Field

[0001 The invention relates to a sorbent material, process for making the sorbent material and method of using the sorbent material.

Priority claim

[0002] The present application claims priority from Australian Provisional Patent Application No. 2012904518, the entire contents of which are incorporated herein by cross-reference.

Background

[0003] Water plays a major role in commercial laundry operations and consumed in large quantities for linen cleaning processes. In a typical laundry operation, water use ranges between 9 to 15 L per kg of linen processed. The discharge rate ranges anywhere from 200 to 300 m ³ of wastewater per day. Treating this volume of wastewater is particularly difficult due to high loading of organic and inorganic compounds combined with soil that has been washed out in the process. The wastewater from a laundry operation which processes heavily soiled linen contains contaminants such as oils, heavy metals and organic compounds that have high chemical oxygen demands.

[0004] Several methods or pre-treatment are currently being used to treat commercial laundry wastewater before it reaches permissible discharge levels. The complexity of the treatment differs from place to place, size of operation, volume of water and type of chemical products in the commercial laundry operation. Simple pre-treatments like coagulation, flocculation and flotation systems have been found to be insufficient for the treatment of highly complicated commercial laundry effluents. This type of pre-treatment may end up commercial laundries releasing exceeding levels of dissolved solids, suspended solids, organics and inorganics which eventually end up in municipal wastewater treatment systems. Globally, there have been increasingly stringent rules and regulations in place to address the water treatment options in commercial laundry and similar operations. [0005] There is a need for an efficient sorbent system for treating wastewaters such as commercial laundry wastewater.

Summary of Invention

[0006] In a first aspect of the invention there is provided a process for preparing a sorbent material, said process comprising: a) combining a particulate siliceous material with a strong acid to form a mixture; b) adjusting the mixture to a pH of between about 3 and about 6; c) separating an acidified solid from the mixture; and d) treating the acidified solid with a treating agent so as to produce the sorbent. The treating agent may be an organic amine or

organoammonium salt. [0007] The following options may be used in conjunction with the first aspect, either individually or in any suitable combination.

[0008] The particulate siliceous material may comprise diatomaceous earth. It may comprise a non-swelling clay. It may comprise both of these.

[0009] The strong acid may be aqua regia. It may be in aqueous solution. It may be at a concentration of about 0.1 to about 1M.

[00010] The process may additionally comprise step a') allowing the mixture to stand for between about 1 and about 5 hours. This may be conducted between steps a) and b).

[0001 1] The process may additionally comprise step c') drying the acidified solid. This may be conducted between steps c) and d). This step may comprise passing a gas through the acidified solid, while said acidified solid is disposed on a mesh. Prior to step c'), the acidified solid may be washed, e.g. with water or with some other washing liquid. This may comprise passing the water or other washing liquid through the acidified solid (e.g. through a bed of the acidified solid) or it may comprise agitating the acidified solid in the water (or other washing liquid) and then at least partially separating the washed acidified solid from the water or other washing liquid. [00012] The treating agent may be a monoalkylamme. It may be a C8 to CI 8 monoalkylamine. It may be a tetraalkylammonium salt. The tetraalkylammonium salt may be a C8 to C 18 alkyltrimethylammonium salt.

[00013] Step d) may comprise soaking the acidified solid in a solution of the treating agent. The solution of the treating agent may be an alcoholic solution.

[00014] The process may comprise step d') at least partially separating the sorbent from the treating agent following step d). It may comprise step d") drying the sorbent. The step of drying may be conducted after step d). If step d') is conducted, step d") may be conducted after step d'). The drying may be to a residual moisture level of less than about 15% w/w, or less than about 14, 13, 12, 1 1 or 10%.

[00015] The acidified solid obtained in step c) may itself be used as a sorbent. The options discussed above may equally applied to this material where appropriate. Thus, for example the acidified solid from step c) may be dried. It may be washed prior to said drying. The acidified solid may be used as a sorbent in conjunction with, or independently from, the sorbent obtained by step d) described above.

[00016] In an embodiment there is provided a process for preparing a sorbent material, said process comprising: a) combining a particulate siliceous material with a strong acid to form a mixture; b) adjusting the mixture to a pH of between about 3 and about 6; c) separating an acidified solid from the mixture; c') washing the acidified solid with water and optionally drying the washed acidified solid; and d) treating the washed acidified solid with an organic amine or organoammonium salt so as to produce the sorbent.

[00017] The invention also encompasses a sorbent made by the process of the first aspect.

[00018] In a second aspect of the invention there is provided a sorbent comprising a particulate siliceous substance having ammonium groups on the surface thereof.

[00019] The ammonium groups may comprise a C8 to CI 8 alkyl group. The ammonium groups may be primary, or may be secondary, or may be tertiary or may be quaternary. [00020] The sorbent of the second aspect may be made by the process of the first aspect. The process of the first aspect may produce the sorbent of the second aspect.

