葡甲胺改性活性炭的制备及其对硼的吸附特性

摘要

NMDg-C was prepared and used as adsorbent for boron with concentration of four times as high as that in GB 5749-2006.The effect of adsorption time,pH value,temperature and initial boron ions concentration on removal efficiencies were studied.Kinetic and thermodynamic analysis was also carried out.The experimental results showed that adsorption effect was significantly improved by using NMDg-C,and boron concentration after adsorption could comply with Standards for Drinking Water Quality (GB 5749-2006).The optimal condition:pH value was 7,the temperature was 15 ℃,and the removal rate could reach 90.59％,while adding 1.5 g modified carbon into 30 mL,2.5 mg/L boron concentration.The adsorption reached equilibrium within 30 min.The adsorption process fit well with the Langmuir isotherm model and pseudo second-order kinetic model (R2 ≈ 1),and saturated adsorption capacity for boron was 1.16 mg/g.The adsorption velocity was rapid.KC1 solutionis used as the desorption agent and NMDg-C could be used repeatedly.%通过葡甲胺和活性炭制备了葡甲胺改性活性炭(NMDg-C),去除超标4倍的微量硼.试验考察了吸附时间、pH、温度和硼初始浓度对葡甲胺改性活性炭吸附硼效果的影响,并进行了吸附动力学和热力学分析.试验结果表明:改性后的活性炭吸附效果提高显著,吸附后的硼浓度降低到《生活饮用水卫生标准》(GB 5749-2006)以下;改性活性炭吸附硼的最佳条件:pH值为7,温度为15℃,30 mL的2.5mg/L的硼溶液,投加1.5 g改性活性炭,去除率达到90.59％,吸附平衡时间为30 min,理论饱和吸附量约为1.16 mg/g,其吸附过程较好地符合了准二级动力学模型(R2≈1)和Langmuir等温吸附模型,吸附快速.用1 mol/L的KCl溶液作解吸剂,NMDg-C可重复使用.