高活性Cu-MnO2类氧化物酶降解罗丹明B

Degradation of Rhodamine B by highly active Cu-MnO2 oxidase-like enzymes

摘要:

纳米酶因其优良的催化活性在环境修复领域引起人们的广泛关注。元素掺杂可提升纳米酶催化性能。采用一步水热法制备了高活性铜掺杂二氧化锰（Cu-MnO2）类氧化物纳米酶（简称为类氧化物酶），并探究了Cu-MnO2催化降解罗丹明B（RhB）染料的效果。结果表明，铜掺杂后Cu-MnO2产生了协同效应，增强了Cu-MnO2的类氧化物酶催化活性，当溶液pH=3、RhB初始质量浓度为50 mg/L、Cu-MnO2用量为0.01 g时，30 min内可完全降解RhB，并且催化剂使用5次后RhB降解率仍达75%。此外，对环丙沙星、氧氟沙星、四环素和对苯二酚等难降解的污染物的降解率分别为88.86%、90.47%、92.62%和90.99%。Cu-MnO2类氧化物酶催化降解RhB的机理研究表明，富含氧空位的Cu-MnO2中存在丰富的空穴（h+），有利于吸附和催化溶解氧生成大量的单线态氧（1O2）和少量的超氧自由基（O2·-）等活性氧物种用于快速降解有机污染物。

Abstract:

Nanozymes have attracted much attention in the field of environmental remediation due to their excellent catalytic activity. Elemental doping can improve the catalytic performance of nanozymes. A highly active copper-doped manganese dioxide(Cu-MnO2) oxidase-like nanozyme(referred to oxidase-like enzyme) was prepared by a one-step hydrothermal method, and its degradation of rhodamine B (RhB) dye was investigated. It has been shown that the catalytic activity of Cu-MnO2 is enhanced by the synergistic effect of Cu-MnO2 upon copper doping. With a solution pH of 3, an initial mass concentration of RhB of 50 mg/L, and a dose Cu-MnO2 dosage of 0.01 g, RhB was fully degraded within 30 min, and the degradation rate of RhB was still 75% after 5 times the catalyst used. In addition, the degradation rates of ciprofloxacin, ofloxacin, tetracycline, and hydroquinone were 88.86%, 90.47%, 92.62% and 90.99%, respectively. The mechanism of catalytic degradation of RhB by Cu-MnO2 oxidase-like enzyme showed that there were abundant holes (h+) in Cu-MnO2 rich in oxygen vacancies, which was beneficial for adsorbing and catalyzing dissolved oxygen to produce a large amount of singlet oxygen (1O2) and a small number of superoxide radicals (O2·-) and other reactive oxygen species for the rapid degradation of organic pollutants.