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 m(2) g(-1)) was larger than that of unmodified biomass (0.3081 m(2) g(-1)). Possible dye-biosorbent interactions were confirmed by Fourier transform infrared spectroscopy.