Comparative evaluation of NTA and EDTA for extractive decontamination of Pb-polluted soils
Tóm tắt
Nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) were compared for their ability to solubilize Pb from a highly-contaminated (PbT 21%) soil collected from a battery recycling facility. For chelant concentrations below 0.04 M (representing a 1:1 chelant-to-PbT molar ratio), EDTA released 10 to 30% more Pb than NTA. NTA-to-Pb T ratios greater than 1:1 reduced Pb recovery because of readsorption of Pb(NTA)2
4− onto positively-charged oxide soil components at pH < 8.5. For the EDTA system, however, complexation completely bound all coordination sites of Pb and EDTA, leaving no functional groups available for surface adsorption. Thus, Pb recovery progressively increased with higher EDTA concentrations, although the additional Pb release with each EDTA increment became smaller. For pH < 5 and EDTA/Pb of 2:1, Pb recovery exceeded 90%. The addition of 0.5 M NaC1O4 enhanced Pb recovery by EDTA for pH 5 to 12, but substantially suppressed recovery by NTA for pH < 11. Because Pb release by NTA was diminished by high ionic strength and chelant-to-metal ratios, NTA may be limited as a soil washing reagent. Stronger complexation and consistent Pb desorption behavior by EDTA favors its use.
Tài liệu tham khảo
Anson, F. C.: 1975, Ace. Chem. Res. 8, 400.
Assink, J. W.: 1986, ‘Extractive Methods for Soil Decontamination: A General Survey and Review of Operational Treatment Installations’, in J. W. Assink and W. J. van den Brink (eds.), Contaminated Soil, Martinus Nijhoff, Dordrecht, Holland, p. 655.
Banat, K., Forstner, V., and Muller, G.: 1974. Chem. Geol. 14, 199.
Benjamin, M. M. and Leckie, J. O.: 1981, Environ. Sci. Tech. 15, 1050.
Borggaard, O. K.: 1979, J. Soil Sci. 30, 727.
Bowers, A. R.: 1982, ‘Adsorption Characteristics of Various Heavy Metals at the Oxide-Solution Interface’, PhD thesis. University of Delaware, Newark. U.S.
Childs, C. W.: 1971, ‘Chemical Equilibrium Models for Lake Water Containing Nitrilotriacetate and for Normal Lake Water’, Proc. 14th Conf. Great Lakes Res., Intl. Assoc. Great Lakes Res., p. 198.
Chubin, R. G. and Street, J. J.: 1981, J. Environ. Qual. 10, 225.
Elliott, H. A. and Huang, C. P.: 1979, J. Colloid Interface Sci. 70, 29.
Elliott, H. A., Linn J. H., and Shields, G. A.: 1989, Hazard. Wastes Hazard. Mat. 6, (in press).
Elliott, H. A. and Denneny, C. M.: 1982, J. Environ. Qual. 11, 658.
Ellis, W. D., Fogg, T. C., and Tafuri, A. N.: 1986, USEPA Hazardous Waste Engr. Res. Lab. Cincinnati, OH.
Farrah, H. and Pickering, W. F.: 1977, Aust. J. Chem. 30, 1417.
Garnett, K., Kirk, P. W. W., Lester, J. N., and Perry, R.: 1985, J. Environ. Qual. 14, 549.
Guy, R. D. and Chakrabarti, D. L.: 1976, Can. J. Chem. 54, 2600.
Karamanos, R. E., Bettany, J. R., and Rennie, D. A.: 1976, Can. J. Soil Sci. 56, 37.
Kobayashi, J. Morii, F., and Muramato, S.: 1974, Removal of Cadmium from Polluted Soil with the Chelating Agent EDTA, in D. N. Hemphill (ed.), Trace Subst. in Environ: Health, XIII. Univ. of Missouri, p. 179.
Lindsay, W. L.: 1979, Chemical Equilibria in Soils, Wiley-Interscience, New York.
Martell, A. E. and Smith, R. M.: 1976, Critical Stability Constants, Plenum Press, New York.
Miller, W. P., Martens, D. C., and Zelazny, L. W.: 1986. Soil Sci. Soc. Am. J. 50, 598.
PEI Associates, Inc.: 1986, Electromembrane Process for Recovery of Lead from Contaminated Soils. Nat. Science Foundation Grant No. ISI-8560730.
Pickering, W. F.: 1986, Ore Geol. Rev. 1, 83.
Preer, J. R., Akintoye, J. O., and Martin, M. L.: 1984, Biol. Trace Element Res. 6, 79.
Sims, R. and Wagner, K.: 1983, ‘In-situ Treatment Techniques Applicable to Large Quantities of Hazardous Waste Contaminated Soils’, in Proc. of Management of Uncontrolled Hazardous Waste Sites, Hazardous Materials Control Res. Inst. Silver Spring, MD, p. 226.
Snoeyink, V. L. and Jenkins, D.: 1980, Water Chemistry, John Wiley, New York.
Temple, P. J., Linzon, S. N., and Chai, B. L.: 1977, Environ. Pollut. 12, 311.
Vuceta, J. and Morgan, J. J.: 1978, Environ. Sci. Tech. 12, 130.
Vydra, F. and Markova, V.: 1962, Talanta 9, 449.
Winslow, G.: 1988, Hazard. Waste Manag. Magazine. Nov-Dec. p. 7.