Simultaneous removal of 2,4-dichlorophenol and Cd from soils by electrokinetic remediation combined with activated...

An in situ electrokinetic remediation technique was designed by combining the uniform electrokinetic technology with a new-type of bamboo charcoal as adsorbent. A bench-scale experiment was conducted to investigate the application of this technique for simultaneous removal of 2,4-dichlorophenol (2,4-DCP) and Cd from a sandy loam at different periodic polarity-reversals. The contaminated soil was artificially spiked with 100 mg/kg 2,4-DCP and 500 mg/kg Cd. Two modes of polarity-reversal intervals of 12 and 24 h were included. After 10.5 d of operation, about 75.97% of Cd and 54.92% of 2,4-DCP were removed from soil at intervals of 24 h, whilst only 40.13% of Cd and 24.98% of 2,4-DCP were removed at intervals of 12 h. Soil water contents under two operation modes both significantly decreased, but evenly distributed spatially. Soil pH values under two operation modes were all maintained in the range from 7.2 to 7.4, close to the initial value. The electricity consumption per day was 12.24 and 11.61 kWh/m(3)/d, respectively at polarity-reversal intervals of 12 and 24 h. In conclusion, at polarity-reversal interval of 24 h, electroremediation combined with activated bamboo charcoal was effective in simultaneous removal of 2,4-DCP and Cd from soil. Our results indicate a promising potential in in situ electroremediation of soils co-contaminated with organics and heavy metals.