Experimental Investigation of Fluid Flow through Zinc Open-Cell Foams Produced by the Excess Salt Replication Process and Suitable as a Catalyst in Wastewater Treatment

International audienceThe "excess salt replication process" is a new simple method of fabrication of open-cell metal foam based on the commonly known salt replication method. Porous materials with porosity between 46% and 66% result when the employed alloy is 25% antimonial lead alloy and when it is 58% to 65% zamak 5. These foams are proposed as structured catalysts instead of packed beds in the treatment of wastewater. The local regimes influencing macroscopic air flow behaviour through these foams are delimited and boundaries are analysed in terms of sample length. Most of the experimental tests in this work exhibited a general trend of air flow in ESR foams dominated by the "strong inertia regime". It was established that the law governing the unidirectional air flow through these foams was the full cubic law. The permeability and inertia coefficient of five samples with a cell diameter between 2.5 and 4.5 mm were calculated, and an empirical correlation was fitted. The irregular cuboid shape of salt grains used in the ESR foam was the origin of the special cell form of ESR foams leading to an anisotropic ordered porous media. This can explain the macroscopic turbulence of air flow because there were many dead zones present in the corner of each cubic cell, thus causing kinetic energy loss starting at earlier regimes

Comparative Investigation of the Effect of EggshellPowder and Calcium Carbonate as Additivesin Eco-Friendly Polymer Drilling Fluids

Drilling fluid systems have seen the addition of new natural additives in recent years in order to replace traditional additives, improve their rheological properties, and ensure the functionality of the drilling fluid taking into account health and environmental factors. This paper aims to study and compare the effect of the addition of eggshell powder (ESP) as a native and local additive and calcium carbonate (CC) as a traditional and conventional additive on the rheological and filtration properties of the drilling fluid system based on Na-bentonite of the region of Meghnia (Algeria). The test results of 10, 20, and 30 g of CCwerecompared to the same concentrations of ESP.The findings showed that the CC with various concentrations (10, 20, and 30 g) increases the rheological properties and the mud density while it reduces the filter cake and the fluid loss values which are desirable, calcium carbonate had aslightly higher effect on the pH. The obtained results following the addition of ESP with different ratios revealed that the latter has a considerable impact on the plastic viscosity, the yield point, the gel strength, and the cake thickness. Additionally, the effect of the presence of eggshell as an additive in pH, fluid loss, and mud density was studied; we observed a slight increase in the pH, while the fluid loss values decreased. However, the mud density values increased. Beyond 20 g of eggshell, the properties of the mud becomeundesirable. Moreover, this study contributes tonewfindings and suggests that the utilization of waste food and local goods in drilling mud mixtures has a bright future respecting the percentages of use

Development of New Alkylated Carrageenan Derivatives: Physicochemical, Rheological, and Emulsification Properties Assessment

In this research, amphiphilic derivatives of kappa carrageenan (KC) were synthesized by hydrophobic modification with an alkyl halide (1-Octyl chloride). Three hydrophobic polymers with different degrees of substitution (DS) were obtained by the Williamson etherification reaction in an alkaline medium. The effect of the molar ratio (R = reagent/polymer) on the DS was investigated at different ratios (1, 2, and 3). The KC derivatives (KCRs) were characterized by different techniques such as FT-IR, 1H-NMR, X-ray Diffraction, Scanning electron microscopy, and a rheological assessment. The FT-IR and 1HNMR analyses confirmed the binding of the hydrophobic groups onto the KC molecule. The degrees of substitution calculated by 1H-NMR demonstrated that the derivative KCR3 (0.68) presented a higher degree of substitution compared to KCR1(0.45) and KCR2 (0.53). The XRD and SEM analyses revealed that the alkaline etherification conditions did not alter the morphological and crystallographic properties, as well as the rheological behavior of the obtained derivatives. The amphiphilic character of the KCRs was investigated using a conductivity method which revealed that the molecular aggregation occurred above the critical aggregation concentration (CAC). Decreasing CAC values of 0.15% (KCR1), 0.11% (KCR2) and 0.08% (KCR3)with the degree of substitution (DS) were found. Furthermore, KCR’s derivatives greatly improved the stability of oil/water emulsions as the droplet size decreased with increasing DS. The derivative (KCR3) with higher DS, showed a greater amphiphilic character, and improved emulsifying power

Optimization of Partially Hydrolyzed Polyacrylamide (HPAM) Utilized in Water-Based Mud While Drilling

International audienceWater-soluble polymers are becoming increasingly important in various applications, such as stabilizer fluids and drilling muds. These materials are used as viscosifiers and filtration control agents, flocculants, and deflocculants due to their superior properties in increasing viscosity and gelling ability in the presence of crosslinkers. In general, studying the rheological behavior of drilling fluids is of paramount importance to ensure successful well drilling operations. Partially hydrolyzed polyacrylamide is one of the polymers widely used in water-based muds. The main objective of this study is to optimize the rheological properties of drilling muds through a characterization study of various parameters, including rheological behavior, viscosity, temperature (23 degrees C, 40 degrees C, and 60 degrees C), salinity using KCl and NaCl contents, aging, pH, solubility, and structural analysis using infrared of partially hydrolyzed polyacrylamide. The study aims to demonstrate the importance of using polymers in drilling muds. The findings revealed that a rate of 3% of HPAM gave better rheological behavior, the influence of KCl (1.5%, 3%, and 4.5%) was greater than that of NaCl (1.5%, 3%, and 4.5%) on polymers, and the aging test showed that the different formulations are stable and maintain their behavior up to 110 degrees C. The solubility test results confirmed the maximum amount absorbed by polyacrylamide ([C-HPAM] = 66.42 g/L) in order to avoid aggregation, gelification, and enhance the drilling mud by utilizing the prescribed contents

