Concentrations Of Magnesium Sulfate Research Articles

A novel electrochemical method for the removal of aluminum from ionic rare earth leachate

The separation of aluminum (Al) from ionic rare earth (RE) leachate is a complex challenge due to their similar chemical properties. Conventional industrial separation process required the use of chemical precipitant leads to considerable loss of RE. Herein, a novel cleaner approach of anionic membrane electrolysis (AME) combined with cyclone electrolysis for removal Al from ionic rare earth leachate was developed. The diffusion of RE3+ and neutralization of H+and OH– were inhibited efficiently by the anionic membrane. Cyclone mixing reduced the loss of rare earth and improved Al removal compared with mechanical mixing. Working parameters including electrode speed, temperature, pH and Al concentration of catholyte, magnesium sulfate concentration and initial pH of anolyte were investigated to explore ways for more efficient Al removal and reduction of rare earth loss. Under the optimal conditions, the removal efficiency of Al and the loss ratio of RE were 93.3 % and 1.84 % respectively. The Al removal data was fitted to the pseudo-zero order model under optimal conditions, k was 0.409 mg·L−1·min−1. Loss of RE was attributed to the direct deposition on the electrode surface due to the high local pH of cathode. This work provides a new insight into the clean removal of Al impurity from actual RE leachate in magnesium sulfate system.

Screening of Factors Influencing Keratinase Fermentation from Bacillus Haynesii BK1H using The Plackett-Burman Design (PBD)

Keratinase is a class of proteases that degrade keratin into polypeptides and amino acids by breaking peptide and disulfide bonds in keratinous proteins. Protease is one of the largest industrial enzymes, the global protease market is increasing rapidly every year. In previous studies, a keratinase-producing microbe was isolated from Bleduk Kuwu which was identified as Bacillus haynesii BK1H. However, further study needs to be done to optimize the production by observing microenvironmental factors that influence keratinase production. In this study, screening some microenvironmental factors is reported. Screening factors including carbon sources, type and concentration of metal ions, agitation speed, amount of inoculum, pH, and temperature. Screening for these factors was started with the One Factor at A Time (OFAT) method and followed by the Plackett-Burman Design (PBD) method. In this study, sequential work was done: (1) Regeneration of Bacillus haynesii BK1H Microbes, (2) Preparation of Tyrosine Standard Series Solutions, (3) Screening of Factors Affecting Protease Fermentation of Bacillus haynesii BK1H using the One Factor at A Time (OFAT) method. ), and (4) Maintaining Significantly Influential Factors by Using Plackett-Burman Design (PBD). The results of the OFAT approach showed that the best condition for keratinase production was achieved at rice husk concentration, additional carbon source, of 1%; pH of 7; a temperature of 35°C; the amount of inoculum of 1%; agitation speed of 150 rpm; magnesium sulfate concentration of 0.04 g/mL, and calcium chloride concentration of 0.0005 g/m. Justification of those factors using PBD confirmed that only additional rice husk, magnesium sulfate and calcium chloride concentration, and agitation speed were significantly important toward keratinase production at selected experiment level limits.

Bacterial model membranes under the harsh subsurface conditions of Mars.

Biomembranes are a key component of all living systems. Most research on membranes is restricted to ambient physiological conditions. However, the influence of extreme conditions, such as the deep subsurface on Earth or extraterrestrial environments, is less well understood. The deep subsurface of Mars is thought to harbour high concentrations of chaotropic salts in brines, yet we know little about how these conditions would influence the habitability of such environments. Here, we investigated the combined effects of high concentrations of Mars-relevant salts, including sodium and magnesium perchlorate and sulphate, and high hydrostatic pressure on the stability, structure, and function of a bacterial model membrane. To this end, several biophysical techniques have been employed, including calorimetry, fluorescence and CD spectroscopy, confocal microscopy, and small-angle X-ray scattering. We demonstrate that sulphate and perchlorate salts affect the properties of the membrane differently, depending on the counterion present (Na+vs. Mg2+). We found that the perchlorates, which are believed to be abundant salts in the Martian environment, induce a more hydrated and less ordered membrane, strongly favouring the physiologically relevant fluid-like phase of the membrane even under high-pressure stress. Moreover, we show that the activity of the phospholipase A2 is strongly modulated by both high pressure and salt. Compellingly, in the presence of the chaotropic perchlorate, the enzymatic reaction proceeded at a reasonable rate even in the presence of condensing Mg2+ and at high pressure, suggesting that bacterial membranes could still persist when challenged to function in such a highly stressed Martian environment.

