摘要
以碱木质素(AL)为原料,经1,2-二氯乙烷、亚氨基二乙酸(IDA)改性制得多齿配体改性碱木质素(AL-IDA)吸附材料,用FT-IR、热重和氮吸附技术对其结构进行表征.通过静态吸附实验,考察了pH值、吸附时间、Hg^(2+)和Cd^(2+)初始浓度、温度和共存离子等因素对AL-IDA吸附Hg^(2+)、Cd^(2+)效果的影响.结果表明,溶液pH值对AL-IDA的吸附性能有显著影响,最适宜pH值范围是5.0—6.0;吸附平衡时间为8 h,吸附动力学可以用准二级动力学模型描述和预测;Langmuir方程可以较好地描述AL-IDA对Hg^(2+)、Cd^(2+)的吸附;在pH值为5、初始浓度为300 mg·L-1、温度为25℃时,对Hg^(2+)和Cd^(2+)最大吸附容量分别为239.5 mg·g^(-1)、129.2 mg·g^(-1);温度升高,吸附容量增大,AL-IDA吸附Hg^(2+)、Cd^(2+)的表观活化能分别为22.49 k J·mo1^(-1)和23.28 k J·mo1^(-1),表明吸附主要为化学作用.AL-IDA对重金属Hg^(2+)、Cd^(2+)主要吸附机理是离子交换作用和表面络合.
A novel chelating ligand modified alkali lignin （AL-IDA） adsorbent from alkali lignin （AL） was prepared using 1,2-dichloroethane and iminodiacetic acid （IDA）. The adsorbent was characterized by Fourier-transformed infrared spectroscopy （FT-IR）, thermogravimetric analysis （TG） and N2 adsorption techniques. The effect of various parameters on Hg2＋/Cd2＋ adsorption process such as initial pH, contact time, initial Hg2＋/Cd2＋ concentration, temperature and coexisting ions were investigated in detail through static batch experiments. The results indicated that the adsorption processes of Hg2＋/Cd2＋ on AL-IDA were strongly dependent on the coexisting ion concentration and pH, and the optimal pH value was between 5.0 and 6.0. The adsorption equilibrium was achieved at 8 h. The sorption kinetic experimental data were best described by the pseudo-second-order model, and the isotherm adsorption equilibrium of AL-IDA was followed by Langmuir isotherm equation. The maximum adsorption capacity obtained was 129.2 mg. g-1 for Cd2＋ and 239.5 mg. g-1 for Hg2＋ at pH 5 when the initial metal concentration was 300 mg·L-1 and the temperature was 298 K. The adsorption capacity of AL-IDA for Hg2＋/Cd2＋ increased with increasing temperature. The activation energy of adsorption on AL-IDA was 22.49 kJ. mo1-1 for Hg2＋ and 23.28 kJ.mol-1 for Cd2＋, respectively, which indicated that the adsorption was mainly chemical action. The adsorption mechanisms were ion exchange and chelation between Hg（ l] ）/Cd（ Ⅱ ） and AL-IDA.
出处
《环境化学》
CAS
CSCD
北大核心
2016年第9期1952-1960,共9页
Environmental Chemistry
基金
四川省教育厅自然科学研究项目(16ZB0315)
国家自然科学基金(31300793)资助~~
关键词
改性碱木质素
吸附
汞离子
镉离子
modified alkali lignin, adsorption, mercury, cadmium.
