure 4a, the non-HSAAM carbon electrode 20 is formed as a double electrode insofar as it has a pair of conductive surfaces that are electrically insulated therebetween. The double electrode 20 is formed by attaching a separate piece of carbon cloth 72a, 72b on both sides of a 3/8"thick sheet of plexiglass 74. The plexiglass serves as a structurally rigid, non-conductive support member, and also prevents the flow of the liquid directly through both pieces of carbon cloth, so glass, acrylic, and the like can be used in place of plexiglass.In the preferred embodiment, the carbon cloth is fixed on both sides of a sheet of plexiglass by means of an epoxy adhesive As is known to those skilled in the art, other adhesives, and also mechanical fastening means such as screws, clamps, and the like can be used to fix the carbon cloth electrode (CC). Once fixed on both sides of the plexiglass sheet 74, the carbon cloth 72a on one side can, if desired, be electrically connected to its counterpart 72b on the other side of the same sheet 74. Usually, without However, this is not the case in such a way that one can apply different voltages to the carbon cloth on each side of the plexiglass, through separate voltage sources. In this case, adjacent cells within a single tank can be activated by different voltage sources. As shown in Figure 4b, in an apparatus of the present invention, these non-HSAAM 20 electrodes from two sides alternate in the tank with the HSAAM electrodes 22, each of which can be applied at any given time only one single voltage. Thus, in one apparatus of the present invention, one side of an HSAAM electrode faces a DC electrode 72b fixed on a first plexiglass sheet 74, while the second reverse side of the HSAAM electrode faces a fixed DC 76a electrode. on a second sheet 78 of plexiglass. In this way, each of the HSAAM electrodes 22 with its corresponding pair of non-HSAAM cloth electrodes forms a deionization cell 80. The end walls 30, 32 have a carbon cloth electrode fixed on their sides facing towards inside, said electrode is part of a cell. In use, two DC electrodes 72b, 76a facing the same HSAAM electrode 22 are usually maintained at the same polarity and voltage level. Alternatively, if desired, they can be maintained at different levels, since each has its own terminal 62 in the busbar 60. When a voltage is applied between the HSAAM electrode 22, and its corresponding non-HSAAM electrodes 72b, 76a, the cell 80 is activated and deionization is carried out on both sides of the HSAAM electrode 22. Preferably, the same voltage level is applied to both non-HSAAM electrodes of a single cell. However, if the two non-HSAAM electrodes on both sides of an HSAAM electrode have different surface areas and can sustain different current densities, it may be possible to activate them at different voltages. An HSAAM electrode can be positively or negatively charged relative to the non-HSAAM electrode. When the HSAAM electrode is positively charged, it attracts, absorbs and stores negative ions. This causes the pH of the water in the immediate vicinity of the cell to rise, or become more caustic. When the HSAAM electrode is negatively charged, it attracts, absorbs and retains positive ions, thus decreasing the pH of the water, and making it more acidic. Since each HSAAM electrode 22 has its own pair of DC electrodes on both sides, adjacent deionization cells within the same tank can be used to remove different types of ions. Thus, if a pair of spaced inputs and outputs are provided on the bottom or sides of the same tank, the deionization cells near these inputs can be activated in such a way that a first set of cells removes ions of a first type and a second set of cells removes ions of a second type. Similarly, when a serpentine fluid flow is desired, the first set of upstream cells found by the fluid can be activated to remove ions of a first type, while a second downstream set is activated to remove ions of a second. kind. In a given tank, several cells are usually present. In order to fully deionize the water in the tank, both negatively charged HSAAM electrodes and positively charged HSAAM electrodes must be present. In general, different voltages must be applied to positive cells and negative cells to effect ion removal, and the number of positively charged cells and positively charged cells may not be the same. This allows positively charged HSAAM electrodes and negatively charged HSSAM electrodes to be independently activated at different voltage levels, the variation of the spacing between plates and applied voltage can allow the removal of specific ions from the fluid under treatment. As shown in Figure 5, several tanks can be chained together, the output of one tank being connected to the entrance of the next tank. In such a case, the deionization cells in each tank can be activated in a common manner so that each tank is focused towards the removal of one type of ion. Alternatively, successive tanks can be used to remove smaller and smaller amounts of the same ion. As shown in Figures 6A and 6B, it is possible to have electrodes of one type that present a slight angle