[00021 ] The sorbent of the second aspect, or the sorbent made by the process of the first aspect, may be porous. It may have a mean particle size of about 1 to about 5mm. It may have a mean pore size of about 0.2 to about 50 microns.

[00022] In a third aspect of the invention there is provided use of a sorbent according to the second aspect, or of a sorbent made by the process of the first aspect, for removing at least one of dissolved solids, suspended solids, organic contaminants and inorganic contaminants from a liquid.

[00023] The liquid may be an effluent liquid. It may be an effluent from a laundry or a car wash.

[00024] In a fourth aspect of a the invention, there is provided a method for removing at least a portion of a contaminant from a liquid, said method comprising exposing said liquid containing the contaminant to a sorbent according to the second aspect, or to a sorbent made by the process of the first aspect.

[00025] The step of exposing may comprise suspending the sorbent in the liquid comprising the contaminant. It may comprise passing the liquid comprising the contaminant through a bed of the sorbent. It may additionally comprise separating the sorbent from the liquid.

[00026] The method may remove at least about 90% of the contaminant.

[00027] The liquid may be an effluent liquid. It may be an effluent from a laundry or a car wash.

Brief Description of Drawings

[00028] Figure 1 is a bar graph showing removal of inorganic contaminants in commercial laundry wastewater.

[00029] Figure 2 is a bar graph showing removal of TSS (total suspended solids) and organic contaminants in commercial laundry wastewater. [00030] Figure 3 is a bar graph showing removal of inorganic contaminants in car wash wastewater.

[00031] Figure 4 is a bar graph showing removal of TSS and organic contaminants in car wash wastewater.

[00032] Figure 5 is a bar graph showing removal of organic contaminants in wastewater by the sorbent of the present invention.

Description of Embodiments

[00033] The invention relates to a process for preparing a sorbent material. In this process a particulate siliceous material is combined with a strong acid to form a mixture. The mixture is then adjusted to a pH of between about 3 and about 6, An acidified solid is then separated from the mixture and treated with a treating agent so as to produce the sorbent. The treating agent may be an organic amine or organoammonium salt. It will be understood that the acidified solid separated from the mixture is the solid material obtained from the particulate siliceous material by the acidification and pH adjustment steps. This acidified solid may be used as a sorbent without treatment with the treating agent.

[00034] The particulate siliceous material may be purely siliceous or may be a mixture of a siliceous material with some other material, e.g. with a non-siliceous material. In this context, "siliceous" refers to a substance that contains silica. It may consist essentially of silica. It may comprise a mixed oxide of silicon and another element, e.g. aluminium. The siliceous material, or at least some portion thereof, may be porous, or it may be non-porous. A suitable siliceous material, or a suitable component thereof, is diatomaceous earth (DE), otherwise known as diatomite or kieselguhr. This material is the remains of diatoms and is highly porous. It commonly has a particle size of below 1 micron to more than 1 millimeter, generally about 10 to 200 microns. It comprises about 80 to 90% silica, together with about 2 to 4% and small amounts of 0.5 to 2% iron oxide. It is well known as a filter aid. The particulate siliceous material, and independently the sorbent material made therefrom, may have a mean pore size (diameter) of about 0.2 to about 50 microns, or about 0.5 to 50, 1 to 50, 5 to 50, 10 to 50, 0.2 to 20, 0.2 to 10, 0.2 to 2, 0.2 to 1 , 0.5 to 20, 1 to 20, 10 to 20, 0.5 to 5, 0.5 to 1 , 1 to 5 or 5 to 10 microns, e.g. about 0.2, 0.3, 0.4, 0.5, 1, 2,.3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 microns, or may have some other mean pore size.

[00035] Other components of the particulate siliceous material may include non-swelling clays such as smectite, kaolinite, montmorillonite, attapulgite, bentonite and dolomite. Mixtures of DE and clays, e.g. kaolinitic clays, are useful as the siliceous material of the present invention. The proportion of DE in such mixtures may be between about 5 and about 50% w/w, or about 5 to 25, 5 to 10, 10 to 50, 25 to 50 or 10 to 30%, e.g. about 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50%, on a w/w basis.

