Combined biological removal of methylene blue from aqueous solutions using rice straw and Phanerochaete chrysosporium

The aim of this study was to develop a low-cost and environmental friendly treatment method for the removal of cationic dye from wastewater. Rice straw powder combined with the white rot fungus Phanerochaete chrysosporium (P. chrysosporium) were used to remove methylene blue (MB) from wastewater at varied operational conditions. Results demonstrated that this combined biodegradation and adsorption method was effective for the removal of MB from aqueous solutions; a maximum removal efficiency of 88 % was achieved for an initial dye concentration of 400 mg/L. Of the total removed MB, 28.4 % was biodegraded by P. chrysosporium, and the rest was adsorbed on the biodegraded rice straw and the fungal cells. The amount of total adsorbed MB in the treatment group (400 mg/L) is almost three times of that in the control without P. chrysosporium group. This significant improvement in the adsorption capacity is mainly because P. chrysosporium increased the specific surface area of the straw and produced more functional groups on it. Besides, P. chrysosporium also affect the pH in a positive way for the adsorption.