Removal of Cu(II) from aqueous solutions using chemically modified chitosan

• Published in: Journal of hazardous materials Vol. 175; no. 1; pp. 939 - 948
• Main Authors: Kannamba, B., Reddy, K. Laxma, AppaRao, B.V.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-03-2010; Elsevier
• Subjects: Adsorption; Applied sciences; Chemical engineering; Chitosan - chemistry; Copper - chemistry; Copper ions; Epichlorohydrin - chemistry; Exact sciences and technology; Hydrogen-Ion Concentration; Ions; Kinetics; Magnetic Resonance Spectroscopy; Photoelectron Spectroscopy - methods; Pollution; Spectroscopy, Fourier Transform Infrared - methods; Thermodynamics; Waste Disposal, Fluid - methods; Water - chemistry; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - isolation & purification; Water Purification - methods; Xanthate chitosan; Thermodynamics; Xanthate chitosan; Copper ions; Kinetics; Adsorption; Stripping; Second order; Adsorption isotherm; Adsorption capacity; Metal ion; Desorption; EDTA; Modeling; Langmuir isotherm; Operating conditions; Hydrochloric acid; Kinetic model; Aqueous medium; Thermodynamic parameter; pH; Aqueous solution; Fourier-transformed infrared spectrometry; Sorbent
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2009.10.098

Chemically modified chitosan namely epichlorohydrin cross-linked xanthate chitosan (ECXCs) has been used for the removal of Cu(II) ions from aqueous medium. The influence of various operating parameters such as pH, temperature, sorbent dosage, initial concentration of Cu(II) ions and contact time on the adsorption capacity of ECXCs has been investigated. Thermodynamic parameters namely Δ
G°, Δ
H° and Δ
S° of the Cu(II) adsorption process have been calculated. Differential anodic stripping voltammetric technique was used to determine the concentration of Cu(II) in the test solution before and after adsorption. The nature of the possible adsorbent–metal ion interactions was studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The studies showed that the adsorption of Cu(II) on ECXCs strongly depends on pH and temperature. The maximum adsorption capacity was observed at pH 5.0 and the adsorption capacity of ECXCs increased with increasing temperature indicating the endothermic nature of adsorption process. Langmuir and Freundlich adsorption equations were used to fit the experimental data. The adsorption process is found to follow the pseudo-second-order kinetic model. The maximum adsorption capacity was found to be 43.47
mg
g
−1 from the Langmuir isotherm model at 50
°C. During desorption studies 97–100% of adsorbed copper ion is released into solution in presence of 1N EDTA, HCl and H
2SO
4.