With the continuous development of the chemical industries, synergistic removal of carbon and nitrogen contaminants has drawn much attention. In this work, a novel strategy for the synergistic removal of methyl orange (MO) and nitrate was developed in a single reactor by combining a TiO2/g-C3N4 nanosheet/graphene photoanode and denitrifying biofilm cathode. Under xenon light illumination, the photocatalytic MO decolorization rate exceeded 90% (the initial concentration of MO was as high as 100 mg·L-1) with a biocathode potential bias of -0.5 V vs Ag/AgCl; additionally, the decolourization rate apparently followed first-order kinetics with a constant of 0.11 ± 0.02 h-1. The improved MO decolourization rate was mainly because the biocathode effectively enhanced the charge separation of the photogenerated charge at the TiO2/g-C3N4 nanosheet/graphene photoanode interface. In the meantime, the effluent nitrate was lower than 1 mg·N·L-1 at a biocathode potential of -0.5 V vs Ag/AgCl. The results indicated that the coupled biocathode-photoanode system could serve the purpose of simultaneously degrading MO and accomplishing nitrate reduction. Considering the sustainability of sunlight and the use of a biocathode, the coupled biocathode-photoanode system is a promising alternative for the simultaneous removal of biorefractory organics and nitrate.

中文翻译：

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使用带有生物阴极-光电阳极系统的单腔室，可以高效，协同地进行脱色和硝酸盐去除。

随着化学工业的不断发展，协同去除碳和氮污染物引起了人们的广泛关注。在这项工作中，通过结合TiO2 / g-C3N4纳米片/石墨烯光电阳极和反硝化生物膜阴极，在单个反应器中开发了一种协同去除甲基橙（MO）和硝酸盐的新策略。氙灯照射下，光催化MO的脱色率超过90％（MO的初始浓度高达100 mg·L-1），生物阴极电势对Ag / AgCl为-0.5V。此外，脱色率显然遵循一阶动力学，常数为0.11±0.02 h-1。MO脱色率的提高主要是因为生物阴极有效地增强了TiO2 / g-C3N4纳米片/石墨烯光阳极界面上光生电荷的电荷分离。同时，相对于Ag / AgCl，生物阴极电位为-0.5 V时，出水硝酸盐低于1 mg·N·L-1。结果表明，耦合的生物阴极-光阳极体系可以同时降解MO和实现硝酸盐还原。考虑到阳光的可持续性和生物阴极的使用，耦合的生物阴极-光电阳极系统是同时去除生物难降解有机物和硝酸盐的有前途的替代方法。结果表明，耦合的生物阴极-光阳极体系可以同时降解MO和实现硝酸盐还原。考虑到阳光的可持续性和生物阴极的使用，耦合的生物阴极-光电阳极系统是同时去除生物难降解有机物和硝酸盐的有前途的替代方法。结果表明，耦合的生物阴极-光阳极体系可以同时降解MO和实现硝酸盐还原。考虑到阳光的可持续性和生物阴极的使用，耦合的生物阴极-光电阳极系统是同时去除生物难降解有机物和硝酸盐的有前途的替代方法。