MODIFIED ZEOLITE FOR HEAVY METAL REMOVAL

Abstract

The present invention relates to the use of particulate mineral material comprising modified heulandite group zeolite for removing heavy metal cations from a liquid medium, wherein at least a part of the exchangeable cations in the heulandite group zeolite is replaced by ammonium cations.

Claims

1-12. (canceled)

13. A method for removing heavy metal cations from a liquid medium comprising the steps of: a) providing a liquid medium containing heavy metal cations, b) providing particulate mineral material comprising modified heulandite group zeolite, wherein at least a part of the exchangeable cations in the heulandite group zeolite is replaced by ammonium cations, c) contacting the particulate mineral material of step b) with the liquid medium of step a) to remove heavy metal cations from the liquid medium by forming a heavy metal loaded particulate mineral material.

14. The method of claim 13, wherein the particulate mineral material of step b) is prepared by a method comprising the steps of: i) providing a particulate heulandite group zeolite source material, wherein the heulandite group zeolite comprises exchangeable cations, ii) providing an aqueous solution comprising at least one water-soluble ammonium salt, iii) treating the particulate heulandite group zeolite source material of step i) with the aqueous solution of step ii) to form particulate mineral material comprising modified heulandite group zeolite, wherein at least a part of the exchangeable cations in the heulandite group zeolite is replaced by the ammonium cations of the water-soluble ammonium salt.

15. The method of claim 14, wherein the at least one water-soluble ammonium salt of step ii) is selected from ammonium nitrate, ammonium chloride, ammonium bromide, ammonium iodide, ammonium perchlorate, ammonium hydroxide, ammonium carbonate, ammonium sulfate, ammonium phosphate, or mixtures thereof, preferably the at least one water-soluble ammonium salt is ammonium nitrate.

16. The method of claim 14, wherein the at least one water-soluble ammonium salt of step ii) is provided in an amount so that the amount of ammonium cations in the water-soluble ammonium salt is from 0.05 to 20 wt.-%, based on the total weight of the particulate mineral material, preferably in an amount from 0.25 to 7.5 wt.-%, more preferably in an amount from 0.5 to 4 wt.-%, and most preferably in an amount from 1 to 3 wt.-%.

17. The method of claim 14, wherein the aqueous solution comprising the at least one water-soluble ammonium salt of step ii) has an ammonium cation concentration from 0.001 to 20 mol/1, preferably from 0.01 to 15 mol/1, more preferably from 1 to 7.5 mol/1, and most preferably from 2 to 5 mol/1.

18. The method of claim 13, wherein the method further comprises a step d) of removing the heavy metal loaded particulate mineral material from the liquid medium after step c), preferably step d) is performed by filtration, centrifugation, sedimentation, or flotation.

19. The method of claim 13, wherein the method is performed in a system for removing heavy metal cations from a liquid medium comprising a reactor, wherein the reactor comprises an inlet for the liquid medium containing heavy metal cations, the particulate mineral material comprising modified heulandite group zeolite, and an outlet for heavy metal cation depleted liquid medium.

20. A system for removing heavy metal cations from a liquid medium comprising a reactor, wherein the reactor comprises an inlet for a liquid medium containing heavy metal cations, particulate mineral material comprising modified heulandite group zeolite, wherein at least a part of the exchangeable cations in the heulandite group zeolite is replaced by ammonium cations, and an outlet for heavy metal cation depleted liquid medium.

21. The system of claim 20, wherein the reactor contains the particulate mineral material in form of pellets and/or the particulate mineral material is provided in form of a bed or column.

22. The method of claim 14, wherein at least 70% of the exchangeable cations in the heulandite group zeolite are replaced by ammonium cations, preferably at least 90% of the exchangeable cations in the heulandite group zeolite are replaced by ammonium cations, more preferably at least 95% of the exchangeable cations in the heulandite group zeolite are replaced by ammonium cations, and most preferably all exchangeable cations in the heulandite group zeolite are replaced by ammonium cations.

