Article Per Year (5 Year)
p-Index From 2020 - 2025
1.203
P-Index
This Author published in this journals
All Journal Bulletin of Chemical Reaction Engineering & Catalysis IJFAC (Indonesian Journal of Fundamental and Applied Chemistry) Indonesian Journal of Chemistry Jurnal Crystal : Publikasi Penelitian Kimia dan Terapannya Makara Journal of Science
Rizki, Widya Twiny
Unknown Affiliation
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Environmental Science

Published : 6 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 6 Documents
Search

 1 
Synthesis of SnO2-Fe3O4 Nanocomposites using Hydrothermal Method Widya Twiny Rizki; Poedji Loekitowati Hariani; Addy Rachmat; Muhammad Said; Nur Hanis Hayati Hairom
IJFAC (Indonesian Journal of Fundamental and Applied Chemistry) Vol 5, No 3 (2020): October 2020
Publisher : IJFAC (Indonesian Journal of Fundamental and Applied Chemistry)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24845/ijfac.v5.i3.88

Abstract

Synthesis of nanocomposite SnO2-Fe3O4 using the hydrothermal method was conducted in this study. The purpose of this study was to determine the best mass ratio in the synthesis of SnO2-Fe3O4. Nanocomposite SnO2-Fe3O4 were made with mass ratio (1:1), (1:2) and (2:1) were characterized using XRD and FTIR. The result of SnO2 characterization using XRD analysis was showed a sharp intensity peak at 2  = 26.5. The result of  Fe3O4 characterization using XRD analysis was showed a sharp intensity peak at 2  = 35.86. The XRD characterization result of SnO2-Fe3O4 (1:2) 2  = 26.74 and 34.08. Based on the XRD characterization, it can be concluded the best mass ratio for SnO2-Fe3O4 was (1:2). Characterization nanocomposite SnO2-Fe3O4 using FTIR showed the absorption band at 590 cm-1 is a characteristic peak of Sn-O and the absorption band at 563 cm-1 corresponds to Fe-O.
Preparation of NiFe2O4 Nanoparticles by Solution Combustion Method as Photocatalyst of Congo red Poedji Loekitowati Hariani; Muhammad Said; Addy Rachmat; Fahma Riyanti; Handayani Citra Pratiwi; Widya Twiny Rizki
Bulletin of Chemical Reaction Engineering & Catalysis 2021: BCREC Volume 16 Issue 3 Year 2021 (September 2021)
Publisher : Department of Chemical Engineering - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.16.3.10848.481-490

Abstract

NiFe2O4 nanoparticles had been successfully synthesized by solution combustion method using urea fuel (organic precursor). The synthesized NiFe2O4 were characterized by X-ray diffraction (XRD), Scanning electron microscopy-Electron Dispersive X-ray Spectroscopy (SEM-EDs), Transmission Electron Microscopy (TEM), Fourier Transform Infra-Red (FTIR), Vibrating Sample Magnetometer (VSM), UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS), and Point of Zero Charge (pHpzc). NiFe2O4 nanoparticles irradiated with visible light were employed to degrade Congo red dye with the following variable: solution pH (3–8), H2O2 concentration (0.5–3 mM), and Congo red concentration (100–600 mg/L). XRD analysis results showed that the NiFe2O4 nanoparticles had a cubic spinel structure. The particle sizes are in the range of 10–40 nm. The magnetic properties of NiFe2O4 nanoparticles determined using VSM showed a magnetization saturation value of 47.32 emu/g. UV-Vis DRS analysis indicated that NiFe2O4 nanoparticles had an optical band gap of 1.97 eV. The success of synthesis was also proven by the EDS analysis results, which showed that the synthesized NiFe2O4 nanoparticles composed of Ni, Fe, and O elements. The removal efficiency of Congo red dye was 96.80% at the following optimum conditions: solution pH of 5.0, H2O2 concentration of 2 mM, Congo red dye concentration of 100 mg/L, and contact time of 60 min. The study of the photodegradation kinetics follows a pseudo-first order reaction with a rate constant value of 0.0853 min−1. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 
Cr (III)-Doped Bentonite: Synthesis, Characterization and Application for Phenol Removal Purwaningrum, Widia; Vilantina, Vilantina; Rizki, Widya Twiny; Desnelli, Desnelli; Hariani, Poedji Loekitowati; Said, Muhammad
Makara Journal of Science Vol. 25, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Study of doping process of metal oxide Cr(III) onto bentonite for phenol removal has been done. The purpose of this study was to increase the capacity and effectiveness of bentonite adsorption.The doped bentonite was characterized using XRD, SEM-EDX and FT-IR spectrophotometer analysis. XRD characterization result showed an angle shift (2θ) characteristic at1.609°. The SEM-EDX characterization result showed that bentonite as control have a more gaps than Cr(III)-doped bentonite. Based on EDX result, the Al element decreased from 7.53% to 3.76%, Si from 19.84% to 10.23% and appeared Cr element 2.06%, The FT-IR characterization result showed no significant friction in the spectrum so it can be identified as physical adsorption. The adsorption of phenol was applied at pHpzc, which for bentonite as control was applied at pH 4 and Cr(III)- doped bentonite was applied at pH 8. The phenol adsorption rate fitted to pseudo-second-order and it was found that the equilibrium data was best followed by Freundlich isotherm model, the amount of adsorption rate constant (k) and adsorption capacity (Qe) was 0.0024 g.mg-1min-1 and 16.95 mg/g. The Enthalpy (ΔH) and entropy (ΔS) values decrease with increasing phenol concentration and the positive free energy value was indicated that the proccess was nonspontaneous because there has been an equilibrium state. Based on the adsorption result, it can be concluded that the doping method can produce better bentonite performance to adsorb phenol.
Tannin Extraction from Bark of Cinnamomum burmannii and Its Application for use as Natural Dye and as Antioxidant Rizki, Widya Twiny; Wahyuni, Winika Sri; Sari, Ririn Depita; Lestari, Siti Marwah; Rahmadevi, Rahmadevi
IJFAC (Indonesian Journal of Fundamental and Applied Chemistry) Vol 9, No 1 (2024): February 2024
Publisher : IJFAC (Indonesian Journal of Fundamental and Applied Chemistry)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24845/ijfac.v9.i1.35

