Removal of Cd2+ from Water by Use of Super-Macroporous Cryogels and Comparison to Commercial Adsorbents

• Published in: Polymers Vol. 12; no. 10; p. 2405
• Main Authors: Baimenov, Alzhan, Berillo, Dmitriy, Azat, Seitkhan, Nurgozhin, Talgat, Inglezakis, Vassilis
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 19-10-2020; MDPI
• Subjects: Acids; Adsorbents; Adsorption; Aqueous solutions; Cadmium; Cation exchanging; Cationic polymerization; complexation; Copolymerization; cryogels; Drinking water; Experiments; Functional groups; Heavy metals; Hydrogels; Ion exchange; Leaching; Methacrylic acid; Polymerization; Polymers; Prepolymers; Spectrum analysis; water treatment; X ray photoelectron spectroscopy; Zeta potential; United Kingdom > UK; United States > US; Germany
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym12102405

In this study amphoteric cryogels were synthesized by the use of free-radical co-polymerization of acrylate-based precursors (methacrylic acid and 2-acrylamido-2-methyl-1-propansulfonic acid) with allylamine at different ratios. The physico-chemical characteristics of the cryogels were examined using SEM/EDX, FT-IR, XPS and zeta potential measurements. The cryogels were tested toward Cd2+ removal from aqueous solutions at various pH and initial concentrations. Equilibrium studies revealed a maximum sorption capacity in the range of 132–249 mg/g. Leaching experiments indicated the stability of Cd2+ in the cryogel structure. Based on kinetics, equilibrium and characterization results, possible removal mechanisms are proposed, indicating a combination of ion exchange and complexation of Cd2+ with the cryogels’ surface functional groups. The cryogels were compared to commercially available adsorbents (zeolite Y and cation exchange resin) for the removal of Cd2+ from various water matrices (ultrapure water, tap water and river water) and the results showed that, under the experimental conditions used, the cryogels can be more effective adsorbents.