23. The method of claim 13, wherein the heulandite group zeolite is clinoptilolite.

24. The method of claim 13, wherein the particulate mineral material has a weight median particle size d50 from 0.05 to 500 μm, preferably from 0.2 to 200 μm, more preferably from 0.4 to 100 μm, and most preferably from 0.6 to 20 μm, and/or a weight top cut particle size d98 from 0.15 to 1500 μm, preferably from 1 to 600 μm, more preferably from 1.5 to 300 μm, and most preferably from 2 to 80 μm.

25. The method of claim 13, wherein the surface of the particulate mineral material is free of halogen compounds, preferably free of halogen compounds selected from the group consisting of chlorides, chlorates, hypochlorites, bromides, bromates, hypobromites, iodides, iodates, hypoiodites, and mixtures thereof, and most preferably free of halogen compounds selected from the group consisting of bromine, chlorine, iodine, sodium bromide, calcium bromide, magnesium bromide, copper (II) bromide, iron (II) bromide, iron (III) bromide, zinc bromide, potassium bromide, copper (I) chloride, copper (II) chloride, iron (II) chloride, iron (III) chloride, zinc chloride, calcium hypochlorite, calcium hypobromite, calcium hypoiodite, calcium chloride, calcium iodide, magnesium chloride, magnesium iodide, sodium chloride, sodium iodide, potassium tri-chloride, potassium tri-bromide, potassium tri-iodide, or mixtures thereof.

26. The method of claim 13, wherein the particulate mineral material has a specific surface area of from 5 m2/g to 200 m2/g, preferably from 10 m2/g to 180 m2/g, more preferably from 20 m2/g to 170 m2/g, even more preferably from 25 m2/g to 150 m2/g, and most preferably from 30 m2/g to 120 m2/g, measured using nitrogen sorption and the BET method.

27. The method of claim 13, wherein the heavy metal cations are selected from the group consisting of arsenic, cadmium, chromium, cobalt, copper, gold, iron, lead, manganese, mercury, molybdenum, nickel, silver, tin, zinc, or mixtures thereof, preferably the heavy metal cations are selected from the group consisting of cadmium, copper, lead, mercury, zinc, or mixtures thereof, more preferably the heavy metal cations are selected from the group consisting of copper, lead, mercury, or mixtures thereof, and most preferably the heavy metal cations are mercury cations.

28. The system of claim 20, wherein the liquid medium is an aqueous medium, preferably the aqueous medium is selected from process water, sewage water, waste water, preferably waste water from the paper industry, waste water from the colour-, paints-, or coatings industry, waste water from breweries, waste water from the leather industry, agricultural waste water, slaughterhouse waste water, process or waste water from power plants, waste water from waste incineration, waste water from mercury recycling, waste water from cement production, waste water from steel production, waste water from production of fossil fuels, from sludge, preferably sewage sludge, harbour sludge, river sludge, coastal sludge, digested sludge, mining sludge, municipal sludge, civil engineering sludge, sludge from oil drilling or the effluents the aforementioned dewatered sludges.

29. The system of claim 20, wherein at least 70% of the exchangeable cations in the heulandite group zeolite are replaced by ammonium cations, preferably at least 90% of the exchangeable cations in the heulandite group zeolite are replaced by ammonium cations, more preferably at least 95% of the exchangeable cations in the heulandite group zeolite are replaced by ammonium cations, and most preferably all exchangeable cations in the heulandite group zeolite are replaced by ammonium cations.

30. The system of claim 20, wherein the particulate mineral material has a weight median particle size d50 from 0.05 to 500 μm, preferably from 0.2 to 200 μm, more preferably from 0.4 to 100 μm, and most preferably from 0.6 to 20 μm, and/or a weight top cut particle size d98 from 0.15 to 1500 μm, preferably from 1 to 600 μm, more preferably from 1.5 to 300 μm, and most preferably from 2 to 80 μm.

