榴莲壳吸附水中十六烷基三甲基溴化铵的研究

STUDY ON THE ADSORPTION OF CETYLTRIMETHYL AMMONIUM BROMIDE FROM AQUEOUS SOLUTIONS WITH DURIAN SHELL

榴莲壳经甲醛，硫酸混合溶液处理后制备成吸附剂。研究了吸附剂对十六烷基三甲基溴化铵（CTAB）的吸附性能，考察了溶液pH值、吸附剂用量、起始浓度、吸附时间、浓度和温度的影响。结果表明，吸附容量在pH值7～11范围内达到最大值，CTAB的去除率随着吸附剂用量增加而增大，当吸附剂用量为0．5g时，CTAB的去除率达97．5％。吸附容量也随着起始浓度的增加而增大，并在120min达到吸附平衡。运用3种动力学模型对吸附过程进行拟合，结果表明吸附过程可以很好地用准二级动力学方程描述。吸附等温线用Langmuir方程的拟合效果优于Freundlich或Tempkin方程。在热力学研究中，△G^o〈0，△H^o〉0，△s^o〉0，表明此吸附过程是自发、吸热和熵增加的过程。

The durian shells（DS） were modified as adsorbents by treating with a mixed solution of formaldehyde/sulphuric acid and the adsorption behavior for cetyltrimethyl ammonium bromide （CTAB） was investigated. The affecting factors such as solution pH, adsorbent dosage, initial concentration, adsorption time, concentration and temperature were disscussed. The results showed that the adsorption capacity reached a maximum value at pH 7-11 and removal rate of CTAB would increase with the increasement of adsorbent dosage. When the adsorbent dosage was up to 0.5 g, removal rate would reach 97.5%. The adsorption capacity also increases with the inereasement of initial concentration, and adsorption equilibrium was achieved after 120 rain. Three kinds of dynamic models were used to simulate adsorption kinetics. The result showed that the adsorption process-well followed a pseudo-second order equation. The adsorption isotherm could be described very well by Langrnuir model rather than Freundiich or Tempkin models. In thermodynamic studies, the parameters of △G^o〈0,△H^o〉0,△s^o〉0 indicated that the adsorption process was spontaneous and endothermic with a increase of entropy.