South African Journal of Chemical Engineering最新文献

Areas with a dry climate constitute about 15% of the Earth's surface, so groundwater can be considered a safe alternative available for people who are living in these areas. Groundwater has special advantages compared to surface water in terms of spatiotemporal presence, high stability, easy access, and often of high quality and capable of resisting pollution and could be the alternative to solve the problem of water shortage.

The current study evaluated Irrigation Water Quality Indices (WQIs) as well as the predicting of GIS maps to evaluate groundwater resources for agricultural uses in Al-Najaf city. 24 samples were taken from the existing wells and examined for the characteristics relating the groundwater quality. Total hardness (TH), Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Soluble Sodium Percentage (SSP), Magnesium Hazard (MH), Permeability Index (PI), and Kelley's Index (KI) were among the irrigation indices that were assessed and evaluated. The results showed that 95.8% of sites fall within the region of extremely high salinity danger /low sodium, and 4.2% of sites fall onto the medium sodium water class, Concerning SSP and RSC all samples are considered of good quality, 95.8% of samples are suitable for irrigation based on Kelly's Ratio index, while only 4.2% regarded unsuitable. The final WQIs values were exported to the ArcMap software to create the final study area's water quality indices maps. Conducting spatial variability of groundwater quality is essential for making reliable groundwater quality interpretations and for making accurate predictions of quality at any particular site, there must be a continuous salinity and contaminants concentrations checking up calculations in case there were a need for groundwater desalination process.

The synthesis of mesoporous Fe₂O₃/TiO₂ heterostructures using a P123-Gelatin hybrid template has been investigated for enhanced photocatalytic degradation of methylene blue under visible light. The study focused on the effect of gelatin concentration on mesoporosity, iron content, particle size, and surface area of Fe₂O₃/TiO₂. The results showed that the Fe₂O₃/TiO₂ composites exhibited superior photocatalytic activity compared to individual TiO₂ and Fe₂O₃. This enhancement was attributed to the optimized gelatin concentration, which increases mesoporosity and Fe₂O₃ incorporation, facilitating efficient electron transfer and photo-electron conversion for methylene blue oxidation. Additionally, a fuzzy logic analysis was conducted to correlate the physicochemical properties of the composites with their photocatalytic activities. This analysis identified iron loading and mesoporosity as theion dominant factors affecting photocatalytic efficiency, with a high correlation coefficient. The study concluded that mesoporous Fe₂O₃/TiO₂ synthesized with the P123-Gelatin template significantly improves methylene blue degradation. This improvement is primarily due to the synergistic effect of large pore diameter and Fe³⁺/Ti⁴⁺ interaction. The fuzzy logic model provided accurate predictions, confirming the critical role of iron loading and mesoporosity in enhancing photocatalytic performance.

Oral drug administration remains one of the most convenient routes due to its Simplicity, high patient compliance, and cost-effectiveness. However, many medicinal products available on the market exhibit poor water solubility, which adversely affects the dissolution rate of drugs in biological fluids. Drug loading is a promising strategy to produce highly stable amorphous drugs with improved dissolution rates, solubility, and bioavailability. Mesoporous silica nanoparticles (MSNs) are particularly advantageous due to their tunable surface area, pore size, and pore volume, making them suitable to load various molecules such as drugs, genes, and proteins. The use of mathematical models is crucial for predicting and analyzing the release profile of active molecules and diffusion patterns within delivery systems. This enables the design and development of new systems with more desirable release patterns. This review provides an overview of MSNs and drug loading methods, discusses the mechanisms of drug release and release kinetic models using mesoporous carriers, and highlights critical considerations in designing MSNs, such as particle stability and cytotoxicity.

In this research work, we have incorporated paramagnetic Cu²⁺ and diamagnetic Cd²⁺ cations in spinel ferrites. By adjusting the concentrations of Cu²⁺ and Cd²⁺, it is possible to achieve a balance between enhanced electrical conductivity, desired magnetic properties, and suitable structural characteristics for applications in high-frequency devices, magnetic sensors, and electromagnetic interference (EMI) suppression through a synergistic effect. The sol-gel auto-combustion method was employed to synthesize Cd²⁺ and Cu²⁺ co-doped Ni_0.5Zn_0.5-x-yCu_xCd_yFe₂O₄ (x = y = 0.0, 0.05, 0.1, 0.15, 0.2) ferrite nanoparticles. Structural, morphological-compositional, functional, and magnetic properties of the nanoparticles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive spectroscopy (FESEM-EDS), Fourier-transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM). The XRD results confirmed the single-phase spinel structures with lattice constants increasing with higher dopant concentrations. The average crystallite sizes were found in the range of 38.14 - 42.68 nm and lattice constants in the range of 8.389 - 8.423 Å. Morphological analysis revealed agglomeration, consistent with the stoichiometric proportions during synthesis. There is a decreasing trend in nanograin sizes in the range of 40 to 73 nm with the concentration. FT-IR spectra verified the spinel structures through characteristic absorption bands around 600 cm⁻¹ and 400 cm⁻¹. Magnetic measurements indicated a decrease in saturation magnetization with increasing dopant levels indicating their potential use in electromagnetic wave absorption and magnetic memory devices.

