摘要
研究了不同实验条件下磷酸铝负载的银-铈催化剂（Ag-Ce/AlPO4）在水中对大肠杆菌（E.coli）的催化杀灭作用.结果表明,催化杀菌效果随初始菌液浓度的增加而减弱,但当初始菌液浓度为5×10^5CFU/ml时,120 min内即可使E.coli100%灭活,可以满足饮用水消毒要求.固定初始菌液浓度后,在室温25-40℃时,催化杀菌活性随温度的升高而显著增强.适当调节反应体系的pH值,发现弱碱性条件下催化杀菌活性较高,而强酸性条件下几乎完全没有杀菌活性.结合不同pH值条件下的电子自旋共振光谱测试结果,证明弱碱性条件更有利于强氧化性的.OH产生,进一步验证了.OH的生成是催化剂具有高杀菌活性的决定因素.
Influencing factors in the catalytically bactericidal process over a Ag-Ce/AlPO4 catalyst against E. coli in water were investigated. The bactericidal effect of the catalyst decreased with the increase in initial bacterial concentration. A 100 % inactivation of E. coli using Ag-Ce/AlPO4 at 25℃ was achieved in 120 rain when the initial bacterial concentration was 5 × 10^5 CFU/ml. Therefore, this catalytic method is sufficient for disinfection of drinking water. Once the initial bacterial concentration was fixed, the bactericidal activity increased with increasing temperature from 25 to 40℃. The pH value also played an important role in the bactericidal process. The Ag-Ce/AlPO4 catalyst exhibited high bactericidal activity under weak alkaline conditions, while almost no bactericidal effect was observed at acidic pH. Electron spin resonance was used to detect the reactive oxygen species involved in the bactericidal process at different pH values. Hydroxyl radical ·OH with strong oxidative ability proved to be formed under weak alkaline conditions and was not observed at acidic pH. These results give evidence of our proposed catalytically bactericidal mechanism, in which ·OH is the key intermediate responsible for the efficient inactivation of E. coli by Ag-Ce/AlPO4 in water at room temperature.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2008年第3期215-220,共6页
基金
国家自然科学基金(50621804)
国家重点基础研究发展计划(973计划,2007CB407301)
关键词
磷酸铝
银
铈
负载型催化剂
活性氧物种
催化杀菌
大肠杆菌
饮用水
aluminum phosphate
silver
cerium
supported catalyst
reactive oxygen species
catalytically bactericidal process
E. coil
drinking water
