Indochina Applied Science

Unpolarized Raman Spectra Shift in Solidified Oil-Water-Saltwater

Saddam Dhobi — 2025-05-01

The study of unpolarized Raman spectral shifts in solidified oil-water-saltwater systems is crucial for understanding complex multiphase interactions under varying environmental conditions. Such systems are commonly found in natural and industrial processes, including oil spill remediation, geological formations, and desalination technologies. The need for detailed insights into molecular behavior and structural changes during solidification arises from the necessity to optimize these processes and mitigate environmental impacts. By analyzing Raman spectral shifts, this research provides essential information on the reorganization of molecular bonds and the influence of saltwater on oil-water interfaces, contributing significantly to environmental science, materials engineering, and energy resource management. The objective of this study is to analyze the transmittance, absorbance, and Raman shift spectra of water, soybean oil, and saltwater using an unpolarized visible spectrum at a low temperature of –10 °C. Experimental observations indicate that transmittance decreases with increasing wavelength, while absorbance increases. The transmittance and absorbance behaviors exhibit a nonlinear (bumping) pattern due to molecular rotational and vibrational effects. Additionally, intensity ratio analysis before and after the increase reveals two Gaussian peaks: one between 2 × 103 cm⁻¹ and 4 × 103 cm⁻¹ and another between 5 × 103 cm⁻¹ and 8 × 103 cm⁻¹ for water, soybean oil, and saltwater. The intensity ratio for water and the water-soybean oil-saltwater sample is higher when observed with Raman spectral shifts. This is due to the high polarizability of the molecules caused by molecular vibrations and dipole moments. At the considered temperature, in terms of transmittance, soybean oil exhibits the highest transmittance at higher wavelengths, making it the most efficient for light transmission. In contrast, saltwater has the highest absorbance at high wavelengths, meaning it absorbs more light compared to water and soybean oil.

Removal of Iron and Copper Ions from Water Using Cashew Nut Shell Adsorbent: Langmuir, Freundlich, Redlich-Peterson and Harkin-Jura Isotherms

Haruna Mavakumba Kefas — 2025-05-01

Elevated copper (Cu) and iron (Fe) levels can pose a threat to biodiversity. Removal of those metallic impurities was achieved in this study using cashew nut shell (CNS) adsorbent. Greater sorption of 87.40% Cu and 99.50% Fe occurred at 10 min contact time and 0.40 g CNS dosage. This study also targets the determination of the adsorption mechanism of the process, where it was discovered that it satisfied a favorable monolayer adsorption on homogeneous active sites at 1.1106 mg g –1 Cu and 1.0995 mg g –1 Fe uptakes (q_e), described by the Langmuir isotherm with R2 value > 0.9990. The run essentially carried out using Lake Gerio water sample in Nigeria also satisfy the Redlich-Peterson model whose constant exponent, β = 0.9773 for Cu and 0.9985 for Fe ≅ 1, implied similar behavior with Langmuir isotherm assumption at specific temperature of 30°C. Effect of varying contact time and CNS dosage was also tested on % equilibrium sorption and q_e. Both Harkin-Jura and Freundlich equations poorly fit the empirical result with no match to adsorption evidence depicted after Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Atomic Absorption Spectroscopy (AAS) analysis carried out. Removal of heavy metals such as Cu and Fe from lakes and rivers will contribute to benthic organisms and sediment quality, food chain integrity, fish and seafood safety, recreational use, human and environmental health. Thus, the potentials demonstrated by CNS in the removal of Cu and Fe in this study as well as other heavy metals already investigated, will ensure long-term ecosystem resilience.

The Effect of Silver Doping Concentrations in TiO2 Nanoparticles: Characteristic, Morphological, Chemical, and Simple Regression Analyses

Phatcharee Phoempoon — 2025-05-01

This research synthesizes silver-doped TiO2 nanoparticles (TiO2-Ag) using sol-gel and co-precipitation techniques, calcined at 500 °C for 1 h. Silver doping concentrations of 0, 1, 2, 4, 8, and 16 mol% in Titanium dioxide (TiO2) were examined for their impact on particle size, shape, and phase. Characterization via EDX, XRD, TEM, and XPS. TEM micrographs show small, rounded particles (10 – 20 nm) forming clumps. Analyses revealed that increased silver content augments the rutile phase. Simple Regression Analysis was utilized to estimate phase quantity of the anatase and rutile phase of TiO2-Ag.