AKTIVASI DAN KARAKTERISASI LEMPUNG ALAMBESITO-KUDUS UNTUK ADSORBEN ZATWARNA CONGO RED; ACTIVATION AND HARACTERIZATION OF BESITO-KUDUS NATURAL CLAY FOR ADSORBENT OF DYE CONGO RED

Miftahurrohmah, Triyono

2011 | Disertasi | PROGRAM STUDI S2 KIMIA

The ability of clay from Besito, Gebog, Kudus to adsorb congo red from aqueous solution was investigated. Prior to the investigation, the Besito-Kudus natural clay was physically and chemically activated. The activated clay was then analyzed by X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectroscopy methods. Various parameters such as contact time, initial dye concentration, grain size of clay, and temperature of adsorption were studied. The adsorption data were then fitted with the Langmuir and Freundlich isotherm equations. The thermodynamic parameters ?Ho, ?So and ?Go were also determined. The result showed that the chemical activation using H2SO4 1.2 M gave a better result than physical activation. The XRD analysis showed that Besito-Kudus clay may contain feldspar, cristobalite, dickite, muscovite, anatase, aegirineaugite, illite, quartz, dan ferrosillite. The dye adsorption equilibrium was rapidly reached after 10 minutes contact time. Equilibrium adsorption isotherm data of chemical activated Besito-Kudus clay exhibited better fitting to the Langmuir isotherm model than to Freundlich isotherm model. The maximum adsorption capacity of chemical activated Besito-Kudus clay obtained from Langmuir model was 250.00 mg/g. Kinetic studies showed that adsorption of congo red on chemical activated Besito-Kudus clay followed pseudo-second-order kinetics. The adsorption rate constant was found to be 0.025 g.mg-1.min-1 at 100 mg/L dye concentration. The initial dye concentration, grain size of clay, and temperature of adsorption had significant effect to adsorption of congo red. The experiment result of ?Ho was +3.127 kJ.mol-1, ?So was +64.717 J.mol-1.K-1, and ?Go at 30, 35, 40 and 50 oC were -16.483; -16.806; -17.130; and -17.777 kJ.mol-1, respectively. Positive ?Ho and negative ?Go values indicated that the adsorption of CR on chemical activated Besito-Kudus clay was endothermic and spontaneous.

Kata Kunci : activation, characterization, Besito-Kudus clay, adsorbent, dye congo red