Improved production of Bacillus subtilis cholesterol oxidase by optimization of process parameters using response surface methodology

BackgroundCholesterol oxidase has numerous biomedical and industrial applications. In the current study, a new bacterial strain was isolated from sewage and was selected for its high potency for cholesterol degradation (%) and production of high cholesterol oxidase activity (U/OD600). ResultsBased on the sequence of 16S rRNA gene, the bacterium was identified as Bacillus subtilis. The fermentation conditions affecting cholesterol degradation (%) and the activity of cholesterol oxidase (U/OD600) of B. subtilis were optimized through fractional factorial design (FFD) and response surface methodology (RSM). According to this sequential optimization approach, 80.152% cholesterol degradation was achieved by setting the concentrations of cholesterol, inoculum size, and magnesium sulphate at 0.05 g/l, 6%, and 0.05 g/l, respectively. Moreover, 85.461 U of cholesterol oxidase/OD600 were attained by adjusting the fermentation conditions at initial pH, 6; volume of the fermentation medium, 15 ml/flask; and concentration of cholesterol, 0.05 g/l. The optimization process improved cholesterol degradation (%) and the activity of cholesterol oxidase (U/OD600) by 139% and 154%, respectively. No cholesterol was detected in the spectroscopic analysis of the optimized fermented medium via gas chromatography-mass spectroscopy (GC–MS). ConclusionThe current study provides principal information for the development of efficient production of cholesterol oxidase by B. subtilis that could be used in various applications.

An Experimental Study on the Kinetics of Leaching Ion-Adsorbed REE Deposits with Different Concentrations of Magnesium Sulfate

As an important substitute for ammonium-free leaching, magnesium sulfate is applied as a leaching agent for the mining of ion-adsorbed REE (rare earth element) deposits. Upon deriving the equation regulating the leaching kinetics on the basis of the REE “shrinking core model” during the leaching process of magnesium sulfate, we conducted leaching experiments of natural particle-sized REE deposits by applying magnesium sulfate with concentrations of 1%, 2%, 3% and 4%. Hence, the leaching efficiencies and mass transfer rates were obtained. The results show that the hybrid control equation μδD1α+3μr2D21−23α−1−α23=3C0Mρr is applicable for describing the leaching process when the concentration of magnesium sulfate is 1%; when the concentrations reach 2%, 3% and 4%, the external diffusion control equation α=kt is appropriate to describe the leaching processes. The leaching efficiency of REE deposits reaches over 90%, specifically, 94.65%, 97.24% and 97.98%, when the concentration of magnesium sulfate is 2%, 3% and 4%, respectively. The maximum mass transfer rate appears when the concentration of magnesium sulfate is 4%, and the leaching time is reduced by 1.96 times compared to 1% concentration of magnesium sulfate. The results provide a favorable theoretical basis for the green and efficient extraction of ion-adsorbed REEs.

