Eurasian Journal of Soil Science

Abstract

The removal of diclofenac by sorption on a synthetic hydrotalcite and on its calcined product was investigated. The solid [Mg-Al-CO3], prepared by cooprecipitation at constant pH, its calcined mixed oxide was obtained; both solid were characterized by X-ray diffraction and infrared spectroscopy (FTIR). The interaction of these materials with diclofenac shows that the kinetics of sorption was fast and followed the second order model. The effects on the diclofenac concentration, sorbent concentration and temperature were studied. The sorption capacity of the calcined hydrotalcite was close to 1.9 mmole g-1, which represents only 66% of the AEC, but at the concentrations measured that amount represents up 95% of the diclofenac present in solution in the case of HT-C. This suggests that, particularly HT-C could to constitute interesting adsorbent for the removal of diclofenac. Recycling by restitution and calcination-rebuilding should support the recovery of this pollutant.

Keywords

Calcined hydrotalcite, diclofenac, sorption capacity, desorption

References

<p>Aisawa, S., Higashiyama, N., Takahashi, S., Hirahara, H., Ikematsu, D., Kondo, H., Nakayama, H., Narita, E., 2007. Intercalation behavior of L-ascorbic acid into layered double hydroxides. Applied Clay Science 35: 146&mdash;154.</p>

<p>Ambrogi, V., Fardella, G., Grandolini, G., Perioli, L., Tiralti, M.C., 2002. Intercalation compounds of hydrotalcite-like Anionic clays with anti-inflammatory agents, II: Uptake of diclofenac for a controlled release formulation. An Official Journal of the American Association of Pharmaceutical Scientists 3: 1&mdash;6.</p>

<p>Ambrogi, V., Perioli, L., Ricci, M., Pulcini, L., Nocchetti, M., Giovagnoli, S., Rossi, C., 2008. Eudragit and hydrotalcite-like anionic clay composite system for diclofenac colonic delivery. Microporous Mesoporous Mater 115: 405&mdash;415.</p>

<p>Andreozzi, R., Marotta, R., Pra&eacute;xus, N.A., 2003. Pharmaceuticals in STP effluents and their solar photodegradation in aquatic environment. Chemosphere 50: 1319&mdash;1330.</p>

<p>Bascialla, G., Regazzoni, A.E., 2008. Immobilization of anionic dyes by intercalation into hydrotalcite. Colloids and Surfaces A: Physicochemical and Engineering Aspects 328: 34&mdash;39.</p>

<p>Boxall, A.B., Blackwell, P., Cavallo, R., Kay, P., Tolls, J., 2002 The sorption and transport of a sulphonamide antibiotic in soil systems. Toxicology Letters 131: 19&mdash;28.</p>

<p>Bruna, F., Pavlovic, .I, Barriga, C., Cornejo, J., Ulibarri, M.A., 2006. Adsorption of pesticides Carbetamide and Metamitron on organohydrotalcite. Applied Clay Science 33: 116&mdash;124.</p>

<p>Casellas, C., 2006. Les m&eacute;dicaments : Contaminants &eacute;mergents ? Environnement. Risques &amp; Sant&eacute; 5: 225.</p>

<p>Ch&eacute;ttelet, L., Bottero, J.Y., Yvon, J., Bouchelaghem, A., 1996. Competition between monovalent and divalent anions for calcined and uncalcined hydrotalcite: anion exchange and adsorption sites. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 111: 167-175</p>

<p>Cleuvers, M., 2004. Mixture toxicity of the anti-inflammatory drugs diclofenac, ibuprofen, naproxen and acelylsalicylid acid. Ecotoxicology and Environmental Safety 59: 309&mdash;315.</p>

<p>De Roy, A., Forano, C., El Malki, K., Besse, J.P., 1992. Anionic clays: trends in pillaring chemistry, In: Synthesis of microporous materials (M.L. Occelli &amp; H.E. Robson, ed.). Van Nostrand Reinhold, New-York, USA, pp. 108&mdash;169.</p>

<p>Del Hoyo, C., 2007. Layered double hydroxides and human health: An overview. Applied Clay Science 36: 103&mdash;121.</p>

