摘要
利用以环氧氯丙烷、N,N-二甲基甲酰胺、吡啶、二甲胺溶液对天然木薯秸秆进行化学改性得到的新型阴离子吸附剂,研究在不同条件下对KNO3溶液的动态吸附及脱附再生效果.结果表明,与改性前相比,木薯秸秆的吸附性能有了很大提高.随着KNO3溶液质量浓度由50 mg·L-1增加至150 mg·L-1,改性木薯秸秆吸附硝酸根至饱和的时间由120 min缩短至65 min,动态饱和吸附量由11.73 mg·g-1增至26.58 mg·g-1;当KNO3溶液流速分别为3、5、10 mL·min-1时,动态吸附至饱和时间分别为150、120、65 min,改性吸附剂对硝酸根的饱和吸附量和去除率降低;改性木薯秸秆在中性溶液时,吸附效果较好,120 min后达饱和,而在碱性和酸性时40 min即达饱和.Thomas模型能够很好地描述改性木薯秸秆对KNO3的动态吸附动力学.分别选用0.05 mol·L-1NaCl、NaOH和HCl溶液做脱附剂可以得到较好的脱附效果.
Cassava stalk was modified by epichlorohydrin and dimethylamine in the presence of pyridine and N,N-dimethylformamide. Dynamic adsorption and desorption of nitrate from aqueous solutions onto modified cassava stalk was investigated. The factors influencing dynamic adsorption and desorption were examined. The results showed that the adsorption capacity of the modified cassava stalks greatly increased by comparison with raw cassava stalk. The breakthrough time was shortened from 120 min to 65 min with increasing nitrate concentration from 50 to 150 mg·L-1, but the equilibrium adsorption capacity increased from 11.73 to 26.58 mg·g^-1 When the nitrate flow velocity was 3, 5 and 10 mL·min-1, the breakthrough time was 150, 120 and 65 min, respectively, and the nitrate dynamic adsorption capacity and removal efficiency decreased. The adsorption was higher in neutral solution with saturation time of 120 min on the modified cassava stalk, while the time was 40 min in alkaline and acid solution. Thomas model was found to be suitable for describing the kinetics of fixed-bed adsorption,and the equilibrium adsorption capacity derived from the Thomas model is close to the value of the experiments. The 0.05 mol·L^-1 NaCl, HCl and NaOH solutions had good desorption capacities.
出处
《环境化学》
CAS
CSCD
北大核心
2013年第9期1668-1673,共6页
Environmental Chemistry
基金
国家自然科学基金资助项目(21267005)
广西自然科学基金资助项目(2010GXNSFA013008)
广西环境污染控制理论与技术重点实验室项目
广西教育厅立项项目(200807LX023)资助