Multiplication of Dendrobium Sp Orchid Somatic Embries Using In-Vitro Concentrations of MgSO4 and Myo-Inositol in Murashige and Skoog Media

Dendrobium Sp orchid is one type of orchid that occupies the top position in ornamental plants. This study aims to determine the administration of various concentrations of magnesium sulfate (MgSO4) and Myo-inositol to Dendrobium Sp orchid explants on Murashige and Skoog media. The design used in this study was a factorial complete randomized design (CRD) consisting of 2 treatment levels (M= MgSO4 and Y= Myo-inositol) with 3 replications. Namely: M0 (without MgSO4), M1 (MgSO4 350 mg/l ), M2 (MgSO4 370 mg/l), M3 (MgSO4 390 mg/l), and Y0 (Without Myo-inositol), Y1 (Myo-inositol 50 mg/l), Y2 (Myo-inositol 100 mg/l) , Y3 (Myo-inositol 150 mg/l). Based on the results of the study, giving various concentrations of magnesium sulfate (MgSO4) alone had a significant effect on all observed parameters, where the best treatment was found in M3 with an average number of shoots 4.04, shoot height 1.08 cm, number of leaves 7.89 fruit, number of roots 6.64 fruit and root length 1.55 cm in Dendrobium Sp. For the treatment of various Myo-inositol concentrations, a single significant effect on all observed parameters, where the best treatment was found in Y3 with an average number of shoots 4.03, shoot height 1.25 cm, number of leaves 7.81, number of roots 4.96 and root length 1.48 in Dendrobium Sp. In interaction, the administration of MgSO4 and Myo-inisitol had a significant effect on all observation parameters, the best treatment was M3Y3 (390 mg/l MgSO4 and 150 mg/l MS Myo-inisitol) namely the number of shoots 4.33, the height of the shoots 1.68 cm, the number of leaves is 8.89, the number of roots is 7.22 cm and the root length is 2.02 cm.

Leaching Mechanism of Aluminum during Column Leaching of Ion-Adsorption Rare Earth Ore Using Magnesium Sulfate

Aluminum is a significant impurity in the ion-adsorption rare earth ore. The changes in the occurrences of aluminum have a great influence on the leaching of the rare earth ore. In this paper, the column leaching method was employed using magnesium sulfate as a leaching agent to investigate the effects of pH and magnesium sulfate concentration in the leaching agent on the leaching of aluminum and rare earths. The results show that at low magnesium sulfate concentrations, the leaching of rare earths is greatly enhanced, while the leaching of aluminum is not significantly affected by a decrease in the pH of leaching agent. At high magnesium sulfate concentrations, a slight increase in the leaching of rare earths is observed, accompanied by a significant increase in the leaching of aluminum upon decreasing the pH of the leaching agent. The leaching behavior of aluminum is related to the changes in the occurrences of aluminum during the leaching process. At low magnesium sulfate concentrations, low pH promotes the transition of Hy-Al to Sol-Al, but due to the low Mg2+ concentration in the leaching agent, Sol-Al is back-adsorbed onto the clays and transformed into Ex-Al, resulting in no significant increase in the aluminum content in the leach solution. However, at higher magnesium sulfate concentrations, aluminum in the leach solution comes mainly from the transformation of Ex-Al. Lowering the pH of the leaching agent can significantly promote the transition of Hy-Al to Sol-Al, thereby greatly increasing the aluminum content in the leach solution. The above results provide theoretical support for the optimization of the in situ leaching of ion-adsorption rare earth ore using magnesium sulfate.

Efficient preparation of magnesium bicarbonate from magnesium sulfate solution and saponification-extraction for rare earth separation

