Biosorption Of Methylene Green By Pycnoporous Sanguineus : Batch And Column Studies
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Date
2011-07
Authors
Chiu, Han Chen
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
In this study, a white rot fungus, Pycnoporous sanguineus (P. sanguineus) in immobilized cells form was used as a biosorbent for the biosorption of methylene green solution. The adsorption was studied in batch and continuous system using shake flask and a packed bed column, respectively. In the batch system, the effect of contact time (2- 12 hour), initial methylene green concentration (5 mg/L, 15 mg/L and 25 mg/L) and temperature (303 K, 313 K and 323 K), on the dye adsoprtion by the immobilized cells were investigated. It was found that methylene green adsorption increased with increasing contact time, initial methylene green concentration and temperature. Results of the methylene green adsorption by immobilized cells of P. sanguineus fitted well with the Langmuir isotherm model with R2 > 0.99. Different thermodynamic studies were also carried out at different temperature (303 K, 313 K and 323 K), and the results showed that the enthalpy change (ΔHo) and entropy change (ΔSo) for the biosorption process of methylene green onto immobilized mycelium of P. sanguineus were -14.749 kJ/mol and 0.481 kJ/mol K, respectively. The kinetic studies for methylene green dye adsorption by immobilized cells of P. sanguineus at 25 mg/L, 323 K in a batch system fitted well with the pseudo-second order model. The ability of immobilized cells of P. sanguineus to adsorb methylene dye was investigated in a packed bed column system. The effect of bed height (5 cm, 9 cm and 13 cm), flow rate (0.24 mL/min, 0.48 mL/min and 0.72 mL/min) and initial methylene green concentration (5 mg/L, 15 mg/L and 25 mg/L) were studied. Optimum operating conditions were found at the bed height of 13 cm, flow rate of 0.24 mL/ min and initial methylene green concentration of 25 mg/L, while the breakthrough time of the sorption study was determined at 160 min. Experimental breakthrough curves were compared with simulated breakthrough profiles obtained from Thomas, Bohart-Adam and Yoon-Nelson models. The results showed that the experimental data were best described by Thomas model. Biosorption of dye on cell surface was further confirmed by scanning electron micrographs before and after loaded with dye. Results showed the spores shrunk and detached from the mycelium as a result of dye biosorption. This indicate that P. sanguineus has a potential to be an effective low cost adsorbent for the treatment of textile wastewater.
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Keywords
Biosorption of methylene green , by pycnoporous sanguineus