氧化镁/活性炭复合材料的制备及其吸附特性

Preparation of magnesia/activated carbon composites from straw pulp black liquor and magnesium salt and their adsorption characteristic

氧化镁/活性炭复合材料性能优良、用途广泛,但制备成本高.以造纸制浆过程中产生的主要污染物——造纸草浆黑液和镁盐为原料制备了氧化镁/活性炭复合材料,用N2吸附等温线、扫描电镜及X射线能谱等方法进行了表征,并研究了其对阴离子染料的吸附特性.结果表明,制备的氧化镁/活性炭复合材料中氧化镁分散均匀,比表面积为480m2/g,孔体积0.31mL/g,平均孔径2.62nm,碘吸附值为856.12～863.56mg/g;氧化镁/活性炭复合材料对阴离子染料的吸附符合伪二级动力学方程;等温吸附线拟合结果显示,吸附过程可用Langmuir等温吸附方程描述;该吸附是自发进行的吸热过程.

Magnesia/activated carbon composites were prepared from straw pulp black liquor and magnesium salt. The composites were characterized by nitrogen adsorption isotherm,scanning electron microscope and energy-dispersive spectrometry. The adsorption characteristics of anion dyes onto magnesia/activated carbon composites were investigated. Results showed that the MgO particles in the magnesia/activated carbon composites were well dispersed,the surface area was 480 m2 /g,the pore volume was 0. 31 mL/g,the average pore size was 2. 62 nm,and the iodine number was 856. 12 ～ 863. 56 mg/g. It was found that the composites could remove anion dyes from aqueous solution effectively. The pseudo-second-order kinetic model showed the best correlation with experimental data. Langmuir and Freundlich models were used to fit the equilibrium,and it was indicated that Langmuir best fitted these data. The adsorption of anion dyes onto magnesia/activated carbon composites was found to be an endothermic process in nature.