School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
Water Res. 2016 Mar 1;90:111-118. doi: 10.1016/j.watres.2015.12.022. Epub 2015 Dec 15.
Bacterial inactivation by magnetic photocatalyst receives increasing interests for the ease recovery and reuse of photocatalysts. This study investigated bacterial inactivation by a magnetic photocatalysts, Fe2O3-AgBr, under the irradiation of a commercially available light emitting diode lamp. The effects of different factors on the inactivation of Escherichia coli were also evaluated, in term of the efficiency in inactivation. The results showed that Fe2O3-AgBr was able to inactivate both Gram negative (E. coli) and Gram positive (Staphylococcus aureus) bacteria. Bacterial inactivation by Fe2O3-AgBr was more favorable under high temperature and alkaline pH. Presence of Ca(2+) promoted the bacterial inactivation while the presence of [Formula: see text] was inhibitory. The mechanisms of photocatalytic bacterial inactivation were systemically studied and the effects of the presence of various specific reactive species scavengers and argon suggest that Fe2O3-AgBr inactivate bacterial cells by the oxidation of H2O2 generated from the photo-generated electron and direct oxidation of photo-generated hole. The detection of different reactive species further supported the proposed mechanisms. The results provide information for the evaluation of bacterial inactivation performance of Fe2O3-AgBr under different conditions. More importantly, bacterial inactivation for five consecutive cycles demonstrated Fe2O3-AgBr exhibited highly stable bactericidal activity and suggest that the magnetic Fe2O3-AgBr has great potential for water disinfection.
磁性光催化剂的细菌灭活因其易于回收和再利用催化剂而受到越来越多的关注。本研究利用市售发光二极管灯照射，研究了磁性光催化剂 Fe2O3-AgBr 对大肠杆菌的灭活作用。还评估了不同因素对大肠杆菌灭活效率的影响。结果表明，Fe2O3-AgBr 能够灭活革兰氏阴性（大肠杆菌）和革兰氏阳性（金黄色葡萄球菌）细菌。在高温和碱性 pH 条件下，Fe2O3-AgBr 的细菌灭活效果更好。Ca(2+) 的存在促进了细菌的灭活，而 [Formula: see text] 的存在则具有抑制作用。系统研究了光催化细菌灭活的机制，并通过添加各种特定活性物质清除剂和氩气的实验，表明 Fe2O3-AgBr 通过光生电子产生的 H2O2 的氧化和光生空穴的直接氧化来灭活细菌细胞。不同活性物质的检测进一步支持了所提出的机制。该结果为评估 Fe2O3-AgBr 在不同条件下的细菌灭活性能提供了信息。更重要的是，五次连续循环的细菌灭活实验表明，Fe2O3-AgBr 表现出高度稳定的杀菌活性，表明磁性 Fe2O3-AgBr 在水消毒方面具有巨大的潜力。