with respect to the electrodes of the other type. In Figure 6A, the HSAAM electrodes are illustrated parallel to each other and upright. In contrast, non-HSAAM carbon cloth electrodes on both sides of a HSAAM electrode have symmetrical angles relative to the HSAAM electrode. In this case, the adjacent HSAAM electrodes have their own carbon cloth electrodes with angle in various ways. Similarly, ß ^ when shown in Figure 6B, one can have the 5 carbon cloth electrodes raised, while the HSAAM electrodes have an angle with respect to the carbon cloth electrodes. In the configuration of Figure 6B, the HSAAM electrodes remain parallel to each other, but present an angle relative to the base and walls of the tank. • Figure 7 shows a top view of a tank comprising four deionization cells. A first pair of deionization cells having positively charged HSAAM plates are interspersed with a second pair that has HSAAM plates negatively charged. The base of the tank, in the underlying region of each deionization cell, is equipped with a set of holes. For positively charged deionization cells, holes 82 are shown, for deionization cells loads Negatively, they are shown as holes 84. The purpose of the holes 82, 84 is to allow the selective removal of positive and negative ions collected in the HSAAM plates when the tank is operational. Thus, cells that have positively charged HSAAM plates, ions negatives will accumulate on the plates. When the cell is regenerated, these ions can be collected through the orifices 82. Similarly, during regeneration, the ions accumulated in the negatively charged HSAAM plates can be collected through the orifices 84. As shown in FIG. Figure 7, the holes 82 and 84 have approximately the same size and arrangement. However, it is not a necessity. For example, the holes for the negatively charged ions may be smaller than the holes for the positively charged ions. Also, instead of a set of holes arranged in parallel with the HSAAM and non-HSAAM electrodes, the holes can appear in more irregular patterns such as chess boards or honeycomb. As stated above, the HSAAM electrode is formed of an absorption material of high surface area. In the present invention, this material is formed through an inventive process that requires three ingredients; resorcinoi, formaldehyde and a reinforcer, such as a coal source. A catalyst can also be used to facilitate the polymerization of the resorcinol-formaldehyde resin. Resorcinoi is obtained in several different grades and can be obtained from various suppliers in the form of pellets, flakes and other convenient forms. In the examples presented below, a resorcinol in a form suitable for organic chemical formulations was employed by Hoechst Celanese Company. Formaldehyde is available from several suppliers < < j and it is also obtained in different degrees and forms. In the five examples given below, a formaldehyde in the form of formalin, which is suitable for dyes, resins and biological preservation, was employed from Georgia-Pacific Resin, Spectrum Chemical Company. The source of carbon that was used as reinforcement in the formation of the HSAAM electrodes can be obtained in several ways. As for example, loose carbon fibers, such as for example chopped carbon fibers, THORNEL® P25 4K W available from AMOCO, have been successfully used to form HSAAM electrodes for use in the present invention. An alternative that has also been used successfully is carbon felt, either grade wdf 3331060 graphite felt or VDG 3330500 carbon felt, both available from the National Electric Coal Company. In general, a predetermined amount of a relatively pure source of carbon 20 can be employed to the extent that it is either completely dispersed in a resorcinol-formaldehyde liquor which after solidifying, or it can absorb a similar amount of the liquor in a matrix , and then solidify. It is important that the carbon fibers are electrically conductive. Even when the preferred embodiments require a carbon or carbon felt fabric, the important thing is that a non-sacrificial electrical conductor is employed. Accordingly, such materials as graphite, gold, platinum, conductive plastics, glassy coals such as SIGRADUR, available from SGL Carbon Group of St. Mays, Pennsylvania, and the like can be used in place of the carbon or carbon felt fabric. Regardless of the reinforcer used, the process of forming the HSAAM electrodes starts in the same way. Four pounds of solid resorcinium added to 3.5 liters of formaldehyde, which provides approximately a molar ratio of 1 to 2, at room temperature. The amounts indicated can obviously be modified linearly, either upwards or downwards to prepare different total amounts of this initial mixture. This initial mixture is mixed for a period of time between 30 and 90 minutes or until the dissolution of the resorcinol. When the resorcinol is completely dissolved, the resulting mixture has an amber to pink color. If this mixture is maintained at room temperature or below room temperature, ie, at a temperature of 62 ° C for about 12 to 24 hours after the dissolution of the resorcinol, this color becomes a milk and opalescent liquor.

