Removal of Methyl red in aqueous systems using synthesized NaAlg-g-CHIT/nZVI adsorbent

In this work, nano zero valent iron (nZVI) was dispersed in sodium alginate (NaAlg) grafted chitosan (CHIT). Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance ((HNMR)-H-1), Zeta potential and X-Ray Diffraction (XRD) analysis were used to characterize the adsorbents. Kinetic and thermodynamic studies were conducted on the adsorbents to assess the effects of adsorbent dosage, contact time, pH, initial dye concentration, and temperature. The optimum dosage required for the removal of methyl red (MR) dye was 0.2 g at 60 min. The optimum pH for NaAlg-g-CHIT/nZVI to remove a high percentage of methyl red ions was 2.0. Freundlich, Langmuir and Dubinin-Radushkevich isotherm models were used to assess the adsorption data. Langmuir isotherm was the best amongst the others with an R-2 of 0.9917 for MR adsorption. The adsorption equilibrium's kinetic process followed the pseudo-second order (R-2 =0.9722). A study of the thermodynamic properties confirmed that the adsorption was non-spontaneous and endothermic for both adsorption processes. (C) 2022 The Author(s). Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative.