Biosorption of Acid Blue 25 by unmodified and CPC-modified biomass of Penicillium YW01: Kinetic study, equilibrium isotherm and FTIR analysis

The main objective of this work was to investigate the biosorption performance of unmodified and Cetylpyridinium chloride (CPC)-modified biomass of Penicillium YW 01 for Acid Blue 25 (AB 25). Maximum biosorption capacity of AB 25 onto CPC-modified biosorbent was 118.48 mg g−1 under phosphoric–phosphate buffer with initial dye concentration of 200 mg L−1 at 30 °C. The biosorption pattern of AB 25 onto unmodified biosorbent in aqueous solution and phosphoric–phosphate buffer was well fitted with both Langmuir and Freundlich isotherm models. While the equilibrium data of CPC-modified biosorbent in aqueous solution and phosphoric–phosphate buffer failed to fit the Freundlich isotherm model, indicating the monolayer biosorption formed onto CPC-modified biosorbent. The values of initial biosorption rate of biosorbent in phosphoric–phosphate buffer were found to be higher than that of corresponding values in aqueous solution, indicating phosphoric–phosphate buffer enhanced the initial biosorption rate of biosorption process. Weber–Morris model analysis indicated that the boundary layer effect had more influence on the biosorption process in phosphoric–phosphate buffer. The BET surface area of CPC-modified biosorbent (0.5761 m2 g−1) was larger than that of unmodified biomass (0.3081 m2 g−1). Possible dye–biosorbent interactions were confirmed by Fourier transform infrared spectroscopy.