International Journal of Environmental Science and Development

Abstract—Improved utilization strategies for Sub-Bituminous Coal (SC) can be made using alkaline materials to increase soil productivity and can also reduce metal concentrations in aqueous solution. This study aims to examine the characteristics of SC activated with NaOH (SC-NaOH) and the mechanism of Hg2+ adsorption by SC-NaOH through an adsorption isotherm model approach developed for experimental equilibrium. The SC-NaOH was characterized by proximate composition (29.59% moisture; 76.02% volatile matter; 72.02% ash and 4.02% fixed carbon) and chemical properties (pH 12.60; EC >2.00 dS/m; CEC 141.60 cmol(+)/kg; OC 14.38% C and total N 0.10% N). The adsorption of Hg2+ on SC-NaOH increased with increasing Hg concentration and decreasing pH. The adsorption capacity and coefficient of Hg2+ by SC-NaOH were 262.51 mg/g and 131.12 l/kg at pH 1.68 and Hg2+ concentration of 100 mg/l with a removal efficiency of 65.63%. Hg2+ adsorption isotherms occurred in Freundlich model (1/n = 1.03: cooperative adsorption and R² = 1) = Langmuir model (RL = 0.94: favorable and R² = 1).

Keywords—activation, equilibrium, geochemical, isotherm, mercury, NaOH, sub-bituminous coal

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Cite: Amsar Maulana, Mimien Harianti, Teguh Budi Prasetyo, and Herviyanti Herviyanti, "The Ability of Sub-Bituminous Coal Activated with NaOH in Removal of Mercury: Equilibrium and Isotherm Study," International Journal of Environmental Science and Development vol. 15, no. 3, pp. 130-139, 2024.

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