Search Results (16)

The present study attempted to investigate the best conditions to use 2-(4-chlorophenyle)-1,4,5-triphenyle-H-imidazole as a corrosion inhibitor of mild steel in a 7% HCl and 20% H₂SO₄ pickling bath mixture, using chemical, electrochemical, and surface response methodologies in a spherical field. For this, a Doehlert matrix and two principal factors of the Pickling Process were examined. An experimental evaluation was carried out using weight loss, electrochemical impedance spectroscopy, and polarization curve measurements. Impedance diagrams and Bode plots for uninhibited and inhibited systems were analyzed and simulated using the Z-view program, the fitted data obtained closely followed the same pattern as the experimental results. This study demonstrates that the 2-(4-chlorophenyle)-1,4,5-triphenyle-H-imidazole compound is an effective inhibitor for mild steel in pickling bath solutions, and corrosion inhibition efficiency increases with increases in inhibitor concentration to attain 93.2% imidazole at 10⁻³ M. This is due to the absorbability of Cl⁻ and SO₄²⁻ present in the pickling bath solution and the synergistic effect between both elements. The response used in the exploitation of the design was the determination of inhibitor efficiency. This was assessed through weight loss measurements and electrochemical studies on samples in the absence and presence of 2-(4-chlorophenyle)-1,4,5-triphenyle-H-imidazole. It has been shown that the compound under investigation is an effective cathodic-type inhibitor of mild steel corrosion in pickling bath mixtures. Therefore, the inhibition efficiency was improved with the concentration of the inhibitor, which depended on the molecular structure. The optimal corrosion inhibition efficiency as a function of variation in 2-(4-chlorophenyle)-1,4,5-triphenyle-H-imidazole concentration and pickling bath temperature was simulated and demonstrated using canonical analysis; the obtained efficiency at 324 K for 6 h was 81.3% for the coded variable and 83.4% for the real variable. The experimental results are based on a real-time system and provide much more precise results than the simulated results. Full article

The hot pressing process for 100% coriander-based fiberboards was optimized using an induction RocTool system, which offers rapid mold heating and cooling. The fiberboards were made using deoiled press cake as a protein binder and extrusion-refined straw as reinforcement. Doehlert’s experimental design was used to evaluate the influence of pressure (10–50 MPa), molding time (60–300 s), and mold temperature (155–205 °C) on fiberboard properties, energy consumption, cost, and environmental impact. The results showed that the RocTool device allows for better temperature control during shaping throughout the mold, resulting in mechanical properties that are both more homogeneous across the entire surface of the panel and, more importantly, substantially improved. Using the isoresponse curves, the optimal hot pressing conditions were 35 MPa, 300 s, and 205 °C, corresponding to a 40.6 MPa flexural strength. However, it was observed that to achieve an MDF-like fiberboard with minimal production costs, much less restrictive molding conditions were sufficient, i.e., 32.5 MPa, 170 s, and 160 °C. The study revealed that maximum thermopressing conditions emitted 3.87 kg of CO_2 eq., while conditions leading to the MDF-like board reduced emissions to 1.45 kg CO_2 eq., resulting in a more environmentally friendly material. Full article

In this research, the optimization of the electrochemical advanced oxidation treatment for the degradation of Clopidogrel was investigated. This study examined the influence of various experimental parameters including applied current, initial Clopidogrel concentration, and ferrous ion concentration by the use of the Doehlert design within a response surface methodology framework. The improved grey wolf optimizer was applied in order to define the optimum operating conditions. The monitoring of clopidogrel concentration during treatment revealed that complete disappearance of clopidogrel was achieved under an initial clopidogrel concentration of 0.02 mM, current intensity of 0.55 A, Fe²⁺concentration of 0.7 mM, and a reaction time of 20 min in a solution containing 50 mM Na₂SO₄ at pH 3. A quadratic polynomial model was developed, and its statistical significance was confirmed through the analysis of variance, demonstrating a high level of confidence in the model (R² = 0.98 and p-value < 0.05). Furthermore, following electrolysis treatment for 480 min, the synthetic clopidogrel solutions underwent mineralization, achieving a 70.4% removal rate of total organic carbon. Subsequently, the applicability of the optimized process was tested on real pharmaceutical wastewater, and mineralization was investigated under the identified optimal conditions, resulting in a total organic carbon removal rate of 87% after 480 min of electrolysis time. The energy consumption for this system was calculated to be 1.4 kWh·kg⁻¹ of the total organic carbon removed. These findings underscore the effectiveness and potential applicability of the electrochemical advanced oxidation for industrial wastewater treatment. Full article

