WO2011100804A1

WO2011100804A1 - A composition with adjustable characteristics

Info

Publication number: WO2011100804A1
Application number: PCT/AU2011/000178
Authority: WO
Inventors: Mark Andrew Stevens
Original assignee: Arctic Sunrise Pty Ltd
Priority date: 2010-02-19
Filing date: 2011-02-18
Publication date: 2011-08-25

Abstract

A composition with adjustable characteristics, the composition including charged coir fibre pith or dust charged with at least one material having desirable characteristics.

Description

A Composition with Adjustable Characteristics

Field of the Invention.

The present invention relates to a composition having adjustable characteristics.

Background Art.

The use of coir dusts as an absorber of spills of various types has been known for some time, although not widely used. In United States Patent No. 3,703,464, the use of coir dust or coconut short fibres is described as a satisfactory absorbent material for oil spills on water and on other surfaces. The widespread use of this material as a spill absorbent has been restricted to situations where exposure to high levels of heat or fire are not present since coir dust is capable of burning and is therefore regarded as a potential fire hazard.

It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Summary of the Invention.

The present invention is directed to a composition with adjustable characteristics, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

With the foregoing in view, the present invention in one form resides broadly in a composition with adjustable characteristics, the composition including charged coir fibre pith or dust charged with at least one material having desirable characteristics.

In an alternative form, the present invention resides in a settable composition including a settable component and coir fibres.

In a further form, the present invention resides in a settable composition with adjustable characteristics, the settable composition including a settable component, coir fibres and charged coir fibre pith or dust.

In a further form, the present invention resides in method for charging coir particles or fibres with at least one layer of material having desirable properties in order to provide the charged coir particles or fibres with the desirable property, the method including the step of absorbing or adsorbing at least one material into or onto coir particles or fibres.

In still a further embodiment, the present invention resides in a building product including coir pith at between 40-70% by weight and an organic binder.

According to this embodiment, the mixture is typically pressed into shape and cured. The duration of the pressing and curing will affect the properties, particularly the rigidity of the product once completed. The organic binder will typically be or include a urethane or other organic binder. Typically the range of coir pith is between 50-70% by weight.

In still a further embodiment, the present invention resides in a building product including coir pith at between 10-45% by weight and an inorganic binder.

Typically the range of coir pith is between 15 to 25% by weight. According to this embodiment, the coir pith mixture will be sandwiched between elongate boards. The product is typically pressed and cured, typically heat-cured if rapid curing is required or cured at ambient conditions if longer periods are available.

According to still a further embodiment, the present invention resides in a charged coir substrate material including coir pith or dust substrate charged with at least one material having desirable characteristics in order to provide the substrate with the desirable characteristics of the at least one material.

Typically the charged substrate can be used as a reactive, adsorbent, or absorbent substrate once charged. Providing the at least one material on or in the substrate may allow the at least one material to be more effectively dispersed, stored, transported or collected. The charged substrate may be provided with static rather than reactive properties once charged and may simply be used as a separating layer having desired properties in some circumstances, such as a thermally insulating or protection layer. The charged substrate is particularly well adapted to immobilization of material having properties that preferably react with the at least one material used to charge the substrate.

The method may include the steps of absorbing or adsorbing at least one layer of material having a desirable property into or onto coir particles or fibres and then absorbing or adsorbing at least one entrapping layer of an oil into or onto coir particles or fibres after the first layer.

Without wishing to be limited by theory, coir fibre pith or dust is produced from a coconut husk. It is typically a byproduct when the coconut husks are processed for the extraction of the long fibres. The pith or dust is a homogeneous material composed of a plurality of capillary micro-sponges making the pith or dust absorbent. It has been found that the pith or dust can absorb up to 8 times its own weight in water.

The pith or dust also normally has a pH of between 5.7 and 6.5 plus a surprisingly high cation exchange capacity. Therefore, whilst the pith or dust does absorb water, it is typically oleophilic. This results in a material which has exceptional qualities in absorbing liquids, particularly oils. These oil compounds are not readily released by the coir fibre pith or dust.

Where non-oil compounds are absorbed by coir fibre pith or dust, these compounds can be absorbed and released over extended periods.