<p>Feitosa-Felizzola, J., Temine, B., Chiron, S., 2007. Evaluating on-line solid-phase extraction coupled to liquid chromatography- ion trap mass spectrometry for reliable quantification and confirmation of several classes of antibiotics in urban wastewaters. Journal of Chromatography A 1164: 95&mdash;104.</p>

<p>Ferreira, C.S.G., Nunes, B.A., De Melo Henriques-Almeida, J.M., Guilhermino, L., 2007. Acute toxicity of oxytetracycline and florfenicol to the microalgae Tetraselmis chuii and to the crustacean Artemia parthenogenetica. Ecotoxicology and Environmental Safety 67: 452&mdash;458.</p>

<p>Francis, R. C., Andreas, L., Udo, W., Dieter, J., Liane, H., Gert, H., 2008. Intercalation of Mg&ndash;Al layered double hydroxide by anionic surfactants: Preparation and characterization. Applied Clay Science 38: 153&ndash;164.</p>

<p>Giles, C.H., MacEwan, T.H., Nakhwa, S.N., Smith, D., 1960. Studies in adsorption. Part XI. A system of classification of solution adsorption isotherms, and its use in diagnosis of adsorption mechanisms and in measurement of specific surface areas of solids. Journal of Chemical Society (London) 3973&mdash;3993.</p>

<p>G&ouml;bel, A., Mc Ardell, C.S., Joss, B., Siegrist, H., Giger, W., 2007. Fate of sulfonamide, macrolides, and trimethoprim in different wastewater treatment technologies. Science of the Total Environment 372: 361&mdash;371.</p>

<p>Heberer, T., 2002. Tracking persistent pharmaceutical residues from municipal sewage to drinking water. Journal of Hydrology 266: 175&mdash;189.</p>

<p>Heberer, T., Feldmann, D., 2005. Contribution of effluents from hospitals and private households to the total loads of diclofenac and carbamaz&eacute;pine in municipal sewage effluents. Journal of Hazardous Materials B122, 211&mdash;218.</p>

<p>Hermosin, M.C., Pavlovic, I., Ulibarri, M.A., Cornejo, J., 1996. Hydrotalcite as sorbent for trinitrophenol: Sorption capacity and mechanism. Water Research 30: 171&mdash;177.</p>

<p>Hernando, M.D., Mezcua, M., Fernandez-Alba, A.R., Barcelo, D., 2006. Environmental risk assessment of pharmaceutical residues in wastewater effluents, surface waters and sediments. Talanta 69,:334&mdash;342.</p>

<p>Jean-C, D., Herve&acute;, M., Claude, G., Emil, D., Ioana, F., 2004. Intercalation compounds of Mg&ndash;Al layered double hydroxides with dichlophenac: different methods of preparation and physico-chemical characterization. Applied Clay Science 27: 95&ndash; 106</p>

<p>Kameda, T., Yabuuchi, F., Yoshioka, T., Uchida, M., Okuwaki, A., 2003. New method of treating dilute mineral acids using magnesium-aluminium oxide. Water Research 37: 1545&mdash;1550.</p>

<p>Kaneyoshi, M., Jones, W., 1999. Formation of Mg-Al Layered double hydroxides intercalated with nitrilotriacetate anions. Journal of Materials Chemistry 9: 805&mdash;811.</p>

<p>Kentaro, O., Nobuo, I., Takayoshi, S., 2007. Factors affecting the crystal size of the MgAl-LDH (layered double hydroxide) prepared by using ammonia-releasing reagents. Applied Clay Science 37: 23&ndash;31</p>

<p>Lazaridis, N.K., Karapantsios, T.D., Georgantas, D., 2003. Kinetic analysis for the removal of a reactive dye from aqueous solution onto hydrotalcite by adsorption. Water Research 37: 3023&mdash;3033.</p>

<p>L&uacute;cia, H.M.L.M., Santos Ara&uacute;jo, A.N., Adriano, F., Pena, A., Delerue-Matos, C., Montenegro, M.C.B.S.M., 2010. Ecotoxicological aspects related to the presence of pharmaceuticals in the aquatic environment. Journal of Hazardous Materials 175: 45&mdash;95.</p>

<p>Mehinto, A.C., Hill, E.M., Tyler, C.R., 2010. Uptake and biological effects of environmentally relevant concentrations of the nonsteroidal anti-inflammatory pharmaceutical diclofenac in rainbow trout (Oncorhynchus mykiss). Environmental Science and Technology 44: 2176&mdash;2182.</p>