31. The system of claim 20, wherein the particulate mineral material has a specific surface area of from 5 m2/g to 200 m2/g, preferably from 10 m2/g to 180 m2/g, more preferably from 20 m2/g to 170 m2/g, even more preferably from 25 m2/g to 150 m2/g, and most preferably from 30 m2/g to 120 m2/g, measured using nitrogen sorption and the BET method.

32. The system of claim 20, wherein the heavy metal cations are selected from the group consisting of arsenic, cadmium, chromium, cobalt, copper, gold, iron, lead, manganese, mercury, molybdenum, nickel, silver, tin, zinc, or mixtures thereof, preferably the heavy metal cations are selected from the group consisting of cadmium, copper, lead, mercury, zinc, or mixtures thereof, more preferably the heavy metal cations are selected from the group consisting of copper, lead, mercury, or mixtures thereof, and most preferably the heavy

Description

EXAMPLES

1. Measuring Methods

[0162] In the following, measuring methods implemented in the examples are described. Reference is also made to the methods already described above.

[0163] Elemental Analysis

[0164] For elemental analysis by X-ray fluorescence (XRF), 0.8 g sample and 6.5 g Li-tetraborate were founded to a glass disk by means of melting decomposition. By means of sequential, wavelength dispersive X-ray fluorescence, the elemental composition of the sample was measured in an ARL™ PERFORM′X Sequential X-Ray Fluorescence Spectrometer by Thermo Scientific. The calculation of the elemental composition was made using a calibration optimized for melting decomposition.

[0165] X-Ray Diffraction

[0166] For X-ray diffraction, the powered samples were loaded into PMMA sample holders. To attain a reproducible surface for quantitative analysis, a backloading technique was used where the PMMA sample holder was placed on a flat glass plate, loaded from the back, and pressed manually. Samples were analysed with a Bruker D8 Advance powder diffractometer obeying Bragg's law. This diffractometer consists of a 1 kW X-ray tube, a sample holder, a 0-0 goniometer, and a LYNXEYE XE-T detector. The profiles were chart recorded automatically using a scan speed of 0.02° per second in 20. The resulting powder diffraction pattern can easily be classified by mineral content using the DIFFRACsuite software packages EVA and SEARCH, based on reference patterns of the ICDD PDF. Quantitative analysis of diffraction data refers to the determination of amounts of different phases in a multi-phase sample and has been performed using the DIFFRACsuite software package TOPAS.

[0167] Nitrogen Sorption

[0168] Nitrogen sorption at −196° C. was carried out in a Micromeritics TriStar II instrument by acquiring an 83 point isotherm following a full adsorption-desorption cycle. Prior to the measurement, the samples were evacuated at 300° C. for 3 h. The BET surface (SBET) was determined by applying the Brunauer-Emmett-Teller (BET) equation to the sorption data in the range 0.05<p/p.sup.0<0.25. The mesopore surface (S.sub.meso) was calculated by application of the t-plot method in a thickness range of 4.5-6 Å. Single point pore volumes (V.sub.pore) were calculated based on the total adsorption at at p/p.sup.0=0.98.

2. Manufacture of the Particulate Mineral Materials

[0169] For ion-exchange, natural clinoptilolite obtained from Gordes Zeolite, Turkey (175 g) was introduced into 500 g of a 3.5 wt.-% solution of NaCl, KCl, or NH4NO3, wherein the wt.-% is based on the total weight of the solution, and stirred for 1 h. Subsequently, the slurry was centrifuged at 3000 rpm for 5 min, the supernatant discarded, and the solids re-dispersed in demineralized water for washing. The zeolites were then centrifuged again under identical conditions and the supernatant was discarded.

[0170] The as-received clinoptilolite (denoted Clin-P) was subjected to one, two, or three subsequent ion-exchange treatments as described above. The resulting materials were denoted Clin-CX, where C represents the applied salt (Na, K, and NH for NaCl, KCl, and NH4NO3, respectively) and X represents the number of consecutive ion-exchange treatments applied to the sample. As an example, the material Clin-NH2 was subjected to two ion-exchange treatments with NH4NO3.

