ADSORPTION OF [AUCL4]– ON ULTRASONICALLY AND MECHANICAL-STIRRING ASSISTED MG/AL-NO3 HYDROTALCITE-MAGNETITE
ABSTRACT: It
has been examined the application of Mg/Al-NO3 hydrotalcite-magnetite
synthesized mechanically (MHT) and ultrasonically (UMHT) by co-precipitation
method as adsorbents for [AuCl4]– from aqueous solution. Two techniques of
synthesis were conducted to determine the effect on the increase of adsorption
ability of the [AuCl4]–. Magnetite and Mg/Al-NO3 hydrotalcite-magnetite
synthesized by co-precipitation with modifications hydrothermal treatment at
120 °C for 5 h. The adsorbents were characterized by Fourier Transform Infrared
(FTIR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy
(SEM), Brunauer-Emmett-Teller (BET) and Vibrating sample magnetometer (VSM).
Adsorption studies were done by getting the optimum pH, optimum contact time
and the optimum concentration. A result of the adsorption study of [AuCl4]– on
both adsorbents was optimum at pH 3 and fitted well to Langmuir isotherm and
pseudo second-order kinetic models. The adsorption capacity of UMHT (ultrasonic
technique) was 66.67 mg g-1 and it was higher than that of MHT (mechanic
technique), i.e. 31.25 mg g-1. This shows that the ultrasonic radiation
technique can increase the adsorption capacity of the [AuCl4]–. Based on the
desorption using 0.5 mol L-1 NaOH solution, more [AuCl4]– was eluted from MHT,
indicating that [AuCl4]– was weakly bound on MHT than UMHT.
Author: Triastuti
Sulistyaningsih, Sri Juari Santosa, Dwi Siswanta, Bambang Rusdiarso
Journal Code: jpkimiagg160094
