Electrokinetic Remediation of Nickel From Low Permeability Soil

摘要

Electrokinetic remediation of nickel from low permeability soil using titanium electrodes having inter- electrode spacing of 10 cm was carried out in a cylindrical reactor. The influences of current density,voltage gradient and electrolyte pH were investigated upon removal efficiency for 60 h experimentalruns. Efficiency improved from 49.3% to 57.2% when the current density was increased from 4.362 2 mA/cm to 13.1 mA/cm . Furthermore, an enhancement in efficiency from 38.5% to 54.3% was2 observed when voltage gradient increased from 1 V/cm to 2 V/cm (at 13.1 mA/cm ). Further increasein voltage gradient to 2.5 V/cm improved efficiency during initial runs. However, an overall reductionof 3.2% was observed after 60 h of operation in comparison to that obtained at 2 V/cm. This may beattributed to precipitation and localized accumulation of metallic ions. An inverse relationship between2 efficiency and electrolyte pH was also observed (at 13.1 mA/cm and 2 V/cm). Although a removal of74.1% was achieved at pH = 4.5, the system required optimization as the nickel content in treated soilwas above the maximum values given in international standards.