Electrokinetic removal of mixed heavy metals from

Authors: Bala Ramudu Paramkusam Rakesh Kumar Srivastava Devendra Mohan

Publish Date: 2014/07/09

Volume: 73, Issue: 3, Pages: 1191-1204

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Abstract

This paper presents the experimental findings of electrokinetic EK studies conducted to remove cadmium Cd++ and copper Cu++ present together as contaminants in clayey soil Competitive sorption between cadmium and copper has been studied which provides an insight into selection of Cd++ and Cu++ concentrations for maximum contamination of soil in the EK study To explore the effect of pH on the desorption of both Cd++ and Cu++ and to compare the efficacy of different agents in enhancing the removal of these ions during the EK remediation process the desorption studies have also been conducted using ammonium citrate 1 M sodium citrate 1 M and nonionic surfactant Tween20 02  v/v at pH 2 pH 7 and pH 12 It was found that maximal sorption capacity of the soil for Cd++ and Cu++ was 834 and 121 mg g−1 respectively The desorption of both Cd++ and Cu++ influenced by pH for all desorbing agents is considered in the study Overall desorption values for both Cd++ and Cu++ have been observed to be higher when ammonium citrate 1 M was used as desorbing agent in the study The results indicate the possibility of competition of complexation of Cd++ and Cu++ leading to desorption mechanism in the presence of desorbing agents The EK tests on the Cd++ and Cu++ contaminated soil are carried out at a voltage of 35 V 10 V/cm DC for 5 days Sequential extraction experiments were conducted to determine fractionation of Cd++ and Cu++ in the EKtreated soil using deionized water at pH values of 2 7 and 12 It is observed that current electroosmotic flow and mobilization of Cd++ and Cu++ depend on pH zeta potential ς and specific conductance Removal of these heavy metals was observed to be higher when ammonium citrate was used both for saturation as well as flushing solution during EK process

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