Magnesium Sulfate Heptahydrate Research Articles

Thermal and exergy analysis of solar air heater enhanced with sodium carbonate decahydrate and Magnesium sulfate heptahydrate PCM: Performance evaluation

The advancement of renewable solar energy is prospective for energy, heat exchanger, and air heater applications. The main objective of the present research is enhancing the solar air heater thermal performance by the modification of a collector absorber-like plain absorber featuring rectangular fine (SAH 2) and sodium carbonate decahydrate (Na2CO3·10H2O) and Magnesium sulfate heptahydrate (MgSO4·7H2O) PCM with rectangular fin (SAH 3). During the experimental evaluation, the airflow varied by 0.042 and 0.059 kg/s. Influences of collector modification on the functional behaviour of solar air heaters (SAH) are evaluated. Its results are compared to the system of conventional setup without modification of the solar collector with a plain absorber (SAH-1). With the excellence of Na2CO3·10H2O/MgSO4·7H2O with fin setup performed with 0.059 kg/s found better heat transfer performance including heat gain, thermal & exergy efficiency, heat loss coefficient, and PCM temperatures like 927.3 W, 78.6 %, 33.6 %, 16.9 W/m2K, and 68.3 ⁰C respectively. Moreover, Increasing the airflow rate leads to improved heat transfer, and the SAH proves to be effective at higher flow rates when equipped with fins and PCM.

Nitrogen Requirement and Nitrogen Form Preference by Radermachera hainanensis and R. sinica Plug Seedlings

Abstract Radermachera hainanensis Merr. and R. sinica Hemsl. are popular foliage plants raised from seeds. Nitrogen fertilizer can significantly influence medium pH and EC, plug seedling growth, and photosynthesis. Plug seedlings of both species, each with one pair of leaves, were subjected weekly to nutrient solutions with nitrogen (N) concentrations ranging from 0 to 32 mM. Nitrogen-deficient plants exhibited the lowest leaf area, SPAD-502 value, and shoot dry weight but the highest root-to-shoot ratio. Leaf area, SPAD-502 value, and root and shoot dry weights increased with increasing N concentration up to 12-16 mM, and gradually decreased thereafter. Well-grown plants with 12-16 mM N exhibited peak maximal fluorescence (Fm), photochemical quenching (qP) and the lowest minimal fluorescence (Fo) and non-photochemical quenching (qN). Seedlings received nutrient solutions with varying proportions of NH4-N: NO3-N (0:100, 25:75, 50:50, 75:25, and 100:0, in percentages) at 16 mM N. Both species exhibited reduced leaf area, SPAD-502 value, and plant dry weights when supplied with only NO3-N or NH4-N. Maximum growth was achieved at a 50% NH4-N: 50% NO3-N ratio. Species used in this study: Golden jasmine tree, Radermachera hainanensis Merr.; China Doll, Radermachera sinica Hemsl. Chemicals used in this study: ammonium nitrate; sodium dihydrogen phosphate; potassium sulphate; potassium nitrate; magnesium sulfate heptahydrate; calcium sulfate dihydrate; calcium nitrate tetrahydrate; ammonium sulfate; boric acid anhydrous; potassium chloride; ferrous sulfate heptahydrate; disodium ethylenediaminetetraacetic acid dihydrate; copper sulfate pentahydrate; zinc sulfate heptahydrate; molybdic acid; manganese sulfate monohydrate; nickel sulfate hexahydrate; sodium hydroxide.

Study on the Preparation and Compressive Strength of Boron Mud-Based Basic Magnesium Sulfate Cement.

