Solar-assisted photocatalytic degradation of organic pollutants has emerged as efficient technology for the effective treatment of industrial wastewater. Here, we report a simple technique for the fabrication of a novel ternary photocatalyst from kaolinite (K), $$\hbox {TiO}_{2}$$ (T) and ZnO (Z). The most efficient catalyst was prepared at a calcination temperature of $$600{^{\circ }}\hbox {C}$$. The fabricated ternary composite was characterized using different analytical techniques including Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, field emission-scanning electron microscopy and energy dispersive X-ray spectroscopy. The photocatalytic degradation was performed at room temperature ($$25{^{\circ }}\hbox {C}$$) using Remazol Red (RR), an anionic azo dye, as the model compound. A maximum of 98% degradation of RR was found with the ternary catalyst $$\hbox {K}_{0.50}\hbox {T}_{0.45}\hbox {Z}_{0.05}$$, which was prepared from 50% kaolinite (w/w), 45% $$\hbox {TiO}_{2}$$ (w/w) and 5% ZnO (w/w). The catalyst was found to be suitable for long-term repeated applications. Mechanistic investigation through radical trapping experiments confirmed hydroxyl radicals as the potential contributor to the photocatalytic degradation of RR. It is highly expected that a novel photocatalyst design such as this will pave way towards further development of materials capable of hazardous dye removal from industrial effluents.

中文翻译：

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用于光催化降解阴离子偶氮染料的高岭石/$$\hbox {TiO}_{2}$$TiO2/ZnO 基新型三元复合材料

太阳能辅助光催化降解有机污染物已成为有效处理工业废水的有效技术。在这里，我们报告了一种由高岭石 (K)、$$\hbox {TiO}_{2}$$ (T) 和 ZnO (Z) 制备新型三元光催化剂的简单技术。最有效的催化剂是在 600 美元{^{\circ}}\hbox {C}$$ 的煅烧温度下制备的。使用不同的分析技术对制备的三元复合材料进行表征，包括傅里叶变换红外光谱、X 射线衍射、热重分析、扫描电子显微镜、场发射扫描电子显微镜和能量色散 X 射线光谱。使用 Remazol Red (RR)，一种阴离子偶氮染料，在室温下 ($$25{^{\circ }}\hbox {C}$$) 进行光催化降解，作为模型化合物。发现使用三元催化剂 $$\hbox {K}_{0.50}\hbox {T}_{0.45}\hbox {Z}_{0.05}$$ 最大 98% 的 RR 降解，其制备自50% 高岭石 (w/w)、45% $$\hbox {TiO}_{2}$$ (w/w) 和 5% ZnO (w/w)。发现该催化剂适合长期重复应用。通过自由基捕获实验的机理研究证实羟基自由基是 RR 光催化降解的潜在贡献者。人们高度期待这样的新型光催化剂设计将为进一步开发能够从工业废水中去除有害染料的材料铺平道路。45% $$\hbox {TiO}_{2}$$ (w/w) 和 5% ZnO (w/w)。发现该催化剂适合长期重复应用。通过自由基捕获实验的机理研究证实羟基自由基是 RR 光催化降解的潜在贡献者。人们高度期待这样的新型光催化剂设计将为进一步开发能够从工业废水中去除有害染料的材料铺平道路。45% $$\hbox {TiO}_{2}$$ (w/w) 和 5% ZnO (w/w)。发现该催化剂适合长期重复应用。通过自由基捕获实验的机理研究证实羟基自由基是 RR 光催化降解的潜在贡献者。人们高度期待这样的新型光催化剂设计将为进一步开发能够从工业废水中去除有害染料的材料铺平道路。