Background

Azo dyes represent the most commonly used group of dyes in the textile industry. These organic dyes are mainly resistant to biodegradation and may exhibit toxic and carcinogenic properties. The purpose of this study was to investigate the effects of doping zinc oxide (ZnO) nanoparticles (NPs) with transition metals (silver, manganese, and copper) on the photocatalytic efficiency of ZnO NPs in the removal of Direct Blue 15 dye from aqueous environments under ultraviolet (UV) radiation and visible light irradiation.

Methods

One or two metals were used for doping the NPs. In total, seven types of undoped and transition metal-doped NPs were synthesized using the thermal solvent method with ZnO precursors and transition metal salts. The characteristics of the synthesized NPs were determined based on the scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), atomic force microscopy (AFM), and zeta potential measurements.

Results

The produced ZnO NPs did not exhibit any particular photocatalytic activities under UV radiation and visible light irradiation. The highest removal efficiency under UV radiation was about 74% in the presence of silver-doped ZnO NPs, while the maximum efficiency under visible light was 70% in the presence of copper-doped ZnO NPs. The lowest removal efficiency was related to pure ZnO, which was 18.4% and 14.6% under UV and visible light irradiation, respectively. Although the efficiency of dye removal under visible light was not high compared to UV radiation, this efficiency was noteworthy in terms of both practical and economic aspects since it was achieved without the presence of ultraviolet radiation.

Conclusions

The synthesis of transition metal-doped ZnO nanophotocatalysts (with one or two metals) under UV radiation or visible light irradiation could be used as an efficient and promising technology for the photocatalytic removal of Direct Blue 15 dye from aqueous environments.

中文翻译：

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过渡金属（Ag、Cu、Mn）掺杂氧化锌纳米粒子对紫外和可见光照射下直接蓝15染料光催化降解的影响。

背景

偶氮染料代表纺织工业中最常用的一组染料。这些有机染料主要耐生物降解，并可能表现出有毒和致癌的特性。本研究的目的是研究用过渡金属（银、锰和铜）掺杂氧化锌 (ZnO) 纳米粒子 (NPs) 对 ZnO NPs 去除水环境中直接蓝 15 染料的光催化效率的影响在紫外线（UV）辐射和可见光照射下。

方法

一种或两种金属用于掺杂 NP。总共使用 ZnO 前体和过渡金属盐的热溶剂法合成了七种未掺杂和过渡金属掺杂的纳米颗粒。基于扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDX)、X 射线衍射 (XRD)、傅里叶变换红外 (FTIR) 光谱、动态光散射 (DLS) 确定合成的纳米颗粒的特性)、原子力显微镜 (AFM) 和 zeta 电位测量。

结果

所产生的 ZnO NPs 在紫外辐射和可见光辐射下没有表现出任何特定的光催化活性。在存在银掺杂的 ZnO NPs 的情况下，UV 辐射下的最高去除效率约为 74%，而在存在铜掺杂的 ZnO NPs 的情况下，在可见光下的最大去除效率为 70%。最低的去除效率与纯 ZnO 相关，在紫外光和可见光照射下分别为 18.4% 和 14.6%。尽管与紫外线辐射相比，在可见光下的染料去除效率并不高，但这种效率在实用和经济方面都值得注意，因为它是在没有紫外线辐射的情况下实现的。

结论

在紫外辐射或可见光辐射下合成过渡金属掺杂的 ZnO 纳米光催化剂（含有一种或两种金属）可作为一种有效且有前景的光催化去除水环境中直接蓝 15 染料的技术。