A predetermined amount of a sodium carbonate catalyst is added to a measured portion of the liquor and the carbon source and the liquor is fully combined. The resulting material is then heated and cast in an 8"x 8" mold to a thickness of approximately "where it is allowed to harden in a xerogel block (consisting of polymerized resorcinol-formaldehyde.) The mold is placed on a flat surface at ambient temperature where the polymerization reaction proceeds in the air or as the material is transformed into a xerogel block.It takes approximately 20 to 60 minutes for the material in a mold to solidify at room temperature As the material solidifies shrinks by approximately 0.5-1.0% in each dimension, and detaches from one or more of the sidewalls of the mold.The block can then be removed by simply turning the mold.When removed from its mold each block is subjected to curing and hardening at a temperature of approximately 80 ° F to 90 ° F in the air for about two hours, to ensure complete polymerization. For curing of the prior art, the curing process of the present invention does not involve drying at critical point (ie, supercritical drying). This saves a considerable amount of time and lowers the cost. While curing removes a part of the excess liquid, the resulting canister remains a very limited conductor of electricity. After curing, the blocks are placed flat in an oven and then carbonized. During the carbonization, a weight is placed on each block to avoid the formation of cracks, irregular buckling, and bending of the edges. The carbonization is preferably carried out at a temperature within a range of 1850 ° F and 2200 ° F. However, experiments have shown that temperatures from 1750F and carbonization times between 10 and 20 minutes can also be acceptable, the lower the temperature the longer the carbonization time. The fact of subjecting the blocks to that temperature causes additional drying and combustion of many of the impurities present in the original ingredients. In the preferred embodiment, the carbonization can be carried out in an air environment, since the thickness of the blocks can withstand a certain loss of material due to combustion. This contrasts with previous techniques in which a nitrogen or other inert gas had to be used to prevent relatively thin blocks from being consumed during carbonization. Once the carbonization is finished, the resulting HSAAM plates can be machined and sanded into flat electrodes of a desired shape, size and thickness. Preferably, the electrodes are of sufficient thickness to be self-supporting (for example, capable of resisting their own weight when placed at one end). This requires a thickness of approximately at least 1 mm for a 2"x 4" electrode. Thinner plates can be formed, but the fragility of the material makes such thin plates difficult to handle and severely limits their ability to remove and store ions from the solution. In general, the thickness of the plate should be in proportion to its surface area, larger plates typically requiring a greater thickness. Regardless of the thickness, after the carbonization, the block is a good conductor of electricity. The exact details of the step of adding the catalyst and the coal source to the liquor can be carried out in various ways, depending on the type of coal source used.

This step is now considered in more detail below. First, a case is presented in which THORNEL® carbon fibers are used. Eight hundred milliliters (mis) of liquor is poured into a mixer, along with 3 ounces of the above-mentioned THORNEI - 5 1/4"carbon fibers, and 10 ml of a 1.0 molar solution of sodium carbonate that serves as a catalyst to promote polymerization. This combination is then mixed for about 3-5 minutes until the carbon fibers and the liquor are fully combined with each other. As the mixing is carried out, the carbon fibers are further cut into even smaller pieces. The result of this mixture is a black, viscous broth that includes the resorcinol / formaldehyde liquor mixed with the sodium carbonate, and the carbon fibers combined there. The temperature of the broth after the mixing step is about 90 ° F. It will be noted here that even though only 800 ml of liquor was used in this example, the process can be adjusted in terms of magnitude. Thus, several liters or more can be processed in batches at the same time. 1600 broths prepared in this way are then transferred to a stainless steel mixing vessel and the broth is then gradually heated using an electric table heater. As it warms, the broth is stirred and its temperature is monitored accurately. In this way, the temperature of the broth can rise over a period of 25 to 45 minutes which maintains the temperature at approximately 130-140 ° F, 135 ° F being the optimum temperature. During the heating process, the temperature of the broth is controlled in such a way that it does not exceed 150 ° F, causing the polymerization to get out of control. The control of the temperature can be achieved through several ways such as for example thermoelectric cells, coils that have a cooling agent circulating there, and arid baths in which the mixing vessel can be placed. The automatic regulation of the temperature can also be carried out using any of several well-known monitoring and control devices. The consistency of the broth is also monitored during the heating process. This ensures that the carbon fibers do not agglomerate together or settle, resulting in uneven dispersion agglomerates of agglomerated carbon fiber. If this occurs, the broth can be placed back in the mixer to further homogenize its contents. The broth is maintained at a temperature of about 135 ° F, and is continuously stirred to provide a uniform polymerization. This temperature is maintained for approximately 35 minutes, at this time a light film forms on the surface of the broth when the broth is not stirred for a few seconds. As the polymerization proceeds, the broth becomes thicker, becomes increasingly viscous until it reaches a consistency such that the carbon fibers are suspended within the broth as colloidal particles. When this point is reached, the heated broth is emptied into an 8"x 8" mold to a thickness of about 3/4".

