Glucose as a dual-functional co-substrate in intimately coupled photocatalysis and biodegradation systems: Synergistic enhancement of refractory organics mineralization and nitrate removal

Feng Hu; Wencan Zhang; Peipei Chen; Zhanzhan Yuan; Jianfeng Ye; Zuxin Xu

doi:10.1016/j.jhazmat.2025.138975

Glucose as a dual-functional co-substrate in intimately coupled photocatalysis and biodegradation systems: Synergistic enhancement of refractory organics mineralization and nitrate removal

J Hazard Mater. 2025 Jun 17:495:138975. doi: 10.1016/j.jhazmat.2025.138975. Online ahead of print.

Authors

Feng Hu¹, Wencan Zhang¹, Peipei Chen¹, Zhanzhan Yuan¹, Jianfeng Ye², Zuxin Xu³

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Ministry of Education Key Laboratory of Yangtze River Water Environment, Tongji University, Shanghai 200092, China.
² State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Ministry of Education Key Laboratory of Yangtze River Water Environment, Tongji University, Shanghai 200092, China. Electronic address: yejf@tongji.edu.cn.
³ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Ministry of Education Key Laboratory of Yangtze River Water Environment, Tongji University, Shanghai 200092, China. Electronic address: xzx@tongji.edu.cn.

PMID: 40570628
DOI: 10.1016/j.jhazmat.2025.138975

Abstract

Nitrate contamination threatens water quality and human health; however, conventional denitrification treatment strategies struggle in complex wastewater due to the low bioavailability of refractory organics. The intimately coupled photocatalysis and biodegradation (ICPB) system addresses this by transforming recalcitrant compounds into usable electron donors, enabling simultaneous nitrate and organic pollutant removal. This study demonstrates that adding a small dose of glucose (50 mg/L chemical oxygen demand) to the ICPB system enhanced performance by increasing organic mineralization from 53 % to 81 % and total nitrate and nitrite removal from 40 % to 93 %. Supplementing the ICPB system with glucose significantly stimulated microbial activity. The heightened activity accelerated the mineralization of photocatalytically-derived intermediates, preventing toxic byproduct accumulation. Microbial inhibition was reduced from 68 % to 20 %, further enhancing the pollutant removal efficiency of the ICPB system. Additionally, glucose functioned as an auxiliary electron donor, concurrently enhancing denitrification. Metagenomic analysis suggested that riboflavin biosynthesis upregulation may have promoted electron transfer, potentially boosting system efficiency. This strategy offers a simple and effective means to optimize the synergistic removal of refractory organics and nitrate during wastewater treatment.

Keywords: Carbon source; Denitrification; Mineralization; Nitrate; Sulfamethoxazole.