Utilising the absorptive properties of the coir fibre pith or dust, the coir fibre pith or dust is preferably charged to provide the charged coir fibre pith or dust with particular properties. Coir fibres may be treated similarly.

According to the present invention, the coir fibre pith or dust may be charged with virtually any liquid, solution or suspension in order to provide the charged coir fibre pith or dust with the desired properties.

The coir fibre pith or dust can be charged in layers utilizing the oleophilic nature of the coir. For example, the coir fibre pith or dust can be charged with a fire retardant material first and then charged with an overlayer of an oil in order to prevent leaching or loss of the fire retardant material.

The charging will typically occur through absorption but adsorption may occur during the charging process with some materials.

Examples of materials that may be used to charge the coir fibre pith or dust ^■ include:

• Noflan is a chemical used in carpets and fabrics to assist with fire retardant properties, is a complex of the amide of alkylphosphonic acid ammonium salt with ammonium chloride.

• permithin (insect repellant).

• Acetic acid assists with the reduction of digestible properties of wood and results in the wood being more durable (acetylated woods).

• copper chromium arsenic.

• Starch.

• Resin.

. · Urea formaldehyde

• Urea melamine

• Phenol formaldehyde

• Ammonium Bromide • Urea Phosphate

• Hexamethylene

• Tetramine

• Wax

· Wetting agents

• Release agents

• borax

Any other material having desirable qualities, whether liquid or particulate, can be used as a charging material.

In addition, bacteria_, or other micro-organisms may be used as the charging material in order to provide the coir fibre pith or dust with particular properties, in particular, biodegradation of chemicals, particularly oils and the like.

Examples of oils that may be used to entrap one or more first layers of material include tung oil, linseed oil, sunflower oil, rapeseed oil. These oils are all natural oils arid therefore are biodegradable.

The coir fibre pith or dust can be charged with materials or chemicals required to break down oils, paints, hydrocarbons, chemical spills, or lubricants. Further, these materials themselves may be used as the charging material.

The charged coir fibre pith or dust can be used in wet or dry conditions, it can be added as a component to other materials or as a coating in order to impart the characteristics of the charged coir fibre pith or dust to the material.

Coir fibre pith or dust may have anti skid properties even when impregnated with material required to be absorbed and therefore may find application as an absorbent material for cleanup of spills or the like.

The preferential absorption of oils over water and other liquids makes the coir fibre pith or dust ideally suited for cleanup of water pollution, air pollution and waste pollution spills particularly waterborne spills.

Being absorbent or adsorbent, the coir fibre pith or dust is a dry cleaning method rather than a wet cleanup method.

The coir fibre pith or dust particles are typically small enough in order to be transported easily such as by fluidization using air and also means that they disperse easily into convoluted spaces. When coming into contact with the waste material, the pressed material can hold its shape and still absorb or can be manipulated into its original smaller type particles.

Coir fibre pith or dust, when charged with water or another liquid, typically swells. This property can be useful when the water-charged coir fibre pith or dust is added to a settable material such as concrete or porous plastic as the charging material can then be released after setting forming voids in the set material. This can reduce the weight of the set material and also can be used to increase strength.

The charged coir fibre pith or dust can be utilised in different forms for different purposes-.

The charged coir fibre pith or dust can be used in pillows for the bottom of drains and the like as water can pass through whilst other polluting materials such as paints oils and the like will not pass.

The charged coir fibre pith or dust can be used in carpets or in a mat configuration that is, the mat has the coir material coating the mat or fibres of the mat. This allows for easy application and disposal after the clean up has been completed by collection of the mat rather than requiring collection of the charged coir fibre pith or dust which has absorbed the spilt material.

The charged coir fibre pith or dust can be integrated into bunding (whether moveable or fixed) used to retain the spill or to prevent a spill from dispersing. This will be particularly useful for containing waterborne oil spills and the like..

Use of the charged coir fibre pith or dust or coir fibres in building materials will allow the building materials with the incorporated charged coir fibre pith or dust to provide particular advantageous properties such as fire resistance, insect or rot resistance and the like depending upon the particular charging material used.

The charged coir fibre pith or dust can be used as a coating and/or incorporation into a material to form a material having the advantageous properties of the charging materials.

