Department of Chemistry, National University of Singapore, Singapore.
ACS Appl Mater Interfaces. 2013 May 22;5(10):4443-9. doi: 10.1021/am400901e. Epub 2013 May 13.
The presence of anions such as chromate, arsenate, and arsenite in drinking water is a major health concern in many parts of the world due to their high toxicity. Removal of such anions from water using low cost biomass is an efficient and affordable treatment process. Owing to the easy availability and biodegradability, we chose to use apple peel as a substrate for our investigations. Zirconium cations were immobilized onto the apple peel surface and used for the extraction of anions. Zirconium loaded apple peels were used to extract anions such as phosphate, arsenate, arsenite, and chromate ions from aqueous solutions. The presence of Zr cations on the apple peel surface was characterized using XPS. The modified adsorbent was characterized using SEM, EDS, and FT-IR. Zr treated apple peels showed efficient adsorption toward AsO2(-) (15.64 mg/g), AsO4(3-) (15.68 mg/g), Cr2O7(2-) (25.28 mg/g), and PO4(3-) (20.35 mg/g) anions. The adsorption and desorption studies revealed the adsorption mechanism involves electrostatic interactions. Anion removal efficiency was estimated by batch adsorption studies. Adsorption kinetic parameters for all anions at different concentrations were described using pseudo-first-order and pseudo-second-order rate equations. Langumir and Freundlich isotherms were used to validate our adsorption data. Arsenate and chromate anions were strongly adsorbed at the pH range from 2 to 6, while arsenite was extracted efficiently between pH 9 and 10. Overall, the Zr immobilized apple peel is an efficient adsorbent for common anionic pollutants.
饮用水中存在的阴离子，如铬酸盐、砷酸盐和亚砷酸盐，由于其高毒性，是世界上许多地区的主要健康关注点。使用低成本生物质从水中去除这些阴离子是一种高效且经济实惠的处理方法。由于易于获得和可生物降解性，我们选择使用苹果皮作为我们研究的基质。锆离子被固定在苹果皮表面上，用于提取阴离子。负载锆的苹果皮用于从水溶液中提取磷酸盐、砷酸盐、亚砷酸盐和铬酸盐等阴离子。使用 XPS 对苹果皮表面上 Zr 阳离子的存在进行了表征。使用 SEM、EDS 和 FT-IR 对改性吸附剂进行了表征。Zr 处理的苹果皮对 AsO2(-)（15.64mg/g）、AsO4(3-)（15.68mg/g）、Cr2O7(2-)（25.28mg/g）和 PO4(3-)（20.35mg/g）阴离子表现出高效的吸附作用。吸附和解吸研究表明，吸附机制涉及静电相互作用。通过批量吸附研究估计了阴离子去除效率。使用拟一级和拟二级速率方程描述了所有阴离子在不同浓度下的吸附动力学参数。Langumir 和 Freundlich 等温线用于验证我们的吸附数据。砷酸盐和铬酸盐阴离子在 pH 值为 2 到 6 的范围内被强烈吸附，而亚砷酸盐在 pH 值为 9 到 10 之间被有效地提取。总的来说，Zr 固定化的苹果皮是一种有效的阴离子污染物吸附剂。