The direct discharge of boron mud poses significant environmental hazards to soil and groundwater. Despite extensive research efforts, the reprocessing of boron mud has not yielded significant advancements. Recently, the development of magnesium cement has spurred interest in the reutilization of boron mud. However, the direct treatment of boron mud remains challenging, necessitating pre-treatment in most studies to achieve substantial results. Consequently, research on the direct incorporation of untreated boron mud is scarce. This study explores the feasibility of using uncalcined boron mud as a base material in basic magnesium sulfate cement (BMSC), composed of lightly calcined magnesia and magnesium sulfate heptahydrate. The effects of varying boron mud content on the compressive strength of the BMSC system were investigated. The results indicate that the 5·1·7 phase is the primary strength phase of BMSC. When the boron mud content is 30%, the uncalcined boron mud has a minimal impact on the formation of the 5·1·7 phase. Additionally, the 28 days compressive strength of BMSC-B30 showed a slight difference compared to the control group BMSC-C, registering at 66.7 MPa. TG-DSC analysis revealed that the presence of a small amount of boron mud inhibits the micro-expansion trend of the BMSC structure. Furthermore, XRD and SEM analyses confirmed that the addition of uncalcined boron mud does not significantly alter the phase structure of the 5·1·7 phase in BMSC. This study provides a foundational basis for the long-term development of direct boron mud treatment.

The Use of Magnesium Fertilizer Can Improve the Nutrient Uptake, Yield, and Quality of Rice in Liaoning Province

In this study, the effects of the soil application and foliar spraying with magnesium fertilizers on rice yield and quality in Liaoning Province were investigated. Field experiments were conducted at Kaiyuan, Xinmin, and Dawa in 2022 and 2023. Magnesium fertilizers were used in the soil as magnesium sulfate monohydrate and silicon–magnesium fertilizer and on leaves was magnesium sulfate heptahydrate. The results showed that the application of 12 kg magnesium hm−2 in the soil at the Kaiyuan site can significantly increase rice yield by 14.8% compared with sites without magnesium fertilizer. The use of silicon–magnesium fertilizer showed a more obvious yield increase of 22.2%. The application of 3 kg magnesium hm−2 or 6 kg magnesium hm−2 on the leaf surface increased the rice yield at Kaiyuan by 19.4% and 21.6% and at Xinmin by 17.8% and 5.4%, respectively. The yield increase was more significant under the optimal fertilization treatment compared with the conventional fertilization treatment. The application of magnesium fertilizer increased the magnesium, nitrogen, and phosphorus contents in rice shoots and the potassium and crude protein contents in rice grains. The effect of foliar spraying with magnesium fertilizers was more obvious than soil application. Therefore, the magnesium fertilizer used on the leaf surface plays an important role in improving rice yield and quality in rice-growing areas with relatively rich soil magnesium content. Magnesium fertilizer can compensate for the yield decrease caused by the reduced use of nitrogen and phosphorus fertilizers by promoting nitrogen and phosphorus absorption in rice. Conclusively, the application of magnesium fertilizer is a promising measure to improve rice production in Liaoning province under a reduced nitrogen and phosphate fertilizer background.

Removal of hexavalent chromium using one-step synthesized metal-polyphenol composites epigallocatechin gallate/titanium: Performance, interference, and mechanisms

Chromium-containing wastewater intensifies the shortage of water resources, and how to solve the problem has become a research hotspot. In this study, epigallocatechin gallate and titanium salt were combined to prepare epigallocatechin gallate/titanium composites by one-step synthesis, and the effectiveness and mechanisms of removing hexavalent chromium from wastewater were studied. Based on the characterization results, the epigallocatechin gallate/titanium nanometer-scale materials were irregularly spherical, and their surface was rich in phenolic hydroxyl groups. The average particle size, average pore size, and BET surface area were 448 nm, 6.23 nm, and 15.40 m2/g, respectively. The Freundlich isothermal model for adsorption and pseudo-second-order adsorption kinetics were both applicable to the hexavalent chromium adsorption. The maximum adsorption capacity of hexavalent chromium was 105.8 mg/g, and the adsorption process was more inclined to endothermic reaction. The salinity resistance of epigallocatechin gallate/titanium materials to different salts was sodium chloride > magnesium sulfate heptahydrate. In the organic acid-coexisting system, the removal efficiency of epigallocatechin gallate/titanium materials for hexavalent chromium with 20 mg/L fulvic acid and citric acid was 82.7% and 81.5%, respectively. The epigallocatechin gallate/titanium materials also showed excellent removal ability for hexavalent chromium, lead(II), copper(II), and nickel(II), with removal efficiencies all above 95%. Hexavalent chromium was first adsorbed and then reduced to trivalent chromium with the help of phenol hydroxyl groups on the materials. The trivalent chromium was further immobilized through electrostatic attraction and complexation. This work aimed to provide a new idea for handling hexavalent chromium-contaminated wastewater by using green and versatile polyphenol nanomaterials.

