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 m²/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.

Graphical abstract

中文翻译：

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开发 ZnO/MOGAC 纳米复合材料，用于在各种光照射下增强光催化去除废水中 PO43- 和 NO3- 离子

消除污染水中的磷酸盐和硝酸盐是一个具有挑战性的环境问题，尤其是在大规模环境中。因此，本工作的目的是通过溶胶-凝胶法制备氧化锌（ZnO）/辣木胶活性炭（MOGAC）纳米复合材料，并应用于光催化去除PO ₄ ^3-和NO ₃ ^-在不同光照射下的水溶液中。使用 XRD、FT-IR、FESEM-EDS、UV-Vis-DRS 和 BET 分析仪表征 MOGAC、ZnO NPs 和 ZnO/MOGAC NCs 的相组成和形态。MOGAC 的 FESEM 图像显示其表面的微孔和中孔，类似于蜂窝状空隙结构。ZnO 和 ZnO/MOGAC NCs 的带隙能量值分别为 3.2 eV 和 3.4 eV，对应于 420 nm 的反射波长。ZnO/MOGAC NCs resolute的表面范围记录为172.71 m ² /g。评估了 ZnO/MOGAC NCs 在各种 pH 值、催化剂剂量、接触时间和不同底物离子浓度下的去除性能。去除实验结果表明，红色 LED 光谱和 10 mg ZnO/MOGAC NCs 去除了 PO_{在辐照 105 分钟和 90 分钟后， 4} ^3-和 NO ₃ ^-离子分别达到 95%。_{此外，经过四次 PO 4} ^3-和 NO ₃ ^-去除循环后，ZnO/MOGAC NCs 保持良好的稳定性。

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