Adsorption isotherm model of Hg²⁺ with biochar from young coconut waste

Abstract

Biochar is a carbon-rich byproduct of biomass pyrolysis that may be used to restrict Hg mobility in soil by utilizing amelioration technology. This study examines the ability of biochar from young coconut waste to adsorb Hg in solution. Isothermal adsorption of Hg by batch equilibrium method. The basic principle of Hg adsorption behavior with biochar from young coconut waste (B-YCW) processed through the Kon-Tiki method at a temperature of 682 0C, moisture of 81.27%, and a yield ratio of 20.87% at a size of 0.5 mm. The adsorption of Hg2+ on B-YCW increased with increasing Hg concentration and decreasing pH. The capacity and adsorption coefficient of Hg2+ by biochar from young coconut waste was 312.88 mg g−1 and 69.64 L Kg−1 at a pH of 1.55 and a concentration of 100 mg L−1 Hg2+. The adsorption isotherm of Hg2+ occurs in the Freundlich and Langmuir models (Freundlich > Langmuir). The Freundlich model (y = 1.0375x - 1.2523; R² = 1) with a value of n of 0.96 and KF of 17.78 (L mg−1)1/n, and the Langmuir II model (y = 17.126x - 0.0244; R² = 1), with average Qm was 18.57 mg g−1; KL 68.198 L mg−1 and RL 0.0054 (favorable) from the Langmuir isotherm model.