二氧化氯/TiO_2光催化氧化降解碱性品红模拟废水及反应机理

Investigation of Chlorine Dioxide/TiO_2 Photocatalytic Oxidative Degradation of Simulated Wastewater Containing Fuchsine and Its Reaction Mechanism

以硅胶为载体,采用浸渍-焙烧法制备了TiO2光催化剂,并将其用于二氧化氯/TiO2光催化氧化降解碱性品红模拟废水.经对比实验验证了ClO2/TiO2光催化剂/UV照射对碱性品红的氧化降解作用.50 mL质量浓度为150 mg.L-1的碱性品红模拟废水,在pH值为5.0,二氧化氯质量浓度6.14 mg.L-1和10 g.L-1光催化剂条件下,紫外照射距离20 cm,紫外照射时间13 min,碱性品红的去除率可达80%,远远高于二氧化氯化学氧化处理碱性品红的去除率46%.在废水处理过程中,采用紫外可见光谱和红外光谱分析降解产物,碱性品红被氧化降解为醌和羧酸,并进一步降解为二氧化碳和水,提出了二氧化氯/TiO2光催化氧化降解碱性品红废水的反应机理.

The photocatalyst TiO2 was prepared by dipping-calcination method using silica gel as catalyst support.The chlorine dioxide/TiO2 photocatalyst was used for the photocatalytic oxidation of simulated fuchsine wastewater.The degradation effect of fuchsine by the combination of chlorine dioxide,TiO2 photocatalyst and UV irradiation was confirmed by comparison test.The optimum treatment conditions were as follows：the volume of wastewater containing 150 mg·L-1 fuchsine was 50 mL;ClO2 concentration was 6.14 mg·L-1,pH value was 5.0;the distance between UV lamp and flask was 20 cm;UV irradiation time was 13 min;and photocatalyst dosage was 10 g·L-1.The removal efficiency of fuchsine could reach 80%,compared with 46% of chlorine dioxide chemical oxidation.With UV-vis and FT IR analysis technique,the intermediates in the degradation process were obtained.Fuchsine was degradated into quinone and carboxylic acid,and finally changed into carbon dioxide and water during the photocatalytic oxidation.The degradation reaction mechanism of fuchsine by chlorine dioxide/TiO2 photocatalytic oxidation was proposed.