Antifouling characteristics and mechanisms in visible-light photocatalytic membrane bioreactor based on g-C3N4 modified membrane

Lanyue Qi; Yue Yang; Zhongcheng Yang; Junwen Qi; Yujun Zhou; Zhigao Zhu; Jiansheng Li

doi:10.1016/j.watres.2024.122581

Antifouling characteristics and mechanisms in visible-light photocatalytic membrane bioreactor based on g-C₃N₄ modified membrane

Water Res. 2024 Oct 5;268(Pt A):122581. doi: 10.1016/j.watres.2024.122581. Online ahead of print.

Authors

Lanyue Qi¹, Yue Yang², Zhongcheng Yang¹, Junwen Qi¹, Yujun Zhou¹, Zhigao Zhu¹, Jiansheng Li³

Affiliations

¹ Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, PR China.
² Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, PR China. Electronic address: yangyue2022@njust.edu.cn.
³ Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, PR China. Electronic address: lijsh@njust.edu.cn.

PMID: 39395364
DOI: 10.1016/j.watres.2024.122581

Abstract

A novel visible-light photocatalytic membrane bioreactor (R3) was constructed for membrane fouling control and effluent quality improvement. Specially, g-C₃N₄ modified membrane was evaluated for the performance of synergistic separation and photocatalysis. Another two parallel reactors, MBRs with ceramic membrane (R1) and g-C₃N₄ membrane in dark condition (R2), were operated synchronously for comparison. A satisfactory effluent quality was obtained in R3 with COD and NH₄⁺-N around 22.0 mg/L and 1.02 mg/L during 60-day operation, which was superior to R1 (27.8, 1.42 mg/L) and R2 (29.9, 2.26 mg/L). The thickness of cake layer on membranes in R3 (2.46 μm) was thinner than R1 (3.52 μm) and R2 (4.97 μm) after operation, indicating the introduction of visible light could effectively mitigate membranes fouling. Moreover, microorganism community analysis revealed that visible light increased the relative abundance of Bacteroidetes and Chryseolinea, which not only enhanced the activity of microorganisms in metabolizing organic nutrients, but also improved the transfer and utilization of photogenerated electrons on the semiconductor-microorganism interface. The active aromatic protein metabolism and the upregulated related enzymes further demonstrated the synergistic effect of photocatalysis and microbial communities on the membrane fouling mitigation. This work provides a novel application of photocatalysis into antibiofouling effect in MBRs, and opens a strategy for bacteria inactivation and foulants removal with eco-friendly solar energy.

Keywords: Membrane bioreactors; Membrane fouling; Photocatalysis; Photogenerated electrons; g-C(3)N(4).