Kinetic adsorption modeling of zinc onto hydrogel biochar

Biochar is produced by pyrolysis process under certain temperature and pressure. Previous study shows that the potential of hydrogel biochar from rice husk to adsorb heavy metal like zinc in the wastewater, therefore, this study focus on the potential of the hydrogel biochar from palm kernel shell and fly ash coal which can be applied in wastewater treatment in zinc removal through adsorption method. To understand how sorption of Zinc onto hydrogel biochar, the common isotherms study is required to identify the mechanism, capacity adsorption for the first objective and next objective is the rate of sorption that determined by pseudo kinetic reaction which are mainly, first order, second order and intra-particle diffusion. Three isotherm are chosen as they regularly use which are Langmuir, Freudliuch and Temkin. Best isotherm is determined by R² by taking the highest value. Based on the result, this adsorption of Zinc onto hydrogel biochar (palm kernel shell and flys ash coal) are more favor to Freundliuch isotherms (R²=0.9991) compare Temkin (R²=0.8923-0.8272) of second best fit and Langmuir (R²=0.885) for last isotherm. Besides that this adsorption is likely to be pseudo second order (R²=0.999) compare to the pseudo first order (R²=0.915-0.641).