ADSORPTION STUDY OF METHYL ORANGE DYE USING Co/Fe-CO3 HYDROTALCITE

Abstract

Methyl orange is a hazardous anionic dye for the environment; hence, it is necessary to carry out processing before disposal. One of the methods for its treatment is adsorption. Hydrotalcite is used as an adsorbent due to its significant adsorption capacity. This research aims to study the adsorption of methyl orange using Co/Fe-CO₃ hydrotalcite, with test parameters including pH, contact time, adsorbent mass, methyl orange concentration, and to determine the kinetic and isotherm adsorption models. The synthesis of Co/Fe-CO₃ hydrotalcite is conducted through coprecipitation with a 4:1 mole ratio of Co²⁺ ions to Fe³⁺ ions, followed by hydrothermal treatment at 65^oC for 24 hours. Hydrotalcite was characterized using FTIR and XRD. The optimum conditions for methyl orange adsorption by Co/Fe-CO₃ hydrotalcite are obtained at pH 6, a contact time of 60 minutes, an adsorbent mass of 50 mg, and a methyl orange concentration of 80 mg/L. The adsorption kinetics followed pseudo-second-order dynamics with an R² value of 0,9998; the adsorption rate constant is 0,025 g/mg.minute, and the qe value is 13,793 mg/g. The adsorption isotherm model followed the Freundlich isotherm model, with R², n, K_F, and E values of 0,9969, 3,073 mg/g, and -2,781 kJ/mol, respectively