Growth, structural, thermal, and optical characteristics of L-asparagine monohydrate doped magnesium sulphate heptahydrate semiorganic crystals

A novel semi-organic crystal has been grown using slow evaporation technique by doping organic compound L-asparagine monohydrate (C4H8N2O3·H2O) with inorganic material Magnesium sulphate heptahydrate (MgSO4·7H2O). The crystallographic parameters like strain, dislocation density and crystallite size were calculated by powder X-ray diffraction method. Functional groups were identified and bond length, force constants were calculated from FT-IR spectroscopy. Energy dispersive X-ray (EDX) analysis was used to identify the constituent elements of the crystal. Kinetic and thermodynamic parameters, such as, activation energy Ea, change in Gibb's free energy (ΔG) and change in enthalpy (ΔH) have been determined by thermogravimetric analysis (TGA) analysis. Ea, ΔH and ΔG show positive values and change in entropy (ΔS) shows negative ones. The thermal degradation behavior of the crystals has been analyzed by differential scanning calorimetry (DSC) analysis. Various optical constants such as optical band gap, lattice dielectric constant, absorbance, extinction coefficient, the ratio of free charge carrier concentration to the effective mass, Urbach energy, optical and electrical conductivities were estimated from UV–vis transmittance data. High optical conductivity (1010 s−1) justifies the good photo response nature of the semi-organic crystal.

Study of the Effect of Magnesium Sulfate and Ammonium Nitrate on the Chemical Activity of Solutions of Phosphoric Acid

The present study aimed to study the effect of magnesium sulfate and ammonium nitrate on the chemical activity of phosphoric acid solutions. The results of studies on increasing the chemical activity of extractive phosphoric acid from Central Kyzylkum and Karatau phosphorites due to the concentration of the first hydrogen ions and the pH of the medium are presented. It has been shown that introducing magnesium sulfate heptahydrate into the acid reduces the concentration of the first hydrogen ions. Adding an amount of ammonium nitrate increases the concentration of the first hydrogen ions even higher than in the acid without magnesium. It has been established that the solubility of magnesium hydrophosphate increases with an increase in the content of P2O5 phosphoric acid, dihydrogen phosphate decreases as a result of dissociation with the formation of a hydrophosphate ion, and phosphoric acid dissociates with the formation of a dihydrophosphate ion, which binds with hydrogen ions, forming a dihydrophosphate ion.

Lipid microspheres of different waxes containing urea enriched with a sulfur source for slow release in the rumen

The objective of this study was to obtain and characterize slow-release urea microspheres (SRU) from carnauba wax (CW) and beeswax (BW) with and without enrichment of sulfur source (S). In the 1st experimental stage, we obtained and characterized slow-release urea (SRU) microspheres with a fixed ratio of 2:1(wax:urea), enriched or not of sulfur (magnesium sulfate heptahydrate) from the emulsification/lyophilization technique using urea as core into carnauba wax matrix added (CWUS) or not (CWU) of S source, and urea into beeswax matrix added (BWUS) or not (BWU) of S source. All formulated microencapsulated systems showed high yield values, raging 92.9–107% for BWU and CWU, respectively, with the highest SRU yields (P < 0.001) from CW compared to BW, and higher yields on materials without the presence of sulfur (S). The highest (P < 0.001) microencapsulation efficiency was observed in the SRU using BW, while the lowest yield occurred in the SRU-CWUS, where there was sulfur in the particle (P < 0.001). As for the determination of water activity, with values ranging 0.47–0.72, for BWU and CWUS, respectively. Thermal analyses (TG and DSC) indicated that the presence of the S source reduced the effectiveness of urea protection, and beeswax as an encapsulant showed higher thermal stability. In the 2nd experimental stage, five rumen-fistulated sheep with average body weight 48.9 ± 5.23 kg and age of 24 ± 2 months were assigned in a 5 × 5 Latin square design, with five consecutive 18-day periods divided into 13-day adaptation and five treatments [Urea free (U) as control and four SRU (BWU, BWUS, CWU, and CWUS)]. The SRU showed smooth surfaces with little cavities mainly for BW particles. The use of free urea provided lower concentrations of total proteins and creatinine and higher (P < 0.05) concentrations of BUN and AST compared to animals receiving SRU regardless of the type of encapsulant or the presence of S. However, the serum concentrations of albumin, AST, cholesterol, creatinine, total protein, and triglycerides showed no significant effect comparing only SRU. The sheep show higher concentrations of serum urea 8 h after feeding in comparison to the collection before (0 h) of feeding. Although all microparticles showed potential for SRU in the rumen, the system without added S and with beeswax showed higher encapsulation efficiency and is the most suitable for the diet of adult sheep.

