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Journal : JISTECH: Journal of Information Science and Technology

PENGARUH WAKTU PENYINARAN DAN KONSENTRASI AWAL LARUTAN KROMIUM(VI) TERHADAP HASIL FOTOREDUKSI KROMIUM(VI) YANG TERKATALISIS OLEH SEMIKONDUKTOR ZNO-ZEOLIT: EFFECT OF EXPOSURE TIME AND INITIAL CONCENTRATION CHROMIUM(VI) SOLUTION ON PHOTOREDUCTION RESULTS SEMICONDUCTOR CATALYZED Chromium(VI). ZNO-ZEOLITE Buka di Google Terjemahan • Masukan Google Terjemahan Lestari, Agnes Dyah Novitasari
JISTECH: Journal of Information Science and Technology Vol 7 No 1 (2015): Pebruari 2015
Publisher : Universitas Papua

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Abstract

The Yield of a photoreduction process of chromium(VI) or Cr (VI) catalyzed by ZnO semiconductorstructured in the zeolite/ZnO-zeolite (ZnO-Z) can be influenced by several factors, including the exposure timeand the initial concentration of the Cr (VI) solution. In this study, the photoreduction process of Cr (VI) iscarried out in a closed batch reactor equipped with a magnetic stirrer and a 38 Watt UV lamp. A total of 50 mLof a Cr(VI) solution and 25 mg of ZnO-Z was used to study the effect of exposure time and the initialconcentration of the Cr(VI)solution to the yield of its photoreduction process. The concentrations of Cr (VI) weredetermined by UV-Vis spectrophotometer using difenilkarbazid method. To determine the catalyst performanceof ZnO-Z in the photoreduction process, an examination of the catalyst in the form of bulk ZnO (ZnO bulkform)has been done. The results showed that the optimum exposure time in the photoreduction process of Cr (VI)catalyzed by ZnO-Z is 25 hours and the optimum initial concentration of Cr (VI) is 25 mg/L. Photoreductionyield of Cr (VI) by catalyst ZnO-Z is higher than the ZnO bulkform.
Penentuan Kandungan Kation dan Anion Mayor dalam Abu Serabut Kelapa Berpotensi Katalis Renewable: Determination of Major Cation and Anion Content in Coconut Fiber Ash Potentially Renewable Catalyst Naibaho, Julius; Muin, Ahmad; Lestari, Agnes Dyah Novitasari
JISTECH: Journal of Information Science and Technology Vol 6 No 2 (2014): Vol. 6, No. 2, Agustus 2014
Publisher : Universitas Papua

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Abstract

Coconut fibers ash contain the cations and anions that can be use as renewable catalyst in certain chemical reaction. Coconut fibers ash that used in this experiments was from Manokwari, Papua Barat. Coconut fibers ash samples was destructed by aqua regia and was analyzed by Atomic Absorption Spectrophotometer (AAS) for determine cations and anions. The another part of sample was decarbonated and extracted with in methanol, then carbonats and bicarbonats were determined using acidimetry method. The AAS analyze results that coconut fibers ash samples in this experiments were contains K (20.140 g/kg); Ca (13.897 g/kg); Mg (4.611 g/kg); Fe (34.502 g/kg); dan Mn (8.957g/kg) cations. The major anions is carbonat (145.54 g/kg) and bicarbonate (50.051g/kg). The kalium content that was high in carbonats makes the aqeous of coconut fibers ash have base properties, it be potentially as renewable catalyst in the certain chemical reaction.
Potensi Pengembagan Dye Sensitized Solar Cell (DSSC) dengan Sensitizer Zat Warna Alami dari Tumbuhan Asal Papua sebagai Alternatif Solusi Krisis Energi dan Pemanasan Global: The Potential for Development of Dye Sensitized Solar Cell (DSSC) with Natural Dyes Sensitizers from Papuan Plants as an Alternative Solution to the Energy Crisis and Global Warming Lestari, Agnes Dyah Novitasari
JISTECH: Journal of Information Science and Technology Vol 6 No 1 (2014): Februari 2014
Publisher : Universitas Papua

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Abstract

Currently, the energy crisis and global warming are an important issue internationally, including Papua. Various attempts were made to overcome these problems, for instance the development of alternative energy that does not cause global warming: the solar energy harvested by the solar cells (solar cells). There is an obstacle for solar cell applications: the high production costs. This problem is solved by the discovery of a type of solar cell Dye Sensitizized Solar Cell (DSSC).Utilization of local potential will reduce the cost of fabricating such a device. Papua is well know for its flora abundance and diversity, one of which is a natural dye-producing plants. Color produced by these plants show content that has a group of compounds that can absorb light (chromophore) contained therein. The content of this chromophore compounds provide potential it can be used as a sensitizer in DSSC, thus resulting DSSC that is relatively cheap for Papua.