Thermal stability effect of H4[PVMo11O40]/SiO2

Synthesis and characterization of supported polyoxometalate  H4[PVMo11O40].nH2O with SiO2 through sol-gel method have been done. The compound H4[PVMo11O40]/SiO2 was characterized through FT-IR spectrophotometer, XRD, and SEM-EDX. The results showed that FT-IR spectrum of H4[PVMo11O40]/SiO2 has the primary vibration on wavenumber at 1064.7 cm-1 (P-O); 964.4 cm-1 (Mo=O); 864.1  cm-1 (Mo-Oe-Mo); 779.2 cm-1 (Mo-Oc-Mo); 462.9 cm-1 (Si-O); and 1087.9 cm-1 (Si-O-Si). The XRD diffraction pattern showed that H4[PVMo11O40].nH2O has the highest crystallinity. However, after it’s supported with SiO2, the properties of crystallinity has decreased due to the excess water during the support process. The result of SEM-EDX showed that H4[PVMo11O40]/SiO2 material has homogeneous distribution with particle size distribution of 1330 nm (1,33 μm). The acidity test by qualitative and quantitative methods show that H4[PVMo11O40]/SiO2 more acidic than H4[PVMo11O40].H2O. The effect temperature on the crystallinity showed that increasing calcination temperature made the crystallinity properties of  H4[PVMo11O40]/SiO2 increased. Keywords : polyoxometalate, H4[PVMo11O40].nH2O, SiO2

Studi Interaksi Vanadium dan Nikel dengan Pasir Kuarsa

Pasir kuarsa alam telah dimurnikan dari pengotornya yakni oksida-oksida dan senyawa organik dengan menggunakan asam nitrat. Pasir kuarsa alam dikarakterisasi menggunakan spektrofotometer FT-IR. Selanjutnya pasir kuarsa alam digunakan sebagai adsorben untuk ion vanadium dan nikel. Interaksi antara pasir kuarsa alam dengan ion logam dipelajari melalui proses adsorpsi desorpsi. Hasil penelitian menunjukkan bahwa bahwa proses pencucian pasir kuarsa alam dapat menghilangkan pengotornya. Interaksi vanadium dan nikel dengan pasir kuarsa merupakan interaksi fisik, yang diketahui dari pola isoterm adsorpsinya. Hasil desorpsi juga memperkuat hasil bahwa interaksi antara ion logam dengan pasir kuarsa adalah interaksi fisik

Conversion of cyclohexane to cyclohexanol and cyclohexanone using H3[PMo12O40].nH2O-ZrOCl2 as catalyst

Synthesis and preparation polyoxometalate compound H3[-PMo12O40].nH2O supported with ZrOCl2 at various weights of ZrOCl2 i.e. 0.25 g, 0.50 g, 0.75 g, 1.00 g, 1.25 g, 0.01 g and 0.05 g to form H3[-PMo12O40].nH2O/ZrOCl2 have been conducted. These compound than was characterized through functional group analysis using FT-IR spectrophotometer and XRD analysis. The results showed that the optimal preparation was H3[-PMo12O40].nH2O/ZrOCl2  with support 0.05 g. FT-IR spectrum of H3[-PMo12O40].nH2O/ZrOCl2 show wavenumber at 1033.85 cm-1 for vibration P-O, 887.26 cm-1  for vibration M=O, 840.96 cm-1 and 655.80 cm-1   for vibration Mo-O-Mo. The existence of support was identified at wavenumber 1404.18 cm-1for vibration Zr-OH and 478.35 for vibration Zr-O-Zr. XRD powder analysis showed that material H3[-PMo12O40].nH2O/ZrOCl2 was amorphous material. Material H3[-PMo12O40].nH2O/ZrOCl2 was applied in oxidation of cyclohexane using hydrogen peroxide as oxidant. Oxidation process was optimized through reaction time H2O2 amount, temperature and catalyst weight. The results showed that the highest conversion in the using of H3[-PMo12O40].nH2O/ZrOCl2 catalyst found at 2 hours reaction time, 3 mL H2O2, 80oC temperature and 0.038 g catalyst with conversion 99.18 %. Selectivity of best reaction was 6.96 % for cyclohexanol and 24.9% for cyclohexanone, which was identified by GC-MS.           Keywords : H3[-PMo12O40].nH2O-ZrO2,cyclohexane, cyclohexanol, cyclohexanone

Preparation, characterization, and thermal stability of B2O3-SiO2

Preparation of B2O3-SiO2 compound by inorganic synthesis was carried out. B2O3-SiO2 was characterized by FT-IR spectro-photometer, analysis of crystallinity by XRD, and test of acidity. B2O3-SiO2 was also tested by thermal stability with temperature range at 300-700 ⁰C. The results showed that the FT-IR spectrum of B2O3-SiO2 has some vibrations of B-O, Si-O-Si, Si-O-B stretching, and Si-O-B bending at 1442.8 cm-1, 779.2 cm-1, 925.8 cm-1, and 648.1 cm-1. The X-Ray diffraction pattern results showed that the analysis of B2O3-SiO2 has high crystallinity with two peaks diffraction identified at 26.6⁰ and 20.9⁰. The thermal stability test of B2O3-SiO2 showed that B2O3-SiO2 has high thermal stability with temperature range at 300-700 ⁰C. The results showed that the acidity analysis of B2O3-SiO2 has potential number 122.71 mV so that indicated B2O3-SiO2 was high acidity. Keywords : boric oxide, silica dioxide, boric silica, B2O3-SiO