It should be noted here that the temperature of the broth when emptying should be within a range of approximately 135 ° -150 ° F. This helps to ensure that when • solidifies the broth, the resulting solid blocks have 5 electrical and mechanical isotropic properties. When the broth is emptied at temperatures above 150 ° F or when it is allowed to exceed said temperatures, an uncontrolled reaction is carried out resulting in blocks of formates having ampoules and another surface thus uneven as volumetric characteristics. This results in a block • with electrical and structural anisotropy. The second case is when the carbon felt, plain cellulose fiber, or cellulose fiber impregnated with activated carbon is used to reinforce the resorcinol / formaldehyde resin. The carbon fiber felt, or mat, is cut to fit inside the mold. The resorcinol-formaldehyde liquor is then cast into the mold to cover the carbon filter, thus displacing trapped air within the felt. The mold is then transferred to a curing oven set at a temperature of 92 ° F and allowed to polymerize for about 72 hours to form a xerogel block. The xerogel is then placed in an oven and charred at a temperature between 1850-2200 ° F. While carbonizing in the furnace, the xerogel was restrained with a force of 0.5-0.8 pounds / square inch in the form of refractory blocks. The furnace used for this purpose was an electric oven with superior ventilation. The result of this carbonization is an HSAAM product. After the removal of HSAAM from the oven, it was allowed to cool in the air. The cooled HSAAM was then machined in a flat sanding wheel to a desired uniform thickness. Finally, this plate was cut squarely using a tabletop with a carbide tip. Regardless of the source of coal used, the resulting blocks have a black color and serve as conductors of electricity. In the above description, resorcinoi is used as one of the ingredients. However, experiments showed that suitable blocks can be formed using one of the following chemical agents instead of resorcinol: 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, and 1,4-dihydroxybenzene. Each of these chemical agents forms a polymer with formaldehyde, is successfully carbonized in a block, and subsequently deionizes water when a current is applied. In general, it is believed that any dihydroxyl or trihydroxylbenzene or naphthalene can be used in place of resorcinol. This is due to the fact that these chemicals have a similar chemical structure, share the forging characteristics of polymer with formaldehyde and probably form carbonized blocks that can be used for the removal of ions. Currently, resorcino is preferred due to its low cost, its wide availability in large quantities, its feasibility of reacting with formaldehyde at room temperature and normal pressure. Figure 8 illustrates an apparatus constructed in accordance with the following invention. This apparatus comprises three tanks 102, 104, I06. The three tanks were used in series to de-ionize wastewater effluents from the city of Pueblo, Colorado. The effluent was introduced at the inlet 108 to the first tank 102 and the final product exited the system from the outlet 122 of the tank 106. Overall, the system could deionize up to 1500 milliliters per minute (ml / min). In that system, tanks 102 and 106 presented an identical construction. Each of the tanks was equipped with 6 deionization cells. In both tanks 102, 106, the HSAAM electrodes in adjacent deionization cells had different polarities. This offered a voltage de-ionization arrangement interspersed in each tank. Due, both tanks 102, 106 were arranged to remove both positive ions and negative ions. Accordingly, each of these tanks had two voltage sources, a voltage source arranged to create positively charged deionization cells, and a second voltage source arranged to create negatively charged deionization cells. Tank 102 was connected to an intermediate tank 104. The partially deionized effluent of 102 passed through outlet 110, a valve 112, inlet 114 and in second tank 104. Although illustrated as a single entry, the inlet 114 was in fact a series of pipelines that penetrate the second tank 104. The purpose of the valve 112 is to interrupt the electric conduction process between the tanks 102 and 104. Likewise, the outlet 110 of the tank 102 may be equipped with a device of tap (not shown) to test the partially deionized effluent to evaluate the performance of tank 102. Tank 104 is also equipped with six deionization cells. However, these deionization cells have double length. The HSAAM electrodes of each are equipped with a joint at their ends so that they can correspond with a complementary structure on a similar plate. In contrast to tank 102, all deionization cells in tank 104 have positively charged HSAAM electrodes. That means that only the negative ions are removed in the tank 104. The additionally deionized effluent from the tank 104 exits through the outlet 116 or passes through the valve 118, then enters the inlet 120, and from there enters the tank 106 same. The outlet 116 may also be provided with a sampling device to be able to sample the effluent from the tank 104. As previously stated, the tank 106 is similar in construction to the tank 102. It further deionizes the liquid entering the tank. the inlet 120. The deionized outlet of tank 106 leaves the system at outlet 122. In tanks 102 and 106, the HSAAM electrodes were 6 x 6 W x 0.4"and were formed from two dimension plates. of the tanks 102, 106, a 0.25"gasket was cut on one edge and a complementary gasket was cut on an opposite edge from a support plate. The two plates were cut in four and glued end to end with a conductive epoxy glue. In the case of tank 104, four plates were placed in a similar process. For all the tanks, an electrical connection was made with a carbon fiber wire that was adhesively bonded, as for example by means of an epoxy adhesive, on the clamps that mount the HSAAM plates on the frame. In tanks 102 and 106, water was introduced into each tank near the top of the HSAAM electrodes at a single point. Once inside the tank, the water was continuously mixed during deionization. The purpose of the mixing is to help avoid the creation of acidic or localized caustic regions of the tank during deionization. The mixing can be carried out by aerating the tank at the multiple points along the bottom of this tank, even though