摘要
发展中国家农村地区饮用水普遍存在着微生物超标问题,太阳光消毒法(SODIS)是实现饮用水微生物控制、提高当地居民饮水质量的潜在技术.目前,SODIS法存在光照利用率低的问题,消毒效果完全依赖于环境温度与光照强度,仅在低纬度地区晴朗天气环境下效果较好.本研究通过材料改性强化TiO_(2)光催化性能,利用固定化技术提升催化剂的循环利用效率,开发了固定化改性TiO_(2)光催化消毒用技术,克服了上述SODIS法的缺陷.本研究采用水热法分别合成了暴露(001)或(101)晶面的锐钛矿相二氧化钛,暴露(110)面的金红石相二氧化钛以及不暴露特定晶面的锥形混晶相二氧化钛.通过与对照标准品比较在光照下灭活耐热大肠杆菌速率后发现,晶体类型对灭活速率的影响顺序为晶相>暴露晶面>晶粒形状.XRD、SEM、UV-vis、XPS价带谱、Zeta电位、ICP-MS等表征结果表明,催化剂的较高价带位置与表面电位在消毒过程中起主导作用,尖锐棱角形貌起次要作用.将001-TiO_(2)粉末样品固定化后,减少了循环使用中的催化剂损失,经处理水中细菌残留率仅为0.4%,优于已报道的固定化P25 TiO_(2)样品(1.8%)和仅光照条件下的空白对照组(67.3%).通过对200个凋亡细菌菌体的形貌分析并计数发现,光催化消毒对水中微生物的去除机制按重要性排序,依次为空穴与自由基化学氧化(139个)、晶粒与菌体表面电荷吸引包埋(48个)和晶体颗粒尖锐棱角物理破坏(13个).综上所述,本研究建立的固定化晶面暴露锐钛矿相TiO_(2)基光催化消毒技术在光强70 mW·cm^(-2),25℃下即具有良好消毒效果,为发展中国家农村地区单户型饮用水消毒提供了可行的解决方案.
Currently,the problem of excessive microbes in drinking water occurs frequently in the rural areas of developing countries.Solar disinfection(SODIS)is a potential technology to control the microorganisms in water for potable purpose and improve the water quality for local people.However,its disinfection effect completely depends on the ambient temperature and light intensity.Therefore,the light utilization rate of SODIS is low except in the areas of ediquate sunlight in low latitudes.To promote the efficacy of SODIS,the modification of TiO_(2) materials is used to enhance its photocatalytic performance and the stable recycling of the catalyst is carried out by immobilization.In this study,(001)and(101)faceted anatase TiO_(2),(110)faceted rutile TiO_(2),non-faceted mixed phase TiO_(2) were employed to compare the inactivation rate of heat-resistant Escherichia coli.It was observed that crystal phase has greater influence on inactivation rate than crystal facet and crystal shape.The characterization results signified that the higher valence band position and surface potential of the catalyst played a major role in disinfection process,while the sharp edge morphology played a secondary role.Immobilization of 001-TiO_(2) powder reduced catalyst loss in recycling,and the bacterial survival rate in treated water was only 0.4%,which was better than that reported for immobilized P25 TiO_(2)(1.8%)and blank control(67.3%)under light-only conditions.Through analyzing and counting the morphology of 200 apoptotic bacteria,it is concluded that the mechanisms of photocatalytic disinfection are as follows:①chemical oxidation of holes and radicals(139),②surface charge attraction embedding between grains and bacteria(48)and③physical destruction of sharp edges and corners of crystal particles(13).In summary,the immobilized anatase TiO2-based photocatalytic disinfection technology has a good disinfection performance at a light intensity of 70 mW·cm^(-2) and 25℃,which provides a feasible solution for single-family drinking w
作者
严婉铒
尚子茗
袁庆科
栾富波
孟颖
张国珍
YAN Wan'er;SHANG Ziming;YUAN Qingke;LUAN Fubo;MENG Ying;ZHANG Guozhen(School of Environmental and Municipal Engineering,Lanzhou Jiaotong University,Lanzhou 730070;Key Laboratory of Drinking Water Science and Technology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085;University of Chinese Academy of Sciences,Beijing 100049;Key Laboratory of Yellow River Water Environment in Gansu Province,Lanzhou 730070)
出处
《环境科学学报》
CAS
CSCD
北大核心
2023年第3期162-174,共13页
Acta Scientiae Circumstantiae
基金
国家重点研发计划课题(No.2020YFD1100500)。
关键词
晶面
改性二氧化钛
光催化
消毒
固定化
crystal facet
modified TiO_(2)
photocatalytic
disinfection
immobilized