<p>Mendiboure, A., Sch&ouml;llhom, R., 1986. Formation and anion exchange reaction of layered transition metal hydroxides [Ni1-x Mx](OH)2(CO3)x/2(H2O)x (M=Fe,Co). Revue De Chimie Minerale 23: 819&mdash;827.</p>

<p>Newman, S.P., Jones, W., 1998 Synthesis, characterization and applications of layered double hydroxides containing organic guests. New Journal of Chemistry 22: 105&mdash;115.</p>

<p>Ni, Z.M., Xia, S.J., Wang, L.G., Xing, F.F., Pan, G.X., 2007. Treatment of methyl orange by calcined layered double hydroxides in aqueous solution: Adsorption property and kinetic studies. Journal of Colloid and Interface Science 316: 284&mdash;291.</p>

<p>Palomo, M.E., Ballesteros, M.P., Frutos, P., 1999. Analysis of diclofenac sodium and derivatives. Journal of Pharmaceutical and Biomedical Analysis 21: 83&mdash;94.</p>

<p>Pavan, P.C., Crepaldi, E.L., Valim, J.B., 2000. Sorption of anionic surfactants on layered double hydroxides. Journal of Colloid and Interface Science 229: 346&mdash;352.</p>

<p>Perioli, L., Posati, T., Nocchetti, M., Bellezza, F., Costantino, U., Cipiciani, A., 2011. Intercalation and release of antiinflammatory drug diclofenac into nanosized ZnAl hydrotalcite-like compound. Applied Clay Science 53: 374&mdash;378.</p>

<p>Rafols, C., Roses, M., Bosh, E., 1997. A comparison between different approach to estimate aqueous pKa of several non-steroid antiinflamatory drugs. Analytica Chimica Acta 338: 127</p>

<p>Reichle, W.T., 1986. Synthesis of anionic clay minerals (mixed metal hydroxides, Hydrotalcite). Solid State Ionics 22: 135&mdash;141.</p>

<p>Roelofs, J.C.A.A., Van Bokhoven, J.A., Van Dillen, A.J., Geus, J.W., De Jong, K.P., 2002. The thermal decomposition of Mg-Al hydrotalcites: Effects of interlayer anions and characteristics of the final structure. Chemistry A European Journal 8: 5571&mdash;5578.</p>

<p>San Rom&aacute;n, M.S., Holgado, M.J., Salinas, B., Rives, V., 2012. Characterisation of Diclofenac, Ketoprofen encapsulated in layered double hydroxides. Applied Clay Science 55: 158&mdash;163.</p>

<p>Tauxe-wuersch, A., De Alencostro, L.F., Grandjean, D., Tarradellos, J., 2005. Occurence of several acidic drugs in sewage treatement plants in Switzerland and risk assessement. Water Research 39: 1761&mdash;1772.</p>

<p>Tixier, C., Singer, H.P., Oellers, S., Muller, S.R., 2003. Occurence and fate of carbamazepine, clofibric acid, diclofenac, ibuprofen, ketoprofen and naproxen in surface waters. Environmental Science and Technology 37: 1061&mdash;1068.</p>

<p>Togola, A., Budzinski, H., 2008. Multi-residue analysis of pharmaceutical compounds in aqueous samples. Journal of Chromatography A 1177: 150-158.</p>

<p>Toraishi, T., Nagasaki, S., Tanaka, S., 2002. Adsorption behavior of IO3- by CO32- - and NO3- hydrotalcite. Applied Clay Science 22: 17&mdash;23.</p>

<p>Vaysse, C., 2001. Caract&eacute;risation structurale d&rsquo;hydroxydes doubles lamellaires contenant des anions oxom&eacute;tallates (Mo, W) ou acrylate intercal&eacute;s. Th&egrave;se de Doctorat, Ecole Doctorale des Sciences Chimiques, Universit&eacute; Bordeaux I.</p>

<p>Vieno, N.M., Tuhkanen, T., Kronberg, L., 2006. Analysis of neutral and basic pharmaceuticals in sewage treatment plants and in recipient rivers using solid phase extraction and liquid chromatography-tandem mass spectrometry detection. Journal of Chromatography A 1134: 101&mdash;111.</p>