Plant-based materials are an important source of bioactive compounds (BC) with interesting industrial applications. Therefore, adequate experimental strategies for maximizing their recovery yield are required. Among all procedures for extracting BC (maceration, Soxhlet, hydro-distillation, pulsed-electric field, enzyme, microwave, high hydrostatic pressure, and supercritical fluids), the ultrasound-assisted extraction (UAE) highlighted as an advanced, cost-efficient, eco-friendly, and sustainable alternative for recovering BC (polyphenols, flavonoids, anthocyanins, and carotenoids) from plant sources with higher yields. However, the UAE efficiency is influenced by several factors, including operational variables and extraction process (frequency, amplitude, ultrasonic power, pulse cycle, type of solvent, extraction time, solvent-to-solid ratio, pH, particle size, and temperature) that exert an impact on the molecular structures of targeted molecules, leading to variations in their biological properties. In this context, a diverse design of experiments (DOEs), including full or fractional factorial, Plackett–Burman, Box-Behnken, Central composite, Taguchi, Mixture, D-optimal, and Doehlert have been investigated alone and in combination to optimize the UAE of BC from plant-based materials, using the response surface methodology and mathematical models in a simple or multi-factorial/multi-response approach. The present review summarizes the advantages and limitations of the most common DOEs investigated to optimize the UAE of bioactive compounds from plant-based materials. Full article

There is a growing interest for complex in vitro environments that closely mimic the extracellular matrix and allow cells to grow in microenvironments that are closer to the one in vivo. Protein-based matrices and especially hydrogels can answer this need, thanks to their similarity with the cell microenvironment and their ease of customization. In this study, an experimental design was conducted to study the influence of synthesis parameters on the physical properties of gelatin methacryloyl (GelMA). Temperature, ratio of methacrylic anhydride over gelatin, rate of addition, and stirring speed of the reaction were studied using a Doehlert matrix. Their impact on the following parameters was analyzed: degree of substitution, mass swelling ratio, storage modulus (log(G’)), and compression modulus. This study highlights that the most impactful parameter was the ratio of methacrylic anhydride over gelatin. Although, temperature affected the degree of substitution, and methacrylic anhydride addition flow rate impacted the gel’s physical properties, namely, its storage modulus and compression modulus. Moreover, this experimental design proposed a theoretical model that described the variation of GelMA’s physical characteristics as a function of synthesis conditions. Full article

The aim of this work is to investigate the enhancement of UVC-based tertiary treatments; for this purpose, real wastewater treatment plant (WWTP) effluent was spiked with a model pollutant, namely acetaminophen. UVC irradiation resulted in some photodegradation of the acetaminophen, which was enhanced upon the addition of hydrogen peroxide (11 mM), but higher amounts of this oxidizing agent resulted in no significant acceleration of the process. An experimental design methodology based on Doehlert matrices showed the significance of hydrogen peroxide concentration and the flow rate for the reactor operating in continuous mode. The addition of low amounts of iron had a positive influence on the process, most probably due to a photo-Fenton-like process using the complexing ability of organic matter. For effluents with higher turbidity, a strategy combining coagulation-flocculation with UVC irradiation was tested: this approach was meaningful as flocculation-coagulation decreased water turbidity and resulted in a more efficient acetaminophen removal. However, under those conditions, the presence of iron did not show a positive role, most probably because of the absence of organic matter, which makes the UVC/H₂O₂ process more efficient and, on the other hand, humic-like substances available to complex iron to drive a neutral photo-Fenton process. Full article

In this study, calcium and magnesium were removed from Tunisian dam, lake, and tap water using Donnan Dialysis (DD) according to the Doehlert design. Three cation-exchange membranes (CMV, CMX, and CMS) were used in a preliminary investigation to establish the upper and lower bounds of each parameter and to more precisely pinpoint the optimal value. The concentration of compensating sodium ions [Na⁺] in the receiver compartment, the concentration of calcium [Ca²⁺] and magnesium [Mg²⁺] in the feed compartment, and the membrane nature were the experimental parameters. The findings indicate that the CMV membrane offers the highest elimination rate of calcium and magnesium. The Full Factorial Design makes it possible to determine how the experimental factors affect the removal of calcium and magnesium by DD. All parameters used had a favorable impact on the response; however, the calcium and magnesium concentration were the most significant ones. The Doehlert design’s Response Surface Methodology (RSM) was used to determine the optimum conditions ([Mg²⁺] = 90 mg·L⁻¹, [Ca²⁺] = 88 mg·L⁻¹, [Na⁺] = 0.68 mol·L⁻¹) allowing a 90.6% hardness removal rate with the CMV membrane. Finally, we used Donnan Dialysis to remove calcium and magnesium from the three different types of natural water: Dam, Lake, and Tap water. The results indicate that, when compared to lake water and tap water, the removal of calcium and magnesium from dam water is the best. This can be linked to the water matrix’s complexity. Therefore, using Donnan Dialysis to decrease natural waters hardness was revealed to be suitable. Full article

