表面改性Fe_3O_4去除水中酸性红B的研究

Removal of acid red B from water by surface modified Fe_3O_4

采用氢氧化铁沉淀法对商品Fe3O4细粉进行了表面改性,以酸性红B(ARB)为模型化合物研究了改性Fe3O4的吸附性能,并对Fenton氧化法再生吸附饱和的吸附剂进行了初步探索.结果表明,改性后的Fe3O4磁性基本不变,而其比表面积增加到原来的5倍.酸性条件有利于对ARB的吸附,最大吸附容量较改性前增大了近3倍,并且吸附速率快,20min即可达到平衡.对平衡吸附实验数据进行线性拟合,表明它们均能很好地符合Langmuir吸附模型.Fenton试剂可以有效的将被吸附的染料完全氧化,同时再生吸附剂,再生后吸附剂的吸附能力有所提高.因此,经表面改性的Fe3O4具有较好吸附性能、易于用磁分离法回收、并可再生循环使用.

Despite being able to be separated and recovered easily by magnetic separation technology, the application of Fe_3O_4 in water treatment is limited by the poor adsorption properties of initial Fe_3O_4. In this work, commercial Fe_3O_4 was modified by the precipitate of Fe(III) hydroxide on the surface without affecting its magnetism property. Acid red B was selected as a model organic compound for adsorption studies. The regeneration of modified Fe_3O_4 saturated with ARB by Fenton reagent was also tested. The results showed that the specific surface area and the adsorption capacity of modified Fe_3O_4 for acid red B was as 5 times and 4 times as that of initial Fe_3O_4 respectively. The adsorption capacity for ARB by initial and modified Fe_3O_4 was 6.69?mg·g^(-1) and 25.8?mg·g^(-1) respectively. Acidic condition is in favor of adsorption. The adsorption rate was very fast. Both the adsorption isotherms were fitted by Langmuir model very well. In the test of regeneration of saturated adsorbent, it was indicated that the adsorbed dye could be completely oxidized by Fenton's reagent, and the adsorbent was regenerated at the same time. The adsorption capacity increased after regeneration. Consequently, the surface modified Fe_3O_4 is an excellent adsorbent possessing good adsorption properties, high efficiency of recovery by magnetic separation method and reusability after regeneration.