[00036] The siliceous material is treated with a strong acid. In this context, a "strong" acid is an acid with a low pH. It may have a pKa less than about 0, or less than about -1, -2, -3, -4 or -5. The strong acid may be a strong mineral acid. It may for example comprise nitric acid, hydrochloric acid, sulfuric acid, hydrobromic acid or a mixture of any two or more of these. A suitable strong acid is aqua regia, which is a mixture of hydrochloric acid and nitric acid. The percentage (w/w or v/v) of nitric acid in the mixture may be about 10 to about 50%, or about 10 to 25, 25 to 50 or 20 to 30%, e.g. about 10, 15, 20, 25, 30, 35, 40, 45 or 50%. In this context, the percentage of nitric acid should be taken as the percentage of concentrated nitric acid (i.e. 15N nitric acid) in a mixture of concentrated nitric and concentrated hydrochloric (i.e.10N) acids. It will be clear from this specification that this mixture of concentrated acids may be diluted with water. The final strong acid may be prepared by mixing the two concentrated acids and diluting the resulting mixture with water, or may be made by mixing the two acids in less than concentrated form in a ratio such that the resulting mixture could have been obtained by diluting a mixture (in the desired ratio) of the two acids in concentrated form, or it may be made by mixing one of the acids in concentrated form with the other in less than concentrated form in a ratio such that the resulting mixture could have been obtained by diluting a mixture (in the desired ratio) of the two acids in concentrated form. The strong acid may be about 0.2 to about 2N, or about 0.2 to 1, 0.2 to 0.5, 0.5 to 2, 1 to 2 or 0.5 to IN, e.g. about 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 , 1.2, 1.4, 1.6, 1.8 or 2N, or may be some other concentration. In the case where two different acids are used, the total concentration of the two acids may be as described above. The strong acid may have a pH of less than 1 or less than 0 or about 0 to about 1 , or about 0 to 0.5 or 0.5 to 1 , e.g. about 0, 0.1 , 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1. [00037] The step of combining the particulate siliceous material with the acid may comprise mixing the material with the acid. It may comprise suspending the material in the acid. It may comprise forming a paste or a slurry of the material in the acid. It may comprise passing the acid through a bed of the material. The particulate siliceous material may be exposed to the acid for about 1 to about 5 hours, or about 1 to 3, 3 to 5 or 2 to 4 hours, e.g. about 1 , 2, 3, or 5 hours. These times are suitable for treatment of the material at room temperature, which is commonly the treatment temperature. However if higher temperatures are used, shorter treatment times may be used. Temperatures of up to about 60°C may be used, or between about 10 and 60°C, or about 10 to 50, 10 to 40, 10 to 30, 20 to 60, 30 to 60, 40 to 60, 20 to 40 or 15 to 30°C, e.g. about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 to 60°C. The combining of the particulate siliceous material and the acid may give rise to an exothermic reaction. This may cause the reaction of the resulting mixture to rise spontaneously. The reaction of the siliceous material with the acid may be conducted at least partially at elevated temperature, for example the temperatures described above. The reaction may be conducted in the absence of externally applied heating or may be conducted with external heating. If the temperature is allowed to rise spontaneously, it may subsequently cool naturally, for example to around ambient temperature or only slightly above. This cooling may take for example about 10 to about 30 minutes or more, depending in part on the nature of the siliceous material and of the acid, the volume of the mixture, the nature and dimensions of the container for the mixture etc. The ratio of particulate siliceous material to strong acid may be about 1 :1 to about 1 : 10, at times more than 1 : 10 on a w/w or w/v basis. It may be about 1 :1 to 1 :5, 1 :5 to 1 :10, 1 :3 to 1 :8 or 1 :5 to 1 :7, e.g. about 1 : 1 , 1 :2, 1 :3, 1 :4, 1 :5, 1 :6, 1 :7, 1 :8, 1 :9 or 1 : 10.

[00038] Without wishing to be bound by theory, the inventor considers that the acid treatment step described herein may serve to provide a suitable pore size for the particles. It is also thought that by selecting a suitable concentration of acid in this step, particular elements may be selectively removed from the substrate.

[00039] After treatment with the acid, as described above, the mixture is then adjusted to a pH of about 3 to about 6. It may be adjusted to a pH of about 3 to 5, 3 to 4, 4 to 6, 5 to 6 or 4 to 5, e.g. about 3, 3.5, 4, 4.5, 5, 5.5 or 6. It may be adjusted by addition of a base until the desired pH is achieved or it may be adjusted by addition of a suitable buffer which buffers in the desired range. Suitable bases include hydroxide salts such as sodium hydroxide, potassium hydroxide (either in solution, commonly aqueous, or as solids), ammonia solution, solid hydroxides (e.g. calcium or magnesium hydroxide), solid oxides (e.g. calcium or magnesium oxide) etc. Suitable buffers include phthalate or phosphate based buffer solutions.