<p>You, Y., Vance, G.F., Zhao, H., 2001. Selenium adsorption on Mg-Al and Zn-Al layered double hydroxides. Applied Clay Science 20: 13&mdash;25.</p>

<p>You, Y., Zhao, H., Vance, G.F., 2002 Adsorption of dicamba (3,6-dichloro-2-methoxy benzoic acid) in aqueous solution by calcined-layered double hydroxide. Applied Clay Science 21: 217&mdash;226.</p>

<p>Zhu, M.X., Li, Y.P., Xie, M., Xin, H.Z., 2005. Sorption of an anionic dye by uncalcined and calcined layered double hydroxides: a case study. Journal of Hazardous Materials B120, 163&mdash;171.</p>

Abstract
The removal of diclofenac by sorption on a synthetic hydrotalcite and on its calcined product was investigated. The solid [Mg-Al-CO3], prepared by cooprecipitation at constant pH, its calcined mixed oxide was obtained; both solid were characterized by X-ray diffraction and infrared spectroscopy (FTIR). The interaction of these materials with diclofenac shows that the kinetics of sorption was fast and followed the second order model. The effects on the diclofenac concentration, sorbent concentration and temperature were studied. The sorption capacity of the calcined hydrotalcite was close to 1.9 mmole g-1, which represents only 66% of the AEC, but at the concentrations measured that amount represents up 95% of the diclofenac present in solution in the case of HT-C. This suggests that, particularly HT-C could to constitute interesting adsorbent for the removal of diclofenac. Recycling by restitution and calcination-rebuilding should support the recovery of this pollutant.

Keywords: Calcined hydrotalcite, diclofenac, sorption capacity, desorption

References

Aisawa, S., Higashiyama, N., Takahashi, S., Hirahara, H., Ikematsu, D., Kondo, H., Nakayama, H., Narita, E., 2007. Intercalation behavior of L-ascorbic acid into layered double hydroxides. Applied Clay Science 35: 146—154.

Ambrogi, V., Fardella, G., Grandolini, G., Perioli, L., Tiralti, M.C., 2002. Intercalation compounds of hydrotalcite-like Anionic clays with anti-inflammatory agents, II: Uptake of diclofenac for a controlled release formulation. An Official Journal of the American Association of Pharmaceutical Scientists 3: 1—6.

Ambrogi, V., Perioli, L., Ricci, M., Pulcini, L., Nocchetti, M., Giovagnoli, S., Rossi, C., 2008. Eudragit and hydrotalcite-like anionic clay composite system for diclofenac colonic delivery. Microporous Mesoporous Mater 115: 405—415.

Andreozzi, R., Marotta, R., Praéxus, N.A., 2003. Pharmaceuticals in STP effluents and their solar photodegradation in aquatic environment. Chemosphere 50: 1319—1330.

Bascialla, G., Regazzoni, A.E., 2008. Immobilization of anionic dyes by intercalation into hydrotalcite. Colloids and Surfaces A: Physicochemical and Engineering Aspects 328: 34—39.

Boxall, A.B., Blackwell, P., Cavallo, R., Kay, P., Tolls, J., 2002 The sorption and transport of a sulphonamide antibiotic in soil systems. Toxicology Letters 131: 19—28.

Bruna, F., Pavlovic, .I, Barriga, C., Cornejo, J., Ulibarri, M.A., 2006. Adsorption of pesticides Carbetamide and Metamitron on organohydrotalcite. Applied Clay Science 33: 116—124.

Casellas, C., 2006. Les médicaments : Contaminants émergents ? Environnement. Risques & Santé 5: 225.

Chéttelet, L., Bottero, J.Y., Yvon, J., Bouchelaghem, A., 1996. Competition between monovalent and divalent anions for calcined and uncalcined hydrotalcite: anion exchange and adsorption sites. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 111: 167-175

Cleuvers, M., 2004. Mixture toxicity of the anti-inflammatory drugs diclofenac, ibuprofen, naproxen and acelylsalicylid acid. Ecotoxicology and Environmental Safety 59: 309—315.

De Roy, A., Forano, C., El Malki, K., Besse, J.P., 1992. Anionic clays: trends in pillaring chemistry, In: Synthesis of microporous materials (M.L. Occelli & H.E. Robson, ed.). Van Nostrand Reinhold, New-York, USA, pp. 108—169.

