Treatment of dyeing wastewater including reactive dyes (Reactive Red RB, Reactive Black B, Remazol Blue) and Methylene Blue by fungal biomass

Abstract

The decolourisation potential of growing Rhizopus arrhizus fungal strain in liquid medium containing thiamine was investigated for the removal of anionic reactive dyes such as Reactive Red RB (RR), Reactive Black B (RBB) and Remazol Blue (RB) and a cationic basic dye Methylene Blue (MB). To determine the optimal pH value, pH 2 to 6 was examined. Fungal growth was not observed at pH 2. Maximum fungal decolourisation ocurred at pH 3 for anionic reactive dyes (RR, RBB, RB) and pH 6 for cationic MB dye. The fungal dye bioremoval was associated with the surface charge of the fungus due to electrostatic interactions. Growing R. arrhizus strain decolourised 100% of RB in 2 days, 100% of RBB in 3 days, 71.83% of RR in 8 days at pH 3 and 92.5% of MB in 8 days at pH 6 at 100 mg/. dye concentration. Results indicate that growing Rhizopus arrhizus is an effective candidate for removal of different types of dyes from textile effluents.

Keywords: Rhizopus arrhizus, wastewater treatment, decolourisation, textile dye