Rudy T M Situmeang
Department Of Chemistry, Lampung University, Jl. Sumantri Brojonegoro No. 1, Bandar Lampung 35145

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Characteristics of Nanosize Spinel NixFe3-xO4 Prepared by Sol-Gel Method Using Egg White as Emulsifying Agent Rudy Situmeang; Sukma Wibowo; Wasinton Simanjuntak; R. Supryanto; Rizki Amalia; Mitra Septanto; Posman Manurung; Simon Sembiring
Indonesian Journal of Chemistry Vol 15, No 2 (2015)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (438.236 KB) | DOI: 10.22146/ijc.21204

Abstract

In this study, sol-gel method using egg white as emulsifying agent was applied to prepare nano size spinel NixFe3-xO4 (with x = 0.2–1). Sample preparation was carried out by mixing the solution of Fe(NO3)3.9 H2O and Ni(NO3)3.6 H2O with egg white, and then the sample was stirred thoroughly using magnetic stirrer. After freeze–drying process, the sample was subjected to calcination treatment and subsequently characterized. The phase composition was evaluated using the X-ray diffraction (XRD) technique, followed by quantitative analysis using Rietveld and Debye-Scherrer Methods. The functionality of the sample was identified using Fourier Transform Infrared (FTIR) spectroscopy, and surface morphology and elemental composition were analyzed using scanning electron microscopycoupled with electron dispersive spectroscopy (SEM/EDS). The results of XRD characterization indicated that materials consist of various crystalline phases, with NiFe2O4 as a major phase. FTIR Analysis revealed the existence of both Lewis and Brønsted–Lowry acid sites, with Lewis acid as the prominent site. The sample was found to display relatively homogeneous surface morphology, having the crystallite size in the range of 33 to 61 nm according to the Debye-Scherrer equation. The EDS data indicated that the ratio of Fe/Ni is in agreement with the composition of the raw materials used.
Karakteristik Kekerasan dan Struktur Kristal Cordierite Berbasis Silika Sekam Padi dengan Penambahan Alumina (0, 20, 25, dan 30 wt%) Nindy Elyta Mawarty; Simon Sembiring; Rudy T.M. Situmeang
Jurnal Teori dan Aplikasi Fisika Vol 6, No 1 (2018): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v6i1.1829

Abstract

The synthesis, phase structure and hardness analysis of cordierite ceramic has been done with addition of alumina 0, 20, 25, and 30wt%. Magnesium and alumina from Sigma-Aldrich has been used as raw materials while the silica was obtained from extraction of rice husk used 5% KOH and 10% HCl with sol gel method. This cordierite synthesis used solid state method and sintered at 1200oC for 3 hours. Hardness analysis was determined by Microhardness Tester while the phase structure was determined by X-Ray Diffraction (XRD). Hardness value that obtained for C0, C20, C25, and C30 were 50,03 : 52,44 : 35,69 : and 50,46 kgf/mm2 repeatedly. It was proved that excess alumina will increase hardness value. The XRD patterns revealed that cordierite, corundum, spinel, cristoballite, and periclase were formed in the samplesKarakteristik Kekerasan dan Struktur Kristal Cordierite Berbasis Silika Sekam Padi dengan Penambahan Alumina (0, 20, 25, dan 30 wt%)
Sintesis Mg(OH)2 dari Bittern Menggunakan Metode Elektrokimia Hanif Amrulloh; Wasinton Simanjuntak; Rudy T M Situmeang
ALKIMIA Vol 1 No 1 (2017): ALKIMIA
Publisher : SCIENCE AND TECHNOLOGY FACULTY OF UNIVERSITAS ISLAM NEGERI RADEN FATAH PALEMBANG

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (281.554 KB) | DOI: 10.19109/alkimia.v1i1.1325

Abstract

Penelitian ini dilakukan untuk menghasilkan Mg(OH)2 dari bittern menggunakan metode elektrokimia, dengan menitik beratkan pada kajian pengaruh potensial terhadap rendemen dan kemurnian Mg(OH)2 yang dihasilkan. Proses elektrokimia dilakukan menggunakan sel elektrolisis 2-kompartemen, dihubungkan dengan jembatan garam berupa suspensi NaCl dalam gelatin. Proses elektrolisis dilakukan dengan elektroda nikel sebagai katoda dan elektroda karbon sebagai anoda selama 10 jam dengan variasi potensial 10, 14, 18, dan 22 volt. Hasil yang didapatkan menunjukkan Mg(OH)2 yang dihasilkan dari elektrolisis bittern memiliki kemurnian 81.73 % dengan komponen pengotor NaCl dan CaCO3.
Efek Variasi Konsentrasi NaOH pada Pembentukan Struktur Selulosa Cladophora sp. Sri Wahyu Suciyati; Posman Manurung; Junaidi Junaidi; Rudy Situmeang
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2888