[00040] The solid material in the resulting mixture is then separated. This may be by any suitable method for doing so, for example filtration, evaporation, centrifugation, settling, decanting or any combination of these. The separating may be complete separating or may be incomplete separating. In the latter case, a certain amount of the liquid may remain on the solid material. Thus the solid material may for example remain moist with the liquid, or may retain some of the liquid in pores, or it may be substantially dry. In a suitable example, the mixture is applied to a mesh of suitable mesh size to retain the solid material. The liquid then drains through the mesh, leaving the separated solid. Air may be drawn through the mesh, and hence through the retained solid. This may serve to remove further liquid from the retained solid, by facilitating draining and/or by evaporation. If desired, the resulting solid may be further dried by application of a vacuum or partial vacuum thereto. The mesh may be a sieve of US sieve size about 16 to 30, e.g. 16, 18, 20, 25 or 30, which corresponds to Tyler equivalent of about 14 to 28, e.g. 14, 16, 20, 24 or 28 (corresponding to an opening in the mesh of between about 1.1 to 0.595 mm, ^' e.g. 1.19, 1.00, 0.841 , 0.707 or 0.595mm). The acidified solid obtained as described above may be washed. Suitable washing liquids include water or aqueous solutions, although water miscible organic solvents such as lower alcohols, acetone etc., optionally mixed with water, may also be used. The washing may comprise suspending, optionally agitating, the acidified solid, in the washing liquid or it may comprise passing the washing liquid through the acidified solid, optionally through a packed bed of the acidified solid. The washed acidified solid may be dried using any suitable method, for example those described above.

[00041 ] The resulting solid may then be treated with a treating agent in order to modify the surface thereof. Suitable treating agents may be basic, or may be the salts of a basic material, so as to allow an interaction with the acidic surface of the solid. These are commonly amines, which are thought to form ammonium ions on the surface of the solid, however ammonium salts may also be used. The amine may be a mono-, di- or a tri-alkylamine. The ammonium salt may be a mono-, di-, tri- or tetra-alkylammonium salt. The amines, or ammonium salts, commonly comprise at least one long chain alkyl group. Without wishing to be bound by theory, is thought that this provides a hydrophobic locus to facilitate adsorption onto the surface of the solid of hydrophobic contaminants from waste water to be treated. The long chain alkyl group (or groups, independently) may be a C8 to CI 8 alkyl group..It may be linear, or may be branched. In some cases it may be substituted, e.g. by one or more aryl (e.g. phenyl or alkylphenyl) groups. The alkyl group may be C8 to C18, or may be C8 to C16, C18 to C14, CIO to C18, C12 to C18, C14 to C18, CIO to C18 or C12 to C18, e.g. C8, C9, CIO, CI 1 , C12, C13, C14, C15, C 16, CI 7 or CI 8. In some cases the alkyl group contains a distribution of numbers of carbon atoms (from one molecule to others), so that the above numbers may be the predominant number of carbon atoms or the average number of carbon atoms. The remaining groups on the nitrogen atom of the amine or ammonium salt may be short chain alkyl groups, e.g. ethyl or methyl, or may be hydrogen. Thus for example the treating agent may be n-dodecylamine, or may be an n-dodecyl trimethylammonium salt, or may be methyl-n-dodecylamine or may be some other amine or ammonium salt.

[00042] The amine or ammonium salt may be provided in solution or, if it is a liquid, may be neat. The solution may be an aqueous solution or may be an alcoholic solution or may be in some other type of solution. The solution may have a concentration of treating agent of about 5 to about 50% w/w or w/v, or about 10 to 50, 20 to 50, 5 to 40, 5 to 30 10 to 40 or 20 to 40%, e.g. about 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50% w/w or w/v. It may have a concentration of the treating agent of about 100 to about 200mM, or about 100 to 150, 150 to 200, 120 to 180, 120 to 150, 150 to 180 or 150 to 170mM, e.g. about 100, 1 10, 120, 130, 140, 150, 160, 165, 170, 175, 180, 190 or 200mM, or may be some other concentration. The treatment with the treating agent may be in a ratio of about 1 to about lOOg treating agent per lOOg of solid. It may be in a ratio of about 1 to about 50, 1 to 20, 1 to 10, 10 to 100, 50 to 100, 10 to 50 10 to 20 or 10 to 50g/100g, or about 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90 or lOOg lOOg. In some cases other ratios may be used. Commonly the treating is conducted at room temperature however other temperatures may be used, e.g. up to about 60°C, or between about 10 and 60°C, or about 10 to 50, 10 to 40, 10 to 30, 20 to 60, 30 to 60, 40 to 60, 20 to 40 or 15 to 30°C, e.g. about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 to 60°C. The treating may be for about 5 to about 24 hours, or about 10 to 24, 10 to 24, 5 to 18, 5 to 12 or 12 to 18 hours, e.g. about 5, 6, 7, 8, 9, 10, 1 1, 12, 15, 18, 21 or 24 hours.

