Advanced Journal of Chemistry, Section A
Volume:6 Issue: 3, Summer 2023

Preparing the sample is a vital procedure involving liquid and solid handling approaches toward extracting, enriching, and identifying target analytes from complex environmental matrices. Thus, there is a need for more effective quantitative investigation and green evaluation procedures better than the conventional techniques for the accurate assessment, optimum selection, and testing of analytical techniques. To achieve greenness in analytical methodology, performance criteria such as design procedures, quantities of safe solvent (ionic liquids (IL), deep eutectic solvents (DES)) /toxic reagents consumed, utilization of renewable, reusable and recyclable materials/ biomolecules were evaluated. In this review, economical and eco-friendly approaches are proposed towards an agreement with the novel principles of Green Analytical Chemistry (GAC) using the combination of figures, colorations, unified 0–1 scale, and graphical illustrations: these include National Environmental Methods Index (NEMI), Analytical Greenness Calculator (AGREE), Analytical Eco-Scale (AES), Green Analytical Procedure Index (GAPI) and Pictograms like Hexagon (H) amongst others. These metric tools were proposed and generally adopted to directly assess a systematic and comprehensive improvement of green sample pretreatment, preparation for different extraction, and recovery methods from various modes. These tools are also aimed at evaluating the sustainability of the methods through figures of merits, carbon footprint, and other GAC tools by assigning penalty points (0 to 4) for each block and hexagonal pictograms that provide an easy comparison between analytical procedures

The Alchornea laxiflora leaves were introduced as a sustainable corrosion inhibitor with excellent inhibition action on mild steel in 1.0M acidic medium solution. Alchornea laxiflora leaves are found throughout Africa, including three active compounds: quercetin, Quercetin-3-rhamnoside, and Quercetin-7-rhamnoside. The LC-MS and NMR are utilized using the gravimetric method to track the active components in the Alchornea laxiflora leaves extract. Potentiodynamic polarization, electrochemical current noise measurements, and scanning electron microscope (SEM) were conducted to investigate the corrosion inhibition role of various concentrations of Alchornea laxiflora extract toward mild steel corrosion in 1.0M acidic medium solution. Surface analysis, molecular dynamics, and quantum mechanics simulation methods were combined to get insights into inhibitor molecules’ adsorption on the mild steel surface. The results showed that the inhibitory capacity of the leaf extract increased with an increase in the concentration of the extract, whereas the corrosion rate of the steel material after immersion in the acidic solution decreased with increasing extract concentration. The structures were determined using nuclear magnetic resonance in 1D and 2D, and the molecular weight was determined using mass spectrometry. The electrochemical investigations revealed that the maximum inhibition efficiency of 98.8% was obtained in the present extract. The formation of protecting layer on the mild steel surface was proved by scanning electron microscope and atomic force microscope results. The results derived from Monte Carlo simulation MC and QM calculations revealed the adsorption of Alchornea laxiflora components on the steel substrate via donor-acceptor interactions.

Photocatalytic degradation of organic chemicals such as dyes over semiconductor nanostructures is one of the most effective processes for eliminating them from wastewater. In this study, X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence were used to examine the physicochemical properties of nitrogen-doped TiO2(N/TiO2) photocatalysts. According to the XRD results, the nanoparticles have similar crystal structures as pristine TiO2. The photocatalytic properties of N/TiO2 nanocatalysts at various catalyst concentrations were used to investigate the dye Blue 5's visible light degradation. DRS results show that the absorption band of the doped photocatalyst is shifted toward the visible region, and its bandgap is smaller than that of undoped TiO2. According to DFT calculations, N-doping causes TiO2's band gap value to decrease because the band gap's center is closer to the valence band. For pure and N/TiO2 nanostructures, there is a good agreement between DFT and experimental values of the pristine and N-doped TiO2 band gap.

