A novel sunlight driven Z scheme ZnCdS QDs deposited over g-C3N4 photocatalyst for photoinactivation of E. coli cells

Indication of several microorganisms such as Escherichia coli, Klebsiella oxytoca, and Salmonella sp. in water bodies and their complete harmless remediation is a major challenge for real-time application. Herein, Zn0.7Cd0.3S QDs were synthesized chemically and deposited over g-C3N4 via the simple co -precipitation and aqueous reflux method. The structural, and morphological properties of the as -synthesized nanocomposites (NCs) have been experimented with via XRD, UV-vis DRS, BET, PL, EIS, SEM and TEM. The Zn0.7Cd0.3S QDs 30 %/gC3N4 showed a 95 % inactivation rate within 240 min of visible light irradiation. The powerful contribution of prepared NCs was due to their high chemical stability, excellent optical absorption, generous reactive sites, and effective photo regeneration. Furthermore, different inactivation periods, different NCs dosages, and pH were also studied. Scavenging study suggest that center dot OH, and O2 center dot- as primary reactive oxidant species that carried out the photoinactivation of E. coli. These high reactive oxygen species (ROS) inactivate the bacteria cells through lipid peroxidation and intracellular component leakage. The synthesized Zn0.7Cd0.3S QDs/g-C3N4 NCs depict an excellent reusability efficiency of 97.7 %. Moreover, the photocatalyst efficiency stays the same even after six consecutive cycles, explaining its excellent recyclability and stability for real-time purposes which are confirmed by XRD and XPS analysis. Based on the performed studies, the fabricated Zn0.7Cd0.3S QDs/g-C3N4 NCs can be a superior photocatalyst for several anti -microbial paints, pathogen sterilization in aquatic environments as well as water remediation purposes.