亚砷酸盐光催化氧化反应在不同锐钛矿 TiO 晶面上的 pH 效应。

pH effects of the arsenite photocatalytic oxidation reaction on different anatase TiO facets.

机构信息

School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, PR China.

出版信息

Chemosphere. 2019 Jun;225:434-442. doi: 10.1016/j.chemosphere.2019.03.017. Epub 2019 Mar 7.

DOI:10.1016/j.chemosphere.2019.03.017

Abstract

TiO is one of the most cheap materials which can both adsorb arsenic and oxidize arsenite [As(III)] to arsenate [As(V)]. In this study, anatase TiO crystals with different main facets such as {101}, {001} and {100} are synthesized and used to investigate arsenic adsorption kinetics, adsorption isotherms, photocatalytic oxidation (PCO) process and the pH effects. The adsorption kinetics of arsenic on TiO crystals can be described by the pseudo second-order kinetic model. For the adsorption isotherms, the Langmuir model is better than the Freundlich model for arsenic on these TiO crystals. For the PCO process, the rate of As(III) oxidation can be denoted by the pseudo first-order kinetic model. It should be noted that at neutral condition the adsorption and PCO rates of the three kinds of TiO crystals follow the order of {101} > {001} > {100}. The pH effect is above all important for both the arsenic adsorption and its PCO. The highest PCO speed appears at high pH values such as at pH 11 or 12.

摘要

TiO 是一种廉价的材料，既能吸附砷，又能将亚砷酸盐 [As(III)] 氧化为砷酸盐 [As(V)]。在本研究中，合成了具有不同主晶面如 {101}、{001} 和 {100} 的锐钛矿 TiO 晶体，并用于研究砷的吸附动力学、吸附等温线、光催化氧化 (PCO) 过程以及 pH 效应。砷在 TiO 晶体上的吸附动力学可以用准二级动力学模型来描述。对于吸附等温线，砷在这些 TiO 晶体上的 Langmuir 模型优于 Freundlich 模型。对于 PCO 过程，As(III)氧化的速率可以用准一级动力学模型来表示。需要注意的是，在中性条件下，三种 TiO 晶体的吸附和 PCO 速率遵循 {101}>{001}>{100}的顺序。pH 值对砷的吸附及其 PCO 都有重要影响。在 pH 值较高的情况下，如 pH 为 11 或 12 时，出现了最高的 PCO 速度。