阅读说明：本技术 吸附剂 (Adsorbent and process for producing the same ) 是由 布雷特·特纳 于 2018-08-28 设计创作，主要内容包括：一种用于全氟烷基物质和多氟烷基物质的吸附剂,其中吸附剂包括一种或更多种蛋白质。该一种或更多种蛋白质可以选自植物蛋白、白蛋白、球蛋白、麻仁球蛋白、大豆球蛋白和/或β-伴大豆球蛋白。吸附剂用于处理被全氟烷基物质和多氟烷基物质污染的材料的用途。还提供了一种用于处理被全氟烷基物质和多氟烷基物质污染的地下水的工艺,其中被污染的地下水被泵送到地面并且被引导到包含吸附剂的吸附步骤。(An adsorbent for perfluoroalkyl species and polyfluoroalkyl species, wherein the adsorbent comprises one or more proteins. The one or more proteins may be selected from vegetable proteins, albumin, globulin, edestin, glycinin and/or beta-conglycinin. Use of an adsorbent for the treatment of materials contaminated with perfluoroalkyl species and polyfluoroalkyl species. Also provided is a process for treating groundwater contaminated with perfluoroalkyl species and polyfluoroalkyl species, wherein the contaminated groundwater is pumped to the surface and directed to an adsorption step comprising an adsorbent.)

1. An adsorbent for perfluoroalkyl species and polyfluoroalkyl species, wherein the adsorbent comprises one or more proteins.

2. The sorbent of claim 2, wherein the one or more proteins are plant proteins.

3. The adsorbent of claim 1 or 2, wherein the one or more proteins comprise albumin.

4. The sorbent as claimed in any one of the preceding claims, wherein the one or more proteins comprise globulin.

5. An adsorbent according to any preceding claim, wherein the one or more proteins comprise edestin.

6. The sorbent as claimed in any one of the preceding claims, wherein the one or more proteins comprise glycinin.

7. An adsorbent according to any preceding claim, wherein the one or more proteins comprise β -conglycinin.

8. An adsorbent according to any preceding claim, wherein the one or more proteins are structurally similar to albumin and/or globulin and/or edestin and/or glycinin and/or beta-conglycinin.

9. The sorbent as claimed in any one of the preceding claims, wherein the one or more proteins are derived from cannabis sativa seeds.

10. The adsorbent of claim 9, wherein the adsorbent comprises cannabis sativa seed.

11. The sorbent of claim 9, wherein the sorbent comprises cannabis separation protein.

12. The adsorbent of any one of claims 1 to 11, wherein the adsorbent comprises soy protein.

13. The sorbent of any of the preceding claims, wherein the sorbent further comprises calcite.

14. The sorbent of any of the preceding claims, wherein the sorbent further comprises an inert substance configured to increase a permeability of the sorbent.

15. The sorbent of claim 14, wherein the inert species are glass beads.

16. The sorbent of either claim 14 or 15, wherein the inert material is gravel.

17. Use of the adsorbent according to any one of the preceding claims for treating materials contaminated with perfluoroalkyl substances and polyfluoroalkyl substances.

18. Use according to claim 17, wherein the material is groundwater.

19. Use according to claim 17, wherein the material is residual water from soil washing.

20. A process for treating groundwater contaminated with perfluoroalkyl species and polyfluoroalkyl species, wherein the contaminated groundwater is pumped to the surface and is directed to an adsorption step comprising an adsorbent according to any one of claims 1 to 16.

21. A process for treating groundwater contaminated with perfluoroalkyl species and polyfluoroalkyl species, wherein a permeable reactive barrier comprising an adsorbent according to any one of claims 1 to 16 is located in the path of an aquifer contaminated with perfluoroalkyl species and polyfluoroalkyl species.

22. A process for treating a used sorbent according to any one of claims 1 to 16 comprising thermal destruction of the used sorbent.

