Comparative Study on the Adsorption of [AuCl4]– onto Salicylic Acid and Gallic Acid Modified Magnetite Particles

Maya Rahmayanti (Department of Chemistry, State Islamic University of Sunan Kalijaga, Jl. Marsda Adi Sucipto, Yogyakarta 55281 Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara PO BOX BLS 21, Yogyakarta 55281)
Sri Juari Santosa (Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara PO BOX BLS 21, Yogyakarta 55281)
Sutarno Sutarno (Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara PO BOX BLS 21, Yogyakarta 55281)

Indonesian Journal of Chemistry
Vol 16, No 3 (2016)

Salicylic acid-modified magnetite (Mag-SA) and gallic acid-modified magnetite (Mag-GA) particles were prepared by co-precipitation procedure. Characterization results showed the interaction that occurs between the surface of magnetite with salicylic acid (Mag-SA) and gallic acid (Mag-GA) was through hydrogen bonding. Adsorption of [AuCl4]– onto Mag-SA and Mag-GA surfaces as a function of initial pH, contact time, and initial concentration of the [AuCl4]– solution were comparatively investigated. Result showed that the optimum adsorption of [AuCl4]– onto Mag-SA or Mag-GA was found at pH 3. The adsorption process were found to allow the pseudo-second order equation, both for Mag-SA and Mag-GA. The parameters in isotherm adsorption equations conformed to the Langmuir and Freundlich isotherms very well for Mag-GA, but for Mag-SA, only conformed to the Langmuir isotherm very well. The result of this study demonstrate that the ability Mag-GA to adsorb [AuCl4]– higher than Mag-SA.