[0171] After the desired number of ion-exchange treatments was conducted, the centrifuged material was dried in an oven at 105° C. and disagglomerated.

[0172] Acid treatments were conducted by introducing 175 g of zeolite into 500 g of a HCl solution having a concentration from 0.125 M to 1 M for 1 h, and subsequently applying the same washing and drying protocol as for ion-exchanged zeolites. The resulting materials were denoted Clin-HClY, where Y represents the employed concentration of HCl in M.

3. Characterization of the Particulate Mineral Materials

[0173] The effect of the treatments on the structure and composition of the zeolites was determined by quantitative XRF analysis and nitrogen sorption analysis (Table 1). The parent material (#A), as well as the ion-exchanged samples (#B-J) evidenced a molar Si/Al ratio of ca. 4.85, a BET surface (SBET) of 52-55 m2 g-1, and a pore volume determined by nitrogen sorption (Vpore) of 0.13 cm3 g-1. As the observed differences lie within the experimental uncertainty of the respective analyses, it can be assumed that no pronounced chemical and/or morphological changes occurred besides the exchange of cations.

[0174] In contrast, the samples treated with HCl evidenced an increased surface area, which can result from the dissolution of side-phases, from ion-exchange of the zeolite into protonic form which makes the small micropores accessible to nitrogen, or from the leaching of aluminum from the zeolite which results in the formation of mesopores. The mesopore surface (Smeso) is only increased for the two samples treated at higher concentrations (#K, L), suggesting that the proton ion-exchange of the zeolite is the major source of the increased surface area.

[0175] The mineralogical composition of selected samples was quantified by XRD diffraction and is provided in Table 2.

TABLE-US-00001 TABLE 1 Physico-chemical properties of the zeolite samples. Si/Al Δ.sup.b S.sub.BET.sup.c/ S.sub.meso.sup.d V.sub.pore.sup.e/ Sample zeolite [mol/mol] Na.sup.a [%] K.sup.a [%] Ca.sup.a [%] Mg.sup.a [%] [%] [m.sup.2/g] [m.sup.2/g] [cm.sup.3/g] A Clin-P 4.84 6 26 44 6 18 52.15 41.98 0.13 B Clin-Na1 4.84 51 22 24 3  0 52.54 43.36 0.13 C Clin-Na2 4.84 73 20 12 2 −7 50.64 39.63 0.13 D Clin-Na3 4.86 78 17 12 2 −9 53.47 43.42 0.13 E Clin-K1 4.84 1 76 16 2  5 52.23 42.91 0.12 F Clin-K2 4.84 0 90 6 0  4 51.94 40.63 0.13 G Clin-K3 4.84 1 89 6 1  3 54.89 44.28 0.14 H Clin-NH1 4.84 2 16 16 3 63 53.47 43.42 0.14 I Clin-NH2 4.85 1 7 2 1 89 55.81 45.09 0.13 J Clin-NH3 4.85 2 0 0 1 97 54.33 43.00 0.14 K Clin-C1 5.25 4 22 15 2 57.sup.f 73.20 47.06 0.14 L Clin-C0.5 5.13 5 26 19 4 46.sup.f 66.74 46.79 0.14 M Clin-C0.25 5.00 6 27 23 4 40.sup.f 56.13 43.08 0.14 N Clin-C0.13 4.88 6 28 29 6 31.sup.f 61.30 44.59 0.13 .sup.aFraction of the effective cation exchange capacity (CEC.sub.eff) occupied by the indicated atom. .sup.bFraction of CEc.sub.eff not accounted for by Ca, Mg, Na, K. It can be safely assumed that the indicated value predominantly corresponds to NH.sub.4.sup.+. .sup.cBET equation applied to N.sub.2 sorption data, p/p.sup.0 = 0.05-0.25. .sup.dt-plot method, fitted to N.sub.2 sorption data in a thickness range of 4.5-6 Å. .sup.eSingle point pore volume based on N.sub.2 sorption, p/p.sup.0 = 0.98 (≈50 nm pore size, BJH model). .sup.fPercentage values assuming unaltered CEC (ignoring the evidenced Al leaching).

