Adsorption efficacy of functionalized Cu-BDC MOFs tethered 2-mercaptobenzimidazole analogue: A comparative study

• Published in: Heliyon 2023-02, Vol.9 (2), p.e13223-e13223, Article e13223
• Main Authors: Challa, Malathi, Chinnam, Sampath, Rajanna, Ambika Madalakote, Nandagudi, Apurva, Yallur, Basappa C., Adimule, Vinayak
• Format: Article
• Language: English
• Subjects: 2-Mercaptobenzimidazole analogue; Adsorption; Congo red; Cu-BDC MOFs
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2023.e13223

A novel metal-organic framework [MOFs], and 2-[benzo [d]thiazol-2-ylthio)-3-hydroxy acrylaldehyde-Cu-benzene dicarboxylic acid was synthesized by solvothermal method and characterized using p-XRD, FSEM-EDX, TGA, BET, FTIR. The tethered organic linker, 2-[benzo [d]thiazol-2-ylthio)-3-hydroxyacrylaldehyde was commonly known as 2-mercaptobenimidazole analogue [2-MBIA]. Analysis of BET disclosed that addition of 2-MBIA to Cu-benzene dicarboxylic acid [Cu-BDC], reduced the crystallite size from 70.0 nm to 65.90 nm, surface area from 17.95 to 17.02 m2 g-1 and enhances the pore size from 5.84 nm with 0.027 cm3 g-1 pore volume to 8.74 nm with 0.361 cm3 g-1 pore volume. Batch experiments were conducted to optimize pH, adsorbent dosage, and, Congo red (CR) concentration. The adsorption percentage of CR on the novel MOFs was 54%. Adsorption kinetic studies revealed that the uptake adsorption capacity at equilibrium was 184.7 mg/g from pseudo-first-order kinetics which gave a good fit with the experimental data. Intraparticle diffusion model explained the process of the adsorption mechanism: diffusion from the bulk solution onto the porous surface of the adsorbent. Freundlich and Sips models were the best fit models of the several non-linear isotherm models. Temkin isotherm suggested the adsorption of CR on MOFs was of an exothermic nature.