聚乙烯亚胺交联膨润土对水中Cr(Ⅵ)的吸附性能与机制  

Adsorption performance and mechanism of polyethyleneimine cross-linked bentonite for Cr(Ⅵ)in aqueous solution

作　　者：孙志勇[1] 张宇辰 吴喜军 SUN Zhiyong;ZHANG Yuchen;WU Xijun(School of Energy Engineering,Yulin University,Yulin 719000,China;School of Architecture and Engineering,Yulin University,Yulin 719000,China)

机构地区：[1]榆林学院能源工程学院,榆林719000 [2]榆林学院建筑工程学院,榆林719000

出　　处：《复合材料学报》2025年第2期949-960,共12页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(52064048);陕西省科技创新团队(2022TD-08)。

摘　　要：为提高膨润土的吸附容量,通过交联反应将聚乙烯亚胺(PEI)引入3-氨丙基三乙氧基硅烷(APTES)改性膨润土(APTES/Bent)表面制备得到PEI交联膨润土(PEI-APTES/Bent-4),并采用FTIR、XRD和SEM等手段对其进行表征分析。以水中Cr(Ⅵ)为吸附对象,考察了PEI-APTES/Bent-4的吸附性能,探究了吸附机制和回收利用性。结果表明:PEI成功接枝于膨润土表面,其丰富的活性基团极大地促进了六价铬的去除。吸附最佳pH为2,随pH值增加吸附量降低。PEI-APTES/Bent-4对Cr(Ⅵ)的吸附符合Langmuir等温模型和拟二级动力学模型,吸附过程为化学吸附和单层吸附,在313 K时最大理论吸附量达137.50 mg·g^(-1)。热力学研究表明该吸附为自发吸热过程。结合吸附实验、FTIR和XPS分析推测得出PEI-APTES/Bent-4对Cr(Ⅵ)的吸附机制主要为静电作用、还原和螯合。经6次循环后吸附剂仍保持较好的吸附性能。PEI-APTES/Bent-4去除水中Cr(Ⅵ)具有较大的应用前景。In order to improve the adsorption capacity of bentonite,polyethyleneimine(PEI)was introduced onto the surface of 3-aminopropyltriethoxysilane(APTES)-modified bentonite(APTES/Bent)by crosslinking reaction to prepare PEI-crosslinked bentonite(PEI-APTES/Bent-4),which was characterised by FTIR,XRD and SEM.Taking Cr(Ⅵ)in water as the adsorption target,the adsorption performance of PEI-APTES/Bent-4 was investigated,and its adsorption mechanism and recyclability were explored.The results showed that PEI was successfully grafted onto the surface of bentonite,and the abundant active groups of PEI dramatically promoted the removal of Cr(Ⅵ).The optimum pH for adsorption was 2,and the adsorption capacity decreased with increasing pH.The adsorption of Cr(Ⅵ)by PEI-APTES/Bent-4 conformed to the Langmuir isotherm model and pseudo-second-order kinetic model,and the adsorption process was chemical adsorption and monolayer adsorption.The maximum theoretical adsorption capacity reached 137.50 mg·g^(-1) at 313 K.Thermodynamic studies indicated that the adsorption was a spontaneous endothermic process.Based on the adsorption experiments,FTIR and XPS analysis,it is speculated that the adsorption mechanism of PEI-APTES/Bent-4 for Cr(Ⅵ)is mainly electrostatic interaction,reduction,and chelation.After six cycles,the adsorbent still maintained good adsorption performance.PEI-APTES/Bent-4 has broad application prospects for the removal of Cr(Ⅵ)from water.

关 键 词：聚乙烯亚胺 膨润土 Cr(Ⅵ) 交联 吸附 

分 类 号：X703[环境科学与工程—环境工程] TB332[一般工业技术—材料科学与工程]