Structural, raman, optical and electrical studies of pure and compound crystal of magnesium sulphateheptahydrate and threonine

Pure and compound crystal of magnesium sulphate heptahydrate(MSH) and threonine (THR) is grown from aqueous solution by slow evaporation method at room temperature. The reaction between MSH and THR is confirmed by TLC test. Good quality and transparent crystals are harvested. Pure MSH and THR crystallize in orthorhombic crystal system, while compound crystal shows the presence of both the phases of MSH and THR.The crystallite size is found using the various methods are employed to estimate the crystallite sizes and the lattice strain. The Raman spectra show the presence of characteristic normal modes of vibrations of pure MSH and THR in the compound crystal.The optical band gap is estimated by using K-M function. The various optical parameters such as extinction coefficient, refractive index, optical conductivity and skin depth have been calculated and analyzed with incident photon energy. The dielectric constant and loss of all the grown crystals have exhibited normal behavior over the frequency range considered. The total polarizability of the crystals is calculated by two theoretically methods and matches well with experimental results. The complex impedance and modulus spectroscopy studies suggested the presence of grain effect in all the samples and the same is successfully modelled using R-CPE parallel circuit. Non-debye type relaxation is confirmed from β-parameter. From the Jonscher’s plot, the ideal long range pathways and diffusion limited hopping mechanism is confirmed for all the samples. The results of pure crystal of MSH and THR are compared with the compound crystal and discussed accordingly in detail.

Synthesis, physicochemical properties, and antitumor cytotoxic activity of the Mg(II) coordination complex containing 1,10-phenanthroline and sulfate ligands

The complex mer-triaqua-(1,10-phenanthroline)-(sulfate-O)-magnesium(II) was synthesized by the solvent slow evaporation method from the crystallization of an equimolar saturated solution of 1,10-phenanthroline and magnesium sulfate heptahydrate in a mixed solution of deionized water and DMF. The structural, vibrational, and thermal properties were studied by X-ray powder diffraction (XRPD), Fourier Transform Infrared Spectroscopy (FT-IR), and thermoanalytical analyses. Calculations based on density functional theory (DFT) were also applied to the system for an accurate analysis of vibrational modes and to obtain theoretical data on the nature of bonds, chemical reactivity descriptors, electrostatic potential map, and electronic properties. XRPD results showed that the coordination compound in the study has monoclinic symmetry (space group P21/c) and contains four molecules per unit cell (Z = 4). The thermal measurements revealed that the material presents a thermodynamically irreversible process around 303 K, arising from the evaporation of three coordination water molecules. In addition, all IR absorption bands were assigned, with contributions from the DFT calculations. Finally, cell viability assays were conducted, confirming the antitumor activity of the complex in MCF-7 (breast) and SiHa (cervical) cancer cells, exhibiting a considerable selective cytotoxic effect.

Особенности экстракционной сернокислотно-фторидной технологии переработки ниобий- и танталсодержащего сырья

The results of researching of the leaching of niobium- and tantalum-containing raw materials by solutions of hydrofluoric and sulfuric acids are presented. Researching have been carried out on the solvent extraction purification and separation of niobium and tantalum from their fluoride-sulfuric acid solutions to obtain niobium oxides and tantalum oxides of the required quality using octanol-1 as an extractant. The possibility of recycling waste technological sulphate-fluoride solutions with the production of magnesium sulfate heptahydrate is shown. Information on the work on the use of pyrohydrolysis as a reagentless method for the isolation of products and the regeneration of hydrofluoric acid is presented.

