title: Biodegradation of Methyl Orange by alginate-immobilized Aeromonas sp. in a packed bed reactor: external mass transfer modeling.
abstract: Azo dyes are recalcitrant and xenobiotic nature makes these compounds a challenging task for continuous biodegradation up to satisfactorily levels in large-scale. In the present report, the biodegradation efficiency of alginate immobilized indigenous Aeromonas sp. MNK1 on Methyl Orange (MO) in a packed bed reactor was explored. The experimental results were used to determine the external mass transfer model. Complete MO degradation and COD removal were observed at 0.20 cm bead size and 120 ml/h flow rate at 300 mg/l of initial dye concentration. The degradation of MO decreased with increasing bead sizes and flow rates, which may be attributed to the decrease in surface of the beads and higher flux of MO, respectively. The experimental rate constants (k ps) for various beads sizes and flow rates were calculated and compared with theoretically obtained rate constants using external film diffusion models. From the experimental data, the external mass transfer effect was correlated with a model J D = K Re (-(1 - n)). The model was tested with K value (5.7) and the Colburn factor correlation model for 0.20, 0.40 and 0.60 bead sizes were J D = 5.7 Re (-0.15), J D = 5.7 Re (-0.36) and J D = 5.7 Re (-0.48), respectively. Based on the results, the Colburn factor correlation models were found to predict the experimental data accurately. The proposed model was constructive to design and direct industrial applications in packed bed reactors within acceptable limits.
authors.affiliation: Department of Environmental Engineering, Pioneer Research Center for Controlling of Harmful Algal Bloom, Chosun University, 375 Seosuk-dong, Dong-gu, Gwangju, 501-759, Republic of Korea, mnkathir2025@gmail.com.
authors.forename: Mathur Nadarajan
authors.initials: MN
authors.lastname: Kathiravan
authors.forename: Siluvai Antony
authors.initials: SA
authors.lastname: Praveen
authors.forename: Geun Ho
authors.initials: GH
authors.lastname: Gim
authors.forename: Gui Hawn
authors.initials: GH
authors.lastname: Han
authors.forename: Si Wouk
authors.initials: SW
authors.lastname: Kim
mesh_terms: D000333:Aeromonas / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D000464:Alginates; D001391:Azo Compounds / Q000378:metabolism*; D001673:Biodegradation, Environmental; D057005:Bioengineering; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D018914:Cells, Immobilized / Q000378:metabolism; D004396:Coloring Agents / Q000378:metabolism*; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D057446:Hydrodynamics; D007700:Kinetics; D010802:Phylogeny
chemical_list: D000464:Alginates; D001391:Azo Compounds; D004396:Coloring Agents; D006603:Hexuronic Acids; C100258:methyl orange; D020723:Glucuronic Acid