The extraction process of bioactive components from nutraceutical, food, cosmetic industries, and pharmaceutical is a crucial task in the manufacturing process of natural products that demand green solvents. This all-important process needs the inclusion and utilization of natural deep eutectic solvents (NADES) to yield green products safe for the consumption of human beings and eco-friendly. This value-added green solvent has caught the attention of many researchers worldwide, cutting across different fields owing to its unique properties and vast potential. Also, the ability of the novel NADES to replace ionic liquids and conventional organic solvents in the extraction, and most especially in that of bioactive media, makes it an outstanding feat because it complies with the protocol for green analytical chemistry. In addition, the hydrophobic DESs (HDES) are also considered a suitable category of DES that needs to be explored in the field of extractions because of their stability in contact with water, a problem with using other classes of DESs. The HDESs possess exceptional tunable properties suitable for the optimum extraction and isolation of bioactive compounds, volatile fatty acids, and heavy metals from an aqueous medium. This paper explores and extensively discusses in review the prowess, and properties originating from the characteristics and functionalities of NADES and HDES, harnessing the solubility, other physicochemical characteristics, and possible interactions depending on the prevailing environmental conditions towards the extraction of these compounds.

As a heterogeneous catalyst, Pyrite increases chalcopyrite oxidation by creating more cathodic points and enhancing electron transfer to ferric (Fe3+) ions. In this study, the interaction of ferric ions with 100, 110 pyrite surfaces and 001-S, M (M= Cu and Fe) chalcopyrite surfaces was investigated using the Density functional theory (DFT) method and Material Studio software. The results showed that Fe3+ ion reacted well with the desired surfaces, and free energies were negative in the 25-275 °C temperature range, and interaction enthalpy increased linearly with increasing temperature. However, the two surfaces of 110 pyrite and 001-S chalcopyrite were more active than other surfaces, and a stronger reaction occurred between the ferric ion and that surfaces. Also, due to the strong metal-sulfur bond, the free energy of ferric ion interaction with the 001-M surface of chalcopyrite increased by increasing temperature. However, on the other surfaces, free energy was reduced in the presence of sulfur atoms.

The Alchornea laxiflora leaves were introduced as a sustainable corrosion inhibitor with excellent inhibition action on mild steel in 1.0M acidic medium solution. Alchornea laxiflora leaves are found throughout Africa, including three active compounds: quercetin, Quercetin-3-rhamnoside, and Quercetin-7-rhamnoside. The LC-MS and NMR are utilized using the gravimetric method to track the active components in the Alchornea laxiflora leaves extract. Potentiodynamic polarization, electrochemical current noise measurements, and scanning electron microscope (SEM) were conducted to investigate the corrosion inhibition role of various concentrations of Alchornea laxiflora extract toward mild steel corrosion in 1.0M acidic medium solution. Surface analysis, molecular dynamics, and quantum mechanics simulation methods were combined to get insights into inhibitor molecules’ adsorption on the mild steel surface. The results showed that the inhibitory capacity of the leaf extract increased with an increase in the concentration of the extract, whereas the corrosion rate of the steel material after immersion in the acidic solution decreased with increasing extract concentration. The structures were determined using nuclear magnetic resonance in 1D and 2D, and the molecular weight was determined using mass spectrometry. The electrochemical investigations revealed that the maximum inhibition efficiency of 98.8% was obtained in the present extract. The formation of protecting layer on the mild steel surface was proved by scanning electron microscope and atomic force microscope results. The results derived from Monte Carlo simulation MC and QM calculations revealed the adsorption of Alchornea laxiflora components on the steel substrate via donor-acceptor interactions.

Density (ρ), viscosity (η), and refractive index (nD) for ternary systems include dimethylacetamide, dimethylbenzylamine, and dichloromethane, as well as the related binaries such as dimethylacetamide + dimethylbenzylamine, dimethylacetamide + dichloromethane, and dimethylbenzylamine + dichloromethane, were obtained at ambient pressure. Excess volumes, VmE, viscosity deviations Δη, and refractive index deviations DnD of the mixtures were obtained using the Redlich-Kister and the Cibulka relations for binary and ternary systems, respectively. Adopted values for coefficient and standard deviations were reported. The experimental data for ternary system were also fitted to Tsao-Smith, Radjkovic, and Kohler models. The intermolecular interactions were analyzed based on the experimental findings.