木质素磺酸钠在活性炭/水界面的吸附机理

为了探究木质素磺酸钠在活性炭/水界面的吸附机理,研究了温度、pH 值、无机盐、脲以及直链醇对其吸附动力学及吸附等温线的影响.吸附动力学结果表明,木质素磺酸钠在活性炭/水界面的吸附约在10 min 内快速达到平衡;随着离子强度的增加及脲的加入吸附速率常数增大,pH值增加,吸附速率常数先增大后减小.不同pH值条件下的木质素磺酸钠在活性炭/水界面的吸附等温线符合 Langmuir 方程;随着离子强度增大、脲或直链醇的加入,吸附过程更符合 Freundlich 模型.增加离子强度、降低 pH 值及加入直链醇都可显著提高木质素磺酸钠的平衡吸附量,而脲的加入降低平衡吸附量.在中性条件下木质素磺酸钠主要通过疏水作用和氢键作用吸附在活性炭/水界面,疏水作用有利于加快吸附速率及增加吸附量,该吸附过程不受温度的影响.

Adsorption Mechanism of Sodium Lignosulfonate on the Activated Carbon/Water Interface

In order to explore the adsorption mechanism of sodium lignosulfonate(SL) on the activated carbon in aqueous solution,the influences of pH,ionic strength,urea and straight chain alcohol on the adsorption dynamics and adsorption isotherms of SL was investigated.The results indicate that the adsorption process reaches equilibrium in 10 min.With the addition of urea and the increase of ionic strength,the adsorption rate of SL increases,while with the increase of pH value,the adsorption rate increases at first and then decreases.The adsorption isotherms of SL conform to the Langmuir adsorption model at different pH values;however,the more conform to the Freundlich adsorption model when the salt,urea or straight chain alcohol is added.The main adsorption driving force of SL on activated carbon under neutral condition is controlled by hydrogen bonding and hydrophobic action which contributes to the increase of adsorption rate constant and saturating adsorption amount.The temperature has little influence on the adsorption of SL on the activated carbon/water interface.