other mixing means such as magnetic or mechanical stirrers and rotors can be used instead. The overall retention time of the water in a given tank was determined only by the flow rate which, as previously stated, was below 1500 ml / min. As an alternative to introducing water into a single point in each of the tanks, one can provide several inputs in each tank, one end of the HSAAM plates and non-HSAAM plates, and several outlets on the other end of the plates . In such a case, the water travels along a deionization cell before leaving. Tanks 102 and 106 have voltages applied to them that depend on the conductivity of the water that is being deionized. Applied voltages are located within a range of 0.01-15 volts during deionization in these two tanks. The corresponding amperage is located within a range of 0.01-10 amps during deionization. The speed of deionization of water (ie, the speed with which the ions were removed) depended on the type of water that was being deionized. Accordingly, the rate of deionization in tank 102, which presents more impurities, was greater than the rate of deionization of tank 106, which was treated with water that had been deionized twice. The second tank, 104, removed the negatively charged ions. This resulted in the water in this tank becoming caustic, creating a caustic soda. The second tank was operated in a serpentine flow pattern with the inlet being placed near the bottom of the HSAAM plates. The voltage and current applied to the water within the tank 104 were sufficient to cause electrolysis of the water. The treatment of the water in this second tank resulted in the removal of approximately 300 and 500 μmho / cm or μS / cm of conductivity. However, the caustic outlet of this tank had a pH within the range of 8 to 12, which was then sent to the third tank 106. Table 1 shows the experimental results achieved using the system of figure 8. Particularly, table 1 shows the effects of each deionization step using an apparatus formed in accordance with the present invention. The valves reported in Table 1 indicate that the outlet of tank 106 (the last tank) is consistent with drinking water, as it complies with the limitations of Federal water regulations. Parameter input to output output output system 102 104 106 conductivity μS 2000 1300 900 500 pH range 7.1-7.7 33..33--111.2 10.1-12.4 6.6-7.2 total hardness mg / l 560 492 342 144 colifor e total over 456 5 0 (colonies / 100 ml) increasing total alkalinity 280 60 60 10 mg / l ammonia mg / l) 17.1 12 6 14 dissolved solids 1188 781 540 300 total mg / l sulphates mg / l 840 830 423 400 chloride mg / l 28 10 8 3 slight strong smell absent absent green color light green clear light clear colorless colorless Table 1 Deionization of wastewater effluent from the City of Pueblo, Colorado, using the system of Figure 8. Table 2 shows the experimental results achieved using the system of Figure 8. Particularly, Table 2 shows the effects of each deionization step using an apparatus formed in accordance with the present invention Parameter input to output output output system 102 104 106 conductivity μS 1240 860 680 300 range pH 3.2-4.2 7.1 -7.6 8.6-11.1 7.1-7.7 color opaque / light orange / inclaro / in light orange color or total arsenic color 2 no ensa > mdl > mdl μg / y yy total cadmium 137 not tested 45.7 μg / y y total copper 40 not tested 11 μg / y yy total iron 4060 not tested 176 μg / y yy total lead 8 not tested > mdl > mdl μg / y y total manganese 13800 no ensa5370 2970 μg / i yado total zinc 38600 no ensa23000 11400 μg / i yado total hardness 980 376 64 34 mg / l total alkalinity 0 70 176 72 mg / l sulphate mg / l 778 414 231 39.8 chloride mg / l 16.7 4.8 4.8 5.8 calcium hardness 240 276 64 34 mg / l magne- hardness 740 100 > mdl > mdl sio mg / l Table 2 Super Fund Site Tried Yak Tunnel / California Gulch operated by Asarco, Inc., near Leadville, Colorado, resulting from deionization of the system of Figure 8. In addition to continuous flow deionization, the The apparatus can also be used for batch deionization processes. The results of the batch processing are shown in Figures 9A-9E. Particularly, these figures show the results of the deionization of a batch of water containing known concentrations of iron, sodium, and copper ions. Iron and copper ions were removed at a level below one part per billion, sodium ions were removed at a level below 2 parts per million, and the conductivity was reduced from 12,150 μ to 140 μS. The pH and conductivity level of the water in each of the three tanks was monitored to establish when the HSAAM plates were saturated. An increase in the conductivity of the water outflow without a corresponding change in pH indicates that the HSAAM plates were saturated with ions and that the apparatus requires regeneration. Similarly, charges stored in combination with pH and conductivity in the cells can be used to indicate when the apparatus requires regeneration. In general, HSAAM plates fade when deionizing water. The type and color of change depends on the type of water treated. For example, water having high levels of sulfate causes the plates to turn white as the sulfate deposits on said plates. Similarly, water that has a high content of organic waste causes the HSAAM plates to turn brown. Either way, this discoloration indicates that regeneration is required due to ion saturation levels. With tanks 102 and 106, it was possible to either form an oxidized lump or a concentrated ion solution during regeneration. The creation of one another depended on the level of applied voltage. The application of voltage less than the voltage necessary to cause the electrolysis of water allowed the collection of the ion-rich water from the positively charged or negatively charged deionization cells through the bottom holes 82, 84 as shown in the figure 7. On the other hand, the application of a sufficient voltage to electrolyze the water resulted in the formation of an oxidized lump. In this case, mixtures were required during the regeneration to produce and discharge this lump from the tank. In the second tank 104, negatively charged ions were removed. This resulted in the water becoming caustic, with pH of the order of 8-12. This also resulted in the formation of a caustic crumb. During the operation, the voltage applied to the deionization cells in tank 104 was sufficient to cause electrolysis of the water. Accordingly, the