[00043] Following the treatment with the treating agent, the treating agent (optionally in solution) is separated from the treated solid. This may comprise draining (e.g. as described above for separation from an acidic solution), centrifugation, filtration, decanting or other suitable method. The solid may then be at least partially dried. This may comprise one or more of passing a gas (optionally at elevated temperature), e.g. air, through the solid, mild heating (e.g. to about 30 to about 60°C), application of a partial vacuum etc. The resulting solid may have a liquid content of less than about 5%, or less than about 2, 1 , 0.5, 0.2 or 0.1% w/w.

[00044] The product obtained by the above described process is a particulate solid useful for sorbing (adsorbing and/or absorbing) certain waste contaminants in waste waters. It may be a sorbent. It may be sufficiently hydrophilic as to be capable of mixing readily with water at room temperature, e.g. about 20 to about 30°C. It may have a mean particle size or diameter of about 1 to about 5mm, or about 1 to 3, 1.5 to 3, 3 to 5, 2 to 4, 2 to 3 or 3 to 4mm, e.g. of about 1 , 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5mm. It may be approximately monodispersed, or it may have a broad particle size distribution. In some embodiments it may have a minimum particle diameter of about 0.5 to about 2mm, e.g. of about 0.5, 0.75, 1 , 1.25, 1.5, 1.75 or 2mm. This may be achieved by sieving using a sieve of appropriate mesh size. The particles of the particulate solid may be an aggregate. of smaller particles. The particles of the particulate solid may be approximately spherical, or may be oblate spherical, elongated, acicular, irregular or may be some other shape. They may be in the form of irregular aggregates of smaller particles. In the event that the particles are not approximately spherical, the particle size or diameter referred to above may be a maximum diameter for the particle or may be a minimum diameter for the particle or may be a hydrodynamic diameter for the particle. It may be the equivalent diameter of a spherical particle having the same volume as the particle. The bulk density of the product may be about 0.5 to about lg/cc, or about 0.5 to 0.8, 0.6 to 0.75, 0.7 to 1, 0.7 to 0.9, 0.7 to 0.8 or 0.8 to 0.9, e.g. about 0.5, 0.6, 0.7, 0.8, 0.9 or lg/cc. It may be porous or may be non-porous. It may have a porosity of about 10 to about 50%, or about 10 to 30, 30 to 40 or 20 to 40%, e.g. about 10, 20, 30, 40 or 50%, or may be more than 50%. It may be an ion exchange sorbent. It may be a cation exchange sorbent. It may have a CEC (cation exchange capacity) of at least about 50meq/g, or at least about 60, 70, 80, 90 or lOOmeq/g, or from about 50 to about 150 meq/g, or from 50 to 100, 100 to 150, 80 to 120, 90 to 1 10, 100 to 120 or 100 to HOmeq/g, e.g. about 50, 60, 70, 80, 90, 100, 1 10, 120, 130, 140 or 150meq/g. It may have modifying groups on the surface thereof. In the event that the particles are porous, the modifying groups may be on the surfaces of the pores. The modifying groups may be ionic. They may be positively charged. They may have hydrophobic groups. They may have both ionic groups (e.g. cationic groups) and hydrophobic groups. The modifying groups may be ammonium groups. They may be alkylammonium groups. They may be mono- or di- or tri- or tetra-alkylammonium groups. The alkylammonium salts may have a C8 to CI 8 alkyl group, or more than one such alkyl group (e.g. 2, 3 or 4), directly attached to a nitrogen atom, as described elsewhere herein. The modifying groups may be bound to the surface by ionic bonds, in particular by the ionic attraction between a positive charge on the modifying group and a negative charge on the surface. They modifying groups may have no covalent attachment to the surface.

[00045] The sorbents of the present invention comprise porous particles of metal oxide mixtures. They commonly comprise primarily silicon and aluminium oxides, with lesser amounts of oxides of one or more of magnesium, iron, calcium and potassium. It may comprise a mixed metal oxide of any two or more of the above oxides. Any one or all of these may be at least partially hydrated, i.e. may be at least partially hydroxides. Typical proportions (by weight) of oxides are: silicon dioxide 60 to 70%, aluminium oxide 5 to 15%, magnesium oxide 4 to 8%, iron oxide 2 to 5%, calcium oxide 0.5 to 2%, potassium oxide 1 to 3% and other oxides 1 to 5%. A typical analysis may therefore be silicon dioxide 63.5%, aluminium oxide 9.5%, magnesium oxide 5.6%, iron oxide 4.0%, calcium oxide 1.1%, potassium oxide 1.1% and other oxides 2.0%. Commonly the loss on ignition (which may comprise volatiles such as water as well as combustibles such as organics) is less than about 15%, or less than about 14, 13, 12, 11 or 10% by weight. Organic matter in the sorbent (commonly organoammonium ions) may represent about 1 to about 5% by weight, or about 1 to 3, 3 to 5,1 to 2 or 2 to 3%, or less than about 5%, or less than about 4, 3, 2 or 1%, or about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5%.

