季铵盐改性土壤对水中苯酚的吸附及机理研究

Study on Adsorption and the Mechanism for Adsorption of Phenol onto HDTMA modified Soil

采用十六烷基三甲基溴化铵 ( HDTMA)对土壤进行了改性。结果表明 ,改性时最适温度为 50～ 55℃ ,最适p H为中性 ,最适 HDTMA浓度为 1 %。又考察了 p H、改性土壤用量及振荡时间对吸附效果的影响 ,通过测定吸附等温线探讨了吸附机理。结果表明 ,p H=3～ 1 0时 ,酚的吸附去除率基本不变 ,当 p H>1 0时 ,吸附效率随 p H增大而提高。随着改性土壤用量的增加和振荡时间的延长。酚的去除率升高。改性土壤对苯酚的等温吸附规律可用 Freundlich模式描述 ,在 p H=1 2时 ,亦可用 Langmuir模式模拟 ,但在 p H=5.83时 ,吸附规律不符合 Langmuir模式 ,而符合线性分配模式 ,这与吸附机理不同有关。

Natural soil was midified by hexadecyltrimethylammonium (HDTMA).The results show that the optimum modifying conditions are:modifying temperature is 50℃～55℃,pH is 7.0,HDTMA concentration is 1%,In addition,the effect of pH,HDTMA soil’s amount and shaking time on the adsorption were investigated.The adsorption isotherms and the mechanism for the adsorption were investigated too.The results indicate that the rate of removal for phenol is constant when pH range from 3 to 10,the rate of removal increases with the rise of pH when pH is>10,The adsorption efficiencies also increase with the extension of shaking time and the addition of HDTMA soil amount.The experimental results of isothermal adsorption show that the adsorption of phenol onto HDTMA soil can be well described by Freundlich model.Especially it can also be characterized by Langmuir model when pH is a higher value(pH=12).It can not be fitted by Langmuir model and can be described by linear partition model when pH is lower(pH=5.83).These results are related with mechanisms for the adsorption.