TABLE-US-00002 TABLE 2 Mineralogical composition of the zeolites based on quantitative Riedveld analysis. Clinoptilolite Heulandite.sup.a Stilbite Σzeolites var SiO.sub.2.sup.b Feldspar Clays Muscovite Others Sample zeolite [%] [%] [%] [%] [%] [%] [%] [%] A Clin-P 51 4 55 22 14 4 3 1 D Clin-Na3 51 5 56 24 16 0 3 3.sup.c G Clin-K3 48 3 51 25 15 0 5 3.sup.d J Clin-NH3 48 4 52 25 15 2 5 2 K Clin-C1 49 3 52 28 15 0 2 2 L Clin-C0.5 50 3 53 27 15 0 3 2 M Clin-C0.25 52 3 55 26 15 0 3 2 N Clin-C0.13 53 3 56 25 14 0 3 2 .sup.aClinoptilolite and heulandite are isostructural and with different Si/A1 ratios. This makes discrimination based on XRD challenging, for which reason they were summarized. .sup.bCristobalite, Quartz, Tridymite. .sup.c1% Halite (NaCl). .sup.d1% Sylvite (KC1).

4. Removal of Heavy Metal or Ammonium Cations

[0176] Adsorption experiments with heavy metal cations were conducted using stock solutions having a heavy metal cation concentration of 10 ppm (Cd, Cu, Pb and Zn) or 1 ppm (Hg) prepared by dilution of commercial ICP-standards (Cd: 10000 mg L-1 Cd in 5% HNO3, Sigma-Aldrich product 90006-100ML; Cu: 10000 mg L-1 Cu in 2-3% HNO3, Merck product 1.70378.0100; Pb: 1000 mg L-1 Pb in 2% HNO3 Sigma-Aldrich product 41318 100ML-F; Zn: 10000 mg L-1 Zn in 5% HNO3, Merck product 1.70389.0100; Hg: 10000 mg L-1 Hg in 12% HNO3, Sigma-Aldrich product 75111-100ML) with Milli-Q filtered, deionized water. From the stock solutions, the desired quantity was transferred into a glass flask prepared with the desired quantity of mineral, as indicated in the tables. The solids were suspended by magnetic stirring (800 rpm, 1 h) and subsequently filtered through a syringe filter (Chromafil Xtra, RC-20/25 0.2 μm).

[0177] The concentration of Cd, Cu, Pb and Zn in the filtered solutions was determined on a Hach Lange DR6000 spectral photometer using Hach Lange LCK 308, LCK 529, LCK 306, and LCK 360 cuvette tests, respectively. Samples were diluted as necessary to match the target range of the cuvette tests. The heavy metals removal performance was calculated by comparison with a blank experiment conducted under identical conditions.

[0178] The concentration of Hg was determined in a Perkin Elmer FIMS instrument. For the analysis, 50 μL of the samples was diluted with 50 mL with Milli-Q filtered, deionized water (1:1000), and stabilized with 1 drop of a 5 wt.-% KMnO3 solution and 2 mL of concentrated HNO3. The analysis was conducted within 4 h against a 5-point calibration curve in the range of 0.5-5 ppb.

[0179] Comparative adsorption experiments with ammonium cations were conducted using stock solutions having an ammonium cation concentration of 2 ppm, or 20 ppm prepared by dissolution of ammonium nitrate (Sigma-Aldrich) with deionized water. Ca. 100 g of the desired stock solution was transferred into a glass flask prepared with 0.25-0.2 g of one of the minerals indicated in Table 2. The solids were suspended by magnetic stirring (800 rpm, 1 h) and subsequently filtered through a syringe filter (Chromafil Xtra, RC-20/25 0.2 μm).