To realize the recycling of magnesium sulfate wastewater in the hydrometallurgy and separation process of Baotou mixed rare earth (RE) concentrate, the research on preparation of magnesium bicarbonate (Mg(HCO3)2) solution from magnesium sulfate solution by CO2 carbonation, extraction separation and transformation of RE sulfate solution by saponified HDEHP was investigated. The key influencing factors and carbonation mechanism in the preparation of Mg(HCO3)2, and the distribution of RE, calcium and magnesium elements in the saponification extraction were systematically studied. The results show that the conversion of Mg(HCO3)2 during carbonation is inhibited by calcium sulfate, but promoted by increasing the concentration of magnesium sulfate and decreasing the carbonation temperature. Under the optimized conditions, Mg(HCO3)2 solution with impurities (such as Fe, Al and Si) of less than 15 mg/L is prepared stably and efficiently, and the conversion rate of Mg(HCO3)2 is more than 95%. After multi-stage cascade extraction of RE sulfate solution, the RE extraction recovery is greater than 99.5%. Calcium sulfate crystals do not precipitate during the process, and the raffinate phase is magnesium sulfate solution that is used for the preparation of Mg(HCO3)2 solution.

Effect of Epsom Salt Concentration and Dry-Mix Composition on Bonding Properties of Magnesium Oxysulfate

Non-hydraulic magnesium oxysulfate cement has many superior properties than ordinary portland cement and it draws much research interest due to energy saving and environment protection considerations. It is formed by the exothermic reaction between lightly calcined MgO and MgSO4·7H2O (epsom salt) solution. This heat is responsible for cracking and makes the product unsound. The incorporation of inert filler can overcome this problem by absorbing the excess heat. In present work, a parametric study was conducted to investigate the effect of dry-mix composition (MgO: inert filler) and gauging solution epson (MgSO4·7H2O) concentration on cementing properties of magnesium oxysulfate cement. The results show that a 1:1 dry-mix composition of MgO and dolomite with 25º Be concentration of magnesium sulfate works best in the cementing action of magnesium oxysulfate

The dependence of the efficiency of the ion exchange of manganese ions from water on the type and form of the ionite and its hardness

Drinking water must comply physical, chemical, bacteriological and radiochemical guidelines therefore its quality should be continuously monitored before being introduced into the distribution system. Water used for human consumption may come from various sources: groundwater, spring water; water from rivers, streams, lakes, among other. A large part of the population of Ukraine uses drinking water that does not meet hygienic requirements according to various indicators. Manganese compounds are quite often present in natural waters. Their quantitative content can vary in a wide range, depending on the region, it can be 0,5-10 mg/dm3. It is worth noting that with a high content of manganese compounds in water, their removal is a rather difficult task. Removal of manganese compounds from water can be implemented using the ion exchange method, which consists of filtering water through loading in salt or acidic form. At the same time, softening and desalination of water can occur simultaneously. Therefore, the ion exchange method should be used for comprehensive water purification, softening, and removal of manganese compounds.
 The article presents the results of obtained during the extraction of manganese ions from distilled and tap water using the strongly acidic cationite KU-2-8 and the weakly acidic cationite Dowex MAC-3. Cationites were used in Na+ and Ca2+ form. The concentration of manganese ions (Mn2+) was varied from 5 to 500 mg/dm3. It was shown that the sorption capacity of the cationite KU-2-8 depended on the concentration of manganese ions, the form of the ionite, the presence of hardness ions in water and was little dependent on the pH of the medium. The sorption capacity of the weakly acidic cationite increased with the increase in the concentration of manganese ions and with the increase in the pH of the medium, which changed with the change in the concentration of magnesium sulfate in distilled water. Sorption of manganese ions from tap water decreases for strongly acidic and weakly acidic cations, compared to solutions in distilled water, which is associated with competitive sorption of hardness ions. This is especially noticeable when using ionites in Ca2+ form in solutions in tap water. The use of ionites in Ca2+ form reduces their sorption capacity for Mn2+ and in distilled water to a certain extent. But this effect is smaller compared to tap water. The Thomas model was used in the work to estimate the full exchange capacity of weakly acidic cationite at low concentrations of MnSO4 solution in distilled water.

