三乙烯四胺固化单宁吸附剂制备及性能研究  

Preparation and adsorption performance of tannin cured with triethylenetetramine

作　　者：金绍娣[1] 许雪儿 顾东雅[1] Shaodi Jin;Xueer Xu;Dongya Gu(Yancheng Polytechnic College,Yancheng,Jiangsu 224005,China)

机构地区：[1]盐城工业职业技术学院,江苏盐城224005

出　　处：《日用化学工业（中英文）》2024年第3期290-297,共8页China Surfactant Detergent & Cosmetics

基　　金：江苏省科技厅产学研项目(BY20231102)。

摘　　要：利用曼尼希反应将三乙烯四胺固化到单宁表面,制备得到胺化改性单宁吸附剂TETA-TA,并通过正交实验优化制备工艺。采用红外光谱、扫描电镜、比表面积及孔隙度分析仪对TETA-TA进行了结构表征,探讨了其对Cd^(2+)和Pb^(2+)的吸附性能,研究不同pH值、时间、金属离子初始质量浓度对吸附的影响。正交结果表明反应最佳条件为:反应温度为80℃,反应时间为4 h,醋酸用量为4%(w/%),n(TA)∶n(TETA)∶n(甲醛)=1∶2∶2.5。吸附实验表明:pH值对吸附平衡影响显著,Cd^(2+)和Pb^(2+)最佳pH值均为5.0;TETA-TA对Cd^(2+)的吸附在60 min内能快速达到平衡,对Pb^(2+)能持续24 h的吸附,吸附动力学符合准二级反应动力学模型,为化学吸附;提高金属离子初始质量浓度可以增大平衡吸附量,Cd^(2+)的等温线数据对Langmuir模型线性拟合系数能达到0.995,理论吸附最大值为150.41 mg/g,Pb^(2+)的等温线数据对Sips模型线性拟合较好,理论吸附最大值为210.45 mg/g,推测对Pb^(2+)的吸附除了螯合、氧化还原等化学反应,还存在静电和离子交换作用,氨基和酚羟基为主要参与官能团;TETA-TA对Cd^(2+)和Pb^(2+)可以实现同时吸附,再生5次后仍具有较强的吸附性能。An amine-modified tannin adsorbent(TETA-TA)was prepared by Mannich reaction,in which triethylenetetramine(TETA)was used to cure tannin,and its preparation process was optimized by orthogonal experiment.The structure of TETA-TA was characterized by FT-IR,SEM and BET,and the adsorption properties of the adsorbent to Cd^(2+) and Pb^(2+) were investigated at different pH,different adsorption time and different initial concentrations of metal ions.The results of orthogonal experiment showed that,when the molar ratio of tannin to TETA to formaldehyde was 1∶2∶2.5,the reaction temperature was 80℃,the reaction time was 4 h and the dosage of acetic acid was 4%,the experiment had the best preparation conditions.The results of adsorption indicated that,the adsorption capacity for Cd^(2+)and Pb^(2+)greatly depended on the pH,and the optimal pH values for Cd^(2+)and Pb^(2+)were both 5.0.The adsorption of Cd^(2+)was rapid,which could quickly reach adsorption equilibrium within 60 min,but the adsorption of Pb^(2+)could continue for 24 h.The adsorption process of Cd^(2+)and Pb^(2+)by TETA-TA conformed to the pseudo-second-order kinetic model,which was a chemical adsorption process.Higher initial concentrations of metal ions could lead to higher equilibrium adsorption capacity.The adsorption isotherm of Cd^(2+)could be well described by Langmuir equation(R2=0.995),and the theoretical maximum adsorption capacity was 150.41 mg/g.The adsorption isotherm of Pb^(2+)could be well fitted with Sips equation,and the theoretical maximum adsorption capacity was 210.45 mg/g.The main adsorption mechanism for Pb^(2+)was speculated to be chelation and redox reaction between Pb^(2+)and hydroxyl/amine groups on the surface of the adsorbent,which were accompanied with ion exchange and electrostatic adsorption.It was also found that when more than one kind of metal ions coexisted in aqueous solution,the equilibrium adsorption capacity for each was not affected by others,implying that the TETA-TA adsorbent was effective in simultaneous removal

关 键 词：三乙烯四胺 单宁 Cd^(2+) Pb^(2+) 吸附 

分 类 号：X703.1[环境科学与工程—环境工程]