[0180] The ammonium concentrations were determined using a Hach Lange DR6000 spectral photometer using LCK 304 cuvette tests. Samples were diluted as necessary to match the target range of the cuvette tests.

[0181] 4.1 Cd Removal Experiments

[0182] Experiments were conducted to assess the performance of the natural and modified clinoptilolite in the removal of Cd. The results are provided in Table 3.

TABLE-US-00003 TABLE 3 Experimental details and results of Cd removal. Cd m.sub.zeolite m.sub.solution c.sub.start c.sub.end removal Example Zeolite [g] [g] [mg/L] [%] [%]  1 Clin-P 0.0990 96.39 7.33 5.27 28  2 Clin-Na1 0.1028 97.20 7.33 3.06 58  3 Clin-Na2 0.1021 95.29 7.33 1.62 78  4 Clin-Na3 0.1011 94.84 7.33 1.54 79  5 Clin-K1 0.1000 95.56 7.33 2.82 62  6 Clin-K2 0.1005 93.22 7.33 2.48 66  7 Clin-K3 0.1036 96.94 7.33 4.22 42  8 (inventive) Clin-NH1 0.0992 95.53 7.33 2.64 64  9 (inventive) Clin-NH2 0.0982 96.58 7.33 1.47 80 10 (inventive) Clin-NH3 0.0999 95.07 7.33 0.40 95 11 Clin-C1 0.0987 94.59 7.33 6.36 13 12 Clin-C0.5 0.0990 96.19 7.33 5.82 21 13 Clin-C0.25 0.1041 95.67 7.33 4.71 36 14 Clin-C0.13 0.1013 96.57 7.33 5.85 20

[0183] It can be gathered from the comparison of comparative Example 1 with inventive Examples 8-10 that the modified clinoptilolite zeolite attains a higher Cd removal than the untreated materials. A comparison of the inventive Examples 8-10 with the comparative Examples 2-7 and 11-14 prepared by other treatment protocols evidences a better performance of the inventive particulate mineral materials compared to the comparative particulate mineral materials comprising ion-exchange with other cations or acid treatments.

[0184] 4.2 Cu Removal Experiments

[0185] Experiments were conducted to assess the performance of the natural and modified clinoptilolite in the removal of Cu. The results are provided in Table 4.

TABLE-US-00004 TABLE 4 Experimental details and results of Cu removal. Cu m.sub.zeolite m.sub.solution c.sub.start c.sub.end removal Example Zeolite [g] [g] [mg/L] [%] [%] 15 Clin-P 0.1031 96.51 10.1 7.01 31 19 Clin-K1 0.0994 95.45 10.1 5.89 42 20 Clin-K2 0.0990 96.67 10.1 5.67 44 21 Clin-K3 0.0958 96.89 10.1 5.64 44 22 (inventive) Clin-NH1 0.0978 97.81 10.1 4.94 51 23 (inventive) Clin-NH2 0.1035 97.05 10.1 3.74 63 24 (inventive) Clin-NH3 0.1023 96.45 10.1 3.49 65 25 Clin-C1 0.1011 96.99 10.1 9.27 8 26 Clin-C0.5 0.1009 96.10 10.1 8.79 13 27 Clin-C0.25 0.0988 95.44 10.1 7.76 23 28 Clin-C0.13 0.0971 95.90 10.1 7.58 25

[0186] It can be gathered from the comparison of comparative Example 15 with inventive Examples 22-24 that the modified clinoptilolite zeolite attains a higher Cu removal than the untreated materials. A comparison of inventive Examples 22-24 with comparative Examples 19-21 and 25-28 prepared by other treatment protocols evidences a better performance of the inventive particulate mineral materials compared to the comparative particulate mineral materials comprising ion-exchange with other cations or acid treatments.

