Adsorption of methylene blue dye from aqueous solution by sugar extracted spent rice biomass

This study was aimed at using sugar extracted spent rice biomass (SRB) as a potential adsorbent to remove methylene blue (MB) dye from aqueous solution. The SRB was used without any modification. A three factor full factorial experimental design (23) was employed to investigate the effect of factors (adsorbent dose, dye concentration, temperature) and their interaction on the adsorption capacity and color removal. Two levels for each factor were used; adsorbent dose (0.25–0.5 g/100 mL), dye concentration (25–50 mg/L), and temperature (25–45 °C). Initial dye concentration and adsorbent dosage were found as significant factors for the adsorption of MB dye. Langmuir isotherm (R2 > 0.998) best explained the equilibrium of MB adsorption on SRB with monolayer adsorption capacity of 8.13 mg/g. The pseudo-second order model (R2 > 0.999) was best fitted to explain the adsorption kinetics. Thermodynamic investigation revealed that the adsorption process was spontaneous, endothermic, and was feasible to treat dyeing wastewater.