Development of an optimized colorimetric RT-LAMP for SARS-CoV-2 assay with enhanced procedure controls for remote diagnostics

The coronavirus pandemic accentuated the need for molecular diagnostic tests. A technique highly used to this end is the Polymerase Chain Reaction (PCR)—a sensitive and specific technique commonly used as the gold standard for molecular diagnostics. However, it demands highly trained personnel and high-maintenance equipment and is relatively time-consuming. An alternative is the Loop-Mediated Isothermal Amplification (LAMP) technique, which doesn’t need sample purification or expensive equipment, and is similar to PCR when compared in sensitivity and specificity. In this paper, we developed an optimized colorimetric Reverse Transcriptase Loop-Mediated Isothermal Amplification (RT-LAMP) Point-of-Care test using a portable device to diagnose COVID-19. Variables such as concentration of primers, magnesium sulfate, betaine, hydrochloride guanidine, Bst, and temperature of the reactions were tested. We also created a pipetting quality control system—using a combination of dyes—to avoid false negatives due to a lack of samples added to the reaction test tube. Mineral oil was incorporated in the composition of the RT-LAMP reactions to avoid evaporation when a heating lid isn't available. The final RT-LAMP test is tenfold more sensitive when compared to the WarmStart Colorimetric Master mix from New England Biolabs with a sensitivity of 5 copies per μL.

Magnesium incorporation in fibrinogen scaffolds promotes macrophage polarization towards M2 phenotype

The host inflammatory response to biomaterials conditions their capacity to promote tissue repair, and macrophage polarization shift from M1 to M2 is determinant in this process. Previous work showed that extracts of a combination between fibrinogen and metallic magnesium materials acted synergistically to reduce macrophage inflammatory phenotype. The hypothesis underlying the current work was that the ability of magnesium-modified fibrinogen scaffolds to modulate macrophage phenotype depends on the concentration of magnesium. Thus, Fibrinogen (Fg) scaffolds incorporating precise concentrations of magnesium sulfate (Mg: 0, 10, 25, 50 mM) were developed and characterized. Mg incorporation in Fg scaffolds increased surface charge, while porosity decreased with increasing Mg concentrations, but only Fg scaffolds with 10 mM of Mg (FgMg10) had significantly improved mechanical properties. Human macrophages cultured on FgMg10 scaffolds, showed increased M2 and decreased M1 polarization, when compared to those cultured on scaffolds with 0, 25 and 50 mM of Mg. Macrophage polarization results were independent of the anion used (chloride or sulfate). Macrophage modulation by FgMg10 scaffolds involved reduced NF-κB p65 nuclear translocation, and impacted production of pro-inflammatory mediators (e.g. IFNγ, IL-12, TNF-⍺, IP-10). Importantly, FgMg10 scaffolds implanted in vivo increased the expression of M2 marker CD163, in macrophages from inflammatory exudates, compared to Sham and Fg-implanted animals, increasing the M2:M1 ratio. A cytokine/chemokine array showed that, while both Fg and FgMg10 scaffolds decreased inflammatory mediators, only FgMg10 decreased IL-1β, IP-10, MIP-2, MDC and MIP-3⍺, compared to Sham-operated animals. This study demonstrated that incorporation of 10mM of Mg modulated inflammation, promoting M2 macrophage polarization in vitro and in vivo. Statement of significanceDeveloping biomaterials that can modulate inflammation and promote macrophage phenotype switch from M1 to M2 is crucial to promote a regenerative microenvironment. Our previous work showed that extracts of a combination between fibrinogen (Fg) and metallic magnesium (Mg) materials synergistically reduced macrophage pro-inflammatory phenotype. Herein, we tested the hypothesis that macrophage modulation was dependent on Mg concentration. A new family of Fg porous scaffolds incorporating different amounts of Mg (0, 10, 25 and 50 mM) was produced and characterized. We observed that only the combination of Fg scaffolds with 10 mM of Mg (FgMg10) significantly changed the scaffolds mechanical properties and directed macrophages towards a M2 phenotype, reducing the production of inflammatory mediators, both in vitro and in vivo.

