磁性三乙烯四胺/单宁树脂对Cu^(2+)、Pb^(2+)的吸附性能研究

Study on adsorption performance of Cu^(2+)、Pb^(2+)by magnetic TETA-tannin resin

利用曼尼希反应将三乙烯四胺(TETA)固化到单宁(TA)基体表面,热溶剂法制得磁性单宁基树脂(MTETA-TA)。通过红外光谱、扫描电镜、比表面积及孔隙度分析仪、振动样品磁强计对M-TETA-TA进行表征,表明M-TETA-TA具有疏水性强、比表面积大的优势,Fe_(3)O_(4)的成功引入有效解决吸附剂回收难的问题。对含Cu^(^(2+))、Pb^(2+)废水溶液进行了静态吸附实验,探讨了其对金属的吸附性能。在pH为5的酸性条件下,吸附效果较好;Cu^(^(2+))和Pb^(2+)吸附动力学均符合准二级反应动力学模型,主要为化学吸附;Cu^(^(2+))的吸附等温线符合Langmuir模型,属单层吸附,理论吸附最大值为173.33 mg·g^(-1);Pb^(2+)的吸附等温线符合Sips模型,属多层吸附,理论吸附最大值为217.14 mg·g^(-1)。推测M-TETA-TA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。循环再生5次后,仍有较高的吸附性能和磁性强度。

In the paper,a magnetic tannin(M-TETA-TA)resin was produced by Mannich reaction and hot solvent method,in which tannin(TA)was as the matric,triethylenetetramine(TETA)was as the hardener,Fe3O4 was as the magnetic fller.The morphological and physicochemical properties of M-TETA-TA was characterized by FTIR,SEM,BET and VSM.It was concluded that M-TE-TA-TA had strong hydrophobicity,the advantages of large specific surface area.The successful embedding of Fe_(3)O_(4)solved the problem of difficult recovery of adsorbent.the adsorption properties of the adsorbent on Cu^(2+)and Pb^(2+)were investigated under different pH,adsorption time,and the different initial metal ions concentration conditions.The results indicated that the optimal pH of adsorption on Cu^(2+)and Pb^(2+)was 5.0.The adsorption process of Cu^(2+)and Pb^(2+)conformed to the pseudo-second-order rate model,which was a chemical adsorption process.The adsorption isotherm of Cu^(2+)could be well described by Langmuir equation,indicating that it was single adsorption,and the maximum adsorption capacity on Cu^(2+)was 173.33 mg·g^(-1)The adsorption isothem of Pb^(2+)could be well fitted with Sips equation,indicating that it was multilayer adsorption,and the maximum adsorption capacity on Pb^(2+)was 217.14 mg·g^(-1).The main adsorption mechanism was speculated to be chelation and redox reaction between Pb^(2+)and hydroxyl/amine groups on the surface of the adsorbent,which was accompanied with negative ion-exchange and electrostatic adsorption.After 5 times of recycling,M-TETA-TA still had a high adsorption performance and magnetic strength.