Synthesis and evaluation of CMC-g-AMPS/Fe/Al/AC composite hydrogel and their use in fluoride removal from aqueous solution

Cellulose based hydrogels are emerging adsorbents for treating aqueous pollutants due to their modifiable surface characteristics and superabsorbent properties. This study investigates the sorption of fluoride (F-) on CMC-g-AMPS/Fe/Al composite hydrogel impregnated with activated charcoal. Statistically valid Plackett-Burman design of experiments was employed for determination of most significant factors affecting E removal. The maximum defluoridation efficiency of metal oxide incorporated HG (CMCg-AMPS/Fe/Al/AC) was found to be 84.67% at pH 6 at an initial F- concentration of 5 mg/L which is significantly higher compared to control HG (CMC-g-AMPS/AC). Analysis of variance (ANOVA) revealed the effect of pH followed by contact time as the most significant parameter (P value < 0.05) affecting F- removal. The experimental data fitted well with the Langmuir isotherm model, with the maximum F- adsorption of 67.114 mg/g. The modification mechanism and adsorption process on HGs were examined with equilibrium degree of swelling (EDS), FT-IR spectra, SEM, EDX and XRD analysis. Characterization analysis of CMC-g-AMPS/Fe/Al/AC HG confirms a parallel hydrolysis reaction on fibrous polycrystalline lattice along with the desired metal incorporation and higher gel strength making it an excellent anionic polymer with high F- binding capacity. (C) 2020 Elsevier B.V. All rights reserved.