Burkholderia cepacia Enhanced Electrokinetic-Permeable Reaction Barrier for the Remediation of Lead Contaminated Soils

Abstract

The combination of electrokinetic (EK) and permeable reactive barrier (PRB) is a potentially effective technology for the remediation of heavy-metal-contaminated soils, but high energy expenditure limits its application in practice. In order to further improve the remediation efficiency and reduce the cost, some improvements were made in this study in terms of new PRB material, the spatial configuration of the rod electrode, and the microbial enhancement. Differently from previous powder PRB materials, six thin-film PRB materials were prepared using cheap natural attapulgite (ATP) and metal salts. PRB is a tough material that can be plugged and pulled out in engineering. The heavy metals adsorbed on it can be extracted from the soil, eliminating the risk of subsequent secondary pollution. Therefore, it has a strong operational ability. Among them, the FeMn-ATP material exhibited the best adsorption performance (2521 ± 377.1 mg/kg) for Pb. The results of the transmission electron microscope, X-ray diffractometer, and Fourier-transform infrared spectroscopy showed that iron and manganese were successfully loaded on the material. The Burkholderia cepacia pre-treatment led to soil pH decrease and the dissolution of Pb, and the morphological composition of Pb in the soil was also changed. In the microbial group, the adsorption amount of Pb by PRB at the anode and cathode increased by 69.1% and 42.1%, respectively. The concentration of the residual lead in the anode soil was significantly lower than that in the control group without microorganisms, and the removal rate of Pb was increased by 26%.