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SINTESIS, KARAKTERISASI, DAN UJI AKTIFITAS FOTOKATALITIK NANOPARTIKEL MAGNETIK TiO2-CoFe2O4 -, Rahmayeni,; Septiani, Upita; Arief, Syukri; Hamdi, Hayatul
Jurnal Riset Kimia Vol 4, No 2 (2011): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v4i2.134

Abstract

 ABSTRACT Magnetic nanoparticles of TiO2−CoFe2O4 were prepared using metal nitric and tiatniumisopropoxide as starting materials by coprecipitation and hydrolysis method. XRD, SEM, EDX and VSM were used to characterize the structure, morphology, composition and magnetic property of the particles, respectively. XRD pattern show the diffraction peaks of TiO2 anatase at 2θ = 25.3° and CoFe2O4 at 2θ = 35.5° in TiO2−CoFe2O4 particles. SEM image show the regular morphology and size distribution of particles. From VSM analysis indicate that the particles have paramagnetic properties. Photocatalytic activities of particles were applied for degradation of rhodamin B  and the results showed that CoFe2O4 doped into TiO2 can increase the activities of particles in visible light until 82 %. Key words : nanopartikel magnetik, TiO2−CoFe2O4, fotokatalis    
PEMANFAATAN ZEOLIT ALAM SEBAGAI MEDIA PENDUKUNG AMOBILISASI ENZIM α-AMILASE Septiani, Upita; Lisma, Agrina
Jurnal Riset Kimia Vol 5, No 1 (2011): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v5i1.188

Abstract

 ABSTRACT The utilization of natural zeolite as supporting media of α-amylase enzyme has been done. Natural zeolite which is activated with 3M HCl can remove impurities in the surface natural zeolite, uncover and widen the pores of the zeolite and activate functional groups to interact with α-amylase enzyme in the process of immobilization enzyme process. The mass of activated natural zeolite which is used as a material immobilized to get the optimal activity of α-amylase enzyme was 0.3 gram. Based on the measurement result of optimization of α-amylase enzyme were obtained optimum temperature of 35 oC, pH 5.6 and incubation time of 35 minutes with 0.04845 units/mL of the unit activity. And for α-amylase immobilized enzyme will be stable at the optimum temperature of 50 oC, pH 5.6 and incubation time of 45 minutes with 0.030 units/mL of the unit activity. SEM-EDX pattern shows the differences in surface morphology between natural zeolite and activated natural zeolites which contain α-amylase enzyme. A mobilization technique can increase the stability utilized in a α-amylase enzyme. Keywords : Zeolite, amobilization, α-amylase enzyme
PEMBUATAN DAN KARAKTERISASI KATALIS ZnO/KARBON AKTIF DENGAN METODE SOLID STATE DAN UJI AKTIFITAS KATALITIKNYA PADA DEGRADASI RHODAMIN B Septiani, Upita; Bella, Ilona; -, Syukri
Jurnal Riset Kimia Vol 7, No 2 (2014): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v7i2.186

Abstract

 ABSTRACTComposite catalyst ZnO/Activated Carbon (ZnO/AC) had been synthesized successfully bysolid state method. Synthesis was done by varying the addition of activated carbon (AC) 2%,5%, and 10% ZnO mass. Composite catalyst were calcinated at 400oC and characterized byFTIR (Fourier Transform Infra Red), XRD (X-Ray Diffraction), SEM (Scanning ElectronMicroscopy). Based on the results of FTIR, absorption appeared in the region wave number1400-1600 cm-1, which indicated stretching of C=C was assumed come from AC. From theXRD results, it was known by the addition of AC, not overly change the crystallinity and crystalsize of ZnO, the crystal structure is hexagonal (wurtzite). SEM images showed AC preventedthe agglomeration of ZnO that would expand the surface area of ZnO and increased catalyticactivity of ZnO. For the results of the catalytic activity test, catalyst ZnO/AC was tested on thedegradation of Rhodamine B solution (10 ppm) by UV light irradiation, where the increasingnumber of trains the catalytic ability of ZnO also increased, it could be concluded that activatedcarbon can support to increase the role of ZnO in degrading Rhodamine B.Keywords: composite catalyst, ZnO, activated carbon, solid state, Rhodamine B
EFFECT OF PRE- γ-IRRADIATION DOSE ON THE DURABILITY OF THE SULFONATED ETFE-G-POLYSTYRENE CONDUCTING MEMBRANES Septiani, Upita; Kubota, Hitoshi
Jurnal Riset Kimia Vol 5, No 2 (2012): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v5i2.221

