葫芦[6]脲对印染废水中染料曙红的吸附特性及影响因素

Adsorption characteristics and influencing factors of cucurbit[6]uril for dye eosin Y from printing and dying wastewater

考察了葫芦[6]脲(CB[6])对印染废水中典型染料曙红的吸附特性,研究了初始pH、吸附剂投加量、共存离子等对吸附效果的影响,并探讨了吸附机理。结果表明:在温度为25℃,曙红初始浓度为20 mg/L条件下,CB[6]投加量为0.5 g/L时,2 h吸附去除率为79.5%,吸附动力学特征符合准二级动力学方程;Langmuir等温模型拟合结果比Freundlich模型具更高的相关系数,由Langmuir模型计算得出的最大吸附容量为413.05 mg/g,且随温度升高,最大吸附容量下降,表明CB[6]对曙红的吸附过程为放热过程;随溶液初始pH由3增至11,吸附容量从33.28 mg/g降至9.14 mg/g;共存阴离子对CB[6]吸附的不利影响顺序为PO3-4>CO2-3>NO-2>NO-3;CB[6]具有重复利用性,利用芬顿试剂3次再生后仍保持了原始材料84.9%的吸附容量。通过比表面积、核磁共振氢谱红外图谱和扫描电镜对样品进行表征,采用密度泛函理论计算的静电势分布图分析,揭示了CB[6]可能的吸附原理是其“腰部”与阴离子形式的曙红水解产物产生静电吸引,从而形成超分子外包结构组装体。

The adsorption characteristics of cucurbit[6]uril(CB[6])for the typical dye eosin in printing and dyeing wastewater were investigated.The effects of initial pH,adsorbent dosage and co-existing ions on the adsorption effect were studied,and the adsorption mechanism was discussed.The results showed that the adsorption removal efficiency was 79.5%after 2 hours when the initial concentration of eosin Y(EY)was 20 mg/L at 25℃and the dosage of CB[6]was 0.5 g/L,and the adsorption kinetics characteristics was consistent with the pseudo-second-order kinetic equation.The Langmuir isotherm model had higher correlation coefficient than Freundlich model.The maximum adsorption capacity calculated using Langmuir model was 413.05 mg/g,and with the increase of the temperature,the maximum adsorption capacity of CB[6]decreased,indicating that the adsorption process of CB[6]was exothermic.As the initial pH of the solution increased from 3 to 11,the adsorption capacity decreased from 33.28 mg/g to 9.14 mg/g.The adverse effects of coexisting anions on adsorption were in the order of PO3-4>CO2-3>NO-2>NO-3.CB[6]was recyclable and retained 84.9%adsorption capacity of the original material after 3 times of regeneration using Fenton reagent.The samples were characterized by BET,1H NMR,IR and SEM.The electrostatic potential distribution map of CB[6]was analyzed by the density functional theory(DFT),which revealed that the possible adsorption principle of CB[6]was that the“waist”of CB[6]and the hydrolysate of EY in the form of anions generated electrostatic attraction,thus forming a supramolecular outsourcing package.