Papers by Siti Hadijah L Bempa
Jambura Journal of Chemistry, 2020
Limbah laboratorium kimia merupakan limbah B3 mengandung unsur logam berat seperti besi (Fe) yang... more Limbah laboratorium kimia merupakan limbah B3 mengandung unsur logam berat seperti besi (Fe) yang dihasilkan dari aktivitas praktikum dan penelitian. Penelitian ini bertujuan menganalisa kemampuan karbon aktif ampas tebu teraktivasi ZnCl2 sebagai adsorben logam Fe(III) pada limbah laboratorium Universitas Negeri Gorontalo. Karbon aktif dikarakterisasi kadar air, kadar abu, daya adsorpsi, serta analisis FTIR, SEM, XRD. Aplikasi menggunakan metode adsorpsi dengan pengompleks 0,5 mL KSCN 2M ditambah 0,3 mL HNO3 4M dan absorbansi diukur dalam Spektrometer UV-Visible. Nilai absorbansi dari hasil pengukuran larutan standar dengan variasi konsentrasi 0.1, 0.3, 0.5, 0.7 dan 1 ppm, larutan induk Fe 100 ppm diperoleh persamaan regresi li nier y = 0.0721x + 0.0135 nilai regresi (R2) = 0.9988(λMax) 490 nm dengan nilai absorbansi (A) tertinggi yakni 0.043. Hasil penelitian menunjukkan karbon aktif teraktivasi ZnCl2 efektif dalam mengadsorpsi logam Fe(III) di limbah laboratorium dengan kadar tera...
A. JUDUL : Modeling Ionic Conduction in γ-Bi2VO5.5 B. LATAR BELAKANG : Experimental studies on th... more A. JUDUL : Modeling Ionic Conduction in γ-Bi2VO5.5 B. LATAR BELAKANG : Experimental studies on the oxide conductivity of γ-Bi2VO5.5 have been reported elsewhere [4]. However, the experimental study could not reveal the detail of the mechanism of ionic conduction. Abraham and Krok proposed oxide conduction mechanism which was applied only to BIMEVOX with ME is divalent metal, and derived from crystallographic data [5]. In our knowledge, the conduction mechanism in parent structure of BIMEVOX, γ-Bi2VO5.5, has not been reported yet. Computational studies could be used to study the detail of ionic conductivity mechanism in the atomic level. Some computation study on the layered structure of Aurivillius phases similar to γBi2VO5.5 has been carried out and reported [6]. It could reveal defect energies and maximum dopant concentrations in Aurivillius as ferroelectric material. Here, we report the computational study of γ-Bi2VO5.5 structure that cover trajectory of oxide in γ-Bi2VO5.5. The study was aimed to investigate the oxide pathways that are possible in the γ-Bi2VO5.5 structure via vacancy defect in perovskite-like layer. C. METODE : The method has been successfully used to model the movement of cations in solid materials, such as Na+ in the NASICON (sodium super ionic conductor) and K+ in KFeAs2O7 [7, 8]. In this study, movement or geometry conduction for oxide in γ-Bi2VO5.5 structure is predicted by using the BVS method as has been performed by JUMPITER [9]. D. HASIL : Structures of model were created based on γ-Bi2VO5.5 structure reported by Mairesse et al. as depicted in Figure1. [10]. The γ-Bi2VO5.5 is tetragonal with space group is I4/mmm, and cell unit dimension is a = 3.99176(4), b = 3.99176(4), and c = 15.4309(3) Å. The structure has high symmetry and contains oxygen vacancy in perovskite-like layer. Environment of the V5+ coordinations in perovskite-like layer are recognized as octahedron, tetrahedron, trigonal bipyramid, and tetragonal pyramid with interatomic distances compatible with O atomic size. Based on the vanadium coordination environment, we built a model structure of γ-Bi2VO5.5with P1 space group by creating oxide vacancies at the equatorial site, so the perovskite-like layer becomes entire tetrahedrons, and other layers were octahedron (Figure 2). The structure is far from the real structure of γ-Bi2VO5.5, however we expect that an insight of the role of non octahedron coordination in the oxide conduction could be obtained. Figure 1. The refined crystal structures of γ-Bi2VO5.5; vacancies in perovskitelike layers were not shown. O(3) and O(2) each are equatorial and apical oxides, respectively.
B. Tujuan : Membuat kloroform dari aseton dan kaporit melalui reaksi subsitusi elektrofilik C. Da... more B. Tujuan : Membuat kloroform dari aseton dan kaporit melalui reaksi subsitusi elektrofilik C. Dasar Teori Prinsip dari sintesis kloroform adalah halogenasi dan haloform. Halogenasi merupakan reaksi substitusi yang terjadi pada suatu senyawa yang mempunyai hidrogen alfa yang siap bereaksi dengan halogen. Sedangkan haloform adalah reaksi multihalogenasi.Multi halogenasi atau haloform terjadi pada atom karbon kelompok metil. Haloform terjadi karena substitusi dari halogen pertama membuat sisa alfa hidrogen pada karbon metil lebih asam. Akhirnya perpindahan proton terjadi antara asam karboksilat dan ion positif pada haloform.
MODUL 2 Laporan Praktikum Organik Sintesis
Mahasiswa dapat menyusun model suatu rantai, lingkaran dan isomer-isomer suatu senyawa
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Papers by Siti Hadijah L Bempa