Natural wolframite as a novel visible-light photocatalyst towards organics degradation and bacterial inactivation
Natural wolframite as a novel visible-light photocatalyst towards organics degradation and bacterial inactivation
复制标题
天然黑钨矿作为一种新型可见光光催化剂，用于有机物降解和细菌灭活
DOI：
10.1016/j.cattod.2019.12.013
复制
发表时间：
2020-12-01
期刊：
影响因子：
5.3
通讯作者：
Shi, Junxian
中科院分区：
文献类型：
--
作者：
Li, Linghui;Li, Yan;Shi, Junxian
氧化钨酸盐是一种新型阴离子半导体材料，因其良好的光催化性能和长期稳定性而备受关注。为了便于大规模应用，本研究首次使用氧化钨酸盐的天然对应物黑钨矿作为可见光矿物光催化剂。表征了其矿物学和光催化性能，并与两种合成的端元矿物FeWO4和MnWO4进行了比较。结果表明，天然黑钨矿以（Fe,Mn）WO4形式存在时，其带隙仅为1.5 eV，远低于FeWO4 （2.3 eV）和MnWO4 (2.6 eV)；在可见光下，天然黑钨矿在中性ph下对亚甲基蓝（MB, 5 mg/L）的降解和对大肠杆菌K-12 (10（7) cfu mL(-1)）的消毒表现出显著的光活性，黑钨矿和H2O2存在下的MB降解率分别是无光和无H2O2对照的3倍和14倍。使用黑钨矿的消毒效率比使用MnWO4或FeWO4的消毒效率至少提高5倍。利用电子顺磁共振法检测羟基自由基（OH中心点）是光催化反应中主要的活性氧。OH中心点的生成是光催化和光芬顿效应共同作用的结果。为了证明黑钨矿的长期稳定性和光活性，我们进行了回收实验，经过三轮实验，黑钨矿对MB的降解率几乎保持不变。研究结果表明，天然黑钨矿是一种很有前途的可见光驱动光催化剂，可用于大规模废水处理。
Tungstate oxide is a new kind of anionic semiconductor material, which has been received much attention due to its good photocatalytic performance and long-term stability. To facilitate large-scale application, the natural counterpart of tungstate oxide, wolframite, was firstly used as a visible-light mineral photocatalyst in this study. Its mineralogical and photocatalytic properties were characterized and compared with two synthetic endmember minerals, FeWO4 and MnWO4. The results showed natural wolframite in the form of (Fe,Mn)WO4, had a bandgap of only 1.5 eV, far lower than that of FeWO4 (2.3 eV) and MnWO4 (2.6 eV). Under visible-light, natural wolframite exhibited remarkable photoactivity towards degradation of methylene blue (MB, 5 mg/L) and disinfection of Escherichia coli K-12 (10(7) cfu mL(-1)) under neutral pH. The MB degradation rate in the presence of both wolframite and H2O2 was as 3-fold or 14-fold as that in the controls without light or H2O2, respectively. And the disinfection rate using wolframite was at least 5 times higher than that using MnWO4 or FeWO4. Hydroxyl radical (OH center dot), as detected by electron paramagnetic resonance, was demonstrated as the major reactive oxygen species by using different scavengers in the photocatalytic reactions. The production of OH center dot was due to both photocatalytic and photo-Fenton effects. Recycling experiments were conducted to demonstrate the longterm stability and photoactivity of wolframite, in which the MB degradation rate almost kept unchanged after three experimental rounds. Our results indicated that natural wolframite could be used as a promising visiblelight driven photocatalyst applied for large-scale wastewater treatment.