[00046] As noted earlier, an adsorbent made by the initial acid treatment but without addition of organoammonium ions is also usable in some applications. This sorbent may have similar composition to the above data. Typical proportions (by weight) of oxides are: silicon dioxide 65 to 75%, aluminium oxide 5 to 15%, magnesium oxide 4 to 8%, iron oxide 3 to 7%, calcium oxide 1 to 5%, potassium oxide 1 to 3% and other oxides 1 to 5%. A typical analysis may therefore be silicon dioxide 68.5%, aluminium oxide 10.5%, magnesium oxide 5.6%, iron oxide 5.0%, calcium oxide 3.1%, potassium oxide 1.8% and other oxides 2.0%. Commonly the loss on ignition (which may comprise volatiles such as water) is less than about 15%, or less than about 14, 13, 12, 11 or 10% by weight. Organic matter is typically less than 1% by weight, and may be less than about 0.5, 0.2 or 0.1 %. [00047] The sorbent described above may be used for at least partially removing contaminants from waste or effluent streams, commonly from aqueous waste or effluent streams. These contaminants may be for example solid matter such as suspended solids, organic contaminants, inorganic (e.g. ionic) contaminants etc. Without wishing to be bound by theory, it is thought that the hydrophobic portion of the surface functional groups (commonly alkylammonium ions) serves to attract and/or bind hydrophobic contaminants, either in solution, suspension, emulsion or otherwise, whereas the ionic portion of the functional groups (commonly a quaternary nitrogen atom) serves to attract and/or bind hydrophilic contaminants, either in solution, suspension, emulsion or otherwise. In this way the sorbent is capable of removing a wide range of different contaminants. Suitable contaminants that may be removed include surfactants, including ionic surfactants (anionic, cationic or zwitterionic surfactants), non-ionic surfactants, and fluorinated compounds including fluorocarbons, perfluoroalkanes, fluorosurfactants etc., organochlorine and organobromine compounds. It may be capable of removing MBAS responsing detergents and/or soaps.

[00048] Commonly the sorbent will be simply combined with the liquid to be treated. The resulting mixture may then be agitated, e.g. stirred, shaken, sonicated etc. In a batch process, the sorbent may be used in a ratio of about 10 to about 200g sorbent per litre of liquid. The ratio may be about 10 to 100, 10 to 50, 10 to 20, 20 to 200, 50 to 200, 100 to 200, 20 to 100, 50 to 100 or 80 to lOOg/litre of liquid, e.g. about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 1 0, 150, 160, 170, 1 0, 190 or 200g/litre. The ratio may depend on the level of contaminants in the liquid, with a higher level of contaminants requiring a higher proportion of sorbent to liquid.

[00049] Alternatively the liquid to be treated may be passed through a bed or a column of the sorbent. It may therefore be a continuous process. In this case the flow rate of the liquid through the sorbent may be about 10 to about 200 column volumes per hour, or about 10 to 100, 10 to 50, 10 to 20, 20 to 200, 50 to 200, 100 to 200, 20 to 100, 50 to 100 or 80 to 100 column volumes per hour, e.g. about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190 or 200 column volumes per hour. The rate may depend on the level of contaminants in the liquid, with a higher level of contaminants requiring a lower flow rate. In some embodiments the treated liquid may be monitored for quality. Once the product quality deteriorates, e.g. to a predetermined limit, the sorbent may be replaced by fresh sorbent. [00050] In some instances it may be desirable to at least partially remove particulate matter from the liquid prior to combining it with the sorbent. Thus the liquid may be prefiltered (e.g. using a filter bed or a membrane filter or some other filtration process) or may be centrifuged or may be allowed to settle or may be decanted or may be clarified in some other process. It may for example be desirable to reduce the liquid to be treated to a turbidity of less than about 100NTU, or less than about 75, 50 or 25NTU, prior to combining with the sorbent.

[00051] Commonly the sorbent will not be regenerated following use but will be discarded. It may be treated (e.g. heated or burned) in order to destroy adsorbed organic matter prior to discarding, or may not be treated before discarding. Treatment times may vary depending on the nature and concentration of contaminants to be removed. Typical treatment times are under 60 minutes, or under 45, 30, 20, 15 or 10 minutes, or about 5 to about 60 minutes, or about 5 to 45, 5 to 30, 5 to 20, 5 to 15, 5 to 10, 10 to 60, 10 to 30, 10 to 20, 20 to 30 or 30 to 60 minutes, e.g. about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 minutes. Commonly the treatment will be conducted at ambient temperature, however other temperatures may be used, e.g. up to about 60°C, or between about 10 and 60°C, or about 10 to 50, 10 to 40, 10 to 30, 20 to 60, 30 to 60, 40 to 60, 20 to 40 or 15 to 30°C, e.g. about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 to 60°C. The treatment may remove at least about 50% of any particular contaminant, or of total suspended contaminants, or of total dissolved contaminants, or of total contaminants, or may remove at least about 60, 70, 80, 90, 95 or 99% thereof. The concentration of a particular contaminant, or of total contaminants, in a liquid to be treated which is amenable to treatment with the sorbent of the invention may be up to about 10,000ppm, or up to 5000, 2000, 1000, 500, 200 or lOOppm. The removal of any of the contaminants by the sorbent may be by adsorption or by absorption or by both. Thus the sorbent may be an adsorbent or an absorbent, or may be both.

