Aldes Lesbani

Pillarization of layer double hydroxides (Mg/Al) with keggin type K4[α-SiW12O40]•nH2O and its application as adsorbent of procion red dye

Pillarization of layered double hydroxides with polyoxometalate K4[α-SiW12O40]•nH2O at various times i.e. 3, 6, 9, 12, 24, 36 and 48 hours has been done. The pillared product was characterized by FT-IR spectrophotometer and XRD. The optimum pillared layered double hydroxides of polyoxometalate K4[α-SiW12O40]•nH2O was used as an adsorbent of procion red dye. The results of characterization using FT-IR spectrophotometer is not yet show the optimum pillarization process. The characterisation using XRD the successfully of pillared layered double hydroxides of polyoxometalate K4[α-SiW12O40]•nH2O showing the existence of diffraction angle 8.5o with intensity 355. Furthermore, the pillared layered double hydroxides of polyoxometalate K4[α-SiW12O40]•nH2O with time variation of 12 hours was applied as an adsorbent of procion red dye. The results show the adsorption rate was 0.523 min-1, the highest of absorption capacity at 70oC was 10.8 mol/g, the highest energy of absorption 70 oC was 125 kJ/mol. The enthalpy (∆H) and entropy (∆S), decrease as the increasing concentration of procion red dye. Keywords: layered double hydroxides, polyoxometalate, pillaration, procion red, adsorption

Desulfurization of 4-methyl dibenzothiophene using titanium supported Keggin type polyoxometalate

Titanium supported Keggin type polyoxometalate H5PV2Mo10O40·nH2O has been prepared using tetra isopropyl orthotitanate by sol-gel method and microemulsion to form H5PV2Mo10O40/TiO2. Compound H5PV2Mo10O40·nH2O/TiO2 was characterized using FTTR spectroscopy, X-Ray analysis, and acidity measurement. FTTR spectrum showed that all vibration of titanium and polyoxometalate were appeared in H5PV2Mo10O40·nH2O/TiO2 with decreasing crystallinity. The acidity of H5PV2Mo10O40·nH2O/TiO2 was higher than H5PV2Mo10O40·nH2O. Desulfurization of 4-methyl dibenzothiophene (4-MDBT) using H5PV2Mo10O40·nH2O/TiO2 as catalyst resulted conversion of 4-MDBT was 99% and higher than desulfurization using H5PV2Mo10O40·nH2O under mild conditions.

Kinetic and thermodynamic adsorption studies of congo red on bentonite

Adsorption of congo red on bentonite was studied kinetics and thermodynamically. Bentonite was physically activated at various temperatures and characterized using X-ray, and infrared. By increasing thermal temperature activation up to 500 °C can decrease the montmorillonite fraction with decreasing the peak was observed. The kinetic of adsorption suggests that the interaction of congo red-bentonite could be best represented by the first-order kinetics of Langmuir-Hinshelwood model. The adsorption process was exothermic with ΔH in the range -4.43 to -9.76 kJ.mol−1 accompanied by increase in Gibbs energy. All results have shown that bentonite after physical activation could be used as an adsorbent for congo red adsorption.