23. The process of claim 22, wherein thermal destruction occurs at a temperature selected from <700 ℃, <650 ℃, <600 ℃, <550 ℃, <500 ℃, or <450 ℃.

24. The process of claim 21, wherein the used sorbent is dehydrated and dried prior to thermal destruction.

25. The process according to any one of claims 21 to 24, wherein the gases evolved by thermal destruction are washed with an alkaline solution, wherein the alkaline solution is subsequently reacted with calcite to form fluorite.

Technical Field

The present invention relates generally to adsorbents for the removal of perfluoroalkyl and polyfluoroalkyl species from water.

Background

Perfluoroalkyl and polyfluoroalkyl materials (PFAS) have been widely used for a variety of purposes, including in fire fighting foams. Aqueous film-forming foam (AFFFa) containing PFAS has proven to be very effective in extinguishing hydrocarbon fuel fires, and as a result, a large number of fire training facilities worldwide have been identified as being contaminated with PFAS.

The entire family of PFAS can be divided into four sub-classes, namely perfluoroalkylsulfonic acids (PFSA), perfluoroalkylcarboxylic acids (PFCA), perfluoroalkylsulfonamides (FOSA) and fluorotelomer sulfonic acids (FTS).

PFAS is considered to be hardly degradable in nature and therefore poses a significant challenge to remediation where many conventional methods of treating PFAS in water are not effective. The complex chemistry of PFAS makes it highly soluble and therefore easily transported by ground and surface water. Since the chemistry of PFAS species varies with increasing carbon chain length, pH, salinity and other variables, remediation of PFAS contamination is considered extremely difficult and expensive. Furthermore, there is currently no single method that can adequately remediate contamination of an entire family of PFAS chemicals.

Remediation or removal of groundwater and surface water contaminated with PFAS typically involves adsorption processes because PFAS is not effectively degraded using biological or chemical treatment options. Granular Activated Carbon (GAC) has been demonstrated to be an effective matrix adsorbent for long-chain PFAS. However, GAC is less effective for treating the more hydrophilic shorter chain PFAS, such as PFBS (butyrate; C4 length). Thus, the use of GAC filters can be used in conjunction with other treatment methods, such as reverse osmosis resins, to expand the amount of PFAS removed during treatment. Combining GAC adsorption with reverse osmosis resins significantly increases the complexity and cost of PFAS remediation. In addition, such processes produce byproducts of PFAS-contaminated GAC, as well as high-salinity liquids (hyper-saline liquid) contaminated during RO resin regeneration.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Brief summary

The present invention seeks to provide an invention having improved features and properties.

According to an exemplary aspect, the present invention provides an adsorbent for perfluoroalkyl substances and polyfluoroalkyl substances, wherein the adsorbent comprises one or more plant proteins.

In an embodiment, the one or more proteins comprise albumin.

In embodiments, the one or more proteins comprise globulin.

In an embodiment, the one or more proteins comprise edestin.

In embodiments, the one or more proteins comprise glycinin.

In embodiments, the one or more proteins comprise β -conglycinin.

In embodiments, the one or more proteins are structurally similar to albumin and/or globulin and/or edestin and/or glycinin and/or beta-conglycinin.

In embodiments, the one or more proteins are derived from cannabis sativa seeds.

In embodiments, the adsorbent comprises cannabis sativa seed.

In embodiments, the adsorbent comprises hemp protein isolate (hemp protein isolate).

In embodiments, the adsorbent comprises soy protein.

In embodiments, the sorbent further comprises calcite.

In embodiments, the sorbent further comprises an inert material configured to increase the permeability of the sorbent.

In embodiments, the inert substance is glass beads.

In embodiments, the inert material is gravel.

According to an exemplary aspect, the present invention provides the use of an adsorbent according to any one of the above aspects or embodiments for treating materials contaminated with perfluoroalkyl species and polyfluoroalkyl species.

In embodiments, the material is groundwater.

In embodiments, the material is residual water from soil washing.