When used as a building product, the present invention relates to two methods; the first for the manufacture of a pith board using an organic binder and the second for the manufacture of fire resistant building components (including fire doors, partition walls and others), using an inorganic fire resistant binder.

In fibre reinforced binder systems, the performance properties are dependent on the degree of compatibility between the chemistries of -the fibre material and the binder matrix. The hydroxyl rich surface of lignin in coir pith can serve as reactive sites for various functional groups; one of these is the isocyanate groups in urethane, an organic binder matrix. The reaction between hydroxyl and isocyanate groups not only can produce a strong polymer matrix but it also can increase the overall water resistant properties of the product. The hollow channel structure of coir pith ensures coir pith with urethane a dry and non-sticky mix (easier to handle) suitable for hot pressing. Added water is recommended to facilitate the reaction but the excess water can be squeezed out during the hot pressing stage. The stiffness of the product can be controlled by the applied pressure and/or changed by adding polyol to the mix which provides extra hydroxyl groups. The fire resistant properties can be increased by adding silica or alumina based compounds in small quantities. Unlike the commonly used formaldehyde based binders (e.g. chipboard production), urethane based binders do not produce formaldehyde in post production stage.

The second method of this invention is the use of an inorganic cementitious binder. Treatment of coir pith with highly alkaline solutions tends to increase the number of reactive sites of lignin. This makes the high alkali based alumino-silicate polymer binder (an inorganic binder matrix) an attractive and compatible matrix for coir pith based product development. The alumino-silicate polymer has extremely high fire resistant properties. The high alkaline nature of the binder changes the chemistry of lignin part of coir pith by increasing the number of reactive sites and hence making stronger bonding with the binder. The binder is premixed before coir pith is added. It is comprised of sodium and/or potassium silicate, sodium hydroxide, calcined clay and/or fly ash and alumina. The binder wrapped coir pith is then sandwiched between two magnesium oxide boards, pressed to the desired thickness and cured at 50 - 80°C for approximately 24 hours. Alternatively, the coir pith/binder mix can be extruded into a precast casing (e.g. fire door) and cured. Furthermore, the mix may be modified to suit other application methods such as spraying, rendering and coating to make other building components fire resistant. The claims are: whole product is durable, strong and fire resistant.

The preferred compositions of the two types of products are outlined below as a percentage range by weight, of the final product. Depending on the application of the final product, it is typically necessary to adjust/fine tune the composition. Also, when reinforcement (e.g. glass fibre or steel fibre) is added to the composition, the percentages shift slightly.

Urethane binder system (coir pith board) • Polyurethane 20 - 40 % (we have used moisture cured urethane at 30 % in the majority of the samples but you can use the range depending on the requirement)

• Coir pith 50 - 70 %

• Added water 25 - 35 %

· Polyol (optional) 10 - 15 %

• Glass fibre (chopped to 6 - 12 mm) 4 - 6 % (again this is also optional)

• Fire retardant 5 %

For this particular embodiment, pressing was maintained at 3 bar per square cm for 30 minutes at ambient conditions, but after pressing the boards were cured at 80°C for 4 hours. It is not necessary to press and/or cure for that period if a hot press process is used. It could likely be completed in under 10 minutes.

Silicate binder system (fire resistant building products^')

• Sodium hydroxide 3 - 4 %

• Sodium silicate up to 50 %

· Calcined clay 25 - 30 %

• Coir pith 15 - 25 %

• Fibre reinforcement 4 - 6 %

The proposed product has magnesium oxide boards, preferably 6 or 10 mm in thickness, sandwiching the coir pith mix.

As an extrudable mix, the composition has approximately 17 % coir pith, but depending on the manufacturing process and the final product type, this can be increased up to 25 or 30 %.

Casting pressure was similar to the above, but again this depends on the final product type. This binder system typically requires high temperature curing; for example at approximately 80°C for 24 hours or longer depending on the thickness of the material. However minimum curing (touch dry) would be necessary if the binder is enclosed and waterproofed. In the latter case, the material would be cured at ambient conditions over a long period of time.

