Synthesis and characterization of allyl mannitol cross-linker based novel hydrogel for capturing of toxic metal ions from aqueous solution

• Published in: Separation science and technology Vol. 60; no. 1; pp. 1 - 20
• Main Authors: Chaurasiya, Arbind, Pande, Poorn Prakash, Shankar, Ravi, Chaurasia, Sujeet Kumar, Kumar, Anil, Kumar, Praveen, Kashaudhan, Kopal
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 02.01.2025; Taylor & Francis Ltd
• Subjects: Acrylamide; Acrylic acid; Adsorption; Aqueous solutions; Carbon dioxide; Chemical synthesis; Cobalt; Copolymerization; Copper; Crosslinker; Crosslinking; Distilled water; Fourier transforms; Free radical polymerization; Free radicals; heavy metal removal; Heavy metals; hydrogel; Hydrogels; Infrared analysis; Mannitol; Metal ions; Retention; Retention capacity; reusability; Scanning electron microscopy; Swelling ratio; Wastewater; wastewater treatment
• ISSN: 0149-6395; 1520-5754
• DOI: 10.1080/01496395.2024.2412712

Three grades of allyl-mannitol cross-linker-based hydrogel (AMCLHs hydrogel) have been synthesized with the help of acrylic acid and acrylamide monomers using a free radical co-polymerization technique. The three prepared grades of AMCLHs hydrogel have been referred to as AMCLHs-1, AMCLHs-2, and AMCLHs-3, respectively. The prepared AMCLHs hydrogels have been characterized by several analytical techniques viz. Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG) analysis, point of zero charge (ΔpH PZC ), analysis, and scanning electron microscope (SEM) analysis, respectively. The synthesized hydrogels have been utilized for the elimination of Cu 2+ and Co 2+ ions from wastewater. The properties of prepared AMCLHs hydrogels, i.e. swelling and water retention ratio have been studied in distilled water under optimized conditions. The maximum swelling ratio of the best grade of hydrogel (AMCLHs-1) has been found to be 400.5 g/g with the water retention ratio of 75.09% during 24 h. These findings indicate the AMCLHs-1 hydrogel has remarkable swelling and water retention capacity. The maximum metal ion removal efficiency of AMCLHs-1 hydrogel from aqueous solutions has been found to be 96.6% for Cu 2+ and 94.2% for Co 2+ ions under optimum conditions. The experimental data fitted well with the Langmuir and Freundlich adsorption models, revealing maximum adsorption capacities of 431.03 mg/g for Cu 2+ ions and 414.93 mg/g for Co 2+ ions, respectively. In addition, the rate for the adsorption of Cu 2+ and Co 2+ ions onto AMCLHs-1 hydrogel follows both Pseudo first and second-order kinetic models. The negative ΔG values indicate that the adsorption process occurs spontaneously, while positive ΔH values suggest that the adsorption process is exothermic in nature. The prepared AMCLHs hydrogel is reusable and exhibits high desorption efficiency with 87.63% for Cu 2+ and 85.21% for Co 2+ metal ions even after the fourth cycle. Overall, AMCLHs hydrogel is a cost-effective and reusable adsorbent that possesses a significant potential for heavy metal ion removal from aqueous solutions.