Formulation and Characterization of Double Emulsions W/O/W Stabilized by Two Natural Polymers with Two Manufacturing Processes (Comparative Study)

International audienceFour distinct types of multiple emulsions were synthesized using xanthan gum and pectin through two distinct manufacturing processes. The assessment encompassed the examination of morphology, stability, and rheological properties for the resulting water-in-oil-in-water (W/O/W) double emulsions. Formulations were meticulously crafted with emulsifiers that were compatible with varying compositions. Remarkably stable multiple emulsions were achieved with a 0.5 wt% xanthan concentration, demonstrating resilience for nearly two months across diverse storage temperatures. In contrast, multiple emulsions formulated with a higher pectin concentration (2.75 wt%) exhibited instability within a mere three days. All multiple emulsions displayed shear-thinning behavior, characterized by a decline in apparent viscosity with escalating shear rates. Comparatively, multiple emulsions incorporating xanthan gum showcased elevated viscosity at low shear rates in contrast to those formulated with pectin. These results underscore the pivotal role of the stepwise process over the direct approach and emphasize the direct correlation between biopolymer concentration and emulsion stability. This present investigation demonstrated the potential use of pectin and xanthan gum as stabilizers of multiple emulsions with potential application in the pharmaceutical industry for the formulation of topical dosage forms

Evaluating the Effectiveness of Coagulation–Flocculation Treatment Using Aluminum Sulfate on a Polluted Surface Water Source: A Year-Long Study

International audienceSafeguarding drinking water is a major public health and environmental concern because it is essential to human life but may contain pollutants that can cause illness or harm the environment. Therefore, continuous research is necessary to improve water treatment methods and guarantee its quality. As part of this study, the effectiveness of coagulation–flocculation treatment using aluminum sulfate (Al2(SO4)3) was evaluated on a very polluted site. Samplings were taken almost every day for a month from the polluted site, and the samples were characterized by several physicochemical properties, such as hydrogen potential (pH), electrical conductivity, turbidity, organic matter, ammonium (NH+4), phosphate (PO43−), nitrate (NO3−), nitrite (NO2−), calcium (Ca2+), magnesium (Mg2+), total hardness (TH), chloride (Cl−), bicarbonate (HCO3−), sulfate (SO42−), iron (Fe3+), manganese (Mn2+), aluminum (Al3+), potassium (K+), sodium (Na+), complete alkalimetric titration (TAC), and dry residue (DR). Then, these samples were treated with Al2(SO4)3 using the jar test method, which is a common method to determine the optimal amount of coagulant to add to the water based on its physicochemical characteristics. A mathematical model had been previously created using the support vector machine method to predict the dose of coagulant according to the parameters of temperature, pH, TAC, conductivity, and turbidity. This Al2(SO4)3 treatment step was repeated at the end of each month for a year, and a second characterization of the physicochemical parameters was carried out in order to compare them with those of the raw water. The results showed a very effective elimination of the various pollutions, with a very high rate, thus demonstrating the effectiveness of the Al2(SO4)3. The physicochemical parameters measured after the treatment showed a significant reduction in the majority of the physicochemical parameters. These results demonstrated that the coagulation–flocculation treatment with Al2(SO4)3 was very effective in eliminating the various pollutions present in the raw water. They also stress the importance of continued research in the field of water treatment to improve the quality of drinking water and protect public health and the environment

Advancing Water Quality Research: K-Nearest Neighbor Coupled with the Improved Grey Wolf Optimizer Algorithm Model Unveils New Possibilities for Dry Residue Prediction

International audienceMonitoring stations have been established to combat water pollution, improve the ecosystem, promote human health, and facilitate drinking water production. However, continuous and extensive monitoring of water is costly and time-consuming, resulting in limited datasets and hindering water management research. This study focuses on developing an optimized K-nearest neighbor (KNN) model using the improved grey wolf optimization (I-GWO) algorithm to predict dry residue quantities. The model incorporates 20 physical and chemical parameters derived from a dataset of 400 samples. Cross-validation is employed to assess model performance, optimize parameters, and mitigate the risk of overfitting. Four folds are created, and each fold is optimized using 11 distance metrics and their corresponding weighting functions to determine the best model configuration. Among the evaluated models, the Jaccard distance metric with inverse squared weighting function consistently demonstrates the best performance in terms of statistical errors and coefficients for each fold. By averaging predictions from the models in the four folds, an estimation of the overall model performance is obtained. The resulting model exhibits high efficiency, with remarkably low errors reflected in the values of R, R2, R2ADJ, RMSE, and EPM, which are reported as 0.9979, 0.9958, 0.9956, 41.2639, and 3.1061, respectively. This study reveals a compelling non-linear correlation between physico-chemical water attributes and the content of dry tailings, indicating the ability to accurately predict dry tailing quantities. By employing the proposed methodology to enhance water quality models, it becomes possible to overcome limitations in water quality management and significantly improve the precision of predictions regarding critical water parameters. © 2023 by the authors