[00052] Waste liquids that may be treated by the sorbent of the present invention include waste i water from car washes or other washing operations, laundry waste water industrial waste water, farm wastes, aviation wastewater, mining vehicle wash water, automotive industry wastewater, stormwater run off etc.

[00053] As noted above, the present invention relates to two related sorbent materials. The first is obtained by acid treatment of a particulate siliceous material (steps a to c of the process as defined) and is referred to here as the "acidified solid", and the second is obtained by treatment of the acidified solid with a treating agent, commonly an organic amine or organoammonium salt, referred to here as the "treated acidified solid". The inventor has found that the acidified solid is more effective at sorbing non-ionic surfactants, whereas the treated acidified solid is more effective at sorbing ionic surfactants. In some instances, for example when waste water to be treated contains both ionic and non-ionic surfactants, it may be advantageous to use both the acidified solid and the treated acidified solid as sorbents. In this case they may be used separately, e.g. sequentially, or may be mixed. Thus, for example, waste water may be passed sequentially through a bed of the acidified solid and then a bed of the treated acidified solid (or vice versa), or it may be passed through a mixed bed comprising both the acidified solid and the treated acidified solid. The preferred ratio of treated solid to acidified solid may depend on the expected ratio of ionic to non-ionic surfactants in the waste water to be treated. It may be between about 1 : 10 and 10: 1 on a weight basis, or about 5:1 to about 1:5, 2: 1 to about 1 :2 or about 3:2 to about 2:3, and may be for example about 10: 1, 9:1 , 8:1, 7: 1 , 6:1 , 5:1, 4: 1 , 3: 1, 2: 1, 3:2; 1 : 1 , 2:3, 1 :2, 1 :3, 1 :4, 1 :5, 1 :6, 1 :7, 1 :8, 1 :9 or 1 : 10.

Examples

Example 1: Sorbent preparation

[00054] Blended silicate material in granular form is a specialty sorbent for the removal of organic pollutants and trace metals from process effluent streams especially from commercial laundry, car wash and mine vehicle wash facilities. An example of suitable siliceous material is diatomaceous earth (DE) or non-swelling clay (smectite, kaolinite, attapulgite, bentonite, montmorillonite and dolomite).

[00055] In the present example an 80/20 w/w mixture of DE and kaolinitic clay was used. This siliceous material was placed in an aqueous solution containing about 0.6M aqua regia having a ratio of nitric acid to hydrochloric acid of about 1 :3 (i.e. 0.15M nitric acid and 0.45M HC1). A slight excess of aquaregia solution was used - the weight of siliceous material to volume of aqua regia was between about 1 :5 and l :7w/v. The siliceous material was soaked in the aqueous solution for about 2 hours at room temperature. The pH of the solution was then adjusted to 4.5 using aqueous ammonia solution. The treated material ("Blend A") was then washed with water and dried by passing air through the solid material. [00056] Blend A was then treated with a 1 :3 v/v n-dodecyl amine and denatured alcohol mixture ("Solution A") at a ratio of about 1L Solution A per kg Blend A, and incubated overnight at room temperature. Solution A was then drained from the treated Blend A. Prior to drying, a slight excess of Solution A was added to ensure that all pores in the solid were treated. The resulting solid product was then dried to obtain the final product for testing its sorbent properties. The final product is referred to herein as CMAX.

Example 2: Batch sorption

[00057] Batch sorption studies were performed using the wastewater collected from a commercial laundry and car wash operations. In a typical experiment 5 to 10 g of the CMAX material was added to 100ml of wastewater in a glass jar. The glass jars were occasionally shaken well and allowed to settle (10 mins.) before the supernatant was filtered for analysis. The contaminants that were monitored before and after treatment were chloride, ammonia, phosphorus, sulfate, suspended solids and organic compounds. The sorption efficiency for both commercial laundry and car wash wastewater is presented in Figures 1 and 2. It is demonstrated in these figures that the inorganic contaminants in both laundry and car wash wastewater, prior to treatment with the CMAX material, ranged from 38 to 500 ppm and a significant percentage of each of these have been adsorbed onto the CMAX material within 10 minutes of the experiment. It is clearly observed in Figures 3 and 4 that in addition to the inorganic

contaminants CMAX material has removed the high levels of suspended solids and organic compounds in the wastewater. For comparison, Figures 1 to 4 also include results for adsorption of contaminants onto activated carbon (AC1). As can be clearly seen from these Figures, the sorbent of the present invention is far superior to activated carbon with respect to sorption efficiency.

