超声-TiO_2光催化协同降解聚乙烯醇  

Degradation of Poly(vinyl alcohol) by Ultrasound/UV/TiO_2

作　　者：吴缨[1] 陈红[1] 曹家会[1] 范崇政[2] 

机构地区：[1]合肥学院化学与材料工程系,合肥230022 [2]中国科学技术大学化学物理系

出　　处：《应用化学》2007年第5期570-574,共5页Chinese Journal of Applied Chemistry

基　　金：安徽省高等学校自然科学研究基金(2007KJ090B);合肥学院科学研究发展基金(05ky018zr)资助项目

摘　　要：以纳米TiO2为光催化剂,对聚乙烯醇(PVA)水溶液进行了超声光催化(US+UV)、光催化(UV)和超声波(US)降解,探讨了纳米TiO2晶型、PVA初始浓度和溶液pH值对PVA降解效率的影响。结果表明,PVA的超声光催化协同氧化效果明显优于单独使用超声或光催化的降解效果。锐钛矿型TiO2光催化活性高于金红石型TiO2,降解率随PVA质量浓度的增加而下降,pH值对PVA降解率的影响为pH值8.5>4.5>5.5>7.0。超声光催化降解过程符合一级动力学反应,反应速率常数为0.037 min-1。在超声波频率40 kHz,催化剂用量1.0 g/L,pH=5.5,温度30℃,初始质量浓度90 mg/L的条件下,80 min时的PVA水溶液降解率可达100%。气相色谱、热重、X射线光电子能谱的检测结果证实,降解过程中生成含C O、O C O基团的中间化合物,最终PVA可完全矿化为CO2和H2O。The combination of ultrasound （US） and ultraviolet irradiation （UV） with TiO2 nanoparticles as the photocatalyst was used to degrade poly （vinyl alcohol） （PVA） in aqueous solution. US/UV/TiO2 technique was considerably more effective than US or UV alone, and ultrasound and ultraviolet light exhibited synergistic effect. The sonophotocatalytic activity of rutile TiO2 particles was obviously higher than that of anatase TiO2 particles. The degradation rate of PVA is inversely proportional to the initial PVA concentration. The results show that it is more effective for PVA to be degraded under acidic or basic condition. The order of the reaction rates at different pH was pH 8.5 〉 pH 4. 5 〉 pH 5.5 〉 pH 7.0. The sonophotocatalytic degradation of PVA in the presence of nano anatase TiO2 catalyst followed a pseudo first-order kinetics. The reaction rate constant was 0. 037 min^-1 The degradation ratio of PVA reached almost 100. 0% within 80 min under the experimental conditions of 40 kHz ultrasonic frequency, 1.0 g/L rutile TiO2 catalyst, pH = 5.5, and 30 ℃ temperature at an intial PVA concentration of 90 mg/L. GC, DTG and XPS results showed that the intermediates containing C-O, O-C-O groups were formed during the degradation reaction. The PVA finally mineralized to CO2 and H2O.

关 键 词：聚乙烯醇 超声光催化 纳米锐钛矿型TiO2 

分 类 号：O643[理学—物理化学] X703[理学—化学]