A novel microbe consortium, nano-visible light photocatalyst and microcapsule system to degrade PAHs

Abstract In this study, a MI-MC-photocatalyst compound system (MCS) was prepared for multi-PAHs degradation. Briefly, a high-efficient degradation microbe consortium (MC) was suspended in microcapsule (MI) interior space and nano-visible light photocatalyst Ag3PO4@Fe3O4 was anchored on the membrane of MI. The structure of MCS was investigated through various characteristic analysis methods. Its photocatalytic and biologic degradation potential for PAHs in soil were studied, which confirmed splendid visible light photocatalytic activity of Ag3PO4@Fe3O4 and good inhabitation of MC. Biocompatibility test showed that Ag3PO4@Fe3O4 influenced soil microbe activity slightly (no significant difference compared with CK). With MCS implement, 944.1 mg kg−1 PAHs was removed in 30 days under visible light (49.83% higher than CK). Besides, MCS dramatically improved soil micro-ecology and decreased micro-ecological stress (enhanced microbe counts, activities of dehydrogenase, hydrolase etc. and decreased catalase activity). The soil eco-toxicity decreased sharply testified by seed germinability and reduction of carcinogenic risk assessment (RCRA). Different PAHs reduction in treatments applied with different combination of MC, MI and Ag3PO4@Fe3O4 further proved that the decrement of low and high molecular weight PAHs was mainly contributed by biodegradation of MC and photocatalysis of Ag3PO4@Fe3O4, respectively. To sum up, this system provided a novel perspective for the combined utility of photochemistry and microbiology technology which could potentially facilitate the development of many environmental biotechnology products.