A novel simultaneous coupling of memory photocatalysts and microbial communities for alternate removal of dimethyl phthalate and nitrate in water under light/dark cycles

Efficient and sustainable removal of both organic and inorganic pollutants from contaminated water is an important but difficult task. Here, a novel chemical-biological coupling concept, namely simultaneous coupling of memory photocatalysts and microbial communities (SCMPMC), is proposed for the first time that alternates the removal of organic and inorganic pollutants under successive light/dark cycles. We established this novel coupling system with WO3/g-C3N4 memory photocatalysts and river sediment microbial communities, and applied it to alternately remove dimethyl phthalate (DMP) and nitrate under light/dark cycles. The performance of SCMPMC under the light/dark cycles (12/12 h) showed that ~84.90% of the DMP was removed mainly via robust photocatalytic oxidation during the light phase, and ~86.80% of the nitrate was removed via microbial reduction enhanced by photogenerated electrons stored in the WO3/g-C3N4 memory photocatalysts during the dark phase within one cycle. The microbial communities were positively affected by adding WO3/g-C3N4, as evidenced by increased enzyme activities, cellular antigen metabolism, and relative abundance of typical denitrifiers, including Proteobacteria and Bacteroidetes. These results will contribute to the development of promising decontamination methods and mechanisms to control water pollution driven by the natural day/night cycle. [Display omitted] •A novel simultaneous coupling of memory photocatalysts and microbes was developed.•Unique alternate removal of DMP and nitrate under light/dark cycles was achieved.•Pre-illuminated memory photocatalysts promoted electron transfer/enzyme activities.•Microbial communities from river sediments adjusted themselves in the coupling.•Prospective and possible promotions of SCMPMC the novel coupling were proposed.