负载型催化剂催化臭氧化降解水杨酸

Catalytic Ozonation of Salicylic Acid in Aqueous Solutions by Metal Oxide Supported Catalysts

采用浸渍法,分别制备了以γ-Al_2O_3为载体负载镍、铜、钴、锰氧化物的4种催化剂,并对其相组成、比表面积、电荷零点等进行了表征。考察了催化剂种类、投加量及溶液pH对催化臭氧化降解水杨酸效果的影响,并与单独臭氧化进行了比较。结果表明,4种催化剂均具有一定的催化性能,且负载MnO_2的催化剂催化效果最好;催化臭氧化降解效果主要受催化剂种类及溶液pH的影响。当水杨酸初始浓度为3 mmol·L^(-1),MnO_2催化剂投加量为2.5 g·L^(-1),溶液pH为4~8,O_3投加量为12.56 mg·min^(-1)时,反应60 min,溶液UV296和COD去除率分别在98.0%和88.0%以上。机理分析表明,催化剂的吸附作用和催化O_3产生·OH的量共同影响臭氧化降解效果。

γ-Al_2O_3 supported nickel, copper, cobalt and manganese oxide catalysts were prepared by an impregnation method and their phase composition, surface area, PZC were characterized. Factors including catalysts, dosage and pH value that influence catalytic ozonation degradation efficiency on salicylic acid were investigated, and the effect of catalytic ozonation was compared with that of single ozonation. All of the four catalysts have catalytic effects and the degradation efficiency is significantly influenced by catalysts prepared and pH values. The γ-Al_2O_3 supported MnO_2 catalyst shows the highest catalytic activity. The UV296 and COD removal rates are over 98.0% and 88.0% respectively after 60 min, when the salicylic acid initial concentration is 3 mmol·L^（-1）, catalyst dosage 2.5 g·L^（-1） and O_3 dosage 12.56 mg·min-1 at pH 4^8. Mechanism analysis reveals that the adsorption of catalysts and the amount of ·OH generated by O_3 affect the ozonation degradation efficiency.