A permeable electrochemical reactive barrier for underground water remediation using TiO2/graphite composites as heterogeneous electrocatalysts without releasing of chemical substances.

Zhang, Wen; Gao, Mingming; Miao, Fei; Wu, Xiaoyan; Wang, Shuguang; Wang, Xinhua

Permeable reactive barriers (PRBs) are well-studied and widely-applied technologies in underground water remediation. However, the releasing of chemical substances cannot be avoided during the PRBs operation. In this study, a novel permeable electrochemical reactive barrier (PERB) was fabricated for underground water remediation using a TiO2/graphite composite (TiO2/C) as the heterogeneous electrocatalyst. TiO2/C performed an electro-Fenton-like reaction on cathode and an anodic oxidation on anode respectively, along with the variety of the TiO2 lattice. The performance of this PERB system was evaluated using tetracycline hydrochloride (TTC) degradation. TTC could be degraded at a low applied potential and a wide range of pH. The degradation rate of about 60% was obtained at the optimized reaction condition: the interelectrode potential difference of 1.2 V, pH 3.0, the anode 10 cm above cathode. The relative position and spacing of the electrodes effected the mass transfer equilibrium of TTC. During the 25-day persistent degradation of TTC, the PERB system shown a perfect stability with rarely leaching of Ti. This work explored the potential for underground water remediation by the electrocatalysis with the goal of establishing a clean and eco-friendly PERB system.