title: Application of chitosan-citric acid nanoparticles for removal of chromium (VI).
abstract: In the present study, CS-CA nanoparticle was prepared for forming a new amide linkage, by grafting the amino groups of CS in the presence of carboxylic groups of CA that acts as cross-linking agent. The as-prepared CS-CA nanoparticle samples were characterized by use of dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques, which showed that the cross-linking agent preserved during the chemical modifications. The adsorption capacity of the CS-CA nanoparticles for the removal of Cr (VI) in aqueous solution was studied. The adsorption equilibrium data taken at the optimized condition, i.e., 25 °C and pH of 3, were analyzed with the Langmuir, Freundlich and Redlich-Peterson isotherm models. The kinetics of Cr (VI) adsorption on CS-CA nanoparticles obtained at different initial concentrations were also analyzed using the pseudo-second-order model.
authors.affiliation: Department of Environmental Science, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Mahdiye
authors.initials: M
authors.lastname: Bagheri
authors.affiliation: Department of Environmental Science, Faculty of Natural Resources, Tarbiat Modares University, Imam Reza Street, Noor P.O. Box 46414-356, Iran. Electronic address: hunesi@modares.ac.ir.
authors.forename: Habibollah
authors.initials: H
authors.lastname: Younesi
authors.affiliation: Department of Physics, Yasouj University, Yasouj 75918-74831, Iran; Physics Department, Sharif University of Technology, Tehran P.O. Box 11155-9161, Iran.
authors.forename: Shaaker
authors.initials: S
authors.lastname: Hajati
authors.affiliation: Sharif University of Technology - BBRC, Tehran, Iran.
authors.forename: Seyed Mehdi
authors.initials: SM
authors.lastname: Borghei
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D033362:Powder Diffraction; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification; D014961:X-Ray Diffraction
chemical_list: D014874:Water Pollutants, Chemical; C408130:chitosan citrate; D002857:Chromium; C074702:chromium hexavalent ion; D048271:Chitosan
keywords: Chitosan–CA nanoparticle; Cr (VI); Desorption; Isotherm; Kinetics