Granulated contaminant sorbent

Abstract

A method for the stabilisation and / or immobilisation of contaminants within a material is disclosed. The method comprises contacting said material with a granule or pellet sorbent composition comprising at least one reactive adsorbent and at least one binder under conditions for the granule or pellet to at least partially disintegrate in the material and release at least some of the adsorbent from the granule or pellet into the material.

Description

GRANULATED CONTAMINANT SORBENTPRIORITY DOCUMENT

[0001] The present application claims priority from Australian Provisional Patent Application No. 2023904042 titled “GRANULATED CONTAMINANT SORBENT” and filed on 13 December 2023, the content of which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to remediation of materials. In particular, the present disclosure relates to methods and compositions for the stabilisation and / or immobilisation of contaminants in materials such as soils and other solid or semi-solid matrix types.BACKGROUND

[0003] Soil contamination is a significant problem in many parts of the world where degradation of the ecosystem provided by soil can have long term economic, environmental, societal and health impacts. Soil contamination occurs when a pollutant is present at higher than background concentrations and is causing, or has the potential to cause, adverse effects on society or the environment.

[0004] Stabilisation (or “immobilisation”) is currently considered one of the most viable and mature technologies available for the remediation of contaminated soils. This involves applying a sorbent to the soil to chemically or physically interact with (and therefore immobilise) the contaminants and prevent them from leaching into ground or surface water.1Different sorbents have been used to stabilise contaminants in soil including granular activated carbon (GAC), powdered activated carbon (PAC), biochar, activated biochar, graphene and graphene-based materials, minerals, clays and other synthetic sorbents.2Among different sorbents, activated carbon-based sorbents have been used to immobilise different types of organic or inorganic contaminants including heavy metals, pharmaceuticals, pesticides and per- and polyfluoroalkyl substances (PFAS) due to their low-cost and unique properties such as high specific surface area, high porosity, and desired surface functionalization.3 4While PAC generally has superior physical and chemical properties and a higher adsorption rate and capacity than GAC, the finer material can be a significant source of dust pollution.4One of the drawbacks is the generation of substantial dust during the handling, transport, and deployment of PAC in the field. The airborne dust produced poses health and safety risks for those exposed during PAC applications, and also restricts the range of use cases for which powdered sorbents would otherwise be suitable. The low density, fine properties of PAC also means that it is difficult to shift efficiently using vacuum pumps or augers,restricting transport, storage and mixing equipment options. Also, this difficulty in handling dusty powders often leads to reductions in treatment efficiencies and economics.

[0005] There is a need for sorbent compositions and methods for stabilising and / or immobilising contaminants in soils that allow for easy application without significantly compromising the performance of the sorbent. Alternatively, or in addition, there is a need for sorbent compositions and methods for stabilising and / or immobilising contaminants in soils that address one or more of the problems associated with known composition and methods.SUMMARY

[0006] In a first aspect, provided herein is a method for the stabilisation and / or immobilisation of contaminants within a material, the method comprising contacting said material with a granule or pellet sorbent composition comprising at least one reactive adsorbent and at least one binder under conditions for the granule or pellet to at least partially disintegrate in the material and release at least some of the reactive adsorbent from the granule or pellet into the material.

[0007] In certain embodiments of the first aspect, the at least one reactive adsorbent comprises activated carbon. Optionally, the reactive adsorbent comprising activated carbon further comprises a clay material.

[0008] In certain embodiments of the first aspect, the binder comprises a material that swells in contact with water. In certain of these embodiments, the binder comprises a hydrogel. In certain of these embodiments, the binder comprises carboxymethyl cellulose.

[0009] In certain embodiments of the first aspect, the at least one binder is present in an amount of about 1% to about 10% by weight of the at least one reactive adsorbent.

[0010] In certain embodiments of the first aspect, the contaminant is a per- or polyfluoroalkyl substance.

[0011] In certain embodiments of the first aspect, the material is soil.

[0012] In certain embodiments of the first aspect, the granule or pellet sorbent composition releases substantially all of the reactive adsorbent into the material within about 24 hours of contact with the material.

[0013] In certain embodiments of the first aspect, the sorbent composition further comprises at least one nutrient material.

[0014] In a second aspect, provided herein is a remediation composition comprising a granule or pellet sorbent composition comprising at least one reactive adsorbent and at least one binder.

[0015] In certain embodiments of the second aspect, the remediation composition comprises granules or pellets of relatively uniform size.

[0016] In certain embodiments of the second aspect, the remediation composition comprises granules or pellets of relatively uniform density.

[0017] In certain embodiments of the second aspect, the composition is a per- or polyfluoroalkyl substance (PFAS) remediation composition.

[0018] In certain embodiments of the second aspect, the at least one reactive adsorbent comprises activated carbon. Optionally, the at least one reactive adsorbent comprising activated carbon further comprises a clay material.

[0019] In certain embodiments of the second aspect, the binder comprises a material that swells in contact with water. In certain of these embodiments, the binder comprises a hydrogel. In certain of these embodiments, the binder comprises carboxymethyl cellulose.

[0020] In certain embodiments of the second aspect, the at least one binder is present in an amount of about 1% to about 10% by weight of the at least one reactive adsorbent.

[0021] In certain embodiments of the second aspect, the sorbent composition further comprises at least one nutrient material.

[0022] In a third aspect, provided herein is a process for producing a granulated sorbent composition that is configured to at least partially disintegrate in contact with water, the method comprising mixing at least one solid reactive adsorbent and at least one solid binder to form a dry mixture, adding the dry mixture to a granulator and adding water to the mixture in an amount that is sufficient to form granules having a desired crushing strength.

[0023] In certain embodiments of the third aspect, the amount of water added to the granulation process is from about 70% to about 90% by weight of the dry mixture.

[0024] In a fourth aspect, provided herein is a method for delivering at least one powdered sorbent to a material in order to stabilise and / or immobilise contaminants in the material, the method comprising adding a granule or pellet sorbent composition comprising at least one reactive adsorbent and at least onebinder contacting to the material and allowing the granule or pellet to at least partially disintegrate in the material and release at least some of the powdered adsorbent from the granule or pellet into the material.

[0025] In certain embodiments of the fourth aspect, the at least one reactive adsorbent comprises activated carbon. Optionally, the reactive adsorbent comprising activated carbon further comprises a clay material.

[0026] In certain embodiments of the fourth aspect, the binder comprises a material that swells in contact with water. In certain of these embodiments, the binder comprises a hydrogel. In certain of these embodiments, the binder comprises carboxymethyl cellulose.

[0027] In certain embodiments of the fourth aspect, the at least one binder is present in an amount of about 1% to about 10% by weight of the at least one reactive adsorbent.

[0028] In certain embodiments of the fourth aspect, the contaminant is a per- or polyfluoroalkyl substance.

[0029] In certain embodiments of the fourth aspect, the material is soil.

[0030] In certain embodiments of the fourth aspect, the granule or pellet sorbent composition releases substantially all of the reactive adsorbent into the material within about 24 hours of contact with the material.