The groundwater usage for household, industrial and agricultural needs is largely depends upon the nature and composition of various dissolved components present in the water. A comparison of groundwater quality of Chennai district in 2019 and 2020 for its potability and its hydrogeochemical characteristics were studied using the physicochemical data of representative samples from 36 observation wells obtained during pre monsoon and post monsoon seasons. The chosen wells are spatially distributed in the study region. The present work was carried out using the water quality data consisting of various physicochemical parameters and major ions concentration pertaining to groundwater analysis of the study location obtained from State Groundwater and Surface Water Resources Data Centre (SGSRDC), Taramani, Chennai, India. Water quality parameters such as pH, total dissolved solids(TDS), total hardness(TH), total alkalinity(TA), Ca²⁺, Mg²⁺, Cl^‒, SO₄^2‒, and NO₃^‒,were used to calculate the water quality index (WQI) by weighted arithmetic method. The groundwater quality is ascertained from the calculated WQI values with reference to Bureau of Indian Standards (BIS). The results of WQI calculation reveals that in the pre monsoon period of both 2019 and 2020, around 30 % samples fall under good category and 55 % samples fall under poor quality. In the post monsoon period of 2019, 70 % samples are of good quality, whereas for 2020, 61 % samples are of poor quality. Correlation analysis of water quality parameters and bivariant plots of major ions were plotted to decipher the hydrogeochemical characteristics of groundwater. TDS, TH and electrical conductivity (EC) exhibits a strong positive correlations with Ca²⁺, Mg²⁺, Na⁺, Cl^- and SO₄^2- ions. The Piper diagrams of the ground water samples of the study area reveal its hydrochemical facies as Na-Cl type. The Gibbs diagram of the groundwater samples shows that water-rock interactions and evaporation are the predominant factors in controlling the ground water chemistry.

Biogas is renewable energy produced through anaerobic digestion based on palm oil mill effluent. Biogas production is overgrowing and is carried out in various bioreactors, such as the Upflow Anaerobic Sludge Blanket - Hollow Centered Packed Bed fermentor. Even though this process is considered successful in producing biogas, it has not adopted a recycling system. Therefore, the remaining sludge (effluent) after the processing process is generally not reused and is thrown into the environment, which still has the opportunity to produce biogas. The combination of the performance of the the Upflow Anaerobic Sludge Blanket - Hollow Centered Packed Bed fermentor with an ultrafiltration membrane is one of the latest innovations to reduce the volume of effluent wasted through recycling the effluent (retentate) into the feed tank. This research aims to produce biogas from liquid waste from palm oil mills using an Up-flow Anaerobic Sludge Blanket-Hollow Centered Packed Bed fermentor combined with ultrafiltration membranes under mesophilic conditions. In this research examines the effect of hydraulic retention time and the effluent recycling ratio on the pH profile, alkalinity, production, biogas composition, and kinetics of biogas production. The research began with loading up by varying the hydraulic retention time, namely 40, 25, and 10, until reaching the target hydraulic retention time of 6 days in a 5.4 L fermentor with a pH of 7 ± 0.2 under mesophilic conditions. Next, the effect of the recycling ratio was studied by varying the effluent (retentate) recycling ratio, namely 0, 15, and 25 %. The parameters analyzed are pH, M-Alkalinity, total solids, volatile solids, total suspended solids, volatile suspended solids, chemical oxygen demand, volume, and biogas composition. The organic content in the substrate is used as a kinetic parameter for biogas production using the modified Gompertz, Logistic, and Monod kinetic equation. The research results show that in mesophilic conditions, a recycling ratio of 25 % shows better results compared to ratios of 0 and 15 % where biogas production is 20×10^-5 L/mgVS.day, with a best composition of methane, carbon dioxide and hydrogen sulfide each of 88.2; 10.8; and 0.07 % (v/v), with ΔVS decomposition at 15 % and 25 % recycle ratio of 42.50 and 45.83 % (w/v). The equation for the biogas production rate constant as a function of temperature obtained is the biogas production rate constant: $M=\frac{299.8}{1+\text{exp}\left(\frac{14.28}{299.8}\left(0.39-t\right)+2\right)}$ for logistic model, $M=$