A novel hydrated salt-based phase change material for medium- and low-thermal energy storage

Magnesium nitrate hexahydrate (MNH) was considered as a promising medium- and low-temperature phase change material (PCM) owing to high latent heat, weak corrosion, and low price. While supercooling performance greatly restricted the application of such PCM. In this work, MNH-based composite PCM containing a novel nucleating agent was prepared. Supercooling behavior and thermophysical properties of composites were analyzed. Additionally, thermal performance of composites in a fin-plate heat storage unit was investigated. Results showed that 2 wt% magnesium sulfate heptahydrate (MSH) effectively suppressed supercooling performance and was chemically compatible with MNH. Composites containing 2 wt% MSH and 2 wt% sodium carboxymethyl cellulose (CMC) performed favorable thermal properties, including supercooling degree of 0.6 °C, phase change temperature of 89 °C, latent heat of 166.88 J/g, and heat storage density of 220.78 J/g. Effective working temperature of the composite should be no more than 140 °C. Magnesium sulfate tetrahydrate (MST) was actually the real component in MSH that inhibited the supercooling of MNH. Compared with paraffin, encapsulated MNH-based composite PCM with a 6720 kJ higher heat storage capacity possessed a much shorter charging/discharging time due to the higher thermal conductivity. The results might provide a foundation for the practical application of MNH.

Investigation of the performance of basic magnesium sulfate cement mortar

Basic magnesium sulfate cement (BMSC) is a kind of magnesium oxide (MgO)–magnesium sulfate (MgSO4)–water (H2O) modified ternary cementitious material prepared from light burned magnesia, magnesium sulfate heptahydrate, water and additives. The effects of α-magnesium oxide/magnesium sulfate ratio (MO/MS), water/magnesium sulfate ratio (W/MS), sand-to-binder ratio (s/b) and superplasticiser dosage (SPD) on the performance of BMSC mortar were studied for the first time in this work. The results showed that for, optimal 28-day flexural strength, α-MO/MS = 10:1, W/MS = 16:1, s/b = 0.8 and SPD = 0.3%. For optimal 28-day compressive strength, α-MO/MS = 8:1, W/MS = 14:1, s/b = 0.6 and SPD = 0.4%. For best water resistance, α-MO/MS = 12.5:1, W/MS = 14:1, s/b = 0.2 and SPD = 0.1%. Based on these results, the basic mix proportion ranges of BMSC mortar should be α-MO/MS = 8:1–12.5:1, W/MS = 14:1–16:1, s/b = 0.2–0.6 and SPD = 0.1–0.4%.

The One-Way Analysis of Variance of Heat-Storage Materials Used in Building of Poultry Houses

In this study, a procedure for selecting the optimal heat-accumulating material based on phase transitions for the economical maintenance of poultry farms by applying ANOVA to complex solid bodies’ thermodynamic parameters is described. The relevance of the topic is due to its importance for the development of an energy-saving technology based on the release or absorption of significant heat during the crystallization or melting of materials. The applicability of one-way ANOVA for the selection of the optimal material with a specific functional purpose was demonstrated. As result, the best composition for maintaining a normal temperature regime in poultry farms that could meet all the requirements imposed on heat-storage materials was determined. It was found that magnesium sulphate heptahydrate is such a material.

Research on the Working Performance and the Corresponding Mechanical Strength of Polyaluminum Sulfate Early Strength Alkali-Free Liquid Accelerator Matrix Cement.

