环境化学
杨俊,徐仁扣.阴离子对As(Ⅲ)在砖红壤与TiO2混合体系中的光催化氧化/吸附的影响[J].环境科学学报,2009,29(2):367-372
阴离子对As(Ⅲ)在砖红壤与TiO2混合体系中的光催化氧化/吸附的影响
- Influence of anions on photocatalytic oxidation and adsorption of As(Ⅲ) on an oxisol with TiO2
- 基金项目：国家自然科学基金(No.20577054)
- 作者
- 单位
- 杨俊
- 1. 中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室, 南京 210008; 2. 中国科学院研究生院, 北京 100039
- 徐仁扣
- 中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室, 南京 210008
- 摘要：以磷酸根和硫酸根为例,采用一次平衡法研究了无机阴离子对As(Ⅲ)在砖红壤中光催化氧化和吸附的影响.实验结果表明,磷酸根和硫酸根的加入均降低了As(Ⅲ)在土壤中的氧化和吸附,磷酸根的影响程度大于硫酸根,而且两者的影响机理不同.磷酸根主要通过表面吸附机制即强烈地吸附在催化剂表面导致催化剂活性降低,以及与氧化产物As(V)竞争土壤颗粒表面吸附位来影响反应活性;而硫酸根则是在光催化氧化过程中通过捕获光生空穴(h+)和羟基自由基(OH·)生成光催化效率较低的SO4-·,从而影响As(Ⅲ)的光催化氧化效率.
- Abstract：We studied the influence of inorganic anions such as phosphate and sulfate on photocatalytic oxidation and adsorption of As(Ⅲ) in suspension systems of an oxisol. In batch-experiments, phosphate and sulfate both were found to inhibit photocatalytic oxidation and adsorption of As(Ⅲ), but the former showed a greater effect than the latter and the mechanisms of their effects differ. Phosphate can suppress the activity of the photocatalyst (TiO2) by adsorbing to the surface of TiO2 and can reduce photocatalytic oxidation of As(Ⅲ) by producing arsenate which competes for adsorption sites on variable charge soils. Sulfate can affect the efficiency of photocatalytic oxidation of As(Ⅲ) by capturing photoholes (h+) or hydroxyl free radicals (OH·) to generate less photocatalytically active sulfate radicals (SO4-·).
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