applied voltage was of the order of 1 to 12 volts with an amperage comprised between 1.3 and 12 amps. The effect of this was that the second tank 104 caused the removal of 300-500 μmho / cm or μS / cm of conductivity. The regeneration of the plates in the second tank 104 was carried out by inverting the current applied to the plates with a voltage sufficient to overcome the load stored in the cells (against EMF). Again, an elevation of the conductivity of the water outlet flow without pH change indicated that the HSAAM 's in the second tank 104 were saturated with ions, which means that the apparatus requires regeneration. This could be observed more easily due to the fact that the HSAAM plates showed significant discoloration, type and color change depending on the type of water being cleaned. During regeneration, an oxidized lump was produced by operating the device at a voltage required to counteract the EMF that had been accumulated during the operation of the system. These lumps could then be collected through the holes in the bottom of the tank 104. After regeneration, the tanks 102, 104, 106 can be reused with the same efficiency as the previous one. The power supplies used to supply the voltages necessary for deionization can be controlled preferably in a finite voltage range. Typically, then, the power supplies will be of the type that can be connected to an AC outlet. However, since relatively low voltages and currents are required, battery power supplies can be used in some environments. Within this context, a deionization device powered by solar energy was successfully built and operated, even when the performance was low. Small-scale battery and solar energy systems provide the double advantage of low cost and ease of transportation. Figure 10 shows a general view of an automated deionization control system 130 in accordance with the present invention. The system monitors the water quality to automatically adjust the voltages in order to achieve a white deionization speed. As shown in this figure, the system 130 controls the operation of two tanks 132, 134. However, it should not be forgotten that a control system can also be used with a single tank, or with three or more tanks, since be connected in series or in parallel, or in a combination of the two modes.

The control system uses detection modules 138 that monitor the effluent in several stages in the deionization plant. These detection modules 138 comprise one or more detectors configured to measure such properties as pH, conductivity, water flow rate, temperature, optical characteristics, etc., of the effluent. The detection modules can also include probes specific for ions such as those measuring fluoride, ammonia, chloride and others, such as those listed in Tables 1 and 2. These detectors can continuously sample the effluents, at predetermined periodic intervals, or well at the request of the controller 136. While in the preferred embodiment the detectors sample the effluents in the pipe connecting to a tank, the detectors can be placed inside a tank as well. The detector data is presented to a programmed logic controller 136. The controller can be implemented as a microprocessor or equivalent. The controller 136 evaluates the performance of the tanks 132, 134 based on the detector data. The controller uses this data to determine whether a change in the flow rate and in the flow pattern should be carried out. If this is the case, the controller sends signals to motor-driven valves 140 to adjust the flow rate. These valves can be controlled either simultaneously or individually. In cases where there are several entrances or several exits, it may be possible to control only a subset of these entrances or exits in order to avoid spills of any of the tanks. In addition to selectively controlling the flow rate, the controller 136 also controls the voltages applied by the various power bridges, which is generally illustrated by the number 142. In particular, the controller processes the sensor data and sends control signals to the energy sources to control in this way the voltages and / or currents applied to the deionization cells in the tank. The controller 136 employs the detector data to determine if the electrodes in the tank must be regenerated and, if appropriate, send the appropriate signals to the power sources to effect this. A compliance control system as described above can be useful for a large-scale deionization apparatus capable of handling flow rates of the order of several thousand gallons per hour. Thus, said apparatus can be increased to meet the deionization needs of industrial plants, wastewater treatment plants of cities, and the like. Experimental results have shown that the electrode dimensions and the number of electrodes can be increased linearly without significantly affecting neither the applied voltage nor the pulled current. It will be noted that the apparatus of the present invention does not perform, strictly speaking, a capacitive deionization insofar as non-HSAAM (non-absorption) electrodes never actually store a charge. In fact, the ions never settle on these electrodes, regardless of how these electrodes are charged; only the HSAAM electrodes trap and store ions. It will also be noted that the above preferred embodiments exhibit the formation and use of flat electrodes. However, electrode geometries and alternative deionization cells can also be used. An example of this type is a ring-shaped deionization cell comprising 1) an annular or solid internal non-HSAAM electrode, 2) a concentric annular HSAAM electrode with the internal non-HSAAM electrode, and 3) an external non-HSAAM electrode in ring shape, concentric with the first two electrodes. Such an arrangement would allow fluid flow between the ring-shaped HSAAM electrode and the two non-HSAAM electrodes. However, in such an arrangement, the internal and external non-HSAAM electrodes should have surface areas facing the different HSAAM electrode. Therefore, it may be necessary to use either different voltages or different currents between the two non-HSAAM electrodes and the HSAAM electrode sandwiched between the two. While the present invention has been presented with reference to certain preferred embodiments, these embodiments are not to be construed as limiting the present invention. One skilled in the art will readily observe that variations can be made to these modalities, each falling within the scope of the invention, in accordance with that indicated in the following claims. fifteen • twenty

