Dong Jun, Xu Feifan, Dong Zhaojun, Zhao Yongsheng, Yan Yan, Jin Hua, Li Yangxue
Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University 2519 Jiefangda Road Changchun 130021 P. R. China
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University Changchun 130012 P. R. China.
RSC Adv. 2018 May 23;8(34):19075-19084. doi: 10.1039/c8ra01968a. eCollection 2018 May 22.
With the rapid development of industrialization, population growth and long-term droughts, the scarcity of clean water and increasing environmental pollution are becoming critical issues. Porous organic polymer materials have been proposed as good candidates for removing pollutant compounds from water supplies. However, because of their finite synthetic chemical reactions and monotonous building blocks, fabricating covalent organic polymer materials with multiple linkages and various different multi-functional components remains a huge challenge. Herein, two dual-functionalized covalent organic polymers (JLUE-COP-1 and JLUE-COP-2) were prepared through heterostructural mixed linkers imine and hydrazone linkages based on Schiff base condensation. Possessing the advantages of porosity and π-conjugated phenyl rings, as well as functional -CO-NH- and -SOH building units, the resultant dual-functionalized JLUE-COPs exhibited high capabilities for the removal of the cationic dye methylene blue (MB). Experiments were carried out to investigate the effects of pH, dye concentration, contact time and temperature on the performance of the JLUE-COPs. The kinetics, equilibrium properties, thermodynamics and mechanisms were studied. It was found that the adsorption processes of the two JLUE-COPs both followed the second-order kinetic model and can be described well by the Langmuir model. Notably, the differences in the surface and pore volumes of the two JLUE-COPs lead to differences in the adsorption rate, adsorption efficiency and maximum adsorption capacity. In addition, activation energy values and some thermodynamic parameters such as Δ , Δ and Δ suggest that the adsorption processes of dyes onto the JLUE-COPs are entropy-driven, endothermic and spontaneous. Our work thus paves the way for developing functionalized COPs as a new type of platform for removing cationic dyes from wastewater.
随着工业化的快速发展、人口增长和长期干旱，清洁水的稀缺和环境污染的加剧正成为关键问题。多孔有机聚合物材料已被认为是从供水系统中去除污染物的良好候选材料。然而，由于其有限的合成化学反应和单一的结构单元，制备具有多种连接方式和各种不同多功能组分的共价有机聚合物材料仍然是一个巨大的挑战。在此，通过基于席夫碱缩合的异质结构混合连接体亚胺和腙键制备了两种双功能化的共价有机聚合物（JLUE-COP-1和JLUE-COP-2）。所得的双功能化JLUE-COPs具有孔隙率和π共轭苯环的优势，以及功能性的-CO-NH-和-SOH结构单元，对阳离子染料亚甲基蓝（MB）表现出高去除能力。进行了实验以研究pH、染料浓度、接触时间和温度对JLUE-COPs性能的影响。研究了动力学、平衡性质、热力学和机理。发现两种JLUE-COPs的吸附过程均遵循二级动力学模型，并且可以用朗缪尔模型很好地描述。值得注意的是，两种JLUE-COPs的表面和孔体积差异导致吸附速率、吸附效率和最大吸附容量的差异。此外，活化能值和一些热力学参数如Δ 、Δ 和Δ 表明染料在JLUE-COPs上的吸附过程是熵驱动的、吸热的和自发的。因此，我们的工作为开发功能化的COPs作为从废水中去除阳离子染料的新型平台铺平了道路。