In a further preferred embodiment, charged coir pith can be used to accomplish temporary sequestration that may be harmful to either humans or the environment and release when required of these materials, such as in a location where they can do less harm or where they may actually be useful. One example of this is sequestration of pollutants in a gaseous exhaust stream, such as from an exhaust stack from a coal-fired power station. The coir can preferably be charged with a suitable absorbent or reactant. An example of this is that caustic soda can be used to target removal of carbon dioxide.

The coir pith can then be soaked in a caustic soda solution, typically with the concentration of the solution to be decided depending on the conditions prevailing at the point of application. The solution could be either sodium hydroxide or calcium hydroxide (lime water) depending on the end application of the carbon dioxide absorbed coir pith.

For example, sodium hydroxide solution could be used when the coir pith with absorbed carbon dioxide is used to extract carbon dioxide in the gaseous state and use it in bio-oil projects. Lime water may be used when the carbon dioxide absorbed coir pith is intended for use as a fertiliser or a landfill.

Exhaust gases can then be passed through or past the charged coir pith which is saturated with the solution. The period of the exposure to the gases may be decided by measuring the alkalinity level of the coir pith, so that the solution is saturated with carbon dioxide. .

According to the above example, once the charged coir absorbs carbon dioxide, due to the preferred reaction between the carbon dioxide and the charging material, sodium bi-carbonate or calcium bi-carbonate is typically produced in the coir, dependent upon the type of solution that the coir was initially charged with. Both sodium bi-carbonate and calcium bi-carbonate are stable and un-harmful compounds. The carbon dioxide is therefore sequestered within or on the coir to form carbon dioxide absorbed coir pith.

Alternatively, the charged coir with the carbon dioxide sequestered product therein or thereon, can then be used transport the carbon dioxide absorbed coir pith to stock piles.

The carbon dioxide absorbed coir pith can then be used as required either to extract carbon dioxide again or to use it as a fertilizer, as an example. Coir pith with calcium bi-carbonate or calcium carbonate (similar to limestone) can be a good fertiliser.

Further, the carbon dioxide absorbed coir pith can be treated to liberate the carbon dioxide sequestered therein or thereon. For example, again using the example above, any carbonate will produce carbon dioxide gas when a dilute acid is added. For example, adding diluted hydrochloric acid to sodium carbonate solution will produce sodium chloride (normal salt) and carbon dioxide gas. The salt can be rinsed from the coir and the coir then re-used or simply used in compost as an example.

The carbon dioxide can be liberated in situ for example to enhance the algae growth in a cultivating pond. Since algae need sunlight, carbon-dioxide and water for their growth, they can be cultivated in open ponds & lakes.

Examples of reversible reactions which may be used include:

Lime Water Ca(OH)_{2 (eq)} + C0_{2 (g)}→ CaC0_{3 (s)} + H₂0 ¾

Sodium Hydroxide 2 NaOH + C0₂→ Na₂C0₃ + H₂0

Calcium Carbonate CaC0_3(s) + 2 HCl_(aq)→ CaCl_2(aq) + C0_2(g) + ¾(½

The coir can therefore be used as a temporary sequestering substrate for sequestering and/or subsequent liberation of materials.

In still a further embodiment, the coir pith can be used as a shelter for microorganisms to perform certain tasks. According to this embodiment, the coir pith will be initially charged with micro-organisms and or barely sufficient food for micro-organisms to live until they are exposed to a particular environment to carry out a task, typically for which the micro-organisms have been specifically chosen and are suited to.

The micro-organism with which the coir pith is initially charged or the food with which the coir pith is initially charged in order to attract the micro-organism will be chosen according to the task with different bacteria for different tasks. For example, researchers from the UCLA Henry Samueli School of Engineering and Applied Science have genetically modified a cyanobacterium to consume carbon dioxide and produce the liquid fuel isobutanol, which holds great potential as a gasoline alternative. The reaction is powered directly by energy from sunlight, through photosynthesis.

Similarly, there are different types of bacteria which can break down crude oil.

Some examples of bacteria are Pseudomonas oleovorans and Pseudomonas formicans.

Further once the micro organisms have carried out their specific task, the end or by product(s) being either a liquid, or solid can be housed within the coir pith for future use as they will typically be formed in situ within the coir pith.

