Risfidian Mohadi

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 -9.76u2005kJ.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.

PENGGUNAAN SPEKTROSKOPI 31P NMR DAN FT-IR UNTUK KARAKTERISASI SENYAWA POLIOKSOMETALAT TIPE DAWSON (NH4)6[b-P2W18O62] DAN (NH4)6[a-P2W18O62]

Telah disintesis senyawa polioksometalat tipe Dawson (NH 4 ) 6 [b-P 2 W 18 O 62 ] dan (NH 4 ) 6 [a-P 2 W 18 O 62 ] yang dilanjutkan dengan karakterisasi menggunakan spektrometerxa0 31 P NMR dan FT-IR. Hasil penelitian menunjukkan bahwa senyawa polioksometalat tipe Dawson memberikan sinyalxa0 31 P NMR yang berbeda untuk struktur b dan a. Struktur b pada (NH 4 ) 6 [b-P 2 W 18 O 62 ] menghasilkan dua puncak pada pergeseran kimia -10,90 dan -11,68 ppm sedangkan struktur a memberikan satu puncak pada pergeseran kimia -12,39 ppm yang mengindikasikan adanya rotasi unit W 3 O 13 xa0pada struktur b sebagai penyusun struktur Dawson. Hal ini diperkuat oleh perbedaan spektra FT-IR pada stuktur b yang memiliki vibrasi pada bilangan gelombang 1164 cm -1 xa0sedangkan struktur a tidak. Secara umum spektra FT-IR untuk polioksometalat tipe Dawson (NH 4 ) 6 [b-P 2 W 18 O 62 ] dan (NH 4 ) 6 [a-P 2 W 18 O 62 ] tidak menunjukkan adanya pebedaan yang signifikan terutama pada bilangan gelombang disekitar 1090 cm -1 xa0yang menunjukkan vibrasi P-O.