[0031] In certain embodiments of the fourth aspect, the method further comprises delivering at least one nutrient composition to the material. In these embodiments, the sorbent composition further comprises the at least one nutrient material.BRIEF DESCRIPTION OF THE FIGURES

[0032] Embodiments of the present disclosure will be discussed with reference to the accompanying figures wherein:

[0033] Figure 1 shows the crushing strength of P4 and RemBind pellets with different binders;

[0034] Figure 2 shows microscopic images of P4 (75% fine, 25% clay) pellets with different binders. The line represents the scale bar of 1mm;

[0035] Figure 3 shows microscopic images of RemBind pellets with different binders. The line represents the scale bar of 1mm;

[0036] Figure 4 shows microscopic images of RemBind / P4- CMC-CS (2.5-2.5%) pellets with different water content during pelleting. The line represents the scale bar of 1mm;

[0037] Figure 5 shows the crushing strength of (left) P4 and RemBind granules with 5% CMC produced using high shear granulator and (right) P4 with a mixture of binders produced by high shear granulator;

[0038] Figure 6 shows microscopic images of a) P4-CMC 6% granules and b) RemBind-CMC 6% in different time intervals. The line represents the scale bar of 1mm;

[0039] Figure 7 shows microscopic images of a) P4- 6% CMC and b) RemBind- 6% CMC granules in different time intervals in sand column;

[0040] Figure 8 shows cumulative percentage of different PFAS (Top: PFOS, Middle: PFHxS, Bottom: PFOA) leached from treated soil with powder or granular RemBind;

[0041] Figure 9 shows the crushing strength of different RemBind-fertiliser formulations;

[0042] Figure 10 shows microscopic images of different RemBind-MAP pellets with and without binder at times 0 and 30 sec after immersing in the water. The line represents the scale bar of 1 mm;

[0043] Figure 11 shows microscopic images of a) RemBind-MAP 10%-CMC 6% granules and b) RemBind-MAP 50%-CMC 6% granules in different time intervals. The line represents the scale bar of 1mm;

[0044] Figure 12 shows visualized P diffusion zones in an acid soil (Ferndale) from RemBind- 50% MAP-6% CMC and RemBind- 10% MAP-6% CMC in 24 hours. All products supplied ~8 mg of phosphorus (P) added to soil in the centre of a Petri dish (as shown in this figure). It should be noted that the RemBind-MAP products in the centre of the petri dish were covered with the soil during the visualization;

[0045] Figure 13 shows the crushing strength of pellets with different binders and modes of drying;

[0046] Figure 14 shows microscopic images of Pl pellets with different binders and modes of drying at various time intervals. The line represents the scale bar of 1mm;

[0047] Figure 15 shows microscopic images of P2 pellets with different binders and modes of drying at various time intervals. The line represents the scale bar of 1mm;

[0048] Figure 16 shows microscopic images of P3 pellets with different binders and modes of drying at various time intervals. The line represents the scale bar of 1mm;

[0049] Figure 17 shows microscopic images of RemBind pellets with different binders and modes of drying at various time intervals. The line represents the scale bar of 1mm;

[0050] Figure 18 shows microscopic images of P4 pellets with different binders’ rates at various time intervals. The line represents the scale bar of 1 mm; and

[0051] Figure 19 shows microscopic images of RemBind-10% MAP pellets with CMC and a mixture CMC / CS binder in different time intervals. The line represents the scale bar of 1 mm.DESCRIPTION OF EMBODIMENTS

[0052] Disclosed herein is a method for the stabilisation and / or immobilisation of contaminants within a material. The method comprises contacting said material with a granule or pellet sorbent composition comprising at least one reactive adsorbent and at least one binder under conditions for the granule or pellet to at least partially disintegrate in the material and release at least some of the reactive adsorbent from the granule or pellet into the material. Also disclosed herein is a remediation composition comprising a granule or pellet sorbent composition comprising at least one reactive adsorbent and at least one binder.

[0053] The methods and compositions described herein are particularly suitable for delivering powdered reactive adsorbents, such as powdered activated carbon, to soils on a relatively large scale whilst minimising the creation of dust. Thus, by following the methods described herein, it is possible to deliver a powdered reactive adsorbent over a large area with greater accuracy because the pellet or granule form is easier to handle and administer on a large scale than a powder. Once in contact with the material, such as soil, and with water the granule or pellet at least partially disintegrates and releases the adsorbent from the granule or pellet into the soil. Advantageously, once the granule or pellet has started to disintegrate the adsorbent is released and it then provides a similar performance in the material as would be the case if the adsorbent was added to the material in a powder form. In other words, the granule or pellet form provides significant advantages from a transport, handling and administration (i.e. dosing) perspective but, once added to the material, the adsorbent behaves normally as a powder within the material.

[0054] After the granule or pellet sorbent composition has been added to the material it is ideally mixed within the material to distribute it as evenly as possible. In this way, once the granule or pelletsorbent composition begins to disintegrate (e.g. in contact with water), it will perform in a similar manner to mixing a powdered adsorbent through the material.

[0055] Advantageously, the granule or pellet sorbent composition enables relatively simple distribution of a powdered reactive adsorbent within a solid material such as soil, biosolids, wastes, etc by top surface mixing. For example, the granule or pellet sorbent composition can be distributed over a soil surface and then mixed into the surface 300 mm using standard equipment. After mixing, the granule or pellet sorbent composition will disintegrate and release the powdered reactive adsorbent into the soil where it will be distributed further by water as a result of soil leaching and simultaneous soil mixing by physical agitation. In practice, it is difficult to treat soil in this way using a powdered reactive adsorbent such as PAC because runoff of PAC from surface treated soil is a major issue and also dust results in safety concerns, loss of product, and processing inefficiencies.

[0056] In another application, some mines have vegetated drains contaminated with PF AS but local regulations do not permit removal of the vegetation. The only practical way to remediate the PFAS in these drains is to spread a powdered reactive adsorbent in the drains. However, this is very difficult to carry out in practice due to the aforementioned problems with dust. In contrast, the granule or pellet sorbent composition described herein can be easily applied using a suitable spreader (e.g. a fertiliser spreader) or even manually spread ‘by hand’.

[0057] Still another application of the methods and compositions described herein is in broad acre agriculture. For example, the granule or pellet sorbent composition described herein can be easily applied to an area of agricultural land using conventional agricultural equipment, such as a fertiliser spreader, after which the reactive adsorbent will bind contaminants in the soils such as PFAS and prevent uptake of them into plants grown in the soil. It will be appreciated that this application may be used with soils that do not have any known contamination as a preventative measure. In embodiments where the composition also contains a plant or soil nutrient, the compositions and methods can provide a two-fold benefit.

[0058] Still another application of the methods and compositions described herein is in home gardening. Like the broad acre agricultural application discussed previously, the compositions and methods described herein can be used by home gardeners to remediate contaminated soils and / or prevent contamination of soils by applying the compositions to the soil. Again, the compositions may optionally contain one or more soil or plant nutrients which then enables the home gardener to apply a fertiliser (for example) in addition to the reactive adsorbent. A particular benefit of the compositions described herein for this application is the compositions are easy to apply by the home gardener with no issues with dust and correct dosing and, once applied, the composition will reduce contaminant uptake into any plants growing in the treated soil.

[0059] Advantageously, the methods described herein can be performed in a manner whereby the composition and contaminants remain in situ (i.e. within the material).

[0060] Granulation of powder materials is one of the methods to eliminate dust formation during transport and storage.5 6One possibility is to granulate powdered sorbents to facilitate safe transportation and economic use of the material. For example, a binder can be added to fine materials to fix them in the form of granules, or it can be extruded into cylindrical-shaped pellets. However, the binder has a coating effect on the pore of fine materials, inevitably causing the adsorption capacity of the final granule to decrease.7The effectiveness of pelletised powdered sorbents can also decrease due to decreased surface area. Therefore, it is necessary to maintain the physical and chemical properties of the adsorbents while mitigating trade-offs with the adsorption / immobilisation efficiency of granulated sorbents.

