磁铁矿
化学
催化作用
水解
光催化
光化学
可见光谱
过氧化氢
分解
电子顺磁共振
有机化学
材料科学
矿物学
核磁共振
物理
赤铁矿
光电子学
作者
Yanfen Fang,Yu Zhang,Wanhong Ma,David Johnson,Yingping Huang
标识
DOI:10.1016/j.apcatb.2014.05.016
摘要
Maghemite, an abundant iron-oxide mineral, was investigated as a visible light catalyst for decomposing and mineralizing Microcystin-LR (MC-LR) in water using hydrogen peroxide (H2O2) as the initial oxidant. Interestingly, of the twelve intermediates identified by LC–MS, half were products of MC-LR peptide bond hydrolysis rather than the oxidation products typical of photocatalytic oxidation (PCO). The catalytic hydrolysis of MC-LR by maghemite and visible light has not been previously reported. Detailed examination of intermediates provided insight into the catalytic pathway. Electron spin resonance (ESR) spectra revealed that visible light irradiation does not increase hydroxyl radical (OH) production from H2O2 decomposition. Visible light appears to play a new role in this unique PCO system, generating Brønsted sites on the maghemite surface via a metal ligand charge transfer (MLCT), rather than producing OH from H2O2. Because opening the cyclic peptide structure detoxifies MC-LR, this catalytic system could be uniquely efficient in detoxifying MC-LR in the presence of relatively high levels of natural organic matter (NOM). This work introduces a new means of selectively and effectively detoxifying MCs in water using an inexpensive, environmentally friendly and bio-compatible mineral.
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