1、第 43 卷第 3 期2023 年 3 月Vol.43,No.3Mar.,2023环境科学学报Acta Scientiae Circumstantiae固定化改性TiO2光催化消毒性能与机理研究严婉铒1,2,尚子茗2,3,袁庆科2,栾富波2,3,孟颖2,*,张国珍1,4,*1.兰州交通大学环境与市政工程学院,兰州 7300702.中国科学院生态环境研究中心,中国科学院饮用水科学与技术重点实验室,北京 1000853.中国科学院大学,北京 1000494.甘肃省黄河水环境重点实验室,兰州 730070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
2、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TiO2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TiO2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
3、、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-TiO2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 TiO2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TiO2基光催化消毒
4、技术在光强70 mWcm-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.关键词:晶面;改性二氧化钛;光催化;消毒;固定化文章编号:0253-2468(2023)03-0162-13 中图分类号:X131 文献标识码:AInvestigation of performance and mechanism of photocatalytic disinfection by immobilized modified TiO2YAN Waner1,2,SHANG Ziming2,3,YUAN Qingke2,LUAN Fubo2,3,MENG Ying2,*
5、,ZHANG Guozhen1,4,*1.School of Environmental and Municipal Engineering,Lanzhou Jiaotong University,Lanzhou 7300702.Key Laboratory of Drinking Water Science and Technology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 1000853.University of Chinese Academy of Scien
6、ces,Beijing 1000494.Key Laboratory of Yellow River Water Environment in Gansu Province,Lanzhou 730070Abstract: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 m
7、icroorganisms 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.T
8、o promote the efficacy of SODIS,the modification of TiO2 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 TiO2,(110)faceted rutile TiO2,non-faceted mixed phase TiO2 were em
9、ployed 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 cata
10、lyst played a major role in disinfection process,while the sharp edge morphology played a secondary role.Immobilization of 001-TiO2 powder reduced catalyst loss in recycling,and the bacterial survival rate in treated water was only 0.4%,which was better DOI:10.13671/j.hjkxxb.2022.0208严婉铒,尚子茗,袁庆科,等.2
11、023.固定化改性TiO2光催化消毒性能与机理研究 J.环境科学学报,43(3):162-174YAN Waner,SHANG Ziming,YUAN Qingke,et al.2023.Investigation of performance and mechanism of photocatalytic disinfection by immobilized modified TiO2J.Acta Scientiae Circumstantiae,43(3):162-174收稿日期:2022-05-23 修回日期:2022-06-06 录用日期:2022-06-07基金项目:国家重点研发计
12、划课题(No.2020YFD1100500)作者简介:严婉铒(1998),女,E-mail:;*责任作者,E-mail:;3 期严婉铒等:固定化改性TiO2光催化消毒性能与机理研究than that reported for immobilized P25 TiO2(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 o
13、f photocatalytic disinfection are as follows:chemical oxidation of holes and radicals(139),surface charge attraction embedding between grains and bacteria(48)and physical destruction of sharp edges and corners of crystal particles(13).In summary,the immobilized anatase TiO2-based photocatalytic disi
14、nfection technology has a good disinfection performance at a light intensity of 70 mWcm-2 and 25,which provides a feasible solution for single-family drinking water disinfection in rural areas of developing countries.Keywords:crystal facet;modified TiO2;photocatalytic;disinfection;immobilized1引言(Int
15、roduction)饮用未经消毒的饮用水,会受病原微生物影响导致腹痛、腹泻等症状,也可引发细菌性痢疾、肠炎等介水传染病,这些水源性病症对体弱的老人儿童甚至会造成生命威胁(Clasen et al.,2004).以缅甸皎漂地区为例(于淼成等,2021),该地区经济与教育水平落后,集中供水覆盖率低,居民饮用水安全意识欠缺,尤其农村地区普遍缺乏消毒设施,居民从自然水体中取水后,经简单静置沉降即直接饮用,水中未被灭活的大肠杆菌直接被摄入,威胁人体健康,一种因地制宜的饮用水消毒技术的诉求已极为迫切.针对当地长年具备充沛自然光资源的情况,可以采用 SODIS 法通过光照中的紫外线灭活部分微生物,保障当地基
16、本饮水安全,SODIS法兼具经济可行性(Lantagne et al.,2009)与实际应用潜力(Luzi et al.,2016),能够缓解饮用水中病原微生物的威胁,WHO曾建议在此类高辐照欠发达地区推行这种消毒方法(Organization,2011).然而,SODIS法光照利用率低,需在天气晴朗的正午时段、水温达到40 以上(Garca-Gil et al.,2020),利用光热协同效应方可在3 h内有效灭活饮用水中细菌,若在低温季节或多云天气下,水温难以达到45,则会导致光照消毒难有显著效果(McGuigan et al.,2012),这使得该方法不仅不适用于辐照和温度较低中高纬度地区,还会因低纬度地区季节或天气变化而失效.因此,开发可突破环境因素制约的高光照利用率消毒方法实现饮用水消毒具有重要意义.相比于单纯使用SODIS方法,使用光催化技术可以强化光灭活灭菌作用,但是纳米级别的微粒可能对水生生物和人体具有严重的遗传毒性(Hussain et al.,2005)和细胞毒性(Lekamge et al.,2018),因而光催化剂的分离回收是限制其应用的主要因素.因此,为了光催化