[0061] It will be appreciated from the following description that a particularly suitable reactive adsorbent is available under the trade name RemBind™. RemBind™ adsorbent comprises a mixture of activate carbon and a mineral such as a clay or an aluminium compound. Further details for the RemBind™ adsorbent can be found in published international patent application No. WO 2011 / 038459 Al, the details of which are incorporated herein by reference.

[0062] Apart from RemBind™ adsorbent, other suitable reactive adsorbents include carbon-based adsorbents, mineral-based adsorbents, clay-based adsorbents, biopolymer-based adsorbents or a combination of any two or more of the aforementioned.

[0063] As used herein the term “adsorbent” means any material that binds contaminants, such as PFAS, by adsorption, electrostatic interaction, charge interaction, hydrophobic interaction, ligand exchange, hydrophilic interaction, etc.

[0064] Suitable carbon-based adsorbents include, but are not limited to, activated carbon, biochar, activated biochar, graphene, graphene oxide or derivatives, organic matter and carbon-based waste materials or by-products.

[0065] The mineral-based adsorbent may be any mineral material having a positive charge and may include double-layer hydroxide and metal organic framework (MOF). Examples of suitable mineral-based adsorbents include, but are not limited to, aluminium compounds and / or complexes and iron compounds and / or complexes. The aluminium compound and / or complex may comprise aluminium hydroxide, aluminium sulphate, alumina (aluminium oxide), activated alumina, or combinations thereof. For example, the aluminium compound and / or complex may comprise alum sludge. The iron compound and / or complex may be iron oxide.

[0066] Suitable clay-based adsorbents include, but are not limited to, zeolites, organoclays, clay minerals and surface modified clays. For example, the clay-based adsorbent may be kaolin or bentonite.

[0067] Suitable biopolymer-based adsorbents include, but are not limited to, cellulose based adsorbents and protein-based adsorbents.

[0068] In certain embodiments, the at least one reactive adsorbent comprises activated carbon. In certain other embodiments, the at least one reactive adsorbent comprises biochar. In certain other embodiments, the at least one reactive adsorbent comprises activated carbon and a clay-based adsorbent.

[0069] A binder is used in the granule or pellet sorbent composition to enhance the mechanical strength of pellets and granules, accelerate the process of granule consolidation, and improve the physical properties of the pellets and granules. Binders with gelling or hydrogel properties assist the formation of granules but also enhance the dispersion and removal efficiency of the reactive adsorbents in soil due to their swelling properties. Thus, the binder may be a material that swells in contact with water, such as a hydrogel. Suitable binders include carboxymethyl cellulose (CMC), corn starch (CS), guar gum (GG), gum Arabic (GA), polyacrylamide (PAM), sodium alginate, calcium alginate, rice starch, Inulin, sodium polyacrylate (PA), tracaganth (TA) gum, carrageenan gum, psyllium husk, xanthan gum, chitosan, barley husk, bean gum, sodium bentonite, and combinations of any two or more of the aforementioned. In certain embodiments, the binder comprises carboxymethyl cellulose.

[0070] The granule or pellet sorbent composition can be used for stabilisation and / or immobilisation of a wide range of environmental or other contaminants, such as those commonly found in soil, including inorganic contaminants such as metals, metalloids, halogens and organic contaminants including, for example, polycyclic aromatic hydrocarbons (PAHs), total petroleum hydrocarbons (TPH), benzene, toluene, ethylbenzene and xylenes (BTEX), benzo[a]pyrene (B(a)P), volatile organic compounds (VOCs), organic pesticides and herbicides, polychlorinated biphenyls (PCBs), fluorinated hydrocarbons such as perfluorooctanylsulfonate (PFOS), dioxins and specific organic compounds such as napthalene, carbon tetrachloride and trichloroethylene.

[0071] Per- and polyfluoroalkyl substances (PFAS) contamination of soils is a particular environmental concern worldwide. PFAS are a group of synthetic organic compounds with unique physicochemical properties. Due to their specific properties, they have been used for various applications which have triggered their release into the environment. The fate of PFAS -containing foams at fire-training facilities is of particular concern due to their mobility and potential to contaminate surface or groundwaters used for potable supplies, resulting in the potential for human exposure.

[0072] The granule or pellet sorbent composition disclosed herein is particularly suitable for stabilising PFAS contaminants in soil. PFAS contaminants that may be stabilised in soil using the methods described herein include sulphonate and carboxylate PFAS. The PFAS may be ionic, anionic or zwitterionic. Examples of PFAS contaminants that may be stabilised in soil using the methods described herein include, but are not limited to, perfluoro-n-octanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluoro-n-nonanoic acid (PFNA), sodium perfluoro- 1 -hexanesulfonate (PFHxS), perfluoro-n-hexanoic acid (PFHxA), potassium perfluoro- 1 -butanesulfonate (PFBS), perfluorobutanoic acid (PFBA), perfluoro- n-pentanoic acid (PFPeA), perfluoro-n-heptanoic acid (PFHpA), perfluoro-n-decanoic acid (PFDA), perfluoro-n-undecanoic acid (PFUnDA), perfluoro-n-dodecanoic acid (PFDoDA), perfluoro-n-tridecanoic acid (PFTrDA), perfluoro-n-tetradecanoic acid (PFTDA), perfluoro-n-hexadecanoic acid (PFHxDA), perfluoro-n-octadecanoic acid (PFODA), sodium perfluoro- 1 -pentanesulfonate (PFPeS), sodium perfluoro- 1 -heptanesulfonate (PFHpS), sodium perfluoro- 1 -nonanesulfonate (PFNS), sodium perfluoro- 1- decanesulf onate (PFDS), sodium perfluoro- 1 -undecanesulfonate (PFUnDS), sodium perfluoro- 1- dodecanesulfonate (PFDoDS), sodium perfluoro- 1 -tridecanesulfonate (PFTrDS), perfluoro-4- ethylcyclohexanesulfonate (PFECHS), 2,3,3,3-tetrafluoro-2-(l , 1 ,2,2,3,3,3-heptafluoropropoxy)propanoic acid (Gen X) (HFPO-DA), perfluoro-2,5-dimethyl-3,6-dioxanonanoic acid (HFPO-TA), sodium dodecafluoro-3H-4,8-dioxanonanoate (DONA), perfluoro-4-oxapentanoic acid (PFMoPrA) (PFMPA), perfluoro-3,6-dioxaheptanoic acid (NFDHA), perfluoro-5-oxahexanoic acid (PFMOBA) (PFMBA), 3- perfluoropropyl propanoic acid (3:3) (3:3 FTCA), 3 -perfluoropentyl propanoic acid (5:3) (5:3 FTCA), 3- perfluoroheptyl propanoic acid (7:3) (7:3 FTCA), perfluoro-(2-ethoxyethane)-sulfonic acid (PFEESA), potassium 9-chlorohexadecafluoro-3-oxanonane-l -sulfonate (F53B Major), potassium 11- chloroeicosafluoro-3-oxaundecane-l-sulfonate (F53B Minor), sodium lH,lH,2H,2H-perfluorohexane sulfonate (4:2) (4:2 FTSA), sodium lH,lH,2H,2H-perfluorooctane sulfonate (6:2) (6:2 FTSA), sodium lH,lH,2H,2H-perfluorodecane sulfonate (8:2) (8:2 FTSA), sodium lH,lH,2H,2H-perfluorododecane sulfonate (10:2) (10:2 FTSA), perfluoro- 1 -butanesulfonamide (FBSA), perfluoro- 1 -hexanesulfonamide (FhxSA), perfluoro- 1 -octanesulfonamide (PFOS A), N-methylperfluoro-1 -octanesulf onamidoacetic acid (N-MeFOSAA), N-ethylperfluoro-l-octanesulfonamidoacetic acid (N-EtFOSAA), N-methylperfluoro-1- octansulfonamide (N-MeFOSA), N-ethylperfluoro-1 -octanesulfonamide (N-EtFOSA), 2-(N- methylperfluoro-1 -octanesulf onamido)-ethanol (MeFOSEO, 2-(N-ethylperfluoro-l-octanesulfonamido)- ethanol (EtFOSE), carboxymethyldimethyl-3-[[(3,3,4,4,5,5,6,6,7,7,8,8,8- tridecafluorooctyl)sulfonyl]amino]prpylammonium hydroxide (6:2 FT AB), sodium bis(lH,lH,2H,2H- [l,2-13C2]-perfluorooctyl)phosphate (6:2 diPaP), etc.

