高比表面积活性炭的制备及对Cr(Ⅵ)吸附的研究

以椰树壳为原料,运用水蒸汽和二氧化碳复合物理活化法在4 h内制备了2 162.84 m2/g的高比表面积活性炭,其孔径分布范围为1.1~2.5 nm。应用此吸附剂考察了溶液pH、吸附剂用量、接触时间和初始浓度对Cr(VI)离子吸附效果的影响,并讨论了固定吸附床中不同溶液流量对Cr(VI)去除效果的影响。结果表明:在温度为298 K、溶液pH为1.96、吸附剂用量为0.10 g、铬离子初始浓度为100 mg/L与接触时间为70 min的条件下,活性炭对铬离子具有较高的吸附容量,去除率高达99.32%;铬离子在吸附床中的穿透曲线具有陡峭的传质锋面,但随着铬离子溶液流量的增大脱除果率降低。

Preparation of activated carbon with high specific surface area and study on Cr(VI) adsorption

Activated carbon was prepared from coconut shell in four hours with the coupling physical activa-tion process of steam and carbon dioxide, which has a high specific surface area of 2 162. 84 m~2/g and a pore size distribution range of 1. 1～2. 5 nm. Effects of pH, adsorbent amount, contact time and initial concentration on the Cr(Ⅵ) adsorption were investigated with this adsorbent. Moreover, the influence of different solution flow rates was discussed on Cr(Ⅵ) removal efficiecy in the packed bed. The results show that activated carbon is of better adsorption capacity and the removal rate is up to 99. 32% at temperature 298 K,pH of solution 4. 4, ad-sorbent amount 0. 10 g, the initial concentration of Cr( Ⅵ ) 100 mg/L and contact time 70 min. Breakthrough curves of Cr( Ⅵ ) in the adsorption bed have steep mass transfer frontal, however, the removal efficiency becomes lower with the increase of flow rate.