Hence in this form, the charged coir pith is used as:

(a) A shelter for microorganisms to live in order carry out specified tasks; and/or

(b) A micro container to store food for micro-organisms to survive for a given period of time; and/or

(c) A micro-container to store the bi-products under atmospheric conditions resulting from the bacterial degradation. These bi-products can be then transported to suitable locations without any difficulty.

The pre-treated coir pith may also find application applied directly on an open wound as a medical application. This is immediately the wound occurs not as a post treatment application -this is more suited to swabs or bandages.

The coir pith "bandage" can deliver, consume and at the same time exchange; deliver- accelerated congealing agents, anti fungal/ antiseptic and sterilising - in soluble or powder form; consume- blood and other foreign particles surrounding the wound; and exchange by design. With direct application this would maximise the exchange procedure.

In a medical swab or bandage it is still possible, although the barrier is created by the packaging ie the sandwich material used to deliver and contain the coir pith. The coir pith will lose some of its ability to consume unwanted foreign substances in the open wound. The exchange rate will be minimised by the packaging barrier.

Coir pith can also be compressed into small light weight parcels that expand when required for use giving added advantage for field injuries ie military, backpackers, sporting etc

The coir pith "bandage" is typically suitable to both animals and humans. It can be pre charged with antibiotics disinfectants sterilizers and or skin moisturisers. As the wound weeps or bleeds the introduced materials are preferably released.

The coir pith "bandage" can be applied directly to open wounds so as to accelerate congealing and prevention of blood flow whilst cleansing and cleaning the wound. It may then stay in place as a barrier until natural skin replacement occurs.

The coir pith "bandage" by design allows for air to pass easily onto the wound. It can also be impregnated or encapsulated in a bandage or large swab and applied to the wound. This allows for a barrier between the raw material and the injury. Also assists with easy and quick application and removal of the bandage.

Coir pith will typically require pre washing/ sterilising and drying prior to use so as to remove tannins, phenols and other impurities. Coir pith may also assist with the removal of puss and secretions from infected wounds In one preferred form, it is also suited to early treatment of burns and similar injuries.

Drawings

Figure 1 is a schematic illustration of the major steps of C0₂ sequestration from coal plants and its refuse in the culture of algae from biofuel production. Figure 2 is a histogram illustrating the change in chemical composition as a percentage (Yabulu W.aste Water as 100%) for all the targeted chemical constituents.

Figure 3 is a histogram illustrating the change in chemical composition as a percentage (Yabulu Waste Water as 100%) for Nickel, Cobalt and Ammonia. As the amount of coir pith is increased from lOOg to 500g, the levels of all three constituents decreased with no significant difference between 1 hour and 24 hours contact times.

Detailed Description of the Preferred Embodiment.

According to a first preferred embodiment of the present invention, a composition with adjustable characteristics is provided.

According to the first preferred embodiment, the composition includes charged coir fibre pith or dust, charged with at least one material having desirable characteristics.

Coconut coir pith is a residual byproduct produced from making coconut fiber ropes and mattresses. Coconut coir pith is a portion of the coconut husk that falls as a residual powder when coconut husk fibers are crushed in the manufacture of ropes and other products.

Coconut coir pith is entirely nontoxic. It is light in weight and creates very little dust even when thrown a considerable distance. Furthermore, coconut coir pith has an additional advantage in that it retains its consistency, even when spread on water and/or saturated with oil. That is, it will not turn to "mush" even when wet and saturated. This feature allows the oil-saturated coconut coir pith to be scooped or raked from the surface of a body of water without great difficulty.

A further advantageous feature of the invention is that a very substantial portion of the charging liquid can be extracted from the coconut coir pith once the coconut coir pith has been removed from the site of use, if required.

Therefore, the coconut coir pith can be used to clean up spills of oil. The coconut coir pith can be dispersed over the spill area, and it absorbs the oil. The coconut coir pith can then be collected, and in order to extract the oil, the saturated coconut coir pith is pressed or squeezed by rollers or by a press. As the oil is squeezed out of the coconut coir pith, it can be filtered and collected in a receptacle. It is possible to recover between about seventy-five percent and about ninety percent of the oil absorbed by the coconut coir pith in this manner.