[0073] The term "stabilisation" and related terms such as "stabilising" as used herein, refers to a process for the conversion of one or more contaminants to a less soluble, mobile and / or toxic form, thereby resulting in a reduction in the hazard potential of the material. The stabilisation process is also known as "fixation".

[0074] The term "immobilisation" and related terms such as "immobilising" as used herein, refers to the encapsulation of contaminants within a solid mass such as a monolithic solid of high structural integrity so as to reduce the leachability of contaminants, thereby resulting in a reduction in the hazard potential of the material.

[0075] The material containing the contaminant may be any solid or semisolid material, such as soil, sand, mining tailings and by-products, sludge wastes, industrial wastes, used asphalt, comminuted concrete, etc.

[0076] After contact with water, the granule or pellet sorbent composition releases substantially all of the reactive adsorbent into the material within about 24 hours of contact with the water and the material.

[0077] Advantageously, the sorbent composition may further comprise at least one nutrient material. The nutrient material may be a plant nutrient material, a microbe nutrient material and / or a soil nutrient material. Thus, the methods and compositions disclosed herein may not only be used to remediate soils by stabilising and / or immobilising contaminants in the soil, but it may also be used to improve the soil and / or plant material growing in the soil.

[0078] The nutrient material may be a source of organic carbon, a nutrient source, a micronutrient source, a fertiliser or a combination of any two or more of the aforementioned. The nutrient source may comprise copper, iron, chlorine, sulphate, magnesium, zinc, boron, manganese, molybdenum, nickel, calcium or a combination of any two or more of the aforementioned. The fertiliser may be an inorganic, organic or microbial fertiliser. For example, the fertiliser may comprise a source of phosphate, nitrogen, potassium or a combination of any two or more of the aforementioned. In another example, the fertiliser may comprise yeasts, nitrogen producing microbes, strains of one or more bacterial species selected from Lactobacillus parafarraginis, Lactobacillus buchneri, Lactobacillus rapi and Lactobacillus zeae.Acetobacter fabarum and / or Candida ethanolica, lignocides or a combination of any two or more of the aforementioned.

[0079] A sorbent composition as disclosed herein that comprises at least one nutrient material may be used for home garden applications for delivering a powdered reactive adsorbent and a nutrient material to the soil with a single, easy application.

[0080] Advantageously, the sorbent composition may further comprise at least one soil remediation agent. The soil remediation agent may be a microbial agent, such as a PFAS degrading microbe. For example, the bacteria Desulfovibrio aminophilus and Sporomusa sphaeroides have been shown to break down PFAS and they may be included in the sorbent composition so that they are delivered to the soil along with the reactive adsorbent and any nutrient material (if present). In these embodiments, thenutrient material may be a microbe nutrient material that supports the soil remediation microbe in the sorbent composition. In this way, nutrients can be used in the granule or pellet sorbent composition to enhance the bioremediation of contaminants, such as PFAS.

[0081] Also disclosed herein is a process for producing a granulated sorbent composition that is configured to at least partially disintegrate in contact with water. The method comprises mixing at least one solid reactive adsorbent and at least one solid binder to form a dry mixture, adding the dry mixture to a granulator and adding water to the mixture in an amount that is sufficient to form granules having a desired crushing strength.

[0082] The amount of water added to the granulation process is from about 70% to about 90% by weight of the dry mixture.

[0083] It will be appreciated from the foregoing discussion and the examples described herein that the remediation composition can be in the form of a granule or a pellet. As used herein, the term “granule”, and related terms, means small, shaped particles, that may have some variation in size, and are formed by granulation, which can involve agglomeration, crystallization, or drying of powders. As used herein, the term “pellet”, and related terms, means particles that are relatively uniform in shape, often cylindrical, spherical, or oval. Pellets are often larger than granules and are produced to be consistent in size and shape. Pellets can be formed by extrusion, spheronization, or pelletizing, where materials are compressed and shaped.

[0084] In certain embodiments, the granulated sorbent composition may further comprise one or more density modifiers. A density modifier is a substance combination of substances that changes the density of a material. The density modifier may increase or decrease the density of the pellets or granules. Density modifiers may be included in the composition in order to provide each pellet or granule with a desired density. In use, the granulated sorbent composition may be distributed over a soil surface or other solid material surface and then mixed within the soil or material by top surface mixing. Distribution of the granulated sorbent composition on top of a soil surface or other solid material surface can be carried out using known apparatus, such as spreaders, augers, etc. A heavier and larger pellet or granule will spread further because the spreader apparatus can put more energy into it. For this reason, a density modifier can be used to increase the density of a pellet or granule in order to increase the ‘throw’ of the pellet or granule. Suitable density modifiers include, without limitation, clays (e.g. kaolin), starch, sucrose, and barium sulfate. The amount of density modifier added to a pellet or granule can be determined by calculating the desired density of the pellet or granule and then adding the required amount of density modifier to achieve the desired density.

[0085] In some examples, the remediation composition described herein is in the form of a pellet. In some of these examples, the binder comprises carboxymethyl cellulose (CMC), corn starch (CS), or a mixture of CMC and CS. In specific examples, the binder comprises about equal amounts by weight of CMC and CS. This provides a pellet with sufficient strength and good swelling properties.

[0086] In some examples, the remediation composition described herein is in the form of a granule. In some of these examples, the binder comprises CMC. The percentage of CMC may be 5% by weight or more. This assists with granule swelling. In specific examples, the granule comprises 6% by weight CMC binder and have a particle size of 2 mm to 2.8 mm.

[0087] It will be appreciated by the skilled person that the pellets or granules in the granulated sorbent composition preferably have a relatively uniform size and / or density. This is because the pellets or granules may be distributed over an area of solid material such as soil, biosolids, wastes, etc. Relatively uniform distribution of the granulated sorbent composition over the area of solid material is typically required. If the pellets or granules do not have a relatively uniform size and / or density, then when they are distributed using known apparatus, such as spreaders, augers, etc., the distribution will not be as uniform as required because denser and / or bigger pellets or granules are likely to be thrown further by the apparatus than lighter or smaller pellets or granules. Pellets or granules for distribution are often held in hoppers connected to spreaders or augers and this presents a hostile physical environment for the pellets or granules. If the pellets or granules break down physically in the hopper, spreader or auger and before spreading, then the distribution may not be sufficiently uniform. For these reasons, it is preferable for pellets or granules to have a high crush strength because these pellets or granules are most likely to withstand the physical environment. However, the crush strength of the pellets or granules needs to be balanced against the disintegration properties of the composition because, for example, pellets or granules with high crush strength tend to take too long to disintegrate in situ in the solid material. Conversely, pellets or granules that disintegrate more readily in situ in the solid material have a greater tendency to break down physically during transport, storage or distribution.

