除氟活性铝氧化物（AlOxHy-Fn）的吸附除砷性能

以活性铝氧化物AlOxHy处理某高氟地下水的中试实验获得的吸附剂废料AlOxHy-Fn为对象，考察其对三价砷（As（Ⅲ））和五价砷（As（Ⅴ））吸附去除性能，并对吸附机理进行了探讨。研究显示，AlOxHy-Fn为多孔无定型且具有不规则表面的絮状结构，比表面积为218．88m2／g，零电荷点pHZPC在pH为8左右；AlOxHy-Fn可快速吸附As（Ⅲ）和As（Ⅴ），且反应24h后的平衡吸附量分别为0．60和3．41mg／g，朗格缪尔模型可以很好地描述As（Ⅲ）和As（Ⅴ）在AlOxHy-Fn表面的吸附，且As（Ⅲ）和As（Ⅴ）的最大吸附容量分别为13．63和63．27mg／g；AlOxHy-Fn在pH=4～10范围内对As（Ⅴ）去除率在90％以上，As（Ⅲ）在中性和弱碱性pH范围内吸附效果较好，但去除率仍在32％以下。AlOxHy-Fn表面性质、砷形态分布特征等对As（Ⅲ）与As（Ⅴ）的吸附有重要影响，电负性As（Ⅴ）较电中性As（Ⅲ）更容易吸附在AlOxHy-Fn表面。AlOxHy-Fn吸附除砷过程中，在pH为6时氟溶出量最低（0．40mg／g），过高或过低pH均会导致氟溶出量增大；氟溶出量与As（Ⅴ）吸附量之间有明显正相关关系（R2=0．97），但与As（Ⅲ）吸附量无相关关系；铝溶出量在pH为4～10范围内均很低。将AlOxHy-Fn回用作为除砷吸附剂去除工业含砷废水的砷具有良好的技术经济可行性，且将As（Ⅲ）氧化为As（Ⅴ）是提高去除效果的重要手段。

Adsorptive behaviors of aluminum hydroxide with adsorbed fluoride （ AlOxHy-Fn） towards arsenic

This study investigates the adsorptive behaviors of aluminum hydroxide with adsorbed fluoride（ AlOxHy-Fn） ,which is obtained from a pilot-scale study for the removal of fluoride by aluminum hydroxide （AlOxHy） ,towards arsenite （As（Ⅲ ）） and arsenate （As（ Ⅴ ））. AlOxHy-Fn shows low crystalline with porous surfaces,and the BET surfaces area and the zero point of charge is determined to be 218.88 m2/g and pH 8. AlOxHy-Fn can quickly adsorb both As（Ⅲ ） and As（ Ⅴ） and the equilibrium adsorption quantity after 24 h con- tact time is 0. 60 mg As（ Ⅲ ）/g and 3.41 mg As（ Ⅴ ）/g,respectively. Langmuir model may well describe the ad- sorption of As（ Ⅲ ） and As（ Ⅴ ） ,and the theoretical maximum adsorption capacity is calculated to be 13.63 mg As（ Ⅲ）/g and 63.27 mg As（ Ⅴ ）/g. The removal of As（ Ⅴ） is above 90% in wide pH ranges from 4 to 10 whereas that of As（ Ⅲ ） is preferred under neutral and weak alkaline conditions. The removal of As（Ⅲ） and As （Ⅴ ） is affected by their species distribution and the surfaces characters of AlOxHy-Fn and the negatively- charged As（ Ⅴ ） is easier to adsorb onto the positive surfaces of AlOxHy-Fn than the neutral As（Ⅲ） species. The dissolution of fluoride is highly dependent on pH and is as low as 0.40 mgF/g at pH 6, which is favored at lowered or elevated pH. The dissolution of fluoride is positively correlated with the adsorption of As （ Ⅴ ） but shows little rel- ativity to that of As（Ⅲ）. The reclamation of AlOxHy-Fn for the treatment of industrial wastewater with arsenic is feasible and cost-effective,and the oxidation of As（Ⅲ） to As（Ⅴ） is valuable to increase the removal efficiency.