Del Hoyo, C., 2007. Layered double hydroxides and human health: An overview. Applied Clay Science 36: 103—121.

Feitosa-Felizzola, J., Temine, B., Chiron, S., 2007. Evaluating on-line solid-phase extraction coupled to liquid chromatography- ion trap mass spectrometry for reliable quantification and confirmation of several classes of antibiotics in urban wastewaters. Journal of Chromatography A 1164: 95—104.

Ferreira, C.S.G., Nunes, B.A., De Melo Henriques-Almeida, J.M., Guilhermino, L., 2007. Acute toxicity of oxytetracycline and florfenicol to the microalgae Tetraselmis chuii and to the crustacean Artemia parthenogenetica. Ecotoxicology and Environmental Safety 67: 452—458.

Francis, R. C., Andreas, L., Udo, W., Dieter, J., Liane, H., Gert, H., 2008. Intercalation of Mg–Al layered double hydroxide by anionic surfactants: Preparation and characterization. Applied Clay Science 38: 153–164.

Giles, C.H., MacEwan, T.H., Nakhwa, S.N., Smith, D., 1960. Studies in adsorption. Part XI. A system of classification of solution adsorption isotherms, and its use in diagnosis of adsorption mechanisms and in measurement of specific surface areas of solids. Journal of Chemical Society (London) 3973—3993.

Göbel, A., Mc Ardell, C.S., Joss, B., Siegrist, H., Giger, W., 2007. Fate of sulfonamide, macrolides, and trimethoprim in different wastewater treatment technologies. Science of the Total Environment 372: 361—371.

Heberer, T., 2002. Tracking persistent pharmaceutical residues from municipal sewage to drinking water. Journal of Hydrology 266: 175—189.

Heberer, T., Feldmann, D., 2005. Contribution of effluents from hospitals and private households to the total loads of diclofenac and carbamazépine in municipal sewage effluents. Journal of Hazardous Materials B122, 211—218.

Hermosin, M.C., Pavlovic, I., Ulibarri, M.A., Cornejo, J., 1996. Hydrotalcite as sorbent for trinitrophenol: Sorption capacity and mechanism. Water Research 30: 171—177.

Hernando, M.D., Mezcua, M., Fernandez-Alba, A.R., Barcelo, D., 2006. Environmental risk assessment of pharmaceutical residues in wastewater effluents, surface waters and sediments. Talanta 69,:334—342.

Jean-C, D., Herve´, M., Claude, G., Emil, D., Ioana, F., 2004. Intercalation compounds of Mg–Al layered double hydroxides with dichlophenac: different methods of preparation and physico-chemical characterization. Applied Clay Science 27: 95– 106

Kameda, T., Yabuuchi, F., Yoshioka, T., Uchida, M., Okuwaki, A., 2003. New method of treating dilute mineral acids using magnesium-aluminium oxide. Water Research 37: 1545—1550.

Kaneyoshi, M., Jones, W., 1999. Formation of Mg-Al Layered double hydroxides intercalated with nitrilotriacetate anions. Journal of Materials Chemistry 9: 805—811.

Kentaro, O., Nobuo, I., Takayoshi, S., 2007. Factors affecting the crystal size of the MgAl-LDH (layered double hydroxide) prepared by using ammonia-releasing reagents. Applied Clay Science 37: 23–31

Lazaridis, N.K., Karapantsios, T.D., Georgantas, D., 2003. Kinetic analysis for the removal of a reactive dye from aqueous solution onto hydrotalcite by adsorption. Water Research 37: 3023—3033.

Lúcia, H.M.L.M., Santos Araújo, A.N., Adriano, F., Pena, A., Delerue-Matos, C., Montenegro, M.C.B.S.M., 2010. Ecotoxicological aspects related to the presence of pharmaceuticals in the aquatic environment. Journal of Hazardous Materials 175: 45—95.

Mehinto, A.C., Hill, E.M., Tyler, C.R., 2010. Uptake and biological effects of environmentally relevant concentrations of the nonsteroidal anti-inflammatory pharmaceutical diclofenac in rainbow trout (Oncorhynchus mykiss). Environmental Science and Technology 44: 2176—2182.