[0088] Dispersible activated carbon compositions are known in the art such as in Chinese patent application No. CN106824074A. However, these compositions are intended for use in dispersing activated carbon in solutions such as water and, therefore, they do not provide any direction to the skilled person to prepare granules or pellets that are suitable for dispersion of sorbents in solid materials, such as soil, biosolids, wastes, etc.EXAMPLES

[0089] Example 1 - Preparation of activated carbon pellets and granules from powdered activated carbon (PAC) and binders with swelling properties

[0090] Four different binders with swelling properties including carboxymethyl cellulose (CMC), corn starch (CS), guar gum (GG), and gum Arabic (GA) were used to prepare activated carbon pellets.Powdered activated carbon (PAC) was mixed with 5% w / w of binder and pelletised using a die and a pressure of 11-13 KgForce (KgF).

[0091] The crushing strength of the PAC granules formed was measured using a ring penetrometer and the results are shown in Table 1.

[0092] Table 1. Summary of different formulations, the weight of granules, their size and crushing strength.

[0093] Key findings:• The PAC-gum Arabic and PAC-corn starch were two formulations that swelled quickly as soon as placed in the water, but both formulations had lower crushing strengths compared to other compacted formulations (Table 1).• The granulated or compacted PAC-CMC-5% started swelling when in contact with water but the swelling rate was less compared to PAC-gum Arabic or corn starch. It dispersed completely in 3 hours.• PAC-guar gum compacted granules swelled slightly in contact with water but did not fall apart and kept their shape after 5 days of soaking in water.• PAC-CMC 2.5% compacted granule also swelled slightly and did not fall apart after 5 days of soaking in water.• Granules with lower crushing strength swelled faster than those with greater crushing strength.• Binder type had an important influence on crushing strength and swelling of pellets.• PAC pellets made by compaction (no binder) were very brittle.

[0094] Example 2 - Preparation of activated carbon pellets and granules from carbon and clay mixtures and binders with swelling properties

[0095] Carbon and clay mixtures (Pl, P2, P3, P4 and RemBind100- Table 2) were mixed with different binders (Table 2) and pelletised using a die under and a pressure of 11-13 KgForce (KgF). All pellets were prepared at the same pressure and moisture content to be able to compare different binders. The pellets were dried overnight or at 100 °C for 2 hours. Different binders or mixtures were used. Swelling of the granules was tested by immersing the granules in water and taking images at different time intervals (e.g., 10 seconds, 30 seconds, 120 seconds and 5 minutes) using a Nikon Microscope.

[0096] Therefore, the effect of binder type, ratio and the moisture content during pelletizing RemBind100and P4 was tested. The water to solid (P4 / RemBind + binder) ratio was chosen 1:0.5, 1:0.7 and 1:0.9 to investigate the effect of moisture content on pellets strength and swelling properties. The ratio of binders (e.g CMC and CS) was changed to 50:50, 80:20 and 75:25 to understand their effect on the strength and swelling properties of pellets.

[0097] P4 and RemBind formulations were granulated using either CMC or a mixture of CMC and CS based on the optimised conditions achieved from the pelletising experiments. A high-shear granulator (EIRICH Laboratory Mixer-Type ELI) was used to granulate the P4 and RemBind. Mixtures of P4 or RemBind with binders (Table 3) were placed in a rotating pan and deionized water was added to the powder (70% to 90 % of total weight) while the drum was rotating at 2500 rpm for 3-7 minutes. The granules were formed in less than 3 minutes. The granules were sieved to different sizes -less than 2.36 pm, 2.36 pm to 2.8 pm, 2.8 pm to 3.35 pm- and their crushing strength was measured.

[0098] Table 2. Summary of carbon formulations.

[0099] Table 3. Summary of different formulations, type, and amount of binders, amount of water added during the pelletising and mode of drying of pellets.

[0100] Testing granule crushing strength

[0101] The crushing strengths of pellets or granules were measured using a motorised test stand (FGD series) connected to a digital force gauge. Crushing strength is the minimum force required to crush an individual granule or pellet. It determines the pressure limit applied during the bag and bulk storage of granules. At least 15 pellets and 25 granules were tested and the average of these measurements are reported. All pellets had a cylinder shape (4 mm (D) and 4 mm (H)), while granules with a different size fraction were tested. In the fertilizer industry, the crushing strength of granules with 2.36 mm to2.8 mm (D) is measured.

[0102] Testing granules expansion in soil

[0103] Effect of pressure

[0104] To determine the swelling properties of granules under pressure, the granules (optimised formulations) of P4- 6% CMC and RemBind-6% CMC were placed in the bottom of a cylindrical container (5.5 cm D and 7.5 cm H) and 120 g of moist sand (soil to water ratio 1:0.3) was added to the container. Expansion of the granules was monitored at different time intervals using a Nikon Microscope.

[0105] Effect of pressure and water flow- Column leaching experiments

[0106] Column leaching experiments (modified LEAF 1314) were performed for granular and powdered materials using a PFAS -contaminated sandy soil. The soil was mixed with 5% of either granular or powdered RemBind or P4 and dry packed in the column without incubation. In another experiment, 5% of RemBind was mixed with soil and the wetted soil was incubated for 2 weeks before performing the column leaching experiment. The same conditions as other columns were applied for this experiment. The column experiments and their conditions are summarised in Table 4.

[0107] Table 4. Summary of different formulations and conditions used for column experiment.

[0108] A Kartell polyethylene drying tube (outer diameter 1.65 cm, inner diameter 1.5 cm, length 30 cm) was packed with approximately 50 + 0.1 g of soil / granules and both ends of the column were packed with acid-washed glass wool (Sigma-Aldrich) and sealed with push-on connectors. A ImM CaCI solution was introduced from the bottom of the column with the aid of a Gilson Miniplus 3 peristaltic pump, and the eluent was collected using a Gilson FC 204 fraction collector. The peristaltic pump speed was calibrated in a way that the collected mass of the eluent in 24 hours equalled 0.75-1.00 times the mass of soil in the column- ~2.4 ml was collected every 90 minutes. The column leaching experiment was performed in duplicate for 5 days, equivalent to 25 pore volumes (PVs), but the samples of 15 PVs were analysed for PFAS. To investigate the effect of sorbents on leachates pH, the mixtures of soil-50% sorbents either powder or granular formulations were mixed with 1 mM CaCL solution in a ratio of 1:20 and tumbled in the end-over-end shaker for 18 hours. The pH values are reported in Table 5.

[0109] Table 5. Summary of pH values of soil and treated soil with 5% of P4 powder, RemBind powder, P4 granules (P4 and CMC) and RemBind granules (RemBind-CMC).

[0110] Example 3 - Preparation of pellets containing RemBind™ sorbent and monoammonium phosphate

[0111] RemBind™ sorbent was mixed with monoammonium phosphate (MAP) and pelletised as described in Examples 1 and 2 to produce a new RemBind™ product containing both sorbents and nutrient. CMC and CS were tested as binders with different ratios of MAP (10% and 50%) as summarised in Table 6. The swelling and crushing strength of the pellets were measured.

[0112] Example 4 - Preparation of granules containing RemBind™ sorbent and monoammonium phosphate

[0113] RemBind™ sorbent was mixed with either 10% or 50% MAP and 6% CMC and granulated using the EIRICH Laboratory Mixer-Type ELI. Optimal conditions identified from the granulation ofRemBind-CMC were used during the granulation with MAP. The optimised conditions were as follows for each formulation:

[0114] RemBind-MAP 10%-CMC 6% granules:1. RemBind was mixed with 6% (w / w) of CMC and 10% (w / w) of MAP. The reason for adding 6% CMC was to make sure that there is 5% CMC in the final granules.2. Performing the experiment a few times, the total amount of water used was proportional to 60% to70% of the powder material weight.3. At the beginning after mixing all powdered materials, 70% of the total water was added. For example, if the total amount of required water was 30 ml, 21 ml was added in the beginning and the rest was added in the next few minutes. The granulation started at 2500 rpm and the small granules formed in less than 2-3 minutes.4. To form larger granules the powder was added at a low granulation rate (between 700 rpm to 1000 rpm). Subsequently, water was added to the granulation drum. The amount of water was proportional to the weight of added powder.5. Granules were dried either in the lab or in the oven at 40 °C to 50 °C overnight.

