Electric field efficiently enhanced thermochemical cleaning for oil recovery from oily sludge

Electric field efficiently enhanced thermochemical cleaning for oil recovery from oily sludge (OS) was proposed in this work, which was inspired by electro-kinetic (EK) remediation of sludge. The effects of different factors (e. g., current density, the concentration of solution, liquid to solid ratio) on oil removal efficiency of OS were investigated. It was found that the oil removal efficiency of OS could reach more than 60 wt% by electric field enhanced the instability of metastable emulsion system with a minimum energy consumption of 604.8 J/g. The content of the residual oil in the sludge could be lowered from 8.6 wt% to 2.8 wt% after being treatment under the optimum conditions, which showed a 143 wt% maximum increase in oil removal effiency compared to non electric field treatment. The recovered oil mainly consisted of long chain alkanes, which had high recovery value. Based on characterization and analysis results, the mechanism was speculated to provide guidance for the resource utilization of OS with low energy consumption in industrial processing.