Authors: T Mosekiemang O Dikinya
Publish Date: 2011/11/24
Volume: 9, Issue: 1, Pages: 129-134
Abstract
This paper presents an evaluation of different chelating agents for their effectiveness in removing Cu Co and Zn in three distinctly different types of sludgeamended soils Soil types Luvisol Arenosol and Vertisol were each mixed with an anaerobically digested sludge at a 11 ratio followed by leaching with three types of chelating agents namely ethylenediamine tetra acetic acid nitrilotriacetic acid and acetic acid Aqua regia method was used to quantify pseudo total metal before and after treatment Generally chelating agents can be out competed by soil colloids in attracting cations The efficiency of chelating agents was found to follow this order ethylenediamine tetra acetic acid nitrilotriacetic = acetic acid in all the three metals with ethylenediamine tetra acetic acid being the most effective chelating agent More heavy metals were removed in Luvisol and Arenosol than in Vertisol implying that soils rich in clay fraction retain more cations than soils with minimal clay fraction Similarly copper responded positively to chelation than zinc and cobalt in Luvisols and Arenosols although the results were not conclusive for VertisolsThe authors wish to thank the anonymous reviewers for the constructive and useful comments of the manuscript Special thanks go the Department of Environmental Science University of Botswana for allowing the authors to use the laboratory facilities for soil analysis
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