According to one exemplary aspect, the present invention provides a process for treating groundwater contaminated with perfluoroalkyl species and polyfluoroalkyl species, wherein the contaminated groundwater is pumped to the surface and directed to an adsorption step comprising an adsorbent according to any of the above aspects or embodiments.

According to an exemplary aspect, the present invention provides a process for treating groundwater contaminated with perfluoroalkyl substances and polyfluoroalkyl substances, wherein a permeable reactive barrier (permeable reactive barrier) comprising an adsorbent according to any of the above aspects or embodiments is located in the path of an aquifer (aquifer) contaminated with perfluoroalkyl substances and polyfluoroalkyl substances.

According to an exemplary aspect, the present invention provides a process for treating a used (spent) adsorbent according to any one of the preceding aspects or embodiments, the process comprising thermal destruction (thermoldestraction) of the used adsorbent.

In embodiments, the thermal disruption occurs at a temperature selected from <700 ℃, <650 ℃, <600 ℃, <550 ℃, <500 ℃, or <450 ℃.

In embodiments, the spent adsorbent is dehydrated and dried prior to thermal destruction.

In embodiments, the gases evolved by thermal destruction are washed with an alkaline solution, wherein the alkaline solution subsequently reacts with calcite to form fluorite.

Brief Description of Drawings

Exemplary embodiments will become apparent from the following description of at least one preferred but non-limiting embodiment, which is to be read in connection with the accompanying drawings, which are given by way of example only.

Figure 1 illustrates PFAS removal from exemplary high ionic strength solutions in terms of total sum (total sum) PFAS compounds and% removal of the sum PFHxS + PFOS;

figure 2 illustrates PFAS removal from an exemplary high ionic strength solution in terms of% removal of PFCA alone;

figure 3 illustrates PFAS removal from an exemplary high ionic strength solution in terms of% removal of PFSA alone;

figure 4 illustrates PFAS removal from exemplary low ionic strength solutions in terms of total sum PFAS compounds and% removal of sum PFHxS and PFOS;

figure 5 illustrates PFAS removal from an exemplary low ionic strength solution in terms of% removal of PFCA alone;

figure 6 illustrates PFAS removal from an exemplary low ionic strength solution in terms of% removal of PFSA alone;

figure 7 illustrates the total sum PFAS compounds and the% removal of the sum PFHxS and PFOS in exemplary low ionic strength solutions for cannabis seed powder and cannabis seeds;

figure 8 illustrates the total sum PFAS compounds and the% removal of the sum PFHxS and PFOS in exemplary high ionic strength solutions for cannabis seed powder and cannabis seeds;

figure 9 illustrates the% removal of total sum PFAS compounds and sum PFHxS + PFOS as a function of solid to liquid ratio in exemplary solutions;

FIG. 10 shows a superposition of three thermogravimetric analysis (TGA) tests; the top series shows the mass loss response as a function of time; the middle series shows the heat flow of the reaction; and the bottom series shows the mass loss as a function of temperature;

figure 11 illustrates the% removal of total sum PFAS compounds and sum PFHxS and PFOS compounds from low ionic strength solutions for HSP and SPI;

figure 12 illustrates the% removal of certain PFCA compounds for HSP as well as HSP and SPI;

figure 13 illustrates the% removal of certain PFSA compounds for HSP and SPI;

fig. 14 illustrates the overall analysis procedure for the removal experiment, including the addition of Total Oxidizable Precursor (TOP) analysis.

Figure 15 illustrates PFOS, PFOA, Σ (PFHxS + PFOS), and Σ PFAS removal at low ionic strength as a function of solid to liquid ratio for HSP.

Figure 16 illustrates PFOS, PFOA, Σ (PFHxS + PFOS), and Σ PFAS removal at high ionic strength as a function of solid to liquid ratio for HSP.

FIG. 17 shows PFAS removal at HSP 10g/L for two-stage (A and B) removal.