Abstract

The influence of pre-g-irradiation dose on durability of the poly(ethylene-co-tetrafluoroethylene) (ETFE) film-based radiation-grafted polymer electrolyte membrane was investigated. The durability of membrane was found to be strongly influence by g-ray pre-irradiation dose. The durability was tested in a 3% H2O2 aqueous solution at 60°C. The durability of the polymer electrolyte membrane with a degree of grafting of about 30% prepared by lower pre-irradiation dose was more stable than that of the membrane prepared with higher pre-irradiation dose.
SINTESIS DAN KARAKTERISASI ZEOLIT FAUJASIT DARI LIMBAH BATUBARA OMBILIN DENGAN METODA ALKALI HIDROTERMAL AIR LAUT Septiani, Upita; Fatiha, Widya Yuliani; Arief, Syukri
Jurnal Riset Kimia Vol 8, No 2 (2015): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v8i2.235

Abstract

Zeolite synthesis using Ombilin coal fly ash at low temperature with alkaline hydrothermal process has been carried out. The used Fly ash was melted by NaOH at a temperature of 550°C. Alkaline hydrothermal processes in zeolite synthesis performed with variations of temperature at 35°C , 45°C and 60°C . The zeolite that obtained was characterized by using Fourier Transform Infra Red (FT - IR), X - Ray Diffraction (XRD) , Scanning Electron Microscopy (SEM) in combination with EDX . The characterization results showed the formation of zeolite were better when an increasing in temperature processes and the use of sea water as a solvent. On the use of seawater, were obtained sodalit zeolite with the chemical formula Na8(Al6Si6O24)Cl2.
PEMBUATAN DAN KARAKTERISASI KATALIS TIO2/KARBON AKTIF DENGAN METODE SOLID STATE Septiani, Upita; Gustiana, Mega; -, Safni
Jurnal Riset Kimia Vol 9, No 1 (2015): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v9i1.257

Abstract

Composite catalyst of TiO2/Activated Carbon (TiO2/AC) had been synthesized with successfully by solid-state method. Synthesis was done by varying the addition of AC 5%, 10% and 15% of the mass of TiO2 was used. Composite catalyst was calcinated at temperature 400°C and characterized by Fourier Transform Infra-Red (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). FTIR spectrum show that the absorption appearedin the regionof C=C at wave number 1600-1800 cm-1, that assumed from AC. From XRD we can see that with variated of AC do not given different XRD patterns significantly, crystal structure of composite catalyst is anatase. SEM images showed that AC prevented the aglomeration of TiO2 that would expand surface area and increased catalytic activity of TiO2.
Struktur dan Sifat Dielektrik Senyawa Aurivillius CaBi3LaTi4O15 yang Disintesis dengan Teknik Hidrotermal Zulhadjri, Zulhadjri; Amir, Firmanul Qadri; Mahmud, Marsal; Septiani, Upita; Arief, Syukri
Jurnal Riset Kimia Vol 11, No 1 (2020): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v11i1.343

Abstract

Synthesis of four-layer Aurivillius CaBi3LaTi4O15 has been successfully carried out by hydrothermal technique using NaOH 4 M as mineralizer. The reaction was carried out at 220 °C for 72 h. Crystal structure, morphology, and dielectric properties were analyzed in this study. X-ray diffraction confirmed that the single-phase product was successfully obtained. The refinement result shows the product has orthorhombic crystal structure with space group A21am. The morphology analyzed using SEM shows plate-like grains are observed, which is characteristic of Aurivillius phase. Dielectric curves show peaks at 585 °C which indicate ferroelectric transition temperature.
Adsorpsi Asam Humat pada Zeolit Alam yang Dimodifikasi dengan TiO2 Septiani, Upita; Tasari, Fiska Julian; Zilfa, Zilfa
Jurnal Riset Kimia Vol 11, No 1 (2020): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v11i1.344

