Statistical evaluation of cow-dung derived activated biochar for phenol adsorption: Adsorption isotherms, kinetics, and thermodynamic studies.

Sustainable and economical wastewater treatment forms a vital step towards long-term sustainability of petrochemical refineries and industries. An affordable solution to this challenge is to employ biowaste as the key consumable active component. This paper describes the synthesis and characterization of activated biochar derived from cow-dung, a readily available raw material in low-resource settings, and its application for adsorption of phenol, one of the major pollutants in industrial wastewater. Adsorption parameters are optimized by using response surface methodology. Phenol adsorption equilibrium and kinetics data are well fitted to Freundlich isotherm (R2 = 0.97) and pseudo-second-order model (R2 = 0.99), respectively. The maximal adsorption capacity (518.89 mg/g) was attained using the Langmuir isotherm model at pH 6.0. Negative values of thermodynamic parameters confirmed the spontaneity, feasibility, and exothermic behaviour of adsorption reaction. The results demonstrate that synthesized activated biochar showed an excellent phenol adsorption capacity of 98.8 %.