FIG. 18 shows PFAS removal at HSP 50g/L for two-stage (A and B) removal.

FIG. 19 shows PFAS removal at HSP 100g/L for two-stage (A and B) removal.

Figure 20 illustrates a) at low (native) ionic strength, with HSP only; B) at low (native) ionic strength with HSP and 1.00g/L calcite (<150 μm); C) at high ionic strength, HSP alone; and D) kinetics of PFCA removal with HSP and 1.00g/L calcite (<150 μm) at high ionic strength using HSP.

Figure 21 illustrates a) at low (native) ionic strength, with HSP only; B) at low (native) ionic strength with HSP and 1.00g/L calcite (<150 μm); C) at high ionic strength, HSP alone; and D) kinetics of PFSA removal with HSP and 1.00g/L calcite (<150 μm) at high ionic strength using HSP.

Figure 22 illustrates the removal of specific PFCA by HSP, HSP with calcite and activated carbon.

Figure 23 illustrates the removal of specific PFAS by HSP, HSP and calcite and activated carbon at different ionic strengths.

Fig. 24 illustrates a pseudo-secondary (PSO) model for the instantaneous sorption rate (h) as a function of PFSA carbon chain length.

Fig. 25 illustrates PFAS removal isotherms for PFOS, Σ (PFAS), and Σ (PFHxS + PFOS).

Figure 26 illustrates modeling of maximum removal in terms of mass of PFAS removed per gram of solids and 95% confidence intervals derived from the model fitting process for a) PFOA, B) PFHxA, C) PFOS, D) PFHxS, E) Σ (PFHxS + PFOS), and F) Σ PFAS.

Figure 27 shows PFHxS + PFOS sorption isotherms using HSP.

FIG. 28 is a schematic diagram of a sequential batch reactor (sequential batch reactor).

Fig. 29 illustrates the Thermogravimetric (TG) and heat flow curves during combustion of HSPs exposed only to deionized water.

FIG. 30 is a graph showing thermogravimetric analysis (TG) and heat flow curves during combustion of HSP's exposed to an initial concentration of PFOS of 9.6 mg/L.

Figure 31 shows graphically the infrared difference spectra of HSP samples exposed to three different concentrations of PFOS.

Figure 32 shows FTIR spectra after thermal disruption of HSP control and PFOS-exposed HSP.

Figure 33 illustrates the evolved gas analysis during thermal destruction (at 10 ℃/min) under an oxygen atmosphere for cannabis protein powder exposed to PFOA.

Fig. 34 is a photograph of a laboratory scale Rotary Drum Vacuum (RDV) showing the removal of spent HSP solids from a treated water stream.

Figure 35 shows PFAS% removal for each of the multiple protein powders prior to normalization.

FIG. 36 is a graph showing K for each plant protein after normalization for total protein content_dThe value is obtained. Both a) linear plot and B) logarithmic plot are shown.

Preferred embodiments

The following modes, given by way of example only, are described in order to provide a more precise understanding of the subject matter of one or more preferred embodiments.

In the drawings incorporated to illustrate features of exemplary embodiments, like reference numerals are used to identify like parts throughout the drawings.

It has been surprisingly found that an adsorbent comprising a protein can effectively remove aqueous PFAS. In embodiments, it has been surprisingly found that an adsorbent comprising a plant protein can effectively remove aqueous PFAS. Exemplary non-limiting plant proteins that can serve as adsorbents for PFAS can include: edestin, albumin, globulins such as glycinin and beta-glycinin and/or lupin (lupin). In some embodiments, it has been found that the inclusion of calcite in a sorbent comprising a vegetable protein can enhance the effectiveness of the sorbent. It will be appreciated that the invention is not limited to the proteins listed above and may include proteins having similar properties such as structural similarity and/or similar configuration of functional groups and/or amino acids.