Abstract

This research modified natural zeolite with TiO2 synthesized by the sol-gel process which was applied as a humic acid adsorbent. The purpose of this study was to coat natural zeolites with TiO2 to increase the adsorption capacity of natural zeolites as humic acid adsorbents. The natural zeolite powders were obtained from Kabupaten Solok, West Sumatra, based on X-ray Fluorescence (XRF) analysis, the ratio of silica/alumina (Si/Al) was 4.35, indicating that natural zeolite was clinoptilolite zeolite. Scanning Electron Microscopy (SEM) analysis showed natural zeolite has a rough surface with closed pores while zeolite coated with TiO2 (zeolite/TiO2) has a homogeneous, smooth surface with open pore. The results of the Energy Dispersive X-Ray Spectroscopy (EDS) analysis showed that the level of TiO2 was 7.1%, this result showed that TiO2 has been coated on the surface of the zeolite. Natural zeolite and zeolite/TiO2 were applied as humic acid adsorbents. Maximum adsorption capacity of natural zeolites and zeolites/TiO2 were 0.2787 mg/g and 1.199 mg/g, respectively.
Pengaruh HCl terhadap Aktifasi Zeolit Alam Clipnotilolit-Ca Pada Penyerapan Pb(II) Zilfa, Zilfa; Septiani, Upita; Mirawati, Mirawati
Jurnal Riset Kimia Vol 11, No 2 (2020): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v11i2.355

Abstract

Research about the effect of HCl on the activation of clinoptilolite-Ca natural zeolite on Pb(II) absorption has been done. The purpose of this study is to determine the capacity of zeolite clinoptilolite-Ca activation by HCl can be used as an adsorbent. For analysis of the adsorption we used AAS whereas for zeolite characterization were used XRF and XRD. The analysis parameters are the effect of HCl concentration, particle size, adsorbent mass, contact time, total solution volume, concentration of Pb(II), and PH solution. These parameters were studied to determine the optimum conditions in the adsorption process. The optimum conditions absorption of Pb(II) for the acid activation process shows that the zeolite clinoptilolite-Ca can be used as an absorbent. The adsorption results show that the value of Pb(II) capacity in the activation process with HCl of 0.2 N produces adsorption capacity of 0.0821 mg/g, for particle size 125 µm produces and adsorption capacity 0.0821 mg/g, for an adsorbent mass of 0.1 g produces an adsorption capacity of 0.5110 mg/g, for contact time of 10 minutes is 0.5662 mg/g, for a metal solution volume of 12.5 mL is 0.5493 mg/g, for the concentration of metal ion solution 40 mg/L is 2.608 mg/g, and at pH = 7 is 4.923 mg/g. The output of several parameters can be concluded that the adsorption capacity of zeolite clinoptilolite-Ca to the absorption of Pb(II) is 4.923 mg/g. Characterization of zeolite adsorbents with XRF and XRD shows that the zeolite used is zeolite clinoptilolite-Ca.   
Struktur, Sifat Dielektrik dan Optik Senyawa Aurivillius (Ca0,5Ba0,5)Bi4Ti4O15 yang Disintesis dengan Teknik Lelehan Garam Veronita, Silvi; Septiani, Upita; Zulhadjri, Zulhadjri
Jurnal Riset Kimia Vol 13, No 1 (2022): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v13i1.463

Abstract

Synthesis of ferroelectric material based onAurivillius phases, (Ca0.5Ba0.5)Bi4Ti4O15 (CBBT), have been done using a molten salts technique.The results of X-ray diffraction (XRD) analysis showed the characteristic peaks at 2θ = 12.93°, 17.31°, 21.64°, 23.23°, 27.71°, 30.33°, and 32.90° which was correspond to the four-layers of Aurivillius phase.Refinement structure using the Le Bail method, the sample is suitable for orthorhombic structures with the A21am space group. The orthorhombicity of the CBBT is small and nearer to tetragonal symmetry.Fourier Transform Infra-red (FTIR) spectra show distortion of TiO6 octahedral at 847 cm-1 and strain vibrations of TiO6 octahedra at 545 cm-1 due to A-O bonds.Analysis using Scanning Electron Microscopy (SEM) shows the morphology of the sample in the form of plate-like which is characteristic of Aurivillius phase.The ferroelectric to paraelectric phase transition temperature (Tc) was obtained at 635ºC.The band gap value of the CBBT compound was 3.17 eV, relatively the same with the CaBi4Ti4O15 (CBT) compound.