有机改性凹凸棒石及其对腐殖酸的吸附研究

Adsorption of humic acid on the surface of modified attapulgite

为了提高凹凸棒石(ATP)的吸附性能,选用表面活性剂十六烷基三甲基溴化铵(CTAB)对ATP进行了改性,利用FT-IR和BET表征了改性前后的结构。通过正交试验探究了其吸附腐殖酸(HA)的较佳方案,并对吸附动力学模型进行分析。结果表明:正交试验中最优的方案为:pH值为6.5,在60℃下吸附10 min,体系中投加0.1 g ATP-CTAB,HA的吸附率为99.82%。ATP-CTAB吸附HA的影响因素顺序为:HA的初始浓度>ATP-CTAB投加量>温度>pH值>反应时间。吸附动力学结果表明,吸附拟合度△q_e<3.4%,R^2>0.996,过程遵循伪二级吸附动力学模型,吸附过程以化学吸附为主。

Primarily attapulgite was modified with surfactants( CTAB) so as to improve the adsorption performance for humic acid. The structure of the attapulgite before and after modification was analyzed by means of FTIR and BET. The adsorption condition was optimized with orthogonal test,and the adsorption model was analyzed as well.The results indicate that the optimal adsorption capacity was acquired at a pH value of 6. 5,a temperature of 60℃,a modified hexadecyl trimethyl ammonium bromide( CTAB) dosage of 0. 1 g,and an oscillation time of 10 min. Under the optimal adsorption condition,humic acid could be adsorbed at a rate of 99. 82 %. Different importance factors influence of removal rate of humic acid were that concentration of humic acid > dosages of ATPCTAB > temperature > pH > reaction time. The adsorption kinetics for ATP-CTAB follows a pseudo-second order model( R^2> 0. 996,△q_e< 3. 4%),and the adsorption process is dominated by chemical interaction.