In particular embodiments, it has been surprisingly found that an adsorbent comprising cannabis sativa seed protein can effectively remove aqueous PFAS. The cannabis sativa seed protein may be in the form of cannabis sativa seed, crushed cannabis sativa seed, cannabis sativa seed powder (referred to herein as HSP, cannabis sativa seed powder may also be referred to as "cannabis sativa powder protein" or HPP), cannabis sativa protein isolate, a mixture thereof, or any other suitable form. Without wishing to be bound by theory, it is believed that edestin and/or albumin of cannabis sativa seed protein may be effective substrates for PFAS treatment by adsorption.

It has been found that PFAS can be removed from water to below australian drinking water standards using an adsorbent comprising substantially only cannabis protein. For example, about 98% -99% removal of PFSA species from low ionic strength solutions may be achieved and about 96% -97% removal of PFSA species from high ionic strength solutions may be achieved using an adsorbent comprising substantially only cannabis seed protein.

It has been found that an adsorbent comprising cannabis sativa seed protein and calcite can effectively remove aqueous PFAS. In some embodiments, the inclusion of calcite may enhance the effectiveness of the sorbent to remove certain PFAS. For example, an adsorbent having approximately equal parts of cannabis kernel protein and particulate limestone can increase removal of PFHxA and PFHpA at low and high ionic strengths. For example, use of an adsorbent comprising equal parts of cannabis seed protein and calcite may increase removal of PFHxA from about 72% to > 99.9% and PFHpA from 78.5% to > 99.9% in a low ionic strength solution of about 6mS/cm when compared to use of cannabis seed protein without calcite. The use of an adsorbent comprising equal parts of cannabis and calcite in a high ionic strength solution can increase the removal of PFHxA from about 42% to about 76% and PFHpA from about 69% to about 84%. Without wishing to be bound by theory, it is believed that an adsorbent comprising cannabis protein and calcite may enhance the adsorption performance for certain classes of PFAS, not just the adsorption performance believed to be the addition of cannabis protein alone and calcite. It is understood that sorbents comprising equal parts of protein and calcite are exemplary embodiments, and sorbents characterized by different ratios may be used.

In embodiments, the soy protein-containing adsorbent may be effective in removing aqueous PFAS. The soy protein may be in the form of soy, ground soy, soy flour (soy bean mean), soy protein isolate, mixtures thereof, or any other suitable form. Without wishing to be bound by theory, it is believed that glycinin and/or β -conglycinin of soy protein may effectively remove aqueous PFAS. In addition, the inclusion of calcite may increase the effectiveness of the soy protein containing sorbent.

In some embodiments, the adsorbent may comprise one or more proteins selected from the group consisting of: hempseed protein, soy protein, pea protein, egg protein, whey protein and lupin protein.

In embodiments, the sorbent comprising a protein as described above may be used in conjunction with a pump and treatment system, wherein groundwater contaminated with PFAS species is pumped to the surface for treatment. The treatment process may comprise an adsorption step wherein PFAS-contaminated water is contacted with an adsorbent as described herein. For example, the adsorbent may be contained in a packed bed through which contaminated groundwater passes. In certain embodiments, the packed bed may contain inert materials to increase the interstitial space in the packed bed, thereby increasing the permeability and flow rate therethrough in order to obtain a suitable residence time. Configuring the permeability of the packed bed may also facilitate an economical design of the hydraulic circuit for directing the contaminated water through the packed bed, for example, by reducing pumping head (pumping head) requirements. The inert substance may be glass beads or any other suitable material and may be distributed in the packed bed together with the adsorbent. In embodiments, the adsorbent and inert material may be provided as a premixed product to facilitate easier charging of the adsorption apparatus, such as a packed bed. The remediated water that has undergone the adsorption step may then be returned to an aquifer, or discharged to a surface water channel (surface water source).