Fixed bed sorption

[00058] Based on the batch sorption results, further experiments have been conducted using a 25 kg fixed bed pilot scale treatment of wastewater in a column of approximately 300 mm diameter and 800 mm length. Figure 5 demonstrates that organic contaminants ranged from 300- 1000 ppm in both laundry and car wash wastewater prior to treatment with the CMAX material. It can be seen that with an organic loading concentration of 300 ppm CMAX sorbent could rapidly remove the organic compounds in less than 10 minutes, stabilising for the rest of the experimental time duration of 2 hours. With various concentrations of organics up to lOOOppm, as demonstrated in the sorption curves, it was shown that 25 kg of the CMAX material could adsorb most of the contaminant loading within about 20 minutes with no breakthrough observed for 120 mins. The flow rate used in the pilot scale fixed bed experiments was between 2 and 3m ³ /hr.

Conclusion

[00059] It has been proven that CMAX material is an efficient sorbent to remove both inorganic and organic contaminants in commercial laundry and car wash wastewater.

Applications Examples

[00060] Examples 3 to 5 (below) represent commercial scale trials in:

• Commercial laundry water recycling

• Aviation wastewater treatment

[00061] The results from these trials demonstrate that the products of the present invention were of benefit to these industries.

[00062] In Examples 3 to 5, the contaminated wastewater (influent) was pumped through a vessel or cylinder containing the sorbent in granular form and the water that came out the other- end (effluent) was then sampled. Samples were sent for independent analysis to NATA accredited laboratories.

Example 3: Commercial Laundry, targeting general surfactant removal

[00063] Queensland laundry: Processing 80- 100T of laundry per week.

Trialed: 400kgs of CMAX product, positioned post membrane filtration.

Throughput: 10,000-12,000 L/hr, 24 hours a day, 15 days.

Operating temp: 25-30°C.

[00064] Results: 85-90% removal of anionic surfactants. Example 4: Commercial Laundry, targeting non-ionic surfactant removal

[00065] A specific challenge was presented to capture non-ionic surfactants. This was challenging in that no charge is present to attract the surfactants to the sorbent. A new product called NISFIX (NIS stands for Non Ionic Surfactants) was therefore developed to address such contaminants.

[00066] Queensland laundry: Processing 80-100T of laundry per week.

Trialed pilot scale: 25kgs of C AX and NISFIX positioned post membrane filtration.

Throughput: 1 ,200 L/hr, 24 hours a day, 7 days.

Operating temp: approximately 40°C.

[00067] Results: 89% removal of nonionic surfactants.

Table 1 : Data for Examples 3 and 4

Total organic carbon (TOC) is the amount of carbon bound in an organic compound and is often used as a non-specific indicator of water quality or cleanliness of pharmaceutical manufacturing equipment.

J

² A methylene blue active substances assay, or MBAS assay, is a colorimetric analysis test method that uses methylene blue to detect the presence of anionic surfactants (such as a detergent or foaming agent) in a sample of water. An anionic surfactant detected by the color reaction is called a methylene blue active substance (MBAS)

³ Cobalt thiocyanate active substances (CTAS) measures nonionic surfactants (similar to hydrocarbons such as diesel)

Example 5: Aviation wastewater treatment of Organofluorine compounds

[00068] Trialed: lOkgs of CMAX positioned post client's existing filtration media, which used a proprietary sorbent.

Throughput: 800- 1000 L/hr., 48 hours

Operating temp: approximately 20-25°C .

[00069] Trialed: 4kgs of Ecofix's product, with CMAX only. Throughput: 150 L/hr., 48 hours; Operating temp: approximately 20-25°C

[00070] Conducted two trials and demonstrated consistent results. It should be noted that the final column of Table 3 demonstrates the ability of CMAX to operate efficiently over an extended time.

Table 2: contaminant concentrations; CMAX only (4kg product was trialed at approximately 1501/h)

OF: Organofluorine compounds. OF1 is perfluorooctane sulfonate, OF2 is perfliiorooctanoic acid and OF3 is 6:2 FtS (fluorotelomer sulfonate)

Table 3: contaminant concentrations; after Client's media and treated through CMAX

Contaminant Influent at time Post client's Post Ecofix's Post Ecofix's

T filtration media CMAX, at CMAX, at T +

(ppm) based on AC, time T+ 1.25 6.25 hours

at time T + 1 hours

hour

Organofluorine 14.38 10.57 <0.02 <0.02

compounds

(ppm)