Mendiboure, A., Schöllhom, R., 1986. Formation and anion exchange reaction of layered transition metal hydroxides [Ni1-x Mx](OH)2(CO3)x/2(H2O)x (M=Fe,Co). Revue De Chimie Minerale 23: 819—827.

Newman, S.P., Jones, W., 1998 Synthesis, characterization and applications of layered double hydroxides containing organic guests. New Journal of Chemistry 22: 105—115.

Ni, Z.M., Xia, S.J., Wang, L.G., Xing, F.F., Pan, G.X., 2007. Treatment of methyl orange by calcined layered double hydroxides in aqueous solution: Adsorption property and kinetic studies. Journal of Colloid and Interface Science 316: 284—291.

Palomo, M.E., Ballesteros, M.P., Frutos, P., 1999. Analysis of diclofenac sodium and derivatives. Journal of Pharmaceutical and Biomedical Analysis 21: 83—94.

Pavan, P.C., Crepaldi, E.L., Valim, J.B., 2000. Sorption of anionic surfactants on layered double hydroxides. Journal of Colloid and Interface Science 229: 346—352.

Perioli, L., Posati, T., Nocchetti, M., Bellezza, F., Costantino, U., Cipiciani, A., 2011. Intercalation and release of antiinflammatory drug diclofenac into nanosized ZnAl hydrotalcite-like compound. Applied Clay Science 53: 374—378.

Rafols, C., Roses, M., Bosh, E., 1997. A comparison between different approach to estimate aqueous pKa of several non-steroid antiinflamatory drugs. Analytica Chimica Acta 338: 127

Reichle, W.T., 1986. Synthesis of anionic clay minerals (mixed metal hydroxides, Hydrotalcite). Solid State Ionics 22: 135—141.

Roelofs, J.C.A.A., Van Bokhoven, J.A., Van Dillen, A.J., Geus, J.W., De Jong, K.P., 2002. The thermal decomposition of Mg-Al hydrotalcites: Effects of interlayer anions and characteristics of the final structure. Chemistry A European Journal 8: 5571—5578.

San Román, M.S., Holgado, M.J., Salinas, B., Rives, V., 2012. Characterisation of Diclofenac, Ketoprofen encapsulated in layered double hydroxides. Applied Clay Science 55: 158—163.

Tauxe-wuersch, A., De Alencostro, L.F., Grandjean, D., Tarradellos, J., 2005. Occurence of several acidic drugs in sewage treatement plants in Switzerland and risk assessement. Water Research 39: 1761—1772.

Tixier, C., Singer, H.P., Oellers, S., Muller, S.R., 2003. Occurence and fate of carbamazepine, clofibric acid, diclofenac, ibuprofen, ketoprofen and naproxen in surface waters. Environmental Science and Technology 37: 1061—1068.

Togola, A., Budzinski, H., 2008. Multi-residue analysis of pharmaceutical compounds in aqueous samples. Journal of Chromatography A 1177: 150-158.

Toraishi, T., Nagasaki, S., Tanaka, S., 2002. Adsorption behavior of IO3- by CO32- - and NO3- hydrotalcite. Applied Clay Science 22: 17—23.

Vaysse, C., 2001. Caractérisation structurale d’hydroxydes doubles lamellaires contenant des anions oxométallates (Mo, W) ou acrylate intercalés. Thèse de Doctorat, Ecole Doctorale des Sciences Chimiques, Université Bordeaux I.

Vieno, N.M., Tuhkanen, T., Kronberg, L., 2006. Analysis of neutral and basic pharmaceuticals in sewage treatment plants and in recipient rivers using solid phase extraction and liquid chromatography-tandem mass spectrometry detection. Journal of Chromatography A 1134: 101—111.

You, Y., Vance, G.F., Zhao, H., 2001. Selenium adsorption on Mg-Al and Zn-Al layered double hydroxides. Applied Clay Science 20: 13—25.

You, Y., Zhao, H., Vance, G.F., 2002 Adsorption of dicamba (3,6-dichloro-2-methoxy benzoic acid) in aqueous solution by calcined-layered double hydroxide. Applied Clay Science 21: 217—226.

Zhu, M.X., Li, Y.P., Xie, M., Xin, H.Z., 2005. Sorption of an anionic dye by uncalcined and calcined layered double hydroxides: a case study. Journal of Hazardous Materials B120, 163—171.