阴阳离子改性甘肃平凉钙基膨润土吸附行为研究

针对甘肃平凉钙基膨润土,以十六烷基氯化吡啶(CPC)和十二烷基磺酸钠(SDS)进行改性,研究了原土及其改性土对亚甲基蓝溶液的吸附特性,并从热力学和动力学角度探讨了吸附作用机理.结果表明,改性前后的膨润土对亚甲基蓝吸附能力大小为:SDS-Bt > Bt > SDS-CPC-Bt > CPC-Bt,其吸附动力学行为均符合伪二级动力学方程,吸附活化能较小.在298～353 K范围内,吸附反应为自发过程,表现为物理吸附,且亚甲基蓝在SDS-Bt、Bt和SDS-CPC-Bt上的吸附符合Langmuir等温方程,在CPC-Bt上的吸附则符合Tempkin等温方程.

STUDY ON THE ADSORPTION BEHAVIOR OF CATION AND ANION MODIFIED Ca-BENTONITES IN PINGLIANG, GANSU PROCINCE

Bentonites (Bt) from Pingliang, Gansu Province,were prepared for experiment from Bt by exchanging with an anion surfactant, sodium dodecyl sulfonate(SDS), and cation surfactant, cetylpyridinium chloride (CPC). The properties, kinetics and thermodynamics of methylene bule from water adsorption process on Bt and modified Bt were studied. The result indicated that the adsorbability follows the order of SDS-Bt>Bt>SDS-CPC-Bt>CPC-Bt. The adsorption followed pseudo-second-order kinetics with low activation energy and presented spontaneous physisorption. The adsorption isotherms showed that SDS-Bt, Bt and SDS-CPC-Bt are in accord with the isothermal adsorption equations of Langmuir, but the CPC-Bt is in accord with the isothermal adsorption equation of Tempkin.