新型多金属氧酸盐光催化降解苯酚废水

Photocatalytic Degradation of Phenol Wastewater with New Types of Polyoxometallates Under Sunlight Irradiation

选取苯酚为目标降解物,采用正交实验法,以1∶11系列Keggin型新型多金属氧酸盐K6Ti W11O39SnⅡ(Ti W11Sn)、K6Zr W11O39SnⅡ(Zr W11Sn)、K8Si W11O39SnⅡ(Si W11Sn),与商品化的1∶12系列多金属氧酸盐H3PW12O40与H4Si W12O40为光催化剂,在阳光辐照下,研究了均相溶液中上述催化剂对苯酚水溶液光催化降解效果.结果表明,阳光辐照下,上述5种光催化剂对苯酚水溶液皆有降解作用,实验条件不同,降解效果差异较大.正交实验结果表明,苯酚溶液初始浓度、初始p H值、光照时间、催化剂种类及催化剂投加量均对其降解效果产生影响.上述影响因素重要性顺序为:光催化剂种类>光照时间>苯酚溶液初始p H值>苯酚溶液初始浓度>POM催化剂投加量.其中,Ti W11Sn光催化苯酚降解效果最好.当苯酚溶液初始浓度为3.05 mg/L,初始p H值为5,光照时间为5 h,溶液中Ti W11Sn浓度为0.25 g/L时,苯酚降解率为51.72%,其光催化降解反应遵循Langmuir-Hinshelwood准一级动力学方程.

Aqueous phenol solution was selected as the goal dagradation compound,and a series new types of1 ∶ 11 Keggin polyoxometallates,K6 Ti W11O39SnⅡ（ Ti W11Sn）,K6 Zr W11O39SnⅡ（ Zr W11Sn）,K8 Si W11O39SnⅡ（ Si W11Sn）,and commercial 1 ∶ 12 Keggin polyoxometallate,H3PW12O40 and H4Si W12O40,were chosen as photocatalysts. The photocatalytic degradation of the homogenous aqueous phenol solution under the sunlight irradiation was studied. Experiment results indicate that the aqueous phenol solution can be degradated with the above five photocatalysts under the sunlight irradiation. The degradation effects of the aqueous phenol solutions are quite different with different experiment conditions. The orthogonal test results show that the photocatalytic degradation efficiency of the aqueous phenol solution is affected by the initial concentration and the initial p H values of the phenol solution,the photolysis time,the kinds of catalysts and the dosage of the catalyst.The order of the importance of the above influence factors are the kinds of catalysts 〉 the illumination time〉 the initial p H of the phenol solution 〉the dosage of catalyst〉 the initial concentration of the phenol solution. Ti W11 Sn is the best photocatalyst for the phenol degradation. When the initial concentration of the phenol solution is 3. 05 mg / L with the initial p H values of 5 and the amount of Ti W11 Sn catalyst of 0. 25 g / L,the decolorization rate of the aqueous phenol solution was 51. 72% for sunlight irradiation 5 h. The reactions of the phenol photocatalytic degradation follow the Langmuir-Hinshelwood pseudo-first-order kinetics.