In embodiments, the adsorbents as described herein may be used to treat PFAS contaminated groundwater using an in situ Permeable Reactive Barrier (PRB) process. Such processes may involve underground walls (surface walls) that may be installed in a direction substantially perpendicular to the hydraulic gradient of the PFAS-contaminated groundwater. When contaminated groundwater passes through PRBs containing adsorbents, the water can be remediated with PFAS. In certain embodiments, the adsorbent in the PRB may be combined with materials to increase permeability therethrough to achieve a suitable residence time. Such materials may include, for example, gravel, calcite, or any other suitable material having a size of 10mm to 20 mm.

In embodiments, the adsorbents as described herein may be used to treat residual water resulting from washing soil. For example, residual wash water produced by washing PFAS-contaminated soil may become contaminated with PFAS compounds and thus may be treated using an adsorbent as described herein.

In embodiments, the adsorbents as described herein may be used to treat PFAS-contaminated water by a series of batch reactors, wherein the contaminated water passes through each reactor in sequence, and wherein each sequential reactor provides additional amounts of adsorbent to further reduce the PFAS level in the water. The effluent of the first reactor in the series becomes the influent to the second reactor in the series.

In embodiments, after the sorbent has been used, it may be disposed of by thermal destruction. In some embodiments, the spent adsorbent may first be dehydrated and dried, for example by air drying, before being destroyed by heat. It has been surprisingly found that used sorbents as described herein can be thermally destroyed at lower temperatures than would otherwise be expected. Without wishing to be bound by theory, it is believed that sorption of PFAS may affect the binding strength of the organic components of the cannabis protein, thereby enhancing the thermal destruction process. In embodiments, the used sorbent may undergo thermal destruction at a temperature of about <700 ℃. In embodiments, the used sorbent may undergo thermal destruction at a temperature of about <650 ℃. In embodiments, the used sorbent may undergo thermal destruction at a temperature of about <600 ℃. In embodiments, the used sorbent may undergo thermal destruction at a temperature of about <550 ℃. In embodiments, the used sorbent may undergo thermal destruction at a temperature of about <500 ℃. In embodiments, the used sorbent may undergo thermal destruction at a temperature of about <450 ℃.

In embodiments, the gas evolved by the thermal destruction process may be scrubbed, for example, using an alkaline solution. The alkaline solution may then react with calcite to form fluorite.

Many modifications will be apparent to those skilled in the art without departing from the scope of the invention.

Example 1

Two approximately 1 liter samples (A and B) were obtained from water flowing from RAAF Williamtown, NSW, Australia to a drain under the Moor's Creek, Medowie line. The samples were placed in cold bags with ice tiles for shipment to the New Cassel University geological Environment laboratories.

Sample A was spiked with analytical grade (Sigma Aldrich) perfluorooctanoic acid (PFOA), while sample B was combined with sample A1: 1 to form sample C. Sample C was then evenly divided to form sample D, to which sufficient KCl was added to increase the ionic strength to-45 mS/cm. The samples were stored at 4 ℃.

A set of batch reactor samples were set up to determine the extent of PFAS removal using five different sorbents (S1-S5). Batch testing was performed in PFAS approved plasticware, capped and left to equilibrate in a tumble blender (end-over-end stirrer) for at least 3 days. A blank was included in each batch test with Deionized (DI) water, and the DI water was made up to 45mS/cm with KCl. All PFAS analyses were performed in the ALS laboratory in Sydney (Sydney) under a standard set of 28 analytes as listed in table 1.

Laboratory sampling for pH, conductivity (EC), and major cations and anions were performed on subsamples taken from each batch test. pH electrode (Orion 9165BN) calibration was done using pH 4, pH 7 and pH 10 NIST buffers until a slope of 92% -102% was obtained. EC calibrations were performed using an Orion Star A322 instrument and 1413mS/cm standards according to the manual instructions. Anions and cations were analyzed using a Dionex ICS5000 ion chromatograph equipped with an AS18/AG18 anion analysis/guard column running Chromeleon 6.8 software and equipped with 30mM potassium hydroxide (KOH) eluent. For cations, CS12A/CG12 analytical/guard column used 20mM methanesulfonic acid (MSA) eluent. Prior to analysis, five point calibration was performed using seven ion standards combined with Dionex anions and six ion standards combined with Dionex cations.