In this work, a rapid, precise, and cost-valuable method has been established to quantify phenolic compounds in olive oil using new-based hydrophilic interaction solid-phase extraction (SPE). Boehlert’s experimental design applied the determination of the optimal operating conditions. An investigation into the effects of the methanol composition (50–100%), the volume of eluent (1–12 mL), and pH (1–3) on the extraction of phenols acids and total phenols from Tunisian olive oils was performed. The results showed that the extraction conditions had a significant effect on the extraction efficiency. The experiment showed that the greatest conditions for the SPE of phenolic acids were the methanol composition at 90.3%, pH at 2.9, and volume at 7.5 mL, respectively. The optimal conditions were applied to different types of olive oils, and it could be concluded that larger concentrations of polyphenols were found in extra virgin olive oil (89.15–218), whereas the lowest levels of these compounds (66.8 and 5.1) were found in cold-pressed crude olive oil and olive pomace oil, respectively. Full article

The pH and substrate-to-inoculum ratio (S/I) are important parameters in the anaerobic fermentation of agroindustrial residues, and therefore the optimization of these two parameters is needed for a stable, efficient, and sustainable reactor operation. In this work, the parameters pH (5–9) and S/I (0.5–3 gVS gVS⁻¹) were optimized to produce biobased volatile fatty acids (VFAs) from hydrothermally pretreated olive mill solid waste (HPOMSW). The response variables evaluated in the Doehlert design were total VFAs concentration (tVFAs) (mg L⁻¹) and amounts (%) of isobutyric, butyric, isovaleric, and valeric acids on the VFAs profile. The pH was the variable that most influenced the mixed culture fermentation of HPOMSW, proving to be a key parameter in the process. Microbial community analyses of conditions 1 (S/I = 3 gVS gVS⁻¹ and pH = 7) and 4 (S/I = 1.13 gVS gVS⁻¹ and pH = 5) showed that Proteobacteria and Firmicutes accounted for more than 87% of the total microorganisms identified for both conditions. In addition, the second-order model best fitted the experimental data for the VFAs production at the desirable condition (S/I = 3 gVS gVS⁻¹ and pH = 8). Full article

This work investigates the effects of various processing parameters (laser power, scanning speed, hatch distance and beam offset) on the resultant inclined up-facing surface roughness of AlSi10Mg alloys produced by laser powder bed fusion (LPBF). A two-step approach, orthogonal test followed by the Doehlert matrix design (DMD) test is used to efficiently optimize the up-facing surface and contour parameters. The former method aims to determine the significance of variables while the latter one facilitates a rapid optimization. The results show that the interaction and interdependency among the parameters are of great significance to the obtainable surface roughness. Using a rational design of experiments, the optimized up-facing surface roughness of Ra of 5.4 μm is achieved. This is attributed to the elimination of the laser partition track and the reduction in irregularities at the edges of the parts. This work demonstrates an effective approach of experimental processing parameter optimization to improve the surface finish of LPBF parts. Full article

Hydrogels have attracted great attention as good adsorbents due to their extraordinary water retention capacity, unique hydrophilic nature, biocompatibility, and abundance in availability. In this work, a superabsorbent polymer (SAP) hydrogel and its composite were synthesized, with the introduction of activated charcoal (SAP-AC) for deep removal of the ecotoxic organic dye methylene blue (MB). The formation of the hydrogel was confirmed by FTIR analysis, and scanning electron microscopy (SEM) revealed the appearance of a porous microstructure due to the incorporation of AC. A continuous upflow column was set up, and the adsorption parameters were optimized using an experimental Doehlert uniform array design. The residual concentration of MB was analyzed by UV-Vis spectrophotometry at 665 nm (λ_max). The experimental data were also discussed in terms of adsorption kinetics and adsorption isotherm models. Accordingly, MB adsorption followed pseudo second-order kinetics and better fits the Freundlich isotherm, suggesting a chemisorption mechanism and a multilayer MB adsorption system. The maximum adsorption capacity was 202.84 mg g⁻¹ (96.96%) using the SAP and 213.2 mg g⁻¹ (99.48%) using the SAP-AC. The present study proved that the synthesized composite hydrogel has good activity and selectivity for deep removal of the MB dye and can be effectively used in wastewater treatment. Full article

