abstract
- The present study evaluated the performance in the biosorption of the azo dyes reactive red 2 (RDR2) and reactive blue 4 (RDB4) on thermally sterilized biomass of the fungus Cladosporium tenuissimum. A decrease in the initial pH and an increase in the temperature improved the biosorption, reaching the higher removal efficiencies of RDR2 (98.5%) and RDB4 (94.1%) at pH 3 and 40 °C. A pseudo-second-order model explained the biosorption kinetics of RDR2 and RDB4. The intraparticle diffusion model showed that the biosorption process was controlled initially by diffusion rate and, later, by the biomass surface saturation with the dye molecules. The Langmuir isotherm explained well the biosorption equilibrium, achieving the maximum biomass biosorption capacities (qmax) of 76.67 mg g¿1 for RDR2 and 70.60 mg g¿1 for RDB4 at pH 3 and 40 ºC. According to the dimensionless separation factor (RL) values and the thermodynamic evaluation, the biosorption process was favorable, reversible, spontaneous, and endothermic. FTIR analysis of unloaded and loaded biomass with the dyes confirmed the interactions between dye molecules and functional groups on the fungal biomass surface. The thermally sterilized biomass of Cladosporium tenuissimum can be used as a biosorbent biomaterial for bioprocess design in removing the azo dyes active red 2 and reactive blue 4 from textile wastewater. © 2024, Universidad Autonoma Metropolitana. All rights reserved.