Development of ZnO/MOGAC nanocomposites for enhanced photocatalytic removal of PO43- and NO3- ions from wastewater under various light irradiations

The elimination of phosphates and nitrates in contaminated water is a challenging environmental issue, especially in a large-scale context. Therefore, the aim of this work is the fabrication of zinc oxide (ZnO)/Moringa oleifera gum activated carbon (MOGAC) nanocomposites constructed by the sol-gel method and applied to the photocatalytic removal of PO43- and NO3- in aqueous solutions under different light irradiations. The phase composition and morphology of the MOGAC, ZnO NPs, and ZnO/MOGAC NCs were characterized using XRD, FT-IR, FESEM-EDS, UV-Vis-DRS, and BET analyzer. The FESEM image of MOGAC reveals the micro- and mesopores on its surface, which resembles a honeycomb voids-like structure. The bandgap energy values of the ZnO and ZnO/MOGAC NCs were 3.2 eV and 3.4 eV, respectively, which were corresponding to the reflectance wavelength of 420 nm. The surface range of ZnO/MOGAC NCs resolute was recorded as 172.71 m(2)/g. The removal performance of the ZnO/MOGAC NCs in various pH, catalyst dose, contact times, and varying substrate ion concentrations was assessed. The removal experimental results exposed that the red LED spectrum and 10 mg of ZnO/MOGAC NCs removed PO43- and NO3- ions to 95% after 105 and 90 min of irradiation, respectively. Also, the ZnO/MOGAC NCs sustained good stability after four cycles of PO43- and NO3- removal.

Automated summary

The utilization of sol-gel method to fabricate ZnO/MOGAC nanocomposites enables the effective removal of phosphates and nitrates in contaminated water. ZnO/MOGAC NCs exhibit excellent removal performance and stability.