The study aimed to develop a method for the separation of dispersed dyes extracted from polyester fibers. Nine commercially available disperse dyes, which were used to dye three polyester fabrics, were tested. Extraction of dyes from 1 cm long threads was carried out in chlorobenzene at 100 °C for 6 h. The separation was performed using microemulsion electrokinetic capillary chromatography (MEEKC) with photodiode array detection. Microemulsion based on a borate buffer with an organic phase of n-octane and butanol and a mixture of surfactants, sodium dodecyl sulphate and sodium cholate, were used. The addition of isopropanol and cyclodextrins to microemulsion resulted in a notable improvement in resolution and selectivity. The content of additives was optimized by using the Doehlert experimental design. Values of the coefficient of variance obtained in the validation process, illustrating the repeatability and intermediate precision of the migration times fit in the range of 0.11–1.24% and 0.58–3.21%, respectively. The developed method was also successfully applied to the differentiation of 28 real samples—polyester threads collected from clothing. The obtained results confirmed that proposed method may be used in the discriminant analysis of polyesters dying by disperse dyes and is promisingly employable in forensic practice. Full article

The removal of boron by Donnan dialysis from aqueous solutions has been studied according to response surface methodology (RSM). First, a preliminary study was performed with two membranes (AFN and ACS) in order to determine the experimental field based on different parameters, such as the pH of the feed compartment, the concentration of counter-ions in the receiver compartment, and the concentration of boron in the feed compartment. The best removal rate of boron was 75% with the AFN membrane, but only 48% with the ACS membrane. Then, a full-factor design was developed to determine the influence of these parameters and their interactions on the removal of boron by Donnan dialysis. The pH of the feed compartment was found to be the most important parameter. The RSM was applied according to the Doehlert model to determine the optimum conditions ([B] = 66 mg/L, pH = 11.6 and [Cl⁻] = 0.5 mol/L) leading to 88.8% of boron removal with an AFN membrane. The use of the RSM can be considered a good solution to determine the optimum condition for 13.8% compared to the traditional “one-at-a-time” method. Full article

This work aims to present an industrial perspective on Catalytic Wet Peroxide Oxidation (CWPO) technology. Herein, process simulation and experimental design have been coupled to study the optimal process conditions to ensure high-performance oxidation, minimum H₂O₂ consumption and maximum energetic efficiency in an industrial scale CWPO unit. The CWPO of phenol in the presence of carbon black catalysts was studied as a model process in the Aspen Plus^® v11 simulator. The kinetic model implemented, based on 30 kinetic equations with 11 organic compounds and H₂O₂ involvement, was valid to describe the complex reaction network and to reproduce the experimental results. The computer experiments were designed on a six-factor Doehlert Matrix in order to describe the influence of the operating conditions (i.e., the different process temperatures, inlet chemical oxygen demands, doses of H₂O₂ and space time) on each selected output response (conversion, efficiency of H₂O₂ consumption and energetic efficiency) by a quadratic model. The optimization of the WPO performance by a multi-criteria function highlighted the inlet chemical oxygen demand as the most influential operating condition. It needed to have values between 9.5 and 24 g L⁻¹ for autothermal operation to be sustained under mild operating conditions (reaction temperature: 93–130 °C and pressure: 1–4 atm) and with a stoichiometric dose of H₂O₂. Full article

Climate models predict an increase in the frequency and duration of heatwaves with an increase in intensity already strongly evident worldwide. The aim of this work was to evaluate the effect of two heatwave-related parameters (intensity and duration) during berry ripening and identify a threshold for berry survival and flavonoid accumulation. A Doehlert experimental design was used to test three temperature intensities (maxima of 35, 46, and 54 °C) and five durations (3 to 39 h), with treatments applied at the bunch level shortly after véraison. Berry skin and seeds were analysed by liquid chromatography-triple quadrupole-mass spectrometry (LC-QqQ-MS) for flavonoids (flavonols, anthocyanins, free flavan-3-ols, and tannins). Berries exposed to 46 °C showed little difference compared to 35 °C. However, berries reaching temperatures around 54 °C were completely desiccated, and all flavonoids were significantly decreased except for skin flavonols on a per berry basis and seed tannins in most cases. Some compounds, such as dihydroxylated flavonoids and galloylated flavan-3-ols (free and polymerised), were in higher proportion in damaged berries suggesting they were less degraded or more synthesised upon heating. Overall, irreversible berry damages and substantial compositional changes were observed and the berry survival threshold was estimated at around 50–53 °C for mid-ripe Shiraz berries, regardless of the duration of exposure. Full article