title: Adsorption behavior of rhodamine B on Rhizopus oryzae biomass.
abstract: The removal of a carcinogenic dye rhodamine B (C. I. 45170) from wastewater by biomass of different moulds and yeasts is described. Among all of the fungal species tested, the biomass of Rhizopus oryzae MTCC 262 is found to be the most effective. Dye adsorption reaches maximum with the biomass harvested from the early stationary phase of growth. The optimum temperature and pH for adsorption are observed to be 40 degrees C and 7.0, respectively. The adsorption rate is very fast initially and attains equilibrium after 5 h. The adsorption isotherm follows the Langmuir isotherm model satisfactorily within the studied dye concentration range. Of the different metabolic inhibitors tested, 2,4-ditrophenol (DNP) and N,N'-dicyclohexylcarbodiimide (DCCD) decrease dye adsorption by approximately 30% suggesting the role of energy metabolism in the process. Spectrophotometric study indicates that the removal of rhodamine B by R. oryzae biomass involves an adsorption process. Scanning (SEM) and transmission (TEM) electron microscopic investigations have been carried out to understand the probable mechanism of the dye-biomass interaction.
authors.affiliation: Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Sujoy K
authors.initials: SK
authors.lastname: Das
authors.forename: Jayati
authors.initials: J
authors.lastname: Bhowal
authors.forename: Akhil R
authors.initials: AR
authors.lastname: Das
authors.forename: Arun K
authors.initials: AK
authors.lastname: Guha
mesh_terms: D000327:Adsorption; D018533:Biomass; D005456:Fluorescent Dyes / Q000737:chemistry; D006860:Hydrogen Bonding; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D012233:Rhizopus / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry* / Q000378:metabolism; D012996:Solutions / Q000737:chemistry; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D012235:Rhodamines; D012996:Solutions; D014867:Water; C029773:rhodamine B