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Journal : Science and Technology Indonesia

Molecular Spectroscopic (FTIR and UV-Vis) Analysis and In Vitro Antibacterial Investigation of a Deep Eutectic Solvent of N,N-Dimethyl Urea-Citric Acid Yudha S., Salprima; Angasa, Eka; Reagen, Muhamad Alvin; Kazi, Mohsin
Science and Technology Indonesia Vol. 9 No. 1 (2024): January
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.1.167-172

Abstract

The intriguing pursuit of environmentally friendly solvents with tailored properties for diverse applications is a focal point of numerous studies, encompassing precursor selection, thorough characterization, and the exploration of potential applications. The study aims to assess the physicochemical properties and antimicrobial activity of deep eutectic solvents (DES) produced from N,N-dimethyl urea (DMU) and citric acid (CA), highlighting differences from their individual precursors. Various mass ratio variations of (DMU, solid) and (CA, solid) (DMU:CA = 1.0:1.0; 1.0:1.5; 1.0:2.0; 2.0: 1.0; 1.5:1.0) have been tested to make DES solvents through the melt process. Both types of blends generally melt at a temperature of 80°C. The overall liquid resulting from the melting of solids was generally clear in color. Molecular analysis using an infrared spectrophotometer showed some insignificant shifts from one product to another, compared with DMU and CA as precursors. Likewise, analysis using a UV–Vis spectrophotometer, when the entire sample was dissolved in demineralized water (2 mg/mL), showed no difference in the spectrum. In addition, functional group analysis using a spectrophotometer showed some minor changes, mainly shifts in peaks due to changes in the DMU:CA ratio. This may be due to the interaction of the hydrogen donor and the hydrogen acceptor in DES. All samples showed absorption peaks in the ultraviolet region of 202-210 nm. The resulting DES application showed growth inhibitory activity for Staphylococcus aureus and Escherichia coli bacteria in all products produced. The same analysis of the two types of precursors used showed that only CA had activity, but DMU did not have similar activity.
Oil Palm Leaves as an In-situ Bio-silica Source in Sustainable Synthesis of V2O5-SiO2 Yudha S., Salprima; Adfa, Morina; Wibowo, Risky Hadi; Reagen, Muhamad Alvin
Science and Technology Indonesia Vol. 10 No. 4 (2025): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2025.10.4.1148-1155

Abstract

Using ammonium vanadate and natural silica from oil palm leaves in situ at 900oC is a sustainable synthesis method for producing V2O5-SiO2 mixed oxides in the form of a brownish powder. Therefore, this study aims to investigate a more environmentally friendly alternative to synthesizing V2O5-SiO2 using oil palm leaves, a by-product from oil palm farming. The XRD analysis of the reaction products showed specific V2O5 peaks and broadened peaks, indicating the presence of amorphous silica. The Fourier transform infrared (FTIR) analysis, which revealed the presence of Si-O-Si and Si-O-V functional groups, also supported the characteristic assessment. In addition, X-ray fluorescence (XRF) analysis showed that V2O5 (46.70 mass%) and SiO2 (52.60 mass%) were present, along with small amounts of other possible metal oxides, such as P2O5, K2O, CaO, Fe2O3, Al2O3, and PdO.