[0115] RemBind-MAP 50%-CMC 6%:1. RemBind, MAP and CMC (47:47:6 w / w) were mixed.2. Performing the experiment a few times, the total amount of water used was proportional to 50% of the powder material weight.3. In the beginning, after mixing PM and CMC, 90% of the total water was added. The granules were formed in less than 100 seconds with sufficient size and form.4. To form bigger granules the powder was added at a low granulation rate (between 700 rpm to 1000 rpm). Subsequently, water was added to the granulation drum. The amount of water was proportional to the weight of added powder.5. Granules were dried either in the lab or in the oven at 40 °C to 50 °C overnight.

[0116] The crushing strength and swelling of the granules were measured. Furthermore, the amount of phosphorus (P) in the granules was measured by mixing 300 mg of different formulations and mixing it with 2 ml of concentrated HNO3 and 8 ml of water. The solution was shaken for 3 hours at 110 rpm in a rotary shaker. The solution was filtered, and the concentration of P was measured using an ICP-OES (Table 6) which showed a very good agreement with the amount of added and measured P to the granules. Phosphorus diffusion in soil was also monitored in different time intervals for both formulations using themethod developed by Degryse and McLaughlin (2014).8Briefly, a few granules containing ~ 8 mg of phosphorus in total were placed in the middle of a petri dish filled with soil. The soils were wetted to the field capacity (20%) and each treatment was replicated three times. The diffusion of P was visualized after 24 hours of RemBind- fertiliser application using Fe oxide-impregnated paper.

[0117] Table 6. Phosphorus analysis of RemBind- 50% MAP-6% CMC and RemBind- 10% MAP-6% CMC.

[0118] Results

[0119] Pelletised products- Pl, P2 and P3 formulations

[0120] The crushing strength of Pl, P2 and P3 formulations was related to the clay % of the initial formulation and binder type with no significant difference (t-test, p-value of 0.2) between the air- and oven- dried pellets (Figure 13). Pl had the greatest crushing strength due to greater % of clay due to the interaction of clay minerals with each other or clay minerals and the binders during pelletising. Considering the type of binders, the crushing strength followed CMC> CS:CMC > CS for all formulations. The swelling of the pellets in the water was related to the binder type, where pellets with CS disintegrated quicker than CMC or CMC / CS (Figures 14, 15 and 16).

[0121] Pelletised products- P4 and RemBind™ sorbent

[0122] Of the six binders and their mixtures used for pelleting P4, the pellets with only CMC had the greatest crushing strength followed by the mixture of CMC with either TA, PAM (Figure 1). Pellets containing RemBind™ with CMC had the highest crushing strength compared to other binders while their crushing strength was ~3 times less than P4 (CMC) pellets. This could be related to the presence of GAC and having a mixture of big and small particles in the RemBind™ formulation.

[0123] While the swelling rate of pellets with CMC was less than other formulations, they still fell apart in contact with water in less than 24 hours (Figure 2). Some pellets (e.g with PVA as binder, or mixture of TA or PAM with CMC) swelled quickly but kept their shapes and did not fall apart (Figure 2). It is important for the pellets to fall apart while swelling to be able to disperse in soil and react with contaminants. The swelling rate of pellets containing RemBind™ was quicker than the P4 formulation with the same binders and almost all the pellets containing RemBind™ s fell apart by 5 minutes soaking in water (Figures 3 and 17).

[0124] Changing the water to solid ratio from 50% to 70% significantly improved the strength of pellets increasing the crushing strength from 1.7+0.3 to 7.5+0.7 kg force for P4-2 (CMC-CS, 2.5-2.5%), while no significant difference (t-test, p-value of 0.5) was observed by increasing the water content to 90% (7.3+0.8 kg force). However, with RemBind™ (CMC-CS, 2.5-2.5%) increasing the water content from 70% to 90% significantly (t-test, p< 0.05) increased the pellet crushing strength from 4.2 to 5.8 Kg force. For both P4-CMC-CS and RemBind™-CMC-CS formulations the addition of 90% water reduced the swelling of the pellets compared to pellets prepared with 70% water (Figure 4). This could be related to the greater strength of pellets and losing some of the CMC / CS during the pressing (dissolved in the water and released during the pelleting) when 90% water was added.

[0125] Varying the CMC content increased the crushing strength of P4-CMC / CS pellets to 7.5+0.7, 8.5+1.2 and 9.6+1.9 for CMC / CS ratio of 2.5:2.5%, 3:2% and 4:1% respectively. However, the swelling rate of the pellets decreased by increasing the CMC concentration of the formulations (Figure 18).

[0126] Key findings:• Binder type had an important effect on the crushing strength and swelling of pellets.• Pellets with lower crushing strength fell apart faster than those with greater crushing strength.• Formulations with greater clay content had higher crushing strength using the same binder.• For most formulations, the oven-dried pellets fall apart slightly more than air-dried formulations despite having similar crushing strength likely because the faster drying process can adversely affect the nucleation and consolidation process of the pellets.• Increasing the water content during pelleting enhanced crushing strength but decreased the swelling property of the pellets.• CMC increased the crushing strength of all formulations with a comparative swelling after 24 hours.• The crushing strength of granules with the mixture of CMC-CS (2.5-2.5%) decreased to half compared to CMC5% but their swelling ability was greater while the mixture will be more economical.• The CMC-CS (2.5-2.5%) can be used as the final formulation for pellet due to the efficient strength and swelling property. This formulation (CMC-CS) is more cost-effective than 5% CMC.

[0127] Granulated products

[0128] Optimal conditions identified from pelletising were used during the granulation. The optimised conditions were as follows for each formulation:

[0129] RemBind™-CMC:1. RemBind™ was mixed with 6% (w / w) of CMC. The reason for adding 6% CMC was to make sure that there is 5% CMC in the final granules.2. Performing the experiment a few times, the total amount of water used was proportional to 60% to 70% of the powder material weight.3. At the beginning after mixing RemBind™ and CMC, 70% of total water was added. For example, if the total amount of required water was 30 ml, 21 ml was added in the beginning and the rest was added in the next 2 minutes. The granulation started at 2500 rpm and the small granules formed in less than 2-3 minutes.4. To form larger granules the powder was added in the low granulation rate (between 700 rpm to 1000 rpm). Subsequently, water was added to the granulation drum. The amount of water was proportional to the weight of added powder.5. Using the CMC solution in water was not applicable for a few reasons: the viscosity of 6% CMC solution was high, adding an extra process to granulation and the granules swelling were not as was expected.6. Granules were dried either in the lab or in the oven at 40 °C to 50 °C.

[0130] Powdered materials (PM-CMC):1. Powdered materials should be mixed with 6% (w / w) of CMC.2. Performing the experiment a few times, the total amount of water used was proportional to 80 % to 90% of the powder material weight.3. In the beginning, after mixing PM and CMC, 70% of the total water was added.4. To form bigger granules the powder was added at the low granulation rate (between 700 rpm to 1000 rpm). Subsequently, water was added to the granulation drum. The amount of water was proportional to the weight of added powder.5. Using the CMC solution in water was not applicable for a few reasons: the viscosity of 6% CMC solution was high, adding an extra process to granulation and the granules swelling were not as we expected.6. Granules were dried either in the lab or in the oven at 40 °C to 50 °C.

