Remediation of Soil Contaminated with Polycyclic Aromatic Hydrocarbons Adsorbed On Microplastics Using Soil Microbial Fuel Cells

Abstract

Microplastics (MPs) adsorb polycyclic aromatic hydrocarbons (PAHs) and accumulate in large quantities in soils to form composite contamination, which has become a major environmental and public health problem. However, the effect of bioflows. In this study, we investigated the treatment efficacy of the soil microbial fuel cells (SMFCs) on the complex pollution of PAHs adsorbed on MPs The degradation efficiency of SMFCs on polypropylene, polyethylene, and polylactic acid (microspheres) adsorbing phenanthrene (Phe) and benzo[a]pyrene (Bap) was analyzed. The results showed that in the anodic area of the closed-circuit SMFCs, the removal rates of Phe and Bap adsorbed on MPs from the soil were the highest, reaching 76.19% after 33 days of operation and 45.37%, respectively. These removal rates were 1.59 times higher than the 1.85 of the open-circuit control. The removal rate of PAHs adsorbed on MPs was positively correlated with microbial activity and dehydrogenase activity. Additionally, the output voltage of the SMFCs device showed a more significant correlation with the removal rate of Bap (P < 0.05). The anode microbial community study revealed that the PAHs-degrading bacteria belonging to Ralstonia, Pseudomonas, and Cupriavidus had higher abundance on the surface of the closed-circuit SMFCs anode and were the genera involved in the degradation of MPs or PAHs. This study provides a new eco-friendly method for remediating combined MPs-contaminated and PAHs-contaminated soil. In addition, this method is capable of generating electrical energy on the contaminated land.

Keywords: soil microbial fuel cells, microplastics, polycyclic aromatic hydrocarbons removal, microbial degradation