title: Experimental study of the removal of copper ions using hydrogels of xanthan, 2-acrylamido-2-methyl-1-propane sulfonic acid, montmorillonite: Kinetic and equilibrium study.
abstract: In this paper, removal of copper ions from aqueous solution using novel xanthan gum (XG) hydrogel, xanthan gum-graft-2-acrylamido-2-methyl-1-propane sulfonic acid (XG-g-P(AMPS)) hydrogel and xanthan gum-graft-2-acrylamido-2-methyl-1-propane sulfonic acid/montmorillonite (XG-g-P(AMPS)/MMT) hydrogel composite were studied. The structure and morphologies of the xanthan-based hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Adsorbents comprised a porous crosslink structure with side chains that carried carboxyl, hydroxyl and sulfonate. Maximum adsorption was observed in the pH=5.2, initial concentrations of Cu(2+)=321.8 mg/L, Temperature=45 °C, contact time=5 h with 0.2 g/50 mL of the hydrogels. Adsorption process was found to follow Langmuir isotherm model with maximum adsorption capacity of 24.57, 39.06 and 29.49 mg/g for the XG, XG-g-P(AMPS) and XG-g-P(AMPS)/MMT, respectively. Adsorption kinetics data fitted well with pseudo second order model. The negative ΔG° values and the positive ΔS° confirmed that the adsorption was a spontaneous process. The positive ΔH° values suggested that the adsorption was endothermic in nature.
authors.affiliation: Chemical Engineering Department, Engineering Faculty, University of Guilan, Rasht, Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Aflaki Jalali
authors.affiliation: Chemical Engineering Department, Engineering Faculty, University of Guilan, Rasht, Iran. Electronic address: dadvand@guilan.ac.ir.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Dadvand Koohi
authors.affiliation: Chemistry Department, University of Guilan, Rasht, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Sheykhan
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000327:Adsorption; D000476:Alkanesulfonates / Q000737:chemistry*; D001546:Bentonite / Q000737:chemistry*; D002413:Cations, Divalent / Q000302:isolation & purification; D003300:Copper / Q000302:isolation & purification*; D020100:Hydrogels / Q000737:chemistry*; D007700:Kinetics; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods
chemical_list: D000178:Acrylamides; D000476:Alkanesulfonates; D002413:Cations, Divalent; D020100:Hydrogels; D011135:Polysaccharides, Bacterial; D014874:Water Pollutants, Chemical; D014867:Water; D001546:Bentonite; C056288:2-acrylamido-2-methylpropanesulfonate; D003300:Copper; C002563:xanthan gum
keywords: 2-Acrylamido-2-methyl-1-propane sulfonic acid; Composite; Copper adsorption; Hydrogel; Xanthan gum