title: Isotherm, kinetic and thermodynamic studies of lead and copper uptake by H2SO4 modified chitosan.
abstract: The kinetic and thermodynamic adsorption and adsorption isotherms of Pb(II) and Cu(II) ions onto H(2)SO(4) modified chitosan were studied in a batch adsorption system. The experimental results were fitted using Freundlich, Langmuir and Dubinin-Radushkevich isotherms; the Langmuir isotherm showed the best conformity to the equilibrium data. The pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models were employed to analyze the kinetic data. The adsorption behavior of Pb(II) and Cu(II) was best described by the pseudo-second order model. Thermodynamic parameters such as free energy change (DeltaG degrees ), enthalpy change (DeltaH degrees ) and entropy change (DeltaS degrees ) were determined; the adsorption process was found to be both spontaneous and exothermic. No physical damage to the adsorbents was observed after three cycles of adsorption/desorption using EDTA and HCl as eluents. The mechanistic pathway of the Pb(II) and Cu(II) uptake was examined by means of Fourier transform infrared (FTIR) and Energy dispersive X-ray (EDX) spectroscopy. The equilibrium parameter (R(L)) indicated that chitosan-H(2)SO(4) was favorable for Pb(II) and Cu(II) adsorption.
authors: Department of Chemistry, Faculty of Science and Technology, Universiti Pendidikan Sultan Idris, 35900 Perak, Malaysia.
authors: A
authors: A
authors: Kamari
authors: W S Wan
authors: WS
authors: Ngah
mesh_terms: D000327:Adsorption / Q000187:drug effects; D001672:Biocompatible Materials / Q000378:metabolism; D048271:Chitosan / Q000737:chemistry / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007700:Kinetics; D007854:Lead / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D009566:Nitrates / Q000494:pharmacology; D009994:Osmolar Concentration; D012965:Sodium Chloride / Q000494:pharmacology; D012995:Solubility / Q000187:drug effects; D012996:Solutions; D013055:Spectrophotometry, Infrared; D013464:Sulfuric Acids / Q000737:chemistry / Q000378:metabolism*; D013816:Thermodynamics; D013997:Time Factors; D017186:Titrimetry
chemical_list: D001672:Biocompatible Materials; D009566:Nitrates; D012996:Solutions; D013464:Sulfuric Acids; D007854:Lead; D012965:Sodium Chloride; D003300:Copper; C031618:sodium nitrate; D048271:Chitosan; C033158:sulfuric acid