[0131] The crushing strength of the granules was related to their size (Figure 5a) and P4 formulations were more resistant to crushing compared to RemBind™. Crushing strength of granular P4 and RemBind™ (size fraction of 2.36 mm to 2.8 mm) having ~6%CMC dropped 5 and 3-folds respectively, compared to pellets due to the smaller size of granules than pellets. However, the granules still have a decent crushing strength to resist breaking during handling. The crushing strength of CMC-CS mixtures decreased compared to only CMC, like pellets (Figure 5b). More importantly the granules with a mixture of binders (CMC and CS) swelled slightly in the water and did not fall apart even after 24 hours, while the granules with only CMC swelled quickly and fell apart in less than 1 hour (Figure 6a). RemBind™- 6% CMC had the same properties and fell apart in less than 1 hour (Figure 6b). Therefore, for granular formulations, CMC was the best binder, and the mixture of CMC / CS was not used.

[0132] The swelling of granules was tested in sand and under pressure for P4-CMC-6% and RemBind™-CMC-6% granules of different sizes in different time intervals. The soil to water ratio was 1:0.3 and a weight of 120 g was applied to a granule with the weight of 0.025 g (12mm2area). The microscopic images showed the swelling ability of the granules under the pressure, in a less moist soil condition. The particles started to diffuse between the sand particles as the granules swelled (Figures 7a and b).

[0133] Key findings:• Like pellets, binder type had an important role on granules crushing strength and swelling.• The percentage of CMC played an important role on granules swelling and should be added 5% or more to assist with granules swelling.• Granules were able to swell and diffuse in the soil under the pressure and weight.• The optimized formulation for granules is 6% CMC binder and particle size of 2 mm to 2.8 mm.

[0134] Column leaching experiments

[0135] The results of column leaching experiments for RemBind™ containing granules (dry-no incubation, wet two weeks incubation) and powder (dry- no incubation) are presented in Figure 8. The soil initial PFAS concentration is reported in Table 7.

[0136] Table 7. Summary of PFAS concentration in contaminated soil used for LEAF 1314. PFAS concentrations are in pg / kg.

[0137] PFOS and PFHxS concentrations were 2855 pg / kg and 88.65 pg / kg, respectively and greater than other PFAS. The efficiency of powdered RemBind™ sorbent was slightly better than RemBind™ containing granules- incubated. RemBind™ containing granules with no incubation were less efficient than the other formulations. The cumulative percentage of leached PFAS for all formulations is also summarized in Table 8.

[0138] Table 8. Cumulative percentage of different PFAS leached from treated soil with powder or granular RemBind™.

[0139] The better performance of powder formulations compared to granules is due to their greater surface area. Furthermore, soil and powder mixing was performed in dry conditions and some of the powder materials were electrostatically attached to soil particles (sand as the soil had a sandy texture). This may not occur in the field as water is added during the mixing of the powder sorbents and soil. For granular RemBind™, most of the PFAS leached in the first 3 pore volumes and as the granules expanded enough and dispersed in the column, the leaching of PFAS decreased. For example, 85% and 50% of total PFOS (leached from the column- not total PFOS of the soil) was leached at the first 3 pore volumes (the first 4.5 hours). We also observed the presence of some of the powdered activated carbons in the first samples (up to 6 pore volumes) in the leachates of granular samples. This could be related to the movement of very small, powdered particles as water flows in the column. The sandy texture of the soil can also contribute to powdered particles movement due to the presence of bigger voids in the soil profile.

[0140] Key findings:• All formulations immobilised PFAS in soil, with powder RemBind™ showing the greatest efficiency compared to granular formulations.• Incubation of granules and mixing them before performing the leaching tests assisted with granule swelling, dispersion of the sorbents, and improved their efficiency compared to the dry packed samples.

[0141] RemBind™- Fertiliser products

[0142] Pellet formulations

[0143] Like the results of other pelletised formulations (with no fertiliser) the binder type and content had the greatest effect on crushing strength of RemBind™-MAP formulations and no significant effect of MAP content was observed (Figure 9). However, addition of MAP improved the strength of pellets compared to RemBind™-Binder pellets (Figure 9) due to the interaction of MAP and binder. Others also showed that the mechanical strength of inorganic nanocomposite membranes based on CMC and synthetic clay can increase by increasing the clay content due to the interaction of CMC with clay.9

[0144] Comparing the swelling of the pellets, the formulation with 50% MAP swelled and fell apart as soon as immersed in water (Figure 10). The swelling rate of the formulation with 10% MAP was less than 50% MAP but still swelled considerably in water and fell apart completely in less than 5 minutes (Figure. 19).

[0145] Granular formulation

[0146] Two formulations were granulated based on the pellets crushing strength and swelling properties. Comparing two granular formulations the RemBind™-50% MAP- 6% CMC had significantly greater (p < 0.01) crushing strength (3.04 ±0.45 KgF) than RemBind-10% MAP- 6% CMC (2.43 ± 0.64 KgF). This could be related to the increased interaction of MAP and CMC in RemBind™ granules with 50% MAP. Both formulations swelled and dispersed in water in less than 1 hour as shown in (Figure 11).

[0147] Visualisation of P from RemBind™- 50% MAP-6% CMC and RemBind™- 10% MAP-6% CMC after 24 hours of granules application in the soil showed the efficient release and diffusion of the P from both granules (Figure 12). The release and diffusion of P were greater from the formulation containing 50%. However, it should be noted that the P diffusion rate will be different in soil with different physical and chemical properties and will decrease in alkaline soil.

[0148] It will be understood that the terms “comprise” and “include” and any of their derivatives (e.g. comprises, comprising, includes, including) as used in this specification, and the claims that follow, is to be taken to be inclusive of features to which the term refers, and is not meant to exclude the presence of any additional features unless otherwise stated or implied.

[0149] In some cases, a single embodiment may, for succinctness and / or to assist in understanding the scope of the disclosure, combine multiple features. It is to be understood that in such a case, these multiple features may be provided separately (in separate embodiments), or in any other suitable combination. Alternatively, where separate features are described in separate embodiments, these separate features may be combined into a single embodiment unless otherwise stated or implied. This also applies to the claims which can be recombined in any combination. That is a claim may be amended to include a feature defined in any other claim. Further a phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

[0150] It will be appreciated by those skilled in the art that the disclosure is not restricted in its use to the particular application or applications described. Neither is the present disclosure restricted in its preferred embodiment with regard to the particular elements and / or features described or depicted herein. It will be appreciated that the disclosure is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope as set forth and defined by the following claims.REFERENCES

[0151] (1) Kabiri, S.; Centner, M.; McLaughlin, M. J. Durability of sorption of per- and polyfluorinated alkyl substances in soils immobilised using common adsorbents: 1. Effects of perturbations in pH. Sci Total Environ 2021, 766, 144857. DOI: 10.1016 / j.scitotenv.2020.144857 From NLM.

[0152] (2) Palansooriya, K. N.; Shaheen, S. M.; Chen, S. S.; Tsang, D. C. W.; Hashimoto, Y.; Hou, D.;Bolan, N. S.; Rinklebe, J.; Ok, Y. S. Soil amendments for immobilization of potentially toxic elements in contaminated soils: A critical review. Environment International 2020, 134, 105046. DOI: https: / / doi.Org / 10.1016 / j.envint.2019.105046.

