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染料污染是纺织、橡胶、造纸等工业废水中常见的一种污染物. 由具有较高的毒性和色度,会对水生态系统造成危害和潜在的致癌效应[1]. 过去的研究报道了多种去除染料的方法,如生物处理、膜过滤、吸附等[2]. 其中,基于硫酸根自由基(SO4−·)的高级氧化技术(AOPs)具有氧化性强,操作简单等优点被研究人员广泛关注[3]. 此外,太阳光作为一种可以长期使用的清洁能源,半导体光催化在去除有机污染物方面也显示出了极大的优势和广阔的应用背景[4].
近年来,铋基金属化合物由于其良好的稳定性、无毒性和可见光活性,被广泛应用于可持续光催化中[5]. 钼酸铋(Bi2MoO6)由于具有较窄的带隙(2.6—2.9 eV)、较高的热稳定性和化学稳定性以及容易产生丰富的自由基物种被广泛研究,然而由于其窄带隙和光生电子-空穴对易复合,限制了其光催化活性[6]. 氧化铜(CuO)作为一种金属氧化物和半导体材料具有合理带隙(1.2—1.8 eV)和独特的物理化学性质,能够展示出优良稳定性和的可见光捕获能力,并且被证明能够有效地激活过一硫酸盐(PMS)[7]. 然而CuO的光催化活性同样易收到光生电子-空穴对复合的影响. 因此将Bi2MoO6−与CuO构成二元异质结可以有效抑制光生电子-空穴对的复合,提高可见光下对污染物的光催化降解性能.
本研究采用水热法和浸渍煅烧法成功制备出在可见光照射下具有良好催化活性的CuO/Bi2MoO6复合材料. 对其形貌、结构等进行分析,研究了CuO/Bi2MoO6复合材料作为PMS的活化剂在可见光照射下对AO7的降解效果,并探究了体系中产生的活性物质和降解机理.
CuO/Bi2MoO6复合材料在可见光下协同过一硫酸盐降解AO7
Efficient degradation of AO7 by CuO/Bi2MoO6 composites synergistically with peroxymonosulfate under visible light
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摘要: 本文采用水热法和浸渍煅烧法成功合成CuO/Bi2MoO6异质结,并建立了CuO/Bi2MoO6复合材料在可见光下活化过一硫酸盐降解AO7的协同催化体系. 采用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和紫外可见漫反射光谱(UV-vis)对复合材料的晶相结构、元素组成、形貌结构和吸收波长进行了表征,并探讨了在不同条件下的对AO7的去除性能. 结果表明,CuO的引入增强了Bi2MoO6的光催化性能,同时增强了对PMS的活化. 当AO7的浓度为0.1 mmol·L−1,催化剂为0.25 g·L−1,PMS为1 mmol·L−1条件下,AO7的降解率可以在30 min内达到99%以上. 提出了AO7一种可能存在的降解机理,并通过自由基消除实验进行了验证. 复合材料在5次降解循环后仍能保持活化性能,具有较高的稳定性.Abstract: In this paper, CuO/Bi2MoO6 heterojunctions were successfully synthesized by hydrothermal method and impregnation calcination method, and a synergistic catalytic system of CuO/Bi2MoO6 composites activated by peroxymonosulfate to degrade AO7 under visible light was established. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis) were used to investigate the crystal phase structure, elemental composition, morphological structure and absorption of the composites The wavelengths were characterized and the removal performance of AO7 under different conditions was discussed. The results showed that the introduction of CuO enhanced the photocatalytic performance of Bi2MoO6 and enhanced the activation of PMS at the same time. When the concentration of AO7 is 0.1 mmol·L−1, the catalyst is 0.25 g·L−1, and the PMS is 1 mmol·L−1, the degradation rate of AO7 can reach more than 99% within 30 min. A possible degradation mechanism of AO7 was proposed and verified by free radical elimination experiments. The composites can still maintain the activation performance after 5 degradation cycles and have high stability.
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Key words:
- bismuth molybdate /
- copper oxide /
- composite material /
- photocatalytic /
- peroxymonosulfate.
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表 1 本文催化体系与其他相关研究的有效性对比
Table 1. Comparison of the effectiveness of the catalytic system in this paper with other related studies
表 2 不同pH条件下Cu2+的浸出
Table 2. Leaching of Cu2+ at different pH
pH 3 5 7 9 11 Cu2+/(mg·L−1) 2.54 0.36 0.04 0.05 0.41 -
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