The Effects of Sulfate on the Parameters for Maximum Pit Size Calculations on Stainless Steel 316L

Dry storage canisters that contain radioactive waste containers in the United States are typically made of stainless steel such as 316L. The longevity of such canisters put into service around forty years ago is a primary concern to the United States Department of Energy. Due to their location, many of these canisters undergo fluctuations in relative humidity and temperature, as well as an accumulation of deliquescent salts on their surface. The nature of the anions present in these salts establishes whether or not proper conditions for pit propagation exist. In order to predict these canisters’ maximum pit size, computational models that employ input parameters on the pit kinetics can be utilized. Such kinetic parameters are the critical pit stability product (i·x)crit and the repassivation potential (Erp), as they are key to the anodic current demand in a pit and the cathodic current supply outside a pit, respectively. Previous models that focused on the effect of chloride concentrations on the maximum observed pit size have shown to be overly conservative. Therefore, to increase the accuracy of the model, a more complex solution that contains inhibiting ions, such as sulfates, should be considered. In this study, artificial 1-D pit electrochemical experiments were carried out in a 50.8μm diameter SS316L wire exposed to solutions containing different concentrations of magnesium chloride (MgCl2) and magnesium sulfate (MgSO4). Maximum pit size calculations were performed utilizing the kinetic parameters obtained from these experiments. A theoretical model that seeks to describe the formation and growth of a complex salt film precipitate at the bottom of the pit is presented as well.

Degradation Mechanisms of Early Strength for High-Fluidization Cement Mortar under Magnesium Sulfate Corrosion

High-fluidization and early strength cement mortar (HECM) has been widely adopted in various fields of civil engineering. Due to the complexity of the engineering environment, sulfate corrosion cannot be ignored for the HECM. Although the effect of sulfate on the properties of the cement-based materials has been addressed, the degradation mechanisms of the HECM in the case of sulfate corrosion are not clear because of the distinct characteristics of the HECM (e.g., early strength and high fluidization) compared with conventional cement-based materials. Hence, considering the more complex corrosion process of magnesium sulfate, the early flexural and compressive strength of the HECM in the case of different magnesium sulfate concentrations and testing ages are investigated in this study. Moreover, the effects of magnesium sulfate concentrations and corrosion times on the microstructure and hydration products of the HECM are analyzed via a Scanning Electron Microscope (SEM) test, an X-ray diffraction (XRD) test, and a Differential Scanning Calorimeter (DSC) test. Finally, the influence mechanisms of the magnesium sulfate on the early strength formation of the HECM are analyzed to reveal the degradation mechanisms of the HECM.

Crescimento e qualidade de cebolinha em sistema hidropônico com concentrações de sulfato de magnésio

ABSTRACT Chives are popular herbs, and highly appreciated by consumers. The experiment was conducted in the period from September to November 2020 in a greenhouse, located at the Federal University of Technology, Paraná, Brazil. This study aimed to evaluate the growth, physiological responses, and quality attributes of chives grown in hydroponic systems containing different concentrations of magnesium sulfate. The experimental design was randomized blocks, and the treatments consisted of a standard solution with the addition of magnesium sulfate at the following doses (g/L): standard solution 0.4; 0.42, 0.44; 0.46, and 0.48, with four repetitions per treatment. The analyzed variables were physiological indicators and growth; physical-chemical characteristics and nutrient content in tissues. The dose of 0.48 g/L resulted in the highest number of leaves (47.3) and contributed to 44% reduction in leaf drop, thereby positively influencing growth with higher fresh mass (231.40 g/plant). The relative chlorophyll index (58.64) obtained at 0.48 g/L dose revealed an increase in the chlorophyll content and, consequently, in the green color of the plants, with °hue angle of 140.54. Greener leaves is a visual aspect preferred by consumers. In addition, the higher concentration of magnesium sulfate provided 50.7% increase in the content of soluble solids and 50.6% rise in phenolic compounds. The dose of 0.48 g/L magnesium sulfate contributed to reduced leaf fall, improved visual appearance, greater bioactive compounds, and enhanced leaf sweetness to meet the quality standards that consumers expect for this condiment.

