Enhanced bisphenol S anaerobic degradation using an NZVI–HA-modified anode in bioelectrochemical systems

Highlights: • NZVI–HA composite modified anode was prepared and used to improve BPS biodegradation. • The formation of Fe-O-HA complex was detected affecting BPS biodegradation positively. • The biodegradation pathway of BPS in NZVI–HA-BES was deduced. • Sulfonyl bond of BPS molecule was easier to be broken by the NZVI–HA modification. As a substitute for bisphenol A (BPA), bisphenol S (BPS) has a longer half-life, higher chemical inertness and better skin permeability than BPA, and it also has a strong endocrine disruption effect. Relatively few studies have focused on the main processing technology for BPS biodegradation, and the findings indicate that the biodegradation efficiency of BPS was relatively low. Therefore, this paper used an NZVI–HA composite-modified bio-anode to enhance the anaerobic degradation of BPS in a Bioelectrochemical Systems (BES). The results showed that the degradation efficiency of BPS was improved from 31.1% to 92.2% with the NZVI–HA modification compared with the control group (CC-BES). FTIR and XPS analyzes demonstrated that HA can accelerate the reduction rate of Fe³⁺ and increase the ratio of Fe²⁺/Fe³⁺. In addition, HA can form Fe-O-HA complexes with NZVI to promote electron transfer. An analysis of the NZVI–HA-BES intermediate metabolites revealed that complex modification properties altered the BPS degradation pathway. An analysis of microbial diversity indicated that the bacteria related to the degradation of BPS may be Terrimonas, Lysobacter, and Acidovorax.