Recovery of catechin and epicatechin from sago waste effluent: Study of kinetic and binary adsorption isotherm studies

• Recovery of catechin and epicatechin from sago waste effluent.
• Supercritical CO2 desorption of catechin and epicatechin from activated carbon.
• Adsorption of catechin and epicatechin in binary system.

The recovery of valuable phenolic compounds (catechin and epicatechin) from sago waste effluent by activated carbon adsorption was studied in this work. Single and binary component of catechin and epicatechin was studied in static mode using synthetic effluent. Langmuir model was applied to evaluate the adsorption equilibrium data in single system. In binary system, the modified extended Langmuir model by inclusion of surface coverage was used to represent the adsorption data. All experimental data were well represented either by Langmuir model or its modified form. For kinetic study, it was found that pseudo-second order model represents the experimental data better than pseudo-first order model. Adsorption study using real sago waste effluent indicated that activated carbon adsorption process is promising for recovery of valuable phenolic compounds. Supercritical CO2 extraction of phenolic compounds from activated carbon resulted in low recovery. The addition of ethanol as co-solvent significantly enhanced the desorption of catechin and epicatechin from activated carbon.