Effect of magnesium salt contamination on the microstructures and properties of metakaolinite-based geopolymer: the role of MgCl2 and MgSO4

Ion contamination considerably influences the properties of geopolymers. This study investigated the effects of magnesium chloride (MgCl2) and magnesium sulfate (MgSO4) concentrations on the microstructure and properties of metakaolinite-based geopolymers with Si/Al ratios of 1.3 (adding NaOH) and 1.6 (adding NaOH and Na2SiO3). The chemical structures and compositions of as-obtained geopolymers formed through the alkali activation of kaolinite were characterized through X-ray diffraction, Fourier-transform infrared spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy, while the microstructure was characterised via scanning electron microscopy and mercury intrusion porosimetry.The salt-free geopolymer with a Si/Al ratio of 1.3 exhibited a loose microstructure and hence poor 28-day compressive strength (9.4 MPa). The addition of magnesium salt to the geopolymer did not considerably influence its microstructure and mechanical properties. Comparatively, the geopolymer with a Si/Al ratio of 1.6 exhibited a compact microstructure and high 28-day compressive strength (43.0 MPa). The geopolymer compressive strength gradually decreased with increasing salt concentration. MgCl2 addition induced halite formation, increased pore diameter and pore volume, and reduced Si incorporated into the geopolymer matrix. In contrast, MgSO4 addition resulted in relatively less change in the pore diameter and pore volume and based on NMR result, more Si was incorporated into the geopolymer matrix. Thus, MgCl2 was more detrimental to the mechanical properties of the kaolinite-based geopolymers than MgSO4.Overall, the results indicate that salt contamination considerably affects the chemical compositions, microstructural characteristics, and compressive strength of metakaolinite-based geopolymers at high Si/Al ratio (adding NaOH and Na2SiO3) and those chlorine ions are more detrimental to the properties of metakaolinite-based geopolymer than sulfate ions.

PERFORMANCE OF POLYMER GROUTS MADE FROM WASTES FOR PERMEABLE RIGID PAVEMENT CONNECTIONS

This research developed polymer grouts made from wastes such as fly ash, palm oil fuel ash, and silica fume. The selected polymer grouts served as an interlocking key between the StormPav covers and as a grout to seal the gaps between the interlocking keys and StormPav covers. Based on compressive strength and workability of the polymer grouts, mix ratio of resin to fly ash = 1:1.00 was chosen as the grout, while mix ratio of resin to fly ash = 1:1.50 was used to form an interlocking key. Mix ratios of resin to fly ash = 1:1.00 and resin to fly ash = 1:1.50 had a compressive strength of 98.90 MPa and 81.70 MPa, respectively, and flexural strength of 53.00 MPa and 61.90 MPa. Moreover, increasing the fly ash content in polymer grout decreased the water absorption and volume of permeable voids. In terms of shear strength, the mix ratio of resin to fly ash = 1:1.00 performed well as grout, with a determined shear strength of 3.98 MPa. Even after 25 days of exposure to the high concentration of sodium hydroxide, sulphuric acid, sodium chloride, and magnesium sulphate, the determined shear strength met the minimum shear strength requirement of 1.38 MPa as stated by the Iowa Department of Transportation. Therefore, it can be concluded that both selected mix ratios were suitable for use as grout and interlocking key due to their good physical and mechanical properties.

