硫酸改性活性炭及其去除水中Cr(Ⅵ)的研究

Study on Sulfuric Acid-modified Activated Carbons and it Removal of Cr(VI) in Water

探讨了硫酸改性活性炭的制备方法,以及改性炭吸附去除水中Cr(VI)的效果、条件与作用机理.结果表明,硫酸改性活性炭制备方法为:将5 g原炭浸泡在100 mL浓度为1 mol/L的硫酸溶液中改性时间4 h,改性温度60℃.改性炭吸附去除Cr(VI)的最佳方式为:溶液pH值3-5,改性炭投加比为1:100(重量比),(补充单位),Cr(VI)去除率为95.6%(较原炭提高了19.6%).改性炭强化Cr(VI)去除的机理主要是:改性炭表面酸性基团含量显著增加,表面极性和亲水性增强,因而对亲水性的Cr2O72-离子吸附能力增强;且活性炭在改性过程中表面形成了大量带正电荷的基团,强化了与Cr2O72-负离子的异电吸附作用.

The preparation method of sulfuric acid-modified activated carbons and its effect ,conditions and mechanism of removing Cr（Ⅵ） in water were discussed.The results showed that the way to prepare sulfuric acid-modified activated carbons was to soak 5g activated carbons in 100mL of sulfuric acid solution with the concentration of lmol/L for four hours under the temperature of 60 ℃ .The optimum conditions are as follows：The solution PH is 3-5, the adding weight ratio of modified activated carbons and original carbons is l：100,the removal efficiency of Cr（VI） is 95.6%（increased by 19.6% compared with original carbons）.The mechanism of removing Cr（VI） strengthenly by modified activated carbons showed the following aspects：.First the content of acidic groups on the modified carbons surface increased and the polarity and hydrophily of it enhanced,therefore the adsorption capacity with hydrophilic Cr2O72^- ions enhanced.Secondly the acidic oxygenic groups on the modified carbons surface formed a lot of groups with positive charge were formated on the surface of activated in the process of its modification,and the different electric adsorption between the modified carbons and Cr2O72^- ions with negative charge was strengthened.