Biosorption of Reactive Yellow 145 and Direct Blue 86 binary dye mixture by Ulocladium chartarum

The biosorption performance of easy, fast, and economically produced fungus was investigated against dye mixtures. Dead Ulocladium chartarum (Uc) was used as the biomass to remove the binary mixture of Reactive Yellow 145 (RY145) and Direct Blue 86 (DB86) textile dyes. The first-order-derivative spectroscopy method was used to calculate the remaining concentrations after the biosorption process due to the overlapping absorption wavelengths of the dyes. Calibration equations were calculated using 477.6 nm for RY145 and 602.0 nm for DB86 wavelength points in the derivative spectrum. Several dye mixtures with different concentrations were prepared to investigate the method's validity, and recovery percentages of approximately 100% were achieved for both dyes. The maximum removal rate (%100) was achieved for both dyes at pH 4, using 1.00 g of biomass and a 50 mg/L concentration of each dye in 60 min. Kinetic parameters of the biosorption were calculated using pseudo-first-order and pseudo-second-order equations. Biosorption capacities were evaluated via Langmuir and Freundlich isotherms models. Biomass characterization was performed using SEM, particle size distribution, and FTIR analysis.