负铁锰砂对水中As(Ⅲ)的吸附作用研究

Adsorption study of As(Ⅲ)from water by iron-oxide-coated-manganese sand

采用锰砂为载体制备负铁锰砂改性滤料,研究了其对水体中As(Ⅲ)的吸附动力学,及pH对改性滤料吸附As(Ⅲ)的影响,并对改性滤料的再生进行了初步探讨.结果表明:负铁锰砂改性滤料吸附动力学符合Lagergren二级动力学方程,其吸附等温线能够用Langmuir吸附模型很好地描述,属于单分子层吸附,最大静态吸附容量为20.61μg/g;能够在pH为5.3～8.4时有效吸附As(Ⅲ);0.01%的NaOH能较好的对吸附As(Ⅲ)饱和的滤料进行再生.同时对负铁锰砂吸附As(Ⅲ)的机理进行了探讨,得出负铁锰砂对As(Ⅲ)的吸附可能是静电非专性吸附及配位络合专性吸附共同作用的结果.

The iron-oxide-coated-manganese sand is prepared. The paper takes this sand as adsorbent to study its adsorption of As（ Ⅲ）, pH and the adsorption kinetics and the regenera tion tests are studied. The results show that the iron-oxide-coated-manganese sand can absorb As（ Ⅲ） over a wide pH from 5.3 to 8.4, the adsorption isotherm can be well described with the Langmuir adsorption model and the maximum static adsorption capacity is 20.61μg/ g, adsorption kinetics fits Lagergren second order kinetics equation, NaOH can better regen- erate the iron oxide-coated-manganese sand. At the same time, iron-oxide-coated-manganese adsorb As（ Ⅲ） adsorption mechanism is discussed, and iron-oxide-coated-manganese sand on the As（ Ⅲ ） adsorption may be electrostatic non-specific adsorption and specific adsorption complexation result of the interaction.