[0187] 4.3 Pb Removal Experiments

[0188] Experiments were conducted to assess the performance of the natural and modified clinoptilolite in the removal of Pb. The results are provided in Table 5.

TABLE-US-00005 TABLE 5 Experimental details and results of Pb removal. m.sub.zeolite m.sub.solution c.sub.start c.sub.end Pb removal Example Zeolite [g] [g] [mg/L] [%] [%] 29 Clin-P — 95.21 11.9 11.9 88.5 33 Clin-K1 0.0519 96.52 11.9 0.138 98.4 34 Clin-K2 0.0506 93.94 11.9 0.192 98.6 35 Clin-K3 0.0520 93.31 11.9 0.169 98.4 36 (inventive) Clin-NH1 0.0513 94.38 11.9 0.192 98.8 37 (inventive) Clin-NH2 0.0507 93.92 11.9 0.141 98.8 38 (inventive) Clin-NH3 0.0493 94.87 11.9 0.137 98.8 39 Clin-C1 0.0498 98.31 11.9 0.138 35.6 40 Clin-C0.5 0.0506 95.25 11.9 7.66 54.8 41 Clin-C0.25 0.0520 94.99 11.9 5.38 76.5 42 Clin-C0.13 0.0514 96.41 11.9 2.8 78.9

[0189] It can be gathered from the comparison of comparative Example 29 with inventive Examples 36-38 that the modified clinoptilolite zeolite attains a higher Pb removal than the untreated materials. A comparison of inventive Examples 36-38 with comparative Examples 33-35 and 39-42 prepared by other treatment protocols evidences a better performance of the inventive particulate mineral materials compared to the comparative particulate mineral materials comprising ion-exchange with other cations or acid treatments.

[0190] 4.4 Zn Removal Experiments

[0191] Experiments were conducted to assess the performance of the natural and modified clinoptilolite in the removal of Zn. The results are provided in Table 6.

TABLE-US-00006 TABLE 6 Experimental details and results of Zn removal. Zn m.sub.zeolite m.sub.solution c.sub.start c.sub.end removal Example Zeolite [g] [g] [mg/L] [%] [%] 43 Clin-P 0.1003 95.21 8.78 6.01 32 44 Clin-Na1 0.1024 93.66 8.78 6.02 31 45 Clin-Na2 0.0999 94.22 8.78 5.65 36 46 Clin-Na3 0.0991 95.05 8.78 5.65 36 47 Clin-K1 0.0980 95.62 8.78 6.44 27 48 Clin-K2 0.1005 96.89 8.78 6.35 28 49 Clin-K3 0.1021 96.81 8.78 6.21 29 50 (inventive) Clin-NH1 0.1022 95.30 8.78 5.42 38 51 (inventive) Clin-NH2 0.0976 93.93 8.78 5.16 41 52 (inventive) Clin-NH3 0.1004 95.69 8.78 5.01 43 53 Clin-C1 0.0961 95.54 8.78 8.77 0 54 Clin-C0.5 0.0952 94.60 8.78 7.74 12 55 Clin-C0.25 0.0997 97.52 8.78 7.06 20 56 Clin-C0.13 0.0996 96.51 8.78 7.00 20

[0192] It can be gathered from the comparison of comparative Example 43 with inventive Example 50-52 that the modified clinoptilolite zeolite attains a higher Zn removal than the untreated materials. A comparison of inventive Examples 50-52 with comparative Examples 44-49 and 53-56 prepared by other treatment protocols evidences a better performance of the inventive particulate mineral materials compared to the comparative particulate mineral materials comprising ion-exchange with other cations or acid treatments.

[0193] 4.5 Hg Removal Experiments

[0194] Experiments were conducted to assess the performance of the natural and modified clinoptilolite in the removal of Hg. The results are provided in Table 7.

