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Karna Wijaya
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara, Yogyakarta 55281, Indonesia
Chemical Engineering, Chemistry & Bioengineering Chemistry

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Investigation of the Structural and Dynamical Properties of Cu+ in Liquid Ammonia: A Quantum Mechanical Charge Field (QMCF) Molecular Dynamics Study Wahyu Dita Saputri; Karna Wijaya; Ria Armunanto
Indonesian Journal of Chemistry Vol 17, No 3 (2017)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (742.786 KB) | DOI: 10.22146/ijc.26809

Abstract

A quantum mechanical charge field (QMCF) molecular dynamics (MD) simulation has been carried out to describe the structural and dynamical properties of Cu+ ion in liquid ammonia. The first and second shells were treated by ab initio quantum mechanics at the Hartree−Fock (HF) level with the DZP-Dunning basis set for ammonia and LANL2DZ ECP basis set for Cu. The system was equilibrated for 4 ps, then the trajectory data was collected every fifth step for 20 ps at 235.15 K. The structural analysis showed that in the first solvation shell, Cu+ is solvated by 4 ammonia molecules forming a stable structure of tetrahedral with Cu-N bond length of 2.15 Å, whereas in the second solvation shell there are 29 ammonia molecules that have an average distance of 4.79 Å to Cu+ ion. Mean residence time of 3.06 ps was observed for the ammonia ligand in the second solvation shell indicating for a highly unstable structure of the solvation shell. The obtained structure of the first solvation shell from this simulation is in excellent agreement with experimental data.
Fuel Production from LDPE-based Plastic Waste over Chromium Supported on Sulfated Zirconia Latifah Hauli; Karna Wijaya; Akhmad Syoufian
Indonesian Journal of Chemistry Vol 20, No 2 (2020)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (15.755 KB) | DOI: 10.22146/ijc.45694

Abstract

The preparation, characterization, and catalytic activity test of sulfated zirconia (SZ) modified with chromium for the hydrocracking of LDPE-based plastic waste have been investigated. SZ was prepared by wet impregnation method using zirconia nanopowder (ZrO2) and H2SO4 solution. SZ was further modified with chromium (0.5, 1.0, and 1.5% wt.%) by refluxing in aqueous solution of Cr(NO3)3·9H2O, followed by calcination and reduction processes. The prepared catalysts were characterized by SEM-Mapping and TEM. Hydrocracking of LDPE-based plastic waste was conducted at various temperatures and various catalysts. In addition, the optimum catalyst was repeatedly used for the reaction to demonstrate the stability of the catalyst. Liquid products obtained by hydrocracking were characterized by GCMS. The results showed that the morphology of the prepared catalysts had different sizes and disordered shapes after the addition of sulfate and Cr. The effective temperature for hydrocracking was 250 °C. The highest selectivity to liquid product and gasoline fraction were 40.99 and 93.42 wt.%, respectively, and were obtained over Cr/SZ with 1.0 wt.% Cr. Hydrocracking of plastic waste over the used Cr/SZ catalyst with 1.0 wt.% Cr showed that the Cr/SZ catalyst was stable and reusable up to three repetitions.
Activity and Selectivity of Mesoporous Silica Catalyst for Hydrocracking Process of Used Palm Oil into Biogasoline Ahmad Suseno; Karna Wijaya; Edy Heraldy; Lukman Hakim; Wahyu Dita Saputri; Gunawan Gunawan
Indonesian Journal of Chemistry Vol 23, No 2 (2023)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.70460

Abstract

Research on the synthesis of mesoporous silica catalyst, as well as its activity and selectivity in the hydrocracking of used palm oil, has been carried out. The research involved the preparation of mesoporous silica catalyst by varying the volume ratio of TEOS:CTAB at 2:1, 4:1, and 8:1, then calcined at 500 °C. Synthesis success was confirmed by FTIR, XRD, SEM-EDX, GSA, and hydrocracking selectivity by GC-MS analysis. The results showed that the more TEOS added, the silica bond composition, crystallinity, pore size, and product selectivity increased. The best catalyst performance was obtained from a TEOS:CTAB ratio of 8:1 at a calcination temperature of 500 °C (MCT81-500), which indicated the presence of Si-OH and Si-O-Si groups with a Si percentage of 45.31%, pore size diameter of 31.912 nm, and a total pore volume of 0.040 cc/g. In addition, the application of MCT81-500 in the hydrocracking process of used palm oil can produce a bio-gasoline (C5-C12) and kerosene (C12-C15) of 92.24 and 7.76 wt.%, respectively. This study shows that mesoporous silica has good potential for catalytic activity to convert used cooking oil waste into an environmentally friendly energy source.
Co-Authors Ahmad Suseno Akhmad Syoufian Edy Heraldy Gunawan Gunawan Latifah Hauli Lukman Hakim Ria Armunanto Wahyu Dita Saputri Wahyu Dita Saputri