Claims (5)

1. Claims 1. A non-sacrificial absorption electrode comprising: at least one of the group consisting of dihydroxybenzenes, trihydroxybenzenes, dihydroxynaphthalenes and trihydroxynaphthalenes; formaldehyde; a carbon reinforcing agent; a catalyst; or reaction products thereof, together in carbonized form, where said electrode has a thickness greater than 3 mm and the carbon reinforcing agent is substantially dispersed in said thickness. . The electrode according to claim 1, wherein: said element of the group consisting of dihydroxybenzenes, trihydroxybenzenes, dihydroxynaphthalenes and trihydroxynaphthalenes is resorcinose. . The electrode according to claim 2, wherein: said carbon reinforcing agent is at least one of the elements of the group consisting of carbon fiber, carbon felt and cellulose. . A liquid deionization apparatus comprising: a first tank member having at least one opening for the entrance of said liquid; a plurality of non-sacrificial absorption electrodes spaced apart from a first type placed in said first tank member, each of said electrodes of a first type having a pair of lateral surfaces facing in different directions; a plurality of non-sacrificial electrodes of a second type placed on both sides of said electrodes of a first type, said electrodes of a second type have a different composition than the electrodes of the first type; and a first voltage source arranged to apply a first differential voltage between the electrode material of a first type and a corresponding pair of electrodes of a second type in a side of said first electrode of a first type; wherein said electrodes of a first type comprise: at least one of the elements of the group consisting of dihydroxybenzenes, trihydroxybenzenes, dihydroxynaphthalenes and trihydroxynaphthalenes; formaldehyde; a carbon reinforcing agent; a catalyst; or reaction products thereof, together in a carbonized form, said electrodes of the first type have a thickness of at least 1 mm. The apparatus according to claim 4, wherein said electrode of a second type is one of the group consisting of carbon cloth, carbon felt, graphite, gold, platinum, conductive plastic and a glassy carbon. The apparatus according to claim 4, further comprising a mixing device placed in the tank and arranged to mix a liquid in the process of deionization in the tank. The apparatus according to claim 4, wherein the mixing device comprises an aerator positioned along an internal bottom surface of the tank, said aerator is arranged to introduce a gas into the liquid. The apparatus according to claim 4, wherein the electrodes of a first type are inclined at an angle relative to the electrodes of a second type, in the first tank member. The apparatus according to claim 4 wherein at least one electrode of a second type is fixed on each of the first and second opposing sides of a non-conductive, substantially planar structural support member, the electrode of the second type on the first side of said structural support member is electrically isolated from the electrode of the second type on the second side of said structural support member, and said structural support member with said electrodes of the second type mounted therein is placed between two electrodes of the first type. . The apparatus according to claim 9 further comprising a plurality of holes placed in a bottom member of the first tank member between said spaced electrodes of a first type and said holes having a size suitable to allow the removal of a solid lump , when the polarity of the first voltage differential is reversed. . The apparatus according to claim 10, which further comprises a first mixing device placed in the tank and arranged to mix a deionized liquid in the tank. . The apparatus according to claim 11, wherein the mixing device comprises an aerator positioned along an internal bottom surface of the tank, said aerator is arranged to introduce a gas into the liquid. A liquid deionization apparatus comprising: a first tank member having at least one opening for the entrance of said liquid;
2. a plurality of non-sacrificial absorption electrodes spaced apart from a first type placed in said first tank member, each of said electrodes of a first type having a pair of lateral surfaces facing in different directions; a plurality of non-sacrificial electrodes of a second type placed on both sides of each of said electrodes of a first type, said electrodes of a second type have a different composition than the electrodes of a first type; a first voltage source arranged to apply a first voltage differential between at least a first electrode of a first type and a corresponding pair of electrodes of a second type on both sides of said first electrode of a first type; and a second voltage source arranged to apply a second voltage differential between a second electrode of a first type, and a corresponding pair of electrodes of a second type placed on both sides of said second electrode of a first type, in the first member of tank. The apparatus according to claim 13, wherein the first voltage differential and the second voltage differential have different polarities. 15. The apparatus according to claim 13, further comprising a second tank member having an inlet connected to an outlet of said first tank member;
3. And a third voltage source arranged to provide a third voltage differential between at least a first electrode of a first type in the second tank, and a corresponding pair of electrodes of a second type on both sides of said first electrode of a first type , in the second tank member. . The apparatus according to claim 15, further comprising a fourth voltage source arranged to provide a fourth voltage differential between at least one second electrode of a first type in the second tank, and a corresponding pair of electrodes of a second type on both sides of said first electrode of a first type, in the second tank member. . The apparatus according to claim 16, wherein the first voltage differential and the second voltage differential have different polarities, and the third voltage differential and the fourth voltage differential have different polarities. The apparatus according to claim 16 further comprising a third tank member having an inlet connected to an outlet of the second tank member; and a fifth voltage source arranged to provide a fifth voltage differential between at least a first electrode of a first type in the third tank and a corresponding pair of electrodes of a second type on both sides of said first electrode of a first type, in the third tank. The apparatus according to claim 18, further comprising a sixth source of voltage arranged to provide a sixth differential voltage between at least a second electrode of a first type in the third tank, and a corresponding pair of electrodes of a second type on both sides of said first electrode of a first type, in the third tank member. 