Fabrication of two dual-functionalized covalent organic polymers through heterostructural mixed linkers and their use as cationic dye adsorbents

Abstract

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 multifunctional 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 via imine and hydrazone linkages based on Schiff base condensation. Possessing the advantages of porosity and p-conjugated phenyl rings, as well as functional -CO-NH-and -SO 3 H 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 DG Q , DH Q and DS Q 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.

Adsorption Behavior of Iodine by Novel Covalent Organic Polymers Constructed Through Heterostructural Mixed Linkers

“…All starting reagents, except benzene-1,3,5-tricarbohydrazide, were purchased commercially and used directly as received without further purification (Dong et al, 2018).…”

“…Among which, both Jiang's group and Zhao's group have done pioneering work in aforementioned respect. Strongly motivated by the heterostructural mixed linker approach, our group have developed two three-component COPs (JLUE-COP-1 and JLUE-COP-2) for removing cationic dyes from wastewater (Dong et al, 2018). Herein, as an extension and expansion of the previous work, we exploited JLUE-COP-3 with benzene-1,3,5-tricarbohydrazide (BTCH), 4,4'-biphenyldicarboxaldehyde (BPDA), and 2,5-diaminobenzenesulfonic acid (DABA) through a simple and high-speed Schiff base chemistry using DMSO as solvent (Scheme 2).…”

Facile Room‐Temperature Synthesis of Novel Porous Three‐Component Hybrid Covalent Organic Polymers and Their Applications towards Sulfadiazine Adsorption

“…There is no doubt that the challenges proposed on synthesis have prevented COPs from developing and expanding their structural innovation and practicable applications. Recently, our group successfully developed two dual‐functionalized COPs through a facile heterostructural mixed linker approach to serve as efficient adsorbents for the removal of cationic dyes . Meanwhile, Wang et al .…”

“…The JLUE‐COPs displayed significantly disappeared stretching vibrations of C−H (2890 cm −1 ), N−H (3374, 3308 and 3200 cm −1 ) and substitution benzene ring (702 cm −1 ) compared with TFP and PDA/BD monomers; besides, a blue shift of N−H stretching in BTCH occurred from 3300 cm −1 to 3432 cm −1 . The newly generated peaks at 1617, 1583 and 1280 cm −1 might be attributed to the C=O, C=C and C=N vibrations arisen after polymerization, indicating the successful occurrence of polymerization synthesis and confirming the existence of keto‐enamine form rather than enol‐imine form . Furthermore, the structural information of JLUE‐COP‐25 and JLUE‐COP‐26 were characterized by X‐ray photoelectron spectroscopy (XPS) spectra.…”

Application of Various Metal-Organic Frameworks (MOFs) as Catalysts for Air and Water Pollution Environmental Remediation

“…However, research studies mainly concentrate on the removal of one type of pollutant, either soluble or insoluble pollutants. Recently, porous materials, such as MOFs, have been applied to water filtration to treat these contaminants [211][212][213][214][215][216][217][218][219]. It is necessary to use an electrospinning process to obtain superhydrophilic-underwater superoleophobic properties.…”