Integrating biochar granular with microbial fuel cell to enhance the remediation of polycyclic aromatic hydrocarbons contaminated soil

Soil microbial fuel cell (SMFC) shedding lights on the remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soil, while the remediation efficiency is hindered by high internal resistance. In this work, biochar granular (BCG) was prepared through alginate sodium and calcium chloride crosslinking method and integrated with SMFC. The results illustrated that the addition of 2% (w/w) BCG increased soil porosity and permeability, reduced the internal resistance, increased the power density and thereby promoted the PAHs removal efficiency to 67.4% (phenanthrene) and 58.6% (pyrene) near the anode. Microbial community results demonstrated that BCG significantly enriched functional bacteria and metabolic genes on the anode and in soil. The composite system achieved high PAHs removal efficiency in a short period of time, suggesting that integrating BCG with SMFC showed great potential for improving the in-situ bioremediation efficiency of PAHs-contaminated soil.