Department of Chemistry, College of Sciences, University of Birjand, Birjand, Iran.
Department of Civil Engineering, Faculty of Engineering, University of Birjand, Birjand, Iran.
Environ Sci Pollut Res Int. 2022 Sep;29(43):65043-65060. doi: 10.1007/s11356-022-19969-3. Epub 2022 Apr 28.
In this study, ZnCoO/g-CN/Cu is synthesized as a new and highly effectual solar light-driven heterogeneous photocatalyst. The prepared photocatalyst is characterized using FT-IR, XRD, XPS, DRS, FESEM, TEM, EDS, and elemental mapping techniques. The performance of ZnCoO/g-CN/Cu is studied towards the metronidazole (MNZ) degradation under solar light irradiation. The kinetics of MNZ degradation and efficacy of the operational parameters comprising the initial MNZ amount (10-30 mg L), photocatalyst dosage (0.005-0.05 g L), pH (3-11), and contact time (5-30 min) on the MNZ degradation process are investigated. Surprisingly, the ZnCoO/g-CN/Cu nanocomposite presents a privileged photocatalytic performance towards the MNZ degradation under solar light irradiation. The enhanced photocatalytic activity of this photocatalyst can be ascribed to the synergistic optical effects of ZnCoO, g-CN, and Cu. The value of band gap energy for ZnCoO/g-CN/Cu is estimated to be 2.3 eV based on the Tauc plot of (αhν) vs. hν. The radical quenching experiments confirm that the superoxide radicals and holes are the principal active species in the photocatalytic degradation of MNZ, whereas the hydroxyl radicals have no major role in such degradation. The as-prepared photocatalyst is simply isolated and recycled for at least eight runs without noticeable loss of the efficiency. Using the natural sunlight source, applying a very low amount of the photocatalyst, neutrality of the reaction medium, short reaction time, high efficiency of the degradation procedure, utilizing air as the oxidant, low operational costs, and easy to recover and reuse of the photocatalyst are the significant highlights of the present method. It is supposed that the current investigation can be a step forward in the representation of an efficacious photocatalytic system in the treatment of a wide range of contaminated aquatic environments.
在这项研究中，我们合成了一种新型高效的太阳能驱动非均相光催化剂 ZnCoO/g-CN/Cu。通过傅里叶变换红外光谱（FT-IR）、X 射线衍射（XRD）、X 射线光电子能谱（XPS）、漫反射光谱（DRS）、场发射扫描电子显微镜（FESEM）、透射电子显微镜（TEM）、能谱仪（EDS）和元素mapping 技术对所制备的光催化剂进行了表征。研究了 ZnCoO/g-CN/Cu 光催化剂在太阳光照射下对甲硝唑（MNZ）的降解性能。考察了初始 MNZ 浓度（10-30 mg L）、光催化剂用量（0.005-0.05 g L）、pH 值（3-11）和接触时间（5-30 min）等操作参数对 MNZ 降解过程的动力学和效率的影响。令人惊讶的是，ZnCoO/g-CN/Cu 纳米复合材料在太阳光照射下对 MNZ 具有优越的光催化降解性能。这种光催化剂的增强光催化活性可以归因于 ZnCoO、g-CN 和 Cu 的协同光学效应。根据（αhν）与 hν 的 Tauc 图，估算出 ZnCoO/g-CN/Cu 的带隙能为 2.3 eV。自由基猝灭实验证实，超氧自由基和空穴是 MNZ 光催化降解的主要活性物种，而羟基自由基在这种降解中没有起主要作用。所制备的光催化剂可以简单地分离和循环使用至少 8 次，而没有明显的效率损失。本方法的显著特点是使用自然光光源、使用极低量的光催化剂、反应介质呈中性、反应时间短、降解过程效率高、利用空气作为氧化剂、运行成本低、以及光催化剂易于回收和再利用。我们认为，目前的研究可以为在处理广泛的受污染水环境方面展示一种有效的光催化系统迈出一步。
