Berehe Biniyam Abdu, Assen Ayalew H, Kumar A Santhana Krishna, Ulla Hidayath, Duma Alemayehu Dubale, Chang Jia-Yaw, Gedda Gangaraju, Girma Wubshet Mekonnen
Department of Chemistry, College of Natural Science, Wollo University, P.O. Box 1145, Dessie, Ethiopia.
Department of Chemistry, National Sun Yat-sen University, No. 70, Lien-Hai Road, Gushan District, Kaohsiung, 80424, Taiwan.
Sci Rep. 2023 Sep 30;13(1):16454. doi: 10.1038/s41598-023-43842-z.
Industrial effluents are a leading major threat for water contamination, subsequently which results in severe health associated risks. Hence, purifying wastewater before releasing into the water resources is essential to avoid contamination. In this study, ZnO/Cu-DPA nano-composites were prepared by altering the percentage of Cu-DPA (20%, 30%, 40%, and 50% which are denoted to be ZnO/20%Cu-DPA, ZnO/30%Cu-DPA, ZnO/40%Cu-DPA and ZnO/50%Cu-DPA) using a simple mechanical grinding process. Several spectroscopic studies were employed such as electron paramagnetic analysis (EPR), powdered X-ray diffractometer (PXRD), UV-Vis absorbance spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscope to characterize these nano-composites. The photo-catalytic activities of the prepared nano-composites were studied by degrading MB under visible light irradiation. ZnO, ZnO/20%Cu-DPA, ZnO/30%Cu-DPA, ZnO/40%Cu-DPA and ZnO/50%Cu-DPA degradation efficiencies were determined to be 71.8, 78.5, 77.1, and 66.1%, respectively. Among the composite catalysts, the ZnO/20%Cu-DPA coupled system are demonstrated the best efficiency (87%) for photo-degradation of MB within 80 min when exposed to visible light. The ZnO/Cu-DPA nano-composites had a greater MB photodegradation efficiency than pristine ZnO owing to p-n heterojunction in the linked system. Under visible light irradiation, the ZnO/20%Cu-DPA catalysed the conversion of dissolved O to hydroxyl radicals (OH·), triggering the reduction of MB. This suggests that ·OH is the primary specific active radical involved in the photo-catalytic decomposition of MB. Furthermore, EPR analysis indicates the existence of ·OH in the photo-catalytic system. The proposed nano-composites (ZnO/20%Cu-DPA) reusability was investigated across three cycles as the most efficient photo-catalyst. The results show that, the ZnO/Cu-DPA nano-catalyst is a potential candidate for the remediation of dirty water.
工业废水是水污染的主要重大威胁，进而导致严重的健康相关风险。因此，在将废水排放到水资源之前进行净化对于避免污染至关重要。在本研究中，通过简单的机械研磨工艺改变Cu-DPA的百分比（20%、30%、40%和50%，分别表示为ZnO/20%Cu-DPA、ZnO/30%Cu-DPA、ZnO/40%Cu-DPA和ZnO/50%Cu-DPA）制备了ZnO/Cu-DPA纳米复合材料。采用了多种光谱研究方法，如电子顺磁共振分析（EPR）、粉末X射线衍射仪（PXRD）、紫外-可见吸收光谱、傅里叶变换红外（FT-IR）光谱和扫描电子显微镜来表征这些纳米复合材料。通过在可见光照射下降解亚甲基蓝（MB）研究了所制备纳米复合材料的光催化活性。ZnO、ZnO/20%Cu-DPA、ZnO/30%Cu-DPA、ZnO/40%Cu-DPA和ZnO/50%Cu-DPA的降解效率分别测定为71.8%、78.5%、77.1%和66.1%。在复合催化剂中，ZnO/20%Cu-DPA耦合体系在暴露于可见光的80分钟内对MB的光降解表现出最佳效率（87%）。由于连接体系中的p-n异质结，ZnO/Cu-DPA纳米复合材料比原始ZnO具有更高的MB光降解效率。在可见光照射下，ZnO/20%Cu-DPA催化溶解的O转化为羟基自由基（OH·），引发MB的还原。这表明·OH是参与MB光催化分解的主要特定活性自由基。此外，EPR分析表明光催化体系中存在·OH。作为最有效的光催化剂，对所提出的纳米复合材料（ZnO/20%Cu-DPA）的可重复使用性进行了三个循环的研究。结果表明，ZnO/Cu-DPA纳米催化剂是净化污水的潜在候选材料。