One key parameter in remediation is the amount of sorbent required to remove a concentration of a contaminant. This requires the establishment of sorption isotherms for each PFAS compound of interest.

Sorption experiments have been performed to establish sorption isotherms for the PFAS/hemp seed powder system. For these experiments, -50L of groundwater was obtained from the most heavily contaminated monitoring well of Williamtown RAAF Base, NSW (MW187 s). The groundwater sample had an amount of PFHxs + PFOS that exceeded 40-fold in the experiment using water samples B, C and D (table 1). Sorption isotherm experiments were performed via the batch reactor method outlined above.

Thermogravimetric analysis (TGA-DSC) using differential scanning calorimetry was performed using a Mettler-toledo TGA2 instrument running STARe software.

The PFAS chemistry used in these experiments is shown in table 1. The term PFAS is used to describe all perfluoroalkyl or polyfluoroalkyl species, however it can be further divided into several categories and then individual species as shown in table 2.

TABLE 1 major PFAS analytes found in groundwater from Williamstown, NSW, in comparison to PFOA-spiked water samples obtained from Moor's Drain, Williamstown and samples collected from monitoring well MW187s adjacent to Williamstown RAAF base

Average of 146 groundwater samples (pH range 3.95-8.56: EC range 0.03-28.6 mS/cm).

Table 2 nomenclature of the most common 28 perfluorinated and polyfluorinated species (PFAS) as analyzed by ALS ENVIRONMENTAL laboratory (ALS environmenttal, 2016). The key PFAS chemicals are coarsened.

The following sorbents were used for the initial tests: (1) cannabis sativa seed protein powder (HSP); (2) hemp Seed (HS); (3) sphagnum peat moss (sphagnum peat moss); (4) humic acid (analytical grade (Sigma Aldrich chemicals)); (5) calcium carbonate (calcite, available from DML Lime, Attunga, NSW); (6) various mixtures of sorbents 1, 2 and 5. Since sorbents 3 and 4 did not show any removal of PFAS contaminants, they were deleted from the test protocol.

Laboratory analysis returned the breakdown of all PFAS species found in the sample as well as the total (sum) of all PFAS and the total of PFHxS + PFOS. Existing studies on PFHxS show that this chemical can cause effects in laboratory test animals similar to those caused by PFOS. However, according to the current studies, PFHxS appears to be less effective than PFOS in animal studies. Thus, PFHxS and PFOS concentrations are reported as combined concentrations.

Health-based guidelines have been established by the Australian Federal Health Department of Health, and currently the maximum drinking water value for PFHxS + PFOS is 0.07 μ g/L and for PFOA is 0.56 μ g/L. These are the only PFAS substances with guiding values.

Figure 1 shows the removal of total (sum) PFAS and PFHxS + PFOS at high ionic strength (water D; table 1). HSP itself removed-90.8% of the initial sum PFAS (2160. mu.g/L) and-96.7% of the initial PFHxS + PFOS (2.41. mu.g/L), giving final concentrations of 0.055. mu.g/L (PFHxS + PFOS) and-198.7 g/L PFAS. It is evident that calcite performs poorly on its own compared to HSP, and that the addition of calcite to HSP does not alter the amount of PFHxS + PFOS removed, but increases the total PFAS removed by-3.1%.

Figure 2 shows the removal of certain PFCA compounds at high ionic strength, while figure 3 shows the removal of certain PFSA compounds at high ionic strength. Figure 2 shows that there is a defined trend in PFCA removal with calcite (1:1) added to HSP, with removal increasing with decreasing carbon chain length. For example, with respect to PFNA (9C (carbon chain)), there is no difference in its removal, PFOA (8C) removal is increased by-2.7%; PFHpA (7C) removal increased by-14.8%; and PFHxA (6C) removal increased by-32.3%.