Abstract

Cinnamon bark (Cinnamomum burmannii) contains tannins which have the potential to act as natural dyes. This research is to synthesize natural dye from cinnamon bark extract (Cinnamomum burmannii). The research was carried out by making cinnamon bark extract by comparing the amount of solvent by maceration using 96% ethanol, calculating the yield, tannin analysis, FTIR analysis, and stability test color. The comparison of the amount of cinnamon bark extraction solvent affected the resulting yield. Testing the tannin compound with 1% gelatin reagent in 10% NaCl showed a white precipitate and 1% FeCl3 reagent produced a greenish-brown color so the extract was positive for tannin, analysis FTIR ratio 1:10 for the presence of O-H, C-H, C=C, C-O groups, ratio 1:15 for the presence of O-H, C-H, C=C, C-O group. The color stability test of cinnamon bark extract is more stable than Rhodamine-B. Based on the extraction results, it was concluded that cinnamon bark extract can be used as an alternative to natural dye in cosmetic products.Keywords: Cinnamon Bark, Extract, FTIR Analysis, Natural dyes, Tannin
Modification of Chitosan using Fe3O4 and Glucose and Its Application for Phenol Removal Rizki, Widya Twiny; Lestari, Siti Marwah; Rahmah, Vindi Annisa; Dauli, Rd Rahmat
Indonesian Journal of Chemistry Vol 25, No 5 (2025)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.103140

Abstract

In this study, chitosan was modified with Fe3O4 and glucose to enhance its capacity and effectiveness in adsorbing phenol from organic waste. XRD analysis revealed distinct differences between unmodified chitosan and the Fe3O4/glucose-modified version, with the resulting nanocomposite showing a particle size of 17.21 nm. FTIR spectra exhibited new, sharper peaks at 531 and 544 cm−1, indicating interactions between chitosan and Fe3O4 via the nitrogen atom in the NH2 group. VSM characterization showed a saturation magnetization of 63.4 emu/g, confirming that the chitosan/Fe3O4/glucose nanocomposite is superparamagnetic. SEM analysis revealed an uneven, porous surface, while the morphology displayed dark Fe3O4 spots dispersed across a lighter chitosan matrix. The optimal adsorption condition was achieved at a contact time of 60 min, with an adsorption efficiency of 16.46%. In addition to reducing phenol content in wastewater, the modified nanocomposite also exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli. This multifunctional material offers a promising solution for wastewater treatment, targeting both organic pollutants and pathogenic bacteria to help address water pollution challenges.
SKRINING POTENSI EKSTRAK KULIT JANTUNG PISANG KEPOK (Musa paradisiaca Linn.) SEBAGAI ZAT ANTIBAKTERI Rahmah, Vindi Annisa; Kurniawan, Agung; Rizki, Widya Twiny; Lestari, Siti Marwah; Khutami, Chindiana
Jurnal Crystal : Publikasi Penelitian Kimia dan Terapannya Vol. 7 No. 2 (2025): Literasi Artikel Penelitian Kimia
Publisher : Program Studi Kimia, Fakultas MIPA, Universitas PGRI Banyuwangi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36526/jc.v7i2.6086

