Panus tigrinus   as a potential biomass source for Reactive Blue decolorization: Isotherm and kinetic study

Background: Textile and dye industries pose a serious threat to the environment. Conventional methods used for dye treatment are generally not always effective and environmentally friendly. This drove attention of scores of researchers to investigate alternative methods for the biodegradation of dyes using fungal strains. In this work, white-rot fungus (Panus tigrinus) was used as a biosorbent for the decolorization of Reactive Blue 19. The process parameters that were varied were initial concentration (50–150 mg/L), contact time (30–90 min), and pH (2–6). In addition, to gain important data for the evaluation of a sorption process, the equilibrium and kinetics of the process were determined.
Results: White-rot fungus showed great potential in decolorizing Azo dyes. The strain showed the maximum decolorization of 83.18% at pH 2, a contact time of 90 min, and an initial concentration of 50 mg/L. The Langmuir isotherm described the uptake of the Reactive Blue 19 dye better than the Freundlich isotherm. Analysis of the kinetic data showed that the dye uptake process followed the pseudo second-order rate expression.
Conclusion: The biosorption process provided vital information on the process parameters required to obtain the optimum level of dye removal. The isotherm study indicated the homogeneous distribution of active sites on the biomass surface, and the kinetic study suggested that chemisorption is the rate-limiting step that controlled the biosorption process. According to the obtained results, P. tigrinus biomass can be used effectively to decolorize textile dyes and tackle the pollution problems in the environment.

Keywords
Azo dyes; Biosorption; Chemisorption; Dye biodegradation; Dye removal; Dye treatment; Freundlich isotherms; Fungal dye biodegradation; Langmuir isotherm; Reactive Blue 19; White-rot fungus