The coconut coir pith is usually charged using a liquid, normally by partial or total immersion but other mechanisms such as spraying may be used. The liquid either is or contains an active ingredient that has a required effect such as fire retardation, insecticidal effects or waterproofing to name a few. By charging the coconut coir pith, the charged coconut coir pith then also has the required effect of the active ingredient and is in a temporarily stable and highly transportable form.

According to a second preferred embodiment, a settable composition including coir fibres is provided.

According to this embodiment, coir fibres are included in a settable material such as concrete or the like. The fibres increase the strength of the concrete once set by forming an irregular network within the set concrete.

The concrete can be further adjusted through the addition of charged coconut coir pith as described above.

The present invention is also suitable for use as an absorbent.

Example 1.

A pilot study was carried out to establish the waste absorbent capacity of coir pith with special emphasis on the major constituents found in the waste water from a tailing dam of a nickel refinery. The waste water was treated with three different ratios of coir pith and two different contact times with coir pith, and then filtered before analysing for the targeted ions, namely nickel (Ni), cobalt (Co), magnesium (Mg), manganese (Mn), iron (Fe), silicate (Si04), sulphate (S04) and ammonia/ammonium (NH4). The pH and the electrical conductivity (EC) were also measured. The test samples were sent to an independent NATA accredited laboratory where the chemical analyses were- performed under a quality system certified as complying with ISO 9001 :2000. There were no appreciable changes to the pH and EC following the treatment with coir pith. However, there were significant reductions in the Ni and Co levels. The nickel levels were down to 12.5% and the cobalt levels were down to 36%, of the control (waste water) after the treatment. Ammonia levels were down by a third. There was no significant change in the sulphate levels, possibly due to pH of the water. There is not much difference between 1 and 24 hours contact time between the waste water and coir pith. The preliminary results strongly indicate that coir pith can effectively be employed to clean up nickel and cobalt ions present in the waste water from the tailing dams. Although there were no changes to the levels of other ions present, it is possible to modify or charge coir pith to target those specific ions.

Based on the available information, the efficacy in the use of coir pith and/or its derived products for the cleaning up of waste water is established.

Methodology The waste water sample from the third tailing dam of Yabulu Refinery (QNL) was clear and had no residues. Therefore, the waste water was directly used for the trial. The coir pith used in this study contained about 25% moisture. In the trial, three different quantities of coir pith were employed (lOOg, 250g or 500g). The coir pith was added to one litre (lOOOg) of waste water and left for either 1 or 24 hours before filtering three times with different grade filter papers, to remove any suspended materials. The filtrate was immediately tested for the pH and electrical conductivity. A control sample was run with tap water and 250g of coir pith. The water samples were then sent to an NATA accredited laboratory where the chemical analyses were performed under a quality system certified as complying with ISO 9001:2000. The ions analysed were nickel, cobalt, magnesium, manganese, iron, silicate, sulphate and ammonia/ammonium which were found to be predominant in the waste water according to the documents received from QNL. The trial was conducted in duplicate and the results were pooled to obtain the average value for each ion.

Results and Interpretation

The preliminary investigation showed that there are no significant changes- to pH and EC measurements in the waste water following the treatment with coir pith. The pH ranged from 4.6 to 5.1 but there was no trend. The pH was not expected to change much. Meanwhile, the EC decreased only slightly. The results are not surprising given the production process of coir pith: i.e. prior to the extraction of coir, the coconut husks are generally submerged in salty or brackish water for several months and therefore, coir pith contains some salts which contribute to high EC. If washed coir pith had been used for the trial, the EC would probably be less compared with the waste water.

The results of the chemical analysis are given in the Table 1. Of the eight targeted constituents of Yabulu waste water (YWW), only nickel, cobalt and ammonium ions showed a significant trend following the coir pith treatment. The nickel levels were dropped to 12.6% after 24 hours in contact with 500g coir pith (1 litre of YWW). The nickel level after 1 hour contact period was 14.4%. The cobalt levels for the corresponding periods were dropped to 36.4% and 38.6% respectively. The ammonium levels were 63.8% and 65.3%. These results clearly show that raw coir pith without any modification can remove nickel, cobalt and ammonium ions from the waste water very effectively. The effective contact time is one hour or less.

