The efficiency of Chitosan Extracted from Persian Gulf Shrimp Shell in Removal of Penicillin G Antibiotic from Aqueous Environment

Antibiotics are discharged into the aqueous environment in various ways. The disposal of wastewater containing antibiotics creates serious environmental problems. Today, given the necessity of using natural materials, natural-based adsorbents have been taken into consideration. Chitosan is a natural polysaccharide derived from the crust of crustaceans of the sea with many useful aspects such as hydrophilicity, biodegradability, and biocompatibility. In this study, after the preparation of chitosan, the effect of various parameters such as pH (۳-۱۱), adsorbent dosage (۰.۲۵-۱g/L), penicillin G concentration (۱۰-۷۰ mg/L), and contact time (۵-۹۰ min) in the removal of antibiotic was investigated. Structural characteristics of synthesized chitosan were determined by Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). Also, the isotherm, thermodynamics, and kinetics of the adsorption process were studied. The results of this study showed that the maximum adsorption capacity of chitosan in optimum condition (pH=۷, adsorbent dose: ۰.۲۵ g/L, the concentration of antibiotics: ۷۰ mg/L, and contact time: ۱۰ min) was ۱۰۱.۴۴ mg/g. SEM image showed that the size of chitosan was ranging from ۷۰۰ nm to ۵ microns. The results of XRD analysis showed the successful synthesis of chitosan. Experimental data indicate that the results are consistent with the Langmuir isotherm model and that the adsorption process was followed by a pseudo-second-order model. According to the results of thermodynamic studies, the standard entropy variations (∆S) were ۲۰.۶۸ (J/mol k) and standard enthalpy changes (∆H) were ۵.۶۹ kJ/mol and standard Gibbs free energy (∆G) values were negative and respectively indicates that adsorption process of penicillin G by chitosan is spontaneous and endothermic.

کلیدواژه ها:

Chitosan ، Antibiotics ، Penicillin G ، Adsorption