四乙烯五胺接枝膨润土对酸性大红GR的吸附性能

在膨润土（Bent）表面接枝四乙烯五胺（TEPA）制备四乙烯五胺改性膨润土（TEPA/Bent），利用FTIR（红外光谱仪）、XRD（X射线衍射仪）、EA（元素分析）、SEM（扫描电镜）和EDS（能谱仪）对其进行表征分析，并考察对水体中阴离子染料酸性大红GR的吸附性能。结果表明：TEPA成功接枝于膨润土表面，提高了膨润土对酸性大红GR的吸附量；pH对TEPA/Bent表面电位和吸附量影响较大；随着初始pH的增大，TEPA/Bent的zeta电位由正变为负，对酸性大红GR吸附量减少；在pH=3，染料初始质量浓度为100mg/L条件下，TEPA/Bent对酸性大红GR的吸附量可达44.63mg/g；TEPA/Bent对酸性大红GR的吸附动力学符合准二级动力学模型；吸附等温线符合Langmuir吸附等温模型，为单分子层吸附；吸附热力学表明该吸附为自发吸热过程。吸附剂经过5次再生后，吸附量仍保持为初始80%以上。研究表明，TEPA/Bent是从水溶液中去除阴离子染料的潜在有效吸附剂。

Adsorption properties of acid scarlet GR by tetraethylenepentamine grafted bentonite

Tetraethylenepentamine modified bentonite (TEPA/Bent) was prepared by grafting tetraethylenepentamine (TEPA) on the surface of bentonite (Bent). It was characterized and analyzed by using several methods, such as FTIR, XRD, EA, SEM and EDS. The adsorption performance of the anionic dye acid scarlet GR in water on the TEPA/Bent was investigated. The results showed that TEPA was successfully grafted on the surface of bentonite, which increased the adsorption capacity of acid scarlet GR. The pH had a greater impact on the surface potential and adsorption capacity of TEPA/Bent. As the initial pH increased, the zeta potential of TEPA/Bent was changed from positive to negative and the adsorption capacity of acid scarlet GR decreased. When pH=3 and the initial mass concentration of dye was 100mg/L, the adsorption capacity of TEPA/Bent for acid scarlet GR could reach 44.63mg/g. The adsorption kinetics followed the quasi-second-order kinetic model. The adsorption isotherms could be well fitted with the Langmuir model, which was a monolayer adsorption. The adsorption thermodynamics showed that the adsorption was a spontaneous endothermic process. After 5 times of regeneration of the adsorbent, the adsorption capacity remained above 80% of the original. This work indicateded that TEPA/Bent can be a potentially efficient adsorbent for the removal of anionic dyes from aqueous solution.