The chemical analysis did not show any definitive trend with other constituents. The data suggest that some of the magnesium ions have been removed by the coir pith. However, the level of Mg was not very high in the YWW; only few parts per million. The water sample from the third tailing dam contained low levels of waste ions with the exception of nickel, cobalt and ammonia. The results are presented below in Table 1 and as histograms in Figures 2 and 3.

Table 1 The change in chemical composition as a percentage (Inlet Waste Water as 100%)

The results clearly are in line with the research reported from a number of groups around the world. Extensive research has been carried out to study the efficacy of coir pith to remove chromium (Cr) from waste water. According to many reports, coir pith can absorb up to 90% of Cr, which can be further improved to the maximum (100%) at low pH. In this pilot study, we did not change the pH, but by doing so using some additives to the coir pith or the waste water one can target complete removal of cobalt and nickel. By altering the pH of the adsorption mixture, it is also possible to make coir pith a preferential adsorbent for the anionic species including sulphates. The natural pH of coir pith is around 5.0 and this can easily be modified (chemical activation) to suit the target ion. If a range of ions (both cationic and anionic) are to be removed, then different batches of coir pith at different pH levels must be used. This would not be a very difficult task at Yabulu refinery since there are several tailing dams which can be isolated to employ different agents in succession. The contact time between the coir pith and waste water also plays a crucial factor in determining the adsorption of ions. Some studies have reported that maximum adsorption of ions can be achieved within 30 minutes. Constant stirring or agitation may also improve the adsorption rate. Another factor that governs the adsorption capacity of the coir pith is the temperature. Sodium hydroxide can increase metal binding sites of modified coir pith. The mechanism of nickel adsorption by coir pith has been confirmed by elution with sulphuric acid, revealing that it was controlled by chemisorption. The evidence showed that lignin and holo-cellulose were the main components in coir pith that played a major role in nickel adsorption. The other important information that is highlighted in this pilot study is that the ratio of coir pith to water^' for the maximum effectiveness. The greatest adsorption was with the highest coir pith:water ratio, i.e. 500g coir pith: 1 litre of waste water. To maximise the adsorption one can use even a higher ratio. Furthermore it is important to note that moistened (-25%) coir pith was used in this pilot study to obtain valid comparative results. In real life, however, fully dried coir pith can be used in the tailing dams, and in that situation the required ratio of coir pith to liquid may be less.

Activated or active carbon, also called activated charcoal or activated coal is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions. Activated carbon has high degree of microporosity, e.g. 1 gram of activated carbon has a surface area in excess of 500 m2 (about one tenth the size of a football field), as determined typically by nitrogen gas adsorption. Sufficient activation for useful applications may come solely from the high surface area, though further chemical treatment often enhances the absorbing properties of the material. Activated carbon is usually derived from carbonaceous source materials like nutshells, peat, wood, coir, coir pith, lignite, coal and petroleum pitch. Out of these, coir pith is a competitive source material since it is cheap, renewable and a waste by-product.

There are two broad methods to produce activated carbon. The first method is the physical reactivation. The precursor is developed into activated carbons using gases. This is generally done by using one or a combination of the carbonisation, activation and oxidation. The second method is called chemical activation: Prior to carbonization, the raw material is impregnated with certain chemicals. The chemical is typically an acid, strong base, or a salt. Then, the raw material is carbonized at lower temperatures (450-900 °C). The carbonization/activation step proceeds simultaneously with the chemical activation. Chemical activation is preferred over physical activation owing to the lower temperatures and shorter time needed for activating material.

Activated carbon sourced from coir pith has been investigated in detail by several research groups around the world and has proven to be very effective in the removal from aquatic systems, of a wide variety of waste ions including arsenic, cadmium, cobalt, copper, mercury, molybdate and nickel. The adsorbed ions can also be later recovered by chemical desorption.

The use of coir pith-based biosorbents for removing various pollutants from water and wastewater offers many attractive features such as the outstanding adsorption capacity for many pollutants and the fact that these materials are low-cost, non-toxic and biocompatible. Although the amount of available literature for the application of coconut based biosorbents in water and wastewater treatment is increasing at a tremendous pace, there are still several gaps which need more attention, such as enhancement of biosorption capacity through modification of biosorbent, assessment of biosorbents under multicomponent pollutants, investigation of these materials with real industrial effluents, recovery of metal ions, regeneration studies, and continuous flow studies.

