Efficient elimination of nonylphenol and 4-tert-octylphenol by weak electrical stimulated anaerobic microbial processes. (April 2023) - Wang, Cuicui
Abstract: The investigation into the degradation of alkylphenol pollutants (APs) has become a hotspot due to their harmful effects on the environment and human health. In this study, microbial electrolysis cells (MECs) were used to degrade nonylphenol (NP) and 4- tert -octylphenol (4- tert -OP). The study found that the degradation rates of NP and 4- tert -OP for a 6-day period were 83.6% and 96.3%, respectively, which were 30.53% and 26.7% higher than those of the group without applied voltage. The double layer area in the degradation of 4- tert -OP was larger than that of NP, and the resistance exhibited by 4- tert -OP (87.47 Ω) in MEC was lower than that of NP (99.42 Ω). Meanwhile, NP had a greater effect on the bioenzyme activity than 4- tert -OP. GC-MS analysis showed that the degradation pathways of both pollutants mainly included oxidation and hydroxylation reactions. Furthermore, the microbial community analysis indicated that the main functional bacteria in NP degradation were Citrobacter, Desulfovibrio and Advenella, and those in 4- tert -OP degradation were Stenotrophomonas, Chryseobacterium, Dokdonella, and the key microbiomes underlying the cooperative relationship. The biotoxicity test indicated that the toxicity of residual substances was significantly reduced. Therefore, the MEC system is efficient and environmentally friendly and has broad application prospects in phenol refractory organics. Graphical abstract: Image 1 Highlights: Degradation ability of NP/4- tert -OP as the sole carbon source in MECs was first evaluated. The degradation rate of NP and 4- tert -OP was effectively improved by weak electrical stimulation. 4- tert -OP showed superior electrochemical performance and low impact on bioenzyme activity. The main metabolic pathways of NP and 4- tert -OP were oxidation and hydroxylation reactions. The correlation between aromatic compounds degrading bacteria and exoelectrogens was existed.