Abstract

Abstract Indonesian Food and Drug Authority or BPOM no longer recommends the use of synthetic preservatives due to their toxic properties and potential carcinogenic risks. One of the natural ingredients that is potential as a natural preservative is the peel of kepok banana blossom (Musa paradisiaca Linn.), which is known to contain secondary metabolites with microbial activity, including steroids, terpenoids, saponins, tanning, alkaloid, flavonoids, and phenols. This study aim to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) in Staphylococcus aureus bacteria. The peel extract of kepok banana blossom (Musa paradisiaca Linn.) was obtained by maceration with a mixture of 96% ethanol: 3% Citric Acid (85:15) solvent. Concentration of extract varied from 12.5%; 25%; 50%; until 100%, it is used for antibacterial activity test in which aquadest as a negative control and Chloramphenicol as a positive control. The Minimum Inhibitory Concentration (MIC) test was conducted using the liquid macrodilution method and the Minimum Bactericidal Concentration (MBC) test was conducted using the spread method. The Minimum Inhibitory Concentration (MIC) value was obtained at a concentration of 50% and the Minimum Bactericidal Concentration (MBC) value was obtained at a concentration of 100%. The peel extract of Kepok banana blossom (Musa paradisiaca Linn.) with a concentration of 50% was able to inhibit the growth of Staphylococcus aureus bacteria and with a concentration of 100% was able to kill Staphylococcus aureus bacteria. Keywords: kepok banana blossom peel extract, natural preservatives, antibacterial acitivity test Abstrak Badan Obat dan Makanan atau BPOM telah menyarankan untuk menghindari penggunaan bahan pengawet sintesis karena cenderung toksi dan karsinogenik. Salah satu bahan alam yang berpotensi sebagai pengawet alami yaitu kulit jantung pisang kepok (Musa paradisiaca Linn.), yang diketahui mengandung metabolit sekunder yang berfungsi sebagai senyawa antimikroba diantaranya steroid, terpenoid, saponin, tanin, alkaloid, flavonoid dan fenol. Penelitian ini bertujuan untuk menentukan Konsentrasi Hambat Minimum (KHM) dan Konsentrasi Bunuh Minimum (KBM) pada bakteri Staphylococcus aureus. Ekstrak kulit jantung pisang (Musa paradisiaca Linn.) diperoleh dengan cara maserasi dengan pelarut yang terdiri dari campuran etanol 96% : Asam Sitrat 3% (85:15). Variasi konsentrasi ekstrak dibuat untuk pengujian aktivitas antibakteri dari 12,5%; 25%; 50%; hingga 100%, aquades sebagai kontrol negatif dan Kloramfenikol sebagai kontrol positif. Uji Konsentrasi Hambat Minimum (KHM) dilakukan dengan metode makrodilusi cair dan uji Konsentrasi Bunuh Minimum (KBM) dilakukan dengan metode sebar (spread). Nilai Konsentrasi Hambat Minimum (KHM) didapatkan pada konsentrasi 50% dan nilai Konsentrasi Bunuh Minimum (KBM) didapatkan pada konsentrasi 100%. Berdasarkan hasil penelitian ini, ekstrak kulit jantung pisang (Musa paradisiaca Linn.) dengan konsentrasi 50% diketahui mampu menghambat pertumbuhan bakteri Staphylococcus aureus dan dengan konsentrasi 100% mampu membunuh bakteri Staphylococcus aureus. Keywords: ekstrak kulit jantung pisang, pengawet alami, uji aktivitas antibakteri
Co-Authors Addy Rachmat Addy Rachmat Agung Kurniawan Desnelli Desnelli Fahma Riyanti Handayani Citra Pratiwi Khutami, Chindiana MUHAMMAD SAID Muhammad Said Muhammad Said Nur Hanis Hayati Hairom Poedji Loekitowati Hariani Rahmadevi Rahmah, Vindi Annisa Rd. Rahmat Dauli Sari, Ririn Depita Siti Marwah Lestari Vilantina, Vilantina Wahyuni, Winika Sri Widia Purwaningrum