Adsorptive study of coagulation treatment of paint wastewater using novel Brachystegia eurycoma extract

Adsorptive component of coagulation–flocculation of paint wastewater using Brachystegia eurycoma (seed) coagulant was investigated. The bio-sample was analyzed for functional groups, surface morphology and thermal characteristics. The effects of coagulant dosage, effluent pH and settling time on the process were studied. The coagulation data were analyzed in light of adsorption kinetics, isotherm and thermodynamics. Pseudo-second-order and Langmuir models best described the models, and the values recorded for Gibb’s free energy, entropy and enthalpy values were—28.692 kJ/mol, 0.206 kJ/mol and 34.857 kJ/mol, respectively. At the experimental condition, maximum process efficiency (96.50%) was obtained at coagulant dosage of 5 g/L, pH 8 and coagulation temperature of 35 °C. Having satisfactorily correlated coagulation data to adsorption models, it could be inferred that significant component of the process was predominated by adsorption.