TABLE-US-00007 TABLE 7 Experimental details and results of Hg removal. Hg m.sub.zeolite m.sub.solution c.sub.start c.sub.end removal Example Zeolite [g] [g] [mg/L] [%] [%] 57 Clin-P 0.0820 42.56 1.00.sup.a 0.306 69 58 Clin-Na1 0.0810 42.02 1.00.sup.a 0.751 25 59 Clin-Na2 0.0825 42.26 1.00.sup.a 0.832 17 60 Clin-Na3 0.0802 40.40 1.00.sup.a 0.742 26 61 Clin-K1 0.0816 40.09 1.00.sup.a 0.482 52 62 Clin-K2 0.0809 42.04 1.00.sup.a 0.732 27 63 Clin-K3 0.0812 39.41 1.00.sup.a 0.729 27 64 (inventive) Clin-NH1 0.0809 40.10 1.00.sup.a 0.001 99.9 65 (inventive) Clin-NH2 0.0812 40.33 1.00.sup.a 0.001 99.9 66 (inventive) Clin-NH3 0.0803 43.27 1.00.sup.a 0.001 99.9 67 Clin-C1 0.0809 40.10 1.00.sup.a 0.848 15 68 Clin-C0.5 0.0803 40.69 1.00.sup.a 0.821 18 69 Clin-C0.25 0.0796 42.21 1.00.sup.a 0.757 24 70 Clin-C0.13 0.0826 40.50 1.00.sup.a 0.777 22 .sup.acalculated starting concentration based on weigh-in.

[0195] It can be gathered from the comparison of comparative Example 57 with inventive Examples 64-66 that the modified clinoptilolite zeolite attains a higher Hg removal than the untreated materials. A comparison of the inventive Examples 64-66 with comparative Examples 58-63 and 67-70 prepared by other treatment protocols evidences a better performance of the inventive particulate mineral materials compared to the comparative particulate mineral materials comprising ion-exchange with other cations or acid treatments.

[0196] 4.6 Ammonium Removal Experiments (Comparative Examples)

[0197] Experiments were conducted to assess the performance of the natural and modified clinoptilolite in the removal of ammonium. The results are provided in Table 8.

TABLE-US-00008 TABLE 8 Experimental details and results of ammonium removal. m.sub.zeolite m.sub.solution c.sub.start c.sub.end Hg removal Example Zeolite [g] [g] [mg/L] [%] [%] 71 Clin-P 0.0982 97.03 20.00 14.70 27 72 Clin-Na1 0.1017 95.78 20.00 12.30 39 73 Clin-Na2 0.1018 94.89 20.00 10.80 46 74 Clin-Na3 0.1003 95.25 20.00 10.70 47 75 Clin-K1 0.1016 93.34 20.00 13.80 31 76 Clin-K2 0.1021 94.48 20.00 14.00 30 77 Clin-K3 0.0994 96.44 20.00 14.00 30 78 Clin-NH1 0.1019 94.51 20.00 18.90 6 79 Clin-NH2 0.1012 97.83 20.00 20.70 −4.sup.a 80 Clin-NH3 0.0952 93.85 20.00 21.10 −6.sup.a 81 Clin-C1 0.1008 96.63 20.00 16.40 18 82 Clin-C0.5 0.1016 93.15 20.00 15.20 24 83 Clin-C0.25 0.1009 94.78 20.00 6.42 68 84 Clin-C0.13 0.1007 96.28 20.00 14.90 26

[0198] It can be gathered from the comparison of Example 71 with Examples 78-80 that the modified clinoptilolite zeolite attains a reduced performance compared to the untreated material. In contrast, the other treatment protocols evidence a better performance, particularly the samples ion-exchanged with NaCl (Examples 72-74), and the HCl-treated samples (Examples 81-84).

5. Conclusions

[0199] It can be gathered from the above data that the modified natural heulandite zeolites described in this document consistently attain an improved performance in the removal of heavy metals from a liquid medium. Furthermore, Examples 64 to 66 show that the inventive particulate mineral material provides an outstanding performance in the removal of mercury cations.