20. The apparatus according to claim 19, wherein the first differential voltage and second differential voltage have different polarities, the third differential voltage and the fourth differential voltage have different polarities, and the fifth voltage differential and the sixth Differential voltage have different polarities. 21. The apparatus according to claim 13 wherein at least one electrode of a second type is fixed on each of a first and second opposite side of a non-conductive, substantially planar structural support member, the electrode of the second type in the first side of said structural support member is electrically isolated from the electrode of the second type on the second side of said structural support member, and said structural support member with said electrodes of the second type mounted there is placed between two electrodes of the first type . The apparatus according to claim 21, wherein said electrodes of a first type comprise: at least one of the elements of the group consisting of dihydroxybenzenes, trihydroxybenzenes, dihydroxynaphthalenes and trihydroxynaphthalenes; formaldehyde; a carbon reinforcing agent; a catalyst; or reaction products thereof, together in a carbonized form, said electrodes of a first type have a thickness of at least 1 mm. The apparatus according to claim 22, wherein said electrode of a second type is an element of the group consisting of carbon cloth, carbon felt, graphite, gold, platinum, conductive plastic, and glassy carbon. The apparatus according to claim 13, comprising: at least one first detector arranged to measure a liquid property in the process of processing and to produce a first data signal corresponding to said property; and a controller receiving said first data signal and sending a first control signal in response to said first data signal, said first control signal adjusting at least one of said first voltage differential and said second voltage differential respectively applied by said first voltage source and said second voltage source. 25. The apparatus according to claim 24, further comprising a valve that controls a liquid flow rate in said first tank, wherein said controller sends a second control signal that adjusts a position of said valve in such a way that it affect said flow velocity. 6. A process for the formation of a non-sacrificial absorption electrode, reinforced with carbon, comprising: dissolving resorcinol in formaldehyde to form a liquor; combine the liquor with a carbon reinforcing agent to form a broth; heating the broth for a sufficient time and at a sufficient temperature until the broth has a consistency such that the carbon reinforcing agent no longer sits in the broth; empty the broth to a thickness of at least 3 mm; curing the broth for a sufficient time and at a sufficient temperature so that the broth solidifies; and firing the solid at a sufficient temperature and for a sufficient time such that the solid is carbonized in an electrically conductive plate. . The process according to claim 26, wherein the carbon reinforcing agent comprises carbon fibers, and the combining step comprises cutting the carbon fibers into smaller pieces. . The method according to claim 26, which comprises controlling the temperature of the broth within a range of 130 ° F - 150 ° F during the heating step. The process according to claim 26, wherein the broth is drained to a thickness comprised between 3 mm and 3/4".
4. 30. The process according to claim 26, wherein the broth is cured in air. 31. The process according to claim 26, comprising coloring a weight on the solid prior to firing the solid, to thereby avoid deformation of the resulting plate. 32. The process according to claim 26, wherein the solid is cooked in air at a temperature between 1750 and 2200 ° F. 33. The process according to claim 32, wherein the solid is cooked in air at a temperature comprised between 965 ° C and 975 ° C. 34. The method according to claim 26, which comprises the mechanical processing of the plate after firing of the solid, said mechanical processing including sanding or machining of the plate.
5. 5. A method for forming a non-sacrificial absorption electrode, reinforced with carbon, comprising: the introduction of a carbon mat having a matrix structure in a container; the dissolution of resorcinoi in formaldehyde to form a liquor; introducing said liquor into said container in such a manner that said liquor is substantially dispersed in said matrix structure, thus displacing the air present in said matrix structure; maintaining the matrix structure having liquor dispersed there at a sufficient temperature and for a sufficient time such that said matrix structure is cured in a xerogel block; and firing the block at a sufficient temperature and for a sufficient time such that the block is carbonized in an electrically conductive plate, where the carbon mat is sufficiently thick so that the block is carbonized in an electrically conductive plate having a thickness greater than 3 mm. . The process according to claim 35, wherein the carbon mat is one of the group consisting of carbon felt, plain cellulose fiber, and cellulose fiber impregnated with activated carbon. . The process according to claim 35, wherein the matrix structure having a liquor dispersed therein is maintained at a temperature of about 92 ° F. . The method according to claim 35, wherein the block is restrained with a weight before the cooking step. The process according to claim 35, wherein the block is fired at a temperature comprised within a range of 1850-2200 ° F. . The method according to claim 35, which comprises the mechanical processing of the plate after the block is cooked, said mechanical processing includes sanding or machining of the plate.