Adsorption of Red 2B dye using synthetic Mg/Al-hydrotalcite like (Mg/Al-HTLc) had been done. The purposes of this research were to know that Mg/Al-HTLc can be used to adsorb Red 2B dye and to determine the optimum adsorption condition. Adsorption isotherm was also determined to know the adsorption type.
The Mg/Al-HTLc was synthesized using co-precipitation method and having Mg/Al mol ratios of 2,5:1; 3,0:1; and 3,5:1. Characterization of the synthetic compounds was done using X-Ray Diffraction (XRD), Fourier Transform Infra Red (FTIR), Differential Thermal Analyser (DTA), and Gas Sorption Analyser (GSA). The optimum adsorption condition of Red 2B by Mg/Al-HTLc was conducted using batch system in contact time of 2 hours and at pH variations of 3, 5, 7, 9, and 11 for each Mg/Al mol ratios. Adsorption isotherm determination was done by adsorbing Red 2B dye at concentration variations of 60, 80, 100, 120, and 140 ppm at optimum adsorption condition. The Freundlich’s and Langmuir’s adsorption isotherm were compared in this determination.
The result of research showed that Mg/Al-HTLc with Mg/Al mol ratio of 2,5:1; 3,0:1; and 3,5:1 could be synthesized and could be used to adsorb Red 2B dye. The optimum adsorption condition was reached by Mg/Al-HTLc with Mg/Al mol ratio of 3,5:1 and at pH 5. Adsorption capacity of Mg/Al-HTLc to Red 2B was 21,069 mg.g-1 at the optimum condition. The adsorption process followed Freundlich’s adsorption isotherm that indicated physisorption.