For PFSA (figure 3), the addition of calcite had no effect on PFOS removal, with HSP final concentrations alone below the laboratory reported limit of reporting (> 99.9% removal). There was a < 1.4% difference in the removal of shorter chain (6C) PFHxS, indicating that the removal of PFSA by HSP is not significantly affected by the presence of calcite.

Calcite (alone) experiments were not performed in the low ionic strength series due to the lack of sample volume. Figures 4 to 6 show the removal from low ionic strength solutions (sample C, table 1) using 100g/L HSP and HSP + calcite PFAS. It is evident from figure 5 that low PFOA removal (-19.1%) is erroneous, indicating-69.9% removal in view of the same sample (not shown) using only 70g/L solid to liquid ratio.

Addition of calcite to HSP resulted in a PFOA removal of > 99.9% (below the laboratory detection limit) at an initial concentration of 969 μ g/L.

As found with the high ionic strength experiments, the addition of calcite to HSPs appears to have a positive effect on PFCA removal, with removal increasing as chain length decreases (in addition to PFOA errors as discussed above). For example, figure 5 shows no increase in PFDA for 10C (carbon chain), 1.4% increase in PFNA (9C), 21.5% increase in PFHpA (7C), and 29.2% increase in PFHxA (6C). Figure 6 shows that the addition of calcite did not affect PFOS removal, however, a slight (-4.0%) increase in PFHxS removal was observed at low ionic strength. After calcite addition to HSP, all other PFAS species present in the initial control sample were removed below the laboratory reported limit (fig. 5-6).

A series of comparative experiments were performed to compare the PFAS removal capacity of a larger hemp seed powder with hemp seed (not powdered). Figure 7 shows a comparison of the removal at low ionic strength and shows that HSP shows much less total (sum) PFAS removed than HS. This is due to the erroneous PFOA results in this experiment (as discussed above), and therefore the total (sum) PFAS removal should be ignored. At high ionic strength (fig. 8), HSP only removed a total (sum) PFAS of-7.3% more than HS. For the total amount of PFHxS + PFOS removed, less than-1% difference between HSP and HS was observed at high ionic strength. This is supported by the low ionic strength results (fig. 7). Thus, depending on cost, it may be advantageous to use HS instead of more refined HSPs.

Figure 9 shows the removal of sum PFAS and sum PFHxS + PFOS as a function of HSP solid to liquid ratio. As expected from sorption reactions, contaminant removal increased with increasing mass, with 100g/L HSP removing-96.7% PFOA reaching 0.22 μ g/L, well below Australian Drinking Water Guidelines (ADWG). However, despite the removal of 98.7% of the initial PFHxS + PFOS, the final concentration (. about.2.12. mu.g/L) still exceeded 0.07. mu.g/L for ADWG.

Figure 10 shows the superposition of three TGA tests using an analytical grade PFOA, unreacted cannabis seed powder and HSP reacted with water sample B. The top series shows the mass loss reaction as a function of time, the middle series shows the heat flow of the reaction, and the bottom series shows the mass loss as a function of temperature (c).

By 140 ℃, PFOA loses its full mass (-99.92%), with two exothermic peaks at-65 ℃ and 125 ℃.

Unreacted HSP's were shown to have only one major mass loss occurring between 180 ℃ and 430 ℃. However, at-82.2%, mass loss is significant and reflects the amount of organic matter (protein) in the sample. In contrast, the reacted HSP had a total mass loss of-80.49% in three different regions (-42.6% between 210 ℃ -260 ℃, 18.47% between 300 ℃ -380 ℃, and 19.42% between 380 ℃ -450 ℃), indicating that sorption of PFAS has altered the binding strength of the organic (possibly protein) components in the HSP. The total mass loss was within 1.5% of the unreacted HSP, indicating that the used HSP showed complete destruction by-450 ℃.