New highly efficient psyllium and sodium vinyl sulfonate-based adsorbent for Hg2+ ions

• Published in: Iranian polymer journal 2023, Vol.32 (5), p.585-598
• Main Authors: Kriti, Ranote, Sunita, Chauhan, Ghanshyam S., Kumar, Puneet, Chauhan, Sandeep, Kumar, Kiran
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Ammonium peroxodisulfate; Biocompatibility; Ceramics; Chemistry; Chemistry and Materials Science; Composites; Copolymerization; Correlation coefficients; Crosslinking; Distilled water; Glass; Graft copolymers; Hydrogels; Mercury (metal); Methylene bisacrylamide; Natural Materials; Optimization; Original Research; Polymer Sciences; Polysaccharides; Sodium vinyl sulfonate; Spectrum analysis; Swelling; Wastewater treatment; Water purification; X-ray spectroscopy
• ISSN: 1026-1265; 1735-5265
• DOI: 10.1007/s13726-023-01149-w

Polysaccharide-based adsorbents are highly attractive materials for waste water purification owing to their renewability, biocompatibility, large abundance of feedstock, and cost-effectiveness. Herein, we report sustainable and environmentally-friendly polysaccharide-based adsorbent for Hg 2+ ions removal from the waste water. Psyllium, a polysaccharide, and sodium vinyl sulfonate (VSA)-based polymeric networks, Psy- cl -poly(VSA), were synthesized through free-radical graft copolymerization reaction using ammonium persulfate (APS)- N , N′ -methylene bisacrylamide ( N , N ′-MBA) as an initiator-cross-linker system. Psy- cl -poly(VSA) was characterized using different techniques, including FTIR spectroscopy, energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) studies, and swelling behavior studies at different time intervals, temperatures, and pH. These studies gave confirmatory evidence of the incorporation of monomer (VSA) moiety onto the psyllium backbone resulting in the formation of Psy- cl -poly(VSA). Psy- cl -poly(VSA) cross-linked with 1% N , N ′-MBA showed maximum swelling (1500%) within 60 min at 40 °C in distilled water. Different Psy- cl -poly(VSA) hydrogels were investigated for Hg 2+ ions adsorption. Adsorption parameters viz . time, temperature, pH, and concentration were optimized. During optimization, rapid Hg 2+ ions uptake was observed with maximum adsorption of 97.5% within 10 min, 25 °C, pH 7.0, and 1.0 ppm initial concentration of Hg 2+ . The data for adsorption best fitted the pseudo-second-order kinetic model and Langmuir isotherm with the maximum adsorption capacity ( q m ) of 114.9 mg/g and maximum correlation coefficient of 0.9767 ( R 2 ). Graphical Abstract