化学改性麦麸吸附去除水溶液中砷（英文）

Adsorption Removal of Arsenic from Aqueous Solutions by Chemically Modified Wheat Bran

采用廉价的化学改性麦麸为吸附剂去除水溶液中的As(Ⅴ).采用静态吸附实验方法,研究不同实验因素如初始溶液p H值、吸附时间、初始As(Ⅴ)质量浓度、吸附剂用量和共存阴离子等对As(Ⅴ)吸附去除的影响.结果表明:在吸附剂用量5.0 g/L,初始溶液p H为4.0～8.0,接触时间1 h条件下,As(Ⅴ)的去除率可达95%以上.在实验条件下,磷酸盐和硅酸盐可显著降低As(Ⅴ)的去除率,而硫酸盐几乎无影响.动力学研究表明:As(Ⅴ)吸附过程符合准二级速率方程.Langmuir和Freundlich模型均能很好地描述吸附剂对As(Ⅴ)的吸附平衡.由Langmuir模型得到改性麦麸对As(Ⅴ)的最大吸附容量为22.65 mg/g,表明改性麦麸可有效去除水溶液中的As(Ⅴ).

Contamination of water with arsenic has received attention as a global problem in recent years. In this study,wheat bran was modified by chemicals and utilized as a low-cost adsorbent to remove As（Ⅴ） from aqueous solutions. Batch experiments were carried out to study the effect of various experimental parameters such as initial solution pH,contact time,initial As（Ⅴ） concentration,adsorbent dosage and co-existing anionic component on As（Ⅴ） adsorption,and the optimal condition was selected. The results showthat the removal percentage of As（Ⅴ） could be over 95 % in the conditions of adsorbent dosage 5. 0 g/L,initial solution p H 4. 0 - 8. 0,and contact time 1 h. Under the experimental conditions,phosphate and silicate causes greater decrease in arsenate removal percentage among the anions,and sulfate has almost no effect on the adsorption of arsenate. Kinetic studies showthat the As（Ⅴ） adsorption process obeyed pseudo-second-order rate equation. The applicability of the Langmuir and Freundlich models for the data was tested. Both the models adequately describe the experimental data of the adsorption of As（Ⅴ）. The maximum adsorption capacity calculated from the Langmuir model is 22. 65 mg/g for As（Ⅴ）. The study has shown that the effectiveness of modified wheat bran in the removal of As（Ⅴ） from aqueous solutions.