Abstract

The effect of NaOH concentration values was observed on the cellulose structure of Cladophora. Cladophora cellulose is synthesized from Cladophora sp., a green alga that lives in aquatic environments (seawater and freshwater) and soil surfaces (rocks and wetlands). Cellulose synthesis is carried out through the processes of bleaching, alkali hydrolysis, and acid hydrolysis. Bleaching uses NaClO2, alkaline hydrolysis uses NaOH with varying concentrations (0.4; 0.5; 0.6; 0.7; 0.8 M), while acid hydrolysis uses 5% HCl. The physical properties of cellulose were analyzed using Fourier Transformation Infra-Red (FTIR) to determine functional groups, X-Ray Diffraction (XRD) to determine crystal structure, and scanning electron microscopy (SEM) to determine the morphology of cellulose structure.  FTIR pattern analysis showed peaks with OH group stretching at 3331, 3347, 3360 cm-1, CH group stretching at around 2929 cm-1, C = O stretching at 1640-1650 cm-1, and CH2 flexural stretching at 1420-1430 cm-1 in all samples. XRD pattern analysis confirmed the recovery of Cladophora cellulose from a highly crystalline of sample c (NaOH 0.5 M) with a crystallinity index of 94.0 % and a particle size of 31.54 nm. SEM image analysis showed the surface morphology of Cladophora rod-shaped raw material with an average diameter of 21.30 µm. At the same time, Cladophora cellulose refers to the formation of a web-like nanofibril network with an average diameter of 30.63 nm. These results indicate that the synthesis has successfully removed lignin, hemicellulose, and amorphous group in Cladophora and formed crystalline cellulose confirmed by nano-sized cellulose.
Effect of Dilution and Electrolysis Time on Recovery of Mg2+ As Mg(OH)2 from Bittern by Electrochemical Method Hanif Amrulloh; Wasinton Simanjutak; Rudy Tahan Mangapul Situmeang; Sophia Lasma Sagala; Rikha Bramawanto; Ridho Nahrowi
The Journal of Pure and Applied Chemistry Research Vol 8, No 1 (2019): Edition January-April 2019
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2019.008.01.455

Abstract

This research was conducted to study the effect of dilution and electrolysis time on therecovery of Mg2+as Mg(OH)2from bittern by electrochemical method. The electrochemical process was carried out using 2-compartment electrochemical cell, connected by salt bridge prepared from NaCl suspended in gelatin. The experiment was carried out using nickel as cathode and carbon as an anode. The electrolysis process was carried out at a potential of 18 volts with dilution factors of 0, 2, 4, 6, and 8 times, and electrolysis time of 1, 2, 4, 6, 8, 10, and 12 hours. The results show that percent of conversion increased with dilution with the best result was obtained at 4x dilution factor and 4 hours electrolysis time with percent conversion of 85 % and purity of Mg(OH)291%
Synthesis and Characterization of Titania-Rice Husk Silica Composites as Photocatalyst Posman Manurung; Rudy Situmeang; Ediman Ginting; Indra Pardede
Indonesian Journal of Chemistry Vol 15, No 1 (2015)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (482.219 KB) | DOI: 10.22146/ijc.21221

Abstract

This article describes the synthesis of titania-silica composites by a sol-gel method using a mixture of silica of rice husk and titanium butoxide sols. Microstructures were examined at calcination temperature in the range of 500 to 700 °C, with temperatures interval of 50 °C. The sintered catalysts were subsequently tested for photodegradation of methylene blue (MB) under ultraviolet and sunlight rays. Physical characteristics were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET). The XRD results did not show the presence of silica crystal phase in each sample. The results showed that the highest BET surface area of samples was obtained at the temperature of 650 °C. In sample calcined 500 °C, the activity of the catalyst on MB was relatively similar in both sunlight and ultraviolet rays.