氧化锰、氧化铁、氧化铝对砷(Ⅲ)的吸附行为研究

Study on Adsorption Behaviors of As(Ⅲ) by Manganese Oxide,Iron Oxide and Aluminium Oxide

合成了氧化锰、氧化铁、氧化铝三种矿物，以氧化铁、氧化锰为吸附剂研究了pH值、离子强度和时间等因素对吸附As（Ⅲ）的影响，并讨论了氧化锰、氧化铁、氧化铝三种矿物对As（Ⅲ）的饱和吸附容量及等温吸附实验。pH值对氧化锰吸附As（Ⅲ）几乎不影响，对氧化铁吸附As（Ⅲ）在很大的范围内（pH为3．5～8．5）影响不大，离子强度对二者吸附As（Ⅲ）的影响不大，吸附反应在0．5h左右达到吸附平衡。在优化吸附条件下氧化锰、氧化铁、氧化铝对As（Ⅲ）的饱和吸附容量分别为48．38mg／g、23．70mg／g、3．52mg／g，三种合成矿物对As（Ⅲ）的饱和吸附容量：氧化锰〉氧化铁〉氧化铝。对实验数据进行Freundlich和Langmuir拟合，相关系数尺均在0．98以上，吸附动力学符合Lagergren二级速率方程。

Three minerals of manganese oxide, iron oxide and aluminium oxide were synthesized and the effects of pH value and ionic strength of the solution, adsorption equilibrium time on adsorption of As （ m ） by manganese oxide and iron oxide were studied. And the saturated adsorption eapacity and the isothermal adsorption of As（Ⅲ） by three minerals were also tested. The results showed that pH value had less influence on adsorption of As（Ⅲ） by manganese oxide and less influence on adsorption of As（Ⅲ） by iron oxide in pH range of 3.5 -8.5. The results also showed that ionic strength had less effect on adsorption of As （ Ⅲ ） by iron oxide and adsorption equilibrium time was about half an hour. The order of the saturated adsorption three minerals was： manganese oxide 〉 iron oxide 〉 aluminium oxide with saturated manganese oxide, The capacity of As （Ⅲ） by adsorp tion capacities of 48.38 mg/g, 23.70 mg/g and 3.52 mg/g respectively under the optimized adsorption condition. The adsorption data were fitted by both Freundlich and Langrnuir isotherm models with correlation coefficient of R 〉 0.98 and adsorption kinetic data correlated well with Lagergren second kinetic equation.