Liquid accelerating agents have the advantages of simple operation and fast construction, and have become indispensable admixtures in shotcrete. However, most liquid accelerating agents in the market at present contain alkali or fluorine, which adversely affect concrete and seriously threaten the physical and mental health of workers. Therefore, in view of the above deficiencies, it is necessary to develop a new type of alkali-free fluorine-free liquid accelerating agent. In this paper, the polyaluminum sulfate early strength alkali-free liquid accelerator is prepared using polymeric aluminum sulfate, diethanolamine, magnesium sulfate heptahydrate and nano-silica. The influence of this agent on the setting time of fresh cement paste and compressive strength of the corresponding cement mortar is determined. Thermogravimetric analysis curves, X-ray diffraction and scanning electron microscopy images are obtained to investigate the mechanism. Findings show that the initial setting time and the final setting time of cement paste are 2 min 30 s and 7 min 25 s. The compressive strengths of cement mortar cured for 1 d, 28 d and 90 d are 2.4 MPa, 52.2 MPa and 54.3 MPa respectively. Additionally, the corresponding flexural strengths are 3.4 MPa, 9.8 MPa, 11.8 MPa. When the mass rate of accelerator is 7%, the mechanical strengths of cement mortar are the highest. The additions of fly ash and blast furnace slag can affect the mechanical of cement mortar mixed with accelerator. When the mass ratio of the fly ash and blast furnace slag is 15%, the mechanical strengths of cement mortar reach the highest. Moreover, the hydration heat release rate of cement is increased by the accelerator and the corresponding time of hydration heat peak is decreased by the accelerator. The accelerator can decrease the amount of needle-like hydration products and improve the compactness. The mechanical strengths are improved by consuming a large amount of Ca(OH)2 and forming more compact hydration products. It is recommended that the optimum dosage range of the polyaluminum sulfate early strength alkali-free liquid accelerator is 7%.

Efficacy of hepatoprotectors in prophylaxis of hepatosis of laying hens

Hepatoses of laying hens are quite common in poultry farms as a result of improper practices of poultry maintenance consisting in excessive number of protein feeds for provision of high productivity. The objective of the study was preventive efficacy of Gep-A-Stress hepatoprotectors (carnitine hydrochloride, D L methionine, sorbitol, choline chloride, magnesium sulfate heptahydrate) and Hepasan VS (L-carnitine hydrochloride, sorbitol, choline chloride, magnesium sulfate hepahydrate, betaine hydrochloride, L-arginin) against hepatosis of laying hens. To determine the efficacy of Hep-A-Stres and Hepasan-VS hepatoprotectors during production tests (n = 4,500), we monitored the parameters of survival rate (the final number of individuals as percentage of the initial number) and egg productivity of laying hens. We determined that after 30 days of using the hepatoprotectors, the content of overall protein in blood serum of laying hens of the first and the second experimental groups decreased by 21.4% and 18.9% compared with the parameters prior to providing the hepatoprotectors and by 26.3% and 23.3% compared with the control group after receiving the drug. The urea contents in blood serum increased by 19.0% and 10.5%. Compared with the control, the activity of alanine aminotransferase decreased by 43.7% and 24.1% in the first experimental group and by 23.4% and 14.9% in the second. The activity of aspartate aminotransferase in blood serum of the experimental groups decreased by 10.7%. The cholesterol concentration decreased by 50% and 58.3%. The content of triaglycerols decreased by 24.1% and 8.9% respectively. The concentrations of high-density lipoproteins after 30 days of the experiment decreased by 33.3% and 77.8% respectively, the content of low-density lipoproteins decreased by 61.3% and 40.4% and 42.3%. Population maintenance equaled respectively 97.1%, 98.3% and 98.1%. At the end of the experiment, the egg productivity of laying hens of the first and second groups increased by 4% and 3.6% compared with the control. Therefore, intake of the hepaprotectors by laying hens stimulated their metabolism, positively influenced the blood parameters, survival and egg productivity. The conducted studies confirm the benefits of using hepatoprotectors for the prohylaxis of hepatosis of hens.

A Lower Dose of Mgso4 for Control of Convulsions in Bangladeshi Eclamptic Women

Introduction: Eclampsia is the third major cause of maternal death in Bangladesh contributing to 16 percent of total maternal mortality rate (MMR)¹. Standard practice in eclampsia is urgent control of convulsions and prevention of its recurrence with the help of a suitable anticonvulsant, prompt initiation of general and obstetric care and control of hypertension if needed. Methodology: This prospective cross-sectional analytic study was conducted in Dhaka Medical College