Gindose Teketel Girma, Gebreslassie Gebrehiwot, Hailegebreal Tessema Derbe, Ashebr Tesfay G, Mtunzi Fanyana, Atisme Tsegaye Belege, Zereffa Enyew Amare
Department of Industrial Chemistry, Addis Ababa Science and Technology University P. O. Box 16417 Addis Ababa Ethiopia.
Nanotechnology Centre of Excellence, Addis Ababa Science and Technology University P. O. Box 1647 Addis Ababa Ethiopia.
RSC Adv. 2024 Dec 4;14(52):38459-38469. doi: 10.1039/d4ra06476c. eCollection 2024 Dec 3.
Pristine ZnO (Z), MnO (M), CuO (C) photocatalysts and polyvinyl alcohol (PVA)-assisted MnO-ZnO-CuO (MZC) nanocomposites were synthesized the sol-gel method. The synthesized samples were characterized using thermal analysis (TGA), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), energy dispersive X-ray (EDS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) techniques. The thermal analysis results of the prepared nanomaterial confirmed that the suitable calcination temperature for the synthesis of these nanomaterials is 420 °C. In addition to the morphological and elemental composition, the characteristic diffraction peaks of the MZC nanomaterial were found to align with those of the pristine Z, M, and C photocatalysts. The photocatalytic activities of the synthesized nanomaterials for methylene blue (MB) degradation were evaluated under optimized conditions. The degradation efficiencies of Z, M, C, and MZC were found to be 45%, 57%, 66%, and 93%, respectively, for MB in 180 minutes. The MZC nanocomposite exhibited superior photocatalytic activity compared to the pristine materials, which is attributed to the synergetic effect of the Z, M, and C photocatalysts. The effects of pH, initial dye concentration, and catalyst load were also explored to determine the optimum conditions. The best photocatalytic efficiency was observed at pH 8, with a 130 mg L catalyst load, and a 10 mg L initial dye concentration. The efficiency of the MZC nanocomposite in real textile wastewater was also tested, achieving 80% degradation of pollutants within 180 minutes. Recycling experiments were conducted for four consecutive cycles under optimal conditions. The photodegradation efficiency for the first, second, third, and fourth cycles was 93%, 91%, 90%, and 89%, respectively, demonstrating high consistency in photodegradation performance across the four cycles. Moreover, a Z-scheme photocatalytic mechanism was proposed as a potential mechanism for the MZC photocatalytic system.
采用溶胶 - 凝胶法合成了纯净的氧化锌（Z）、氧化锰（M）、氧化铜（C）光催化剂以及聚乙烯醇（PVA）辅助的氧化锰 - 氧化锌 - 氧化铜（MZC）纳米复合材料。使用热分析（TGA）、X射线衍射（XRD）、动态光散射（DLS）、扫描电子显微镜（SEM）、能量色散X射线（EDS）、透射电子显微镜（TEM）和高分辨率透射电子显微镜（HRTEM）技术对合成的样品进行了表征。制备的纳米材料的热分析结果证实，合成这些纳米材料的合适煅烧温度为420℃。除了形态和元素组成外，还发现MZC纳米材料的特征衍射峰与纯净的Z、M和C光催化剂的衍射峰一致。在优化条件下评估了合成的纳米材料对亚甲基蓝（MB）降解的光催化活性。对于MB，在180分钟内，Z、M、C和MZC的降解效率分别为45%、57%、66%和93%。与纯净材料相比，MZC纳米复合材料表现出优异的光催化活性，这归因于Z、M和C光催化剂的协同效应。还探讨了pH值、初始染料浓度和催化剂负载量的影响，以确定最佳条件。在pH为8、催化剂负载量为130 mg/L和初始染料浓度为10 mg/L时观察到最佳光催化效率。还测试了MZC纳米复合材料在实际纺织废水中的效率，在180分钟内实现了80%的污染物降解。在最佳条件下连续进行了四个循环的回收实验。第一、第二、第三和第四个循环的光降解效率分别为93%、91%、90%和89%，表明四个循环的光降解性能具有高度一致性。此外，还提出了Z型光催化机制作为MZC光催化系统的潜在机制。