It is important to note that further investigations on the practical utility on medium scale and commercial scale are necessary to establish the best practice guidelines for the use. of coir pith in the management of waste in the tailing dams. In addition, the potential of prepared coir pith-based biosorbents should also be compared with commercially available activated carbon from other sources to know the efficacy of prepared biosorbents. Therefore,, it is recommended that a further comprehensive study be undertaken to define the parameters and conditions for the efficient use of coir pith and its derivatives at the Refinery. The next stages of that R&D exercise should address the following:

Laboratory scale:

1. Quantitative analysis on the ratios of coir pith to waste water and the contact time

2. Effectiveness of changing pH on the adsorption of targeted ions

3. Efficiency of charged and non-charged coir pith on adsorption capacity

4. Impact of agitation/stirring of the waste water after the coir pith treatment

5. Comparison of raw coir pith and activated coir pith carbon on waste absorption

6. Desorption and recovery of useful ion species from activated carbon

Small industrial scale:

1. Methodologies to introduce coir pith to, and its removal from the tailing dams ·

2. Logistics and infrastructure needed for the new technology

3. Monitoring of waste removal by coir pith and its derivatives

4! Disposal strategies of used coir pith and its derivatives

5. Cost-benefit analysis of the use of coir pith and its derivatives with other comparable materials and also with alternative & existing technologies .

In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

Claims

The Claims defining the invention are as follows:

1. A composition with adjustable characteristics, the composition including charged coir fibre pith or dust charged with at least one material having desirable characteristics.

2. A settable composition including a settable component and coir fibres.

3. A settable composition with adjustable characteristics, the settable composition including a settable component, coir fibres and charged coir fibre pith or dust.

4. A method for charging coir particles or fibres with at least one layer of material having desirable properties in order to provide the charged coir particles or fibres with the desirable property, the method including the step of absorbing or adsorbing at least one material into or onto coir particles or fibres.

5. A method for charging coir particles or fibres as claimed in claim 4 wherein including the step of absorbing or adsorbing at least one layer of material having a desirable property into or onto coir particles or fibres and then absorbing or adsorbing at least one entrapping layer of an oil into or onto coir particles or fibres after the first layer.

6. A building product including a mixture of coir pith at between 40-70% by weight and an organic binder.

7. A building product as claimed in claim 6 wherein the mixture is pressed into shape and cured.

8. A building product as claimed in claim 6 or claim 7 wherein a urethane binder matrix is used.

9. A building product as claimed in claim 8 wherein the product properties are controlled by applied pressure and/or changed by adding polyol to the mix which provides extra hydroxyl groups.

10. A building product as claimed in claim 6 or claim 7 wherein the duration of the pressing and curing is used to adjust the properties of the product, particularly the rigidity of the product once completed.

11. A building product including a mixture of coir pith at between 10-45%) by weight and an inorganic binder.

12. A building product as claimed in claim 11 wherein the coir pith mixture is sandwiched between elongate boards.

13. A building product as claimed in claim 11 or claim 12 wherein the coir pith is treated with highly alkaline solutions to increase the number of reactive sites of lignin.

14. A building product as claimed in any one of claims 11 to 13 wherein binder wrapped coir pith is sandwiched between magnesium oxide boards, pressed to the desired thickness and cured at 50 - 80°C for approximately 24 hours.

15. A building product as claimed in any one of claims 11 to 13 wherein the coir pith/binder mix can be extruded into a precast casing and cured.

16. A charged coir substrate material including coir pith or dust substrate charged with at least one material having desirable characteristics in order to provide the substrate with the desirable characteristics of the at least one material.

17. A charged coir substrate material as claimed in claim 11 wherein the charged substrate is provided with static properties or reactive properties once charged.

18. A charged coir substrate material as claimed in claim 11 or claim 12 wherein the coir fibre pith or dust is charged with any liquid, solution, suspension, particulate or biological material in order to provide the charged coir fibre pith or dust with the desired properties.

19. A charged coir substrate material as claimed in any one of claims 11 to 13 wherein multiple charging materials are used to provide the charged coir with different properties dependent upon the properties of the charging material.

20. A charged coir substrate material as claimed in claim 14 wherein the different charging materials are provided in layers.