蒙脱石吸附硝基萘的取代基位置效应

制备了两种阳离子交换量(CEC)不同的钾基蒙脱石,用其吸附两种单取代硝基萘和两种双取代硝基萘,研究了硝基取代基位置对吸附的影响.结果表明:吸附等温线能用Freundlich方程很好的拟合;硝基位置直接影响蒙脱石与硝基萘之间的电子供体给体(EDA)作用和K-NO2作用的效果.具体而言,如果化合物中硝基和萘环不共平面,则EDA作用和K-NO2作用对吸附影响不大;反之如果硝基和萘环共平面,则EDA效应和K-NO2作用有较大影响.吸附单取代硝基萘,CEC小的矿物因其层间有更多的吸附域而使吸附量更大;吸附双取代硝基萘,CEC大的矿物因其钾离子密度大,K-NO2作用相应加强而导致吸附量较大.

Steric effects of substituent in the adsorption of nitronaphthalenes by montmorillonites

Batch experiments were conducted to measure the adsorption of four nitronaphthalene compounds by two potassium-saturated montmorillonites with different cation-exchange capacities(CEC).The steric effects of substituent in the adsorption were determined.The results indicated that the adsorption isotherms were well described by the Freundlich equation.The positions of nitro groups on the naphthalene ring directly affected the electron donor-acceptor(EDA) complexation and K-NO2 interaction.The adsorption of nitronaphthalenes without coplanar nitro groups to the naphthalene ring was little influenced by EDA and K-NO2 reactions.By contrary,the adsorption of nitronaphthalenes with coplanar nitro groups to the naphthalene ring was facilitated by EDA and K-NO2 reactions.Montmorillonite of a lower CEC adsorbed more mono-nitronaphthalenes because of more effective sorption domains.By contrary,montmorillonite of a higher CEC adsorbed more di-nitronaphthalenes due to the enhanced K-NO2 interaction.