Lipase from Fusarium solani: optimization of culture conditions, biochemical properties, and production

A Plackett-Burman factorial design with 15 experiments was conducted to evaluate the influence of seven factors on lipases production by Fusarium solani. The factors investigated were peptone, tryptone, yeast extract, calcium chloride, potassium phosphate, magnesium sulfate, and copper sulphate. Five fixed variables (cotton oil, pH, temperature, agitation, and time) were maintained and as a response to the enzymatic activity. The concentration of tryptone, calcium chloride, and magnesium sulphate had a significant effect (p < 0.10) on lipase production and was studied consecutively through a complete DCCR (central rotational compound design), to optimize lipase production of the fungi F. solani. After optimization using DCCR, maximum lipolytic activities of 24.84 U/ml were obtained with the use of 10 g.L-1 tryptone, 3.50 g.L-1 calcium chloride and 0.50 g.L-1 magnesium sulfate, 1 g.L-1 potassium phosphate and 1% soybean oil. The statistical model showed a correlation of 85.67% with the experimental data. The biochemical characterization of lipase showed that the enzyme has a better performance at pH 7 at a temperature of 40 °C, where the statistical model had a correlation of 94.15% with the experimental data. In this way, lipases produced by F. solani have potential for application and use in biodiesel production.

Effects of MgO, γ-Al2O3, and TiO2 Nanoparticles at Low Concentrations on Interfacial Tension (IFT), Rock Wettability, and Oil Recovery by Spontaneous Imbibition in the Process of Smart Nanofluid Injection into Carbonate Reservoirs.

Recently, some nanoparticles have been used to upgrade injected water into oil reservoirs to enhance oil recovery. These nanoadditives can be used in a variety of injectable waters, including smart/engineered water with special salinities. In this study, the performance of smart water containing different concentrations of magnesium sulfate (MgSO4) and calcium chloride (CaCl2) and 500 ppm of titanium dioxide (TiO2), γ-alumina (γ-Al2O3), and magnesium oxide (MgO) nanoparticles in interfacial tension (IFT) and contact angle reduction and oil production under imbibition of the chemical fluids was investigated. Based on the results, the IFT decreased more when ions and nanoparticles were present in the system. An optimum IFT of 4.684 mN/m was recorded for the nanofluid containing 2000 ppm of MgSO4 + 500 ppm of MgO. The results of contact angle tests demonstrated improved saline water capabilities in the presence of nanoparticles and showed that a very effective reduction was accessible and highly hydrophilic wettability was obtained when using smart water with stable nanoparticles as a minimum contact angle of 18.33° was obtained by the optimal fluid containing nano-γ-Al2O3. Finally, an ultimate oil production of 64.1–68.7% was obtained in six experiments with smart water and stable nanoparticles.

The Effect of Some Components Changes of Aspergillus niger Culture Media on the Production of Lipase Enzyme

The current work aimed to study the effect of some component changes of Aspergillus niger culture media on the production of lipase enzyme. Media contained nitrogenous sources, ammonium nitrate, peptone, nitrate phosphate, mono-potassium phosphate, and aqueous magnesium sulfate. It was found that the isolation was unable to grow and produce lipase enzyme efficiently due to the presence of inorganic nitrogen sources. The highest value of the dry weight rate was realized while using ammonium chloride at concentration of 1.23 g/100 ml. Ammonium nitrate was the best source (treatment) compared to the rest of the sources at a concentration of 0.1 g/100 ml, where the dry weight was 1.28 g/100 ml, and the effectiveness of lipase was 22.86 U/ml. Adding peptone with the ammonium nitrate to the medium helped to raise the productivity of isolated fungus, where the dry weight reached 2.75 g/100 ml, while the lipase activity reached 36.93 U/ml. The biomass in the organic nitrogen sources medium reached (2.24 g/100 ml). The highest value of the dry weight of phosphate source media (KH2PO4) reached (2.87 g/100 ml) at a concentration (0.28 g/100 ml), achieving the best value of the lipase’s effectiveness (39.96 U/ml). Aqueous magnesium sulfate concentration media resulted in a sort increase in the fungus isolation biomass, as the highest biomass for aqueous magnesium sulfate media was (3.00 g/100 ml) at (0.05 g/100 ml) concentration.