Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 610031, China; State-province Joint Engineering Laboratory of Spatial Information Technology of High-Speed Rail Safety, Chengdu 610031, China.
Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 610031, China.
Sci Total Environ. 2018 Feb 1;613-614:1317-1323. doi: 10.1016/j.scitotenv.2017.09.256. Epub 2017 Oct 5.
In this study, silver nanoparticle decorated chitosan (CS/Ag NP) cryogels were fabricated through a simple freeze-drying process for point-of-use (POU) water disinfection. The CS/Ag NP cryogels showed high porosity, good mechanical properties, an excellent water absorption capability, and most importantly, an efficient bactericidal feature. The absorption capacity for water was found to be 47g/g, approximately 90% of which was recovered by simple squeezing. Three different sizes of Ag NPs were compared regarding their bactericidal capability against both Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis). Under optimum conditions, a 3 log reduction of bacteria was observed by holding the bacteria suspension (10 colony forming units (cfu)/mL) in the cryogels for 5min. Reduction was further increased to a 4 log when the contact time was doubled. The silver content in the cryogels was found to only be 7.5mg/g. Furthermore, the total Ag in processed water was found to only be 22μg/L, half of the safety limit set by China (<50μg/L). The bactericidal effectiveness of the material for real surface water samples was also demonstrated by treating water samples with different water quality matrices, including lake water and sewage water samples. In all three treated lake water samples, both the total bacteria and E. coli met the regulations for drinking water in China (<100cfu/mL for total bacteria and negative for E. coli). CS/Ag NP cryogels can be used for drinking water disinfection during disaster relief and in contingency water supply applications.
在这项研究中，通过简单的冷冻干燥工艺制备了负载银纳米粒子的壳聚糖（CS/Ag NP）冷冻凝胶，用于现场（POU）水消毒。CS/Ag NP 冷冻凝胶具有高孔隙率、良好的机械性能、优异的吸水性，最重要的是具有高效的杀菌特性。水的吸收能力为 47g/g，其中约 90%可通过简单挤压回收。比较了三种不同尺寸的 Ag NP 对大肠杆菌（E. coli）和枯草芽孢杆菌（B. subtilis）的杀菌能力。在最佳条件下，将细菌悬浮液（10 个菌落形成单位（cfu）/mL）在冷冻凝胶中保持 5min 可观察到细菌减少 3 个对数。当接触时间增加一倍时，减少量进一步增加到 4 个对数。冷冻凝胶中的银含量仅为 7.5mg/g。此外，处理水中的总银含量仅为 22μg/L，是中国设定的安全限值（<50μg/L）的一半。通过处理不同水质基质的水样，包括湖水和污水水样，还证明了该材料对实际地表水样品的杀菌效果。在所有三个处理后的湖水中，总细菌和大肠杆菌均符合中国饮用水标准（总细菌<100cfu/mL，大肠杆菌阴性）。CS/Ag NP 冷冻凝胶可用于救灾期间的饮用水消毒和应急供水应用。
