synthesis and optimization of biochar prepared from cow dung for methylene blue removal

Cost-effective dye wastewater treatment approaches are critically required for the long-term sustainability of textile industries. to fill the gaps, multiple high-potential adsorbents derived from biomass have been proposed. for this purpose, this study was conducted to present an applicable and cost-effective biochar synthesized from cow dung to remove methylene blue from the aqueous solutions. the potential of cow dung-based biochar was optimized under various ph, biochar dose, methylene blue concentration, contact time, and temperature. the maximum removal was 96% achieved at optimum conditions, 20 mg/l methylene blue concentration, 0.2 g biochar dose, ph of 6, and 90 min contact time at ambient temperature. the methylene blue adsorption process followed the freundlich isotherm (r2=0.9827) and pseudo-second-order (r2=0.999) kinetic models, implying multilayered adsorption on the heterogenous surface and chemisorption mechanism, respectively. furthermore, the adsorption process was spontaneous and exothermic due to negative gibbs free energy (δg0) and enthalpy (δh0) with the reduction at randomness of methylene blue molecules and adsorbent interaction based on negative entropy (δs0). regarding the high efficiency of cow dung-based biochar to adsorb methylene blue, it is recommended that further investigations consider the biochar activation and functionalization intending to upgrade its adsorption capacity.