[0153] (3) Sleep, J. A.; Juhasz, A. L. A Review of Immobilisation-Based Remediation of Per- andPoly-Fluoroalkyl Substances (PFAS) in Soils. Current Pollution Reports 2021, 7 (4), 524-539. DOI: 10.1007 / s40726-021 -00199-z.

[0154] (4) Cai, Z.; Deng, X.; Wang, Q.; Lai, J.; Xie, H.; Chen, Y.; Huang, B.; Lin, G. Core-shell granular activated carbon and its adsorption of trypan blue. Journal of Cleaner Production 2020, 242, 118496.

[0155] (5) Kabiri, S.; Baird, R.; Tran, D. N. H.; Andelkovic, I.; McLaughlin, M. J.; Losie, D.Cogranulation of Low Rates of Graphene and Graphene Oxide with Macronutrient Fertilisers Remarkably Improves Their Physical Properties. ACS Sustainable Chemistry & Engineering 2018, 6 (1), 1299-1309. DOI: 10.1021 / acssuschemeng.7b03655.

[0156] (6) Ozga, M. E.; Borowski, G. The Use of Granulation to Reduce Dusting and Manage of FineCoal. J. Ecol. Eng. 2018, 19 (3), 218-224. DOI: 10.12911 / 22998993 / 89794.

[0157] (7) Yan, X.; Liu, X.; Qiao, K.; Wang, Y.; Yan, Z. Research progress of preparation technique of activated carbon monolith. Chemical industry and engineering progress 2008, 27 (12), 1868-1872.

[0158] (8) Degryse, F.; McLaughlin, M. J. Phosphorus Diffusion from Fertiliser: Visualization,Chemical Measurements, and Modeling. Soil Science Society of America Journal 2014, 78 (3), 832-842. DOI: https: / / doi.org / 10.2136 / sssaj2013.07.0293.

[0159] (9) Oliveira, R. L. d.; Barud, H. d. S.; De Salvi, D. T. B.; Perotti, G. F.; Ribeiro, S. J. L.;Constantino, V. R. L. Transparent organic-inorganic nanocomposites membranes based oncarboxymethylcellulose and synthetic clay. Industrial Crops and Products 2015, 69, 415-423. DOI: https: / / doi.org / 10.1016 / j-indcrop.2015.02.015.

[0160] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms part of the common general knowledge.

Claims

CLAIMS1. A method for the stabilisation and / or immobilisation of contaminants within a material, the method comprising contacting said material with a granule or pellet sorbent composition comprising at least one reactive adsorbent and at least one binder under conditions for the granule or pellet to at least partially disintegrate in the material and release at least some of the adsorbent from the granule or pellet into the material.

2. The method of claim 1, wherein the at least one reactive adsorbent comprises activated carbon.

3. The method of claim 2, wherein the at least one reactive adsorbent comprises powdered activated carbon (PAC).

4. The method of any one of claims 1 to 3, wherein the at least one reactive adsorbent comprises biochar.

5. The method of any one of claims 1 to 4, wherein the at least one reactive adsorbent comprises a clay material.

6. The method of claim 5, wherein the clay material comprises kaolin.

7. The method of any one of claims 1 to 6, wherein the at least one reactive adsorbent comprises a mineral-based adsorbent.

8. The method of claim 7, wherein the mineral-based adsorbent is an aluminium compound and / or complex.

9. The method of any one of claims 1 to 8, wherein the binder comprises a material that swells in contact with water.

10. The method of claim 9, wherein the binder comprises a hydrogel.

11. The method of claim 10, wherein the binder comprises carboxymethyl cellulose.

12. The method of claim 10 or claim 11, wherein the binder comprises corn starch.

13. The method of any one of claims 1 to 12, wherein the at least one binder is present in an amount of about 1% to about 10% by weight of the at least one reactive adsorbent.

14. The method of any one of claims 1 to 13, wherein the contaminant is a per- or polyfluoroalkyl substance.

15. The method of any one of claims 1 to 14, wherein the material is soil.

16. The method of any one of claims 1 to 15, wherein the granule or pellet sorbent composition releases substantially all of the reactive adsorbent into the material within about 24 hours of contact with the material.

17. The method of any one of claims 1 to 16, wherein the sorbent composition further comprises at least one nutrient material.

18. The method of any one of claims 1 to 17, wherein the sorbent composition further comprises a soil remediation agent.

19. The method of claim 18, wherein soil remediation agent is a microbial agent.

20. The method of claim 19, wherein the microbial agent is a PFAS degrading microbe.

21. A method for the stabilisation and / or immobilisation of contaminants within soil, the method comprising distributing a granule or pellet sorbent composition comprising at least one reactive adsorbent and at least one binder within an upper region of about 300 mm in the soil and allowing the granule or pellet to at least partially disintegrate in the soil and release at least some of the adsorbent from the granule or pellet into the material.

22. A remediation composition comprising a granule or pellet sorbent composition comprising at least one reactive adsorbent and at least one binder.

23. The remediation composition of claim 22, wherein the composition is a per- or polyfluoroalkyl substance (PFAS) remediation composition.

24. The remediation composition of any one of claims 22 to 23, wherein the at least one reactive adsorbent comprises activated carbon.

25. The remediation composition of claim 24, wherein the at least one reactive adsorbent comprises powdered activated carbon (PAC).

26. The remediation composition of any one of claims 22 to 25, wherein the at least one reactive adsorbent comprises biochar.

27. The remediation composition of any one of claims 22 to 25, wherein the at least one reactive adsorbent comprises a clay material.

28. The remediation composition of claim 27, wherein the clay material comprises kaolin.

29. The remediation composition of any one of claims 22 to 28, wherein the at least one reactive adsorbent comprises a mineral-based adsorbent.

30. The remediation composition of claim 29, wherein the mineral-based adsorbent is an aluminium compound and / or complex.

31. The remediation composition of any one of claims 22 to 30, wherein the binder comprises a material that swells in contact with water.

32. The remediation composition of claim 31, wherein the binder comprises a hydrogel.

33. The remediation composition of claim 32, wherein the binder comprises carboxymethyl cellulose.

34. The remediation composition of claim 32 or claim 33, wherein the binder comprises corn starch.

35. The remediation composition of any one of claims 22 to 34, wherein the at least one binder is present in an amount of about 1% to about 10% by weight of the at least one reactive adsorbent.

36. The remediation composition of any one of claims 22 to 35, wherein the sorbent composition further comprises at least one nutrient material.

37. A process for producing a granulated sorbent composition that is configured to at least partially disintegrate in contact with water, the method comprising mixing at least one solid reactive adsorbent and at least one solid binder to form a dry mixture, adding the dry mixture to a granulator and adding water to the mixture in an amount that is sufficient to form granules having a desired crushing strength.

38. The process of claim 37, wherein the amount of water added to the granulation process is from about 70% to about 90% by weight of the dry mixture.

39. A method for delivering at least one powdered sorbent to a material in order to stabilise and / or immobilise contaminants in the material, the method comprising adding the remediation composition of any one of claims 22 to 36 to the material and allowing the granule or pellet to at least partially disintegrate in the material and release at least some of the powdered reactive adsorbent from the granule or pellet into the material.

40. The method of claim 39, wherein the contaminant is a per- or polyfluoroalkyl substance.

41. The method of any one of claims 39 to 40, wherein the material is soil.

42. The method of any one of claims 39 to 41, wherein the granule or pellet sorbent composition releases substantially all of the reactive adsorbent into the material within about 24 hours of contact with the material.

43. The method of any one of claims 39 to 42, wherein the method further comprises delivering at least one nutrient composition to the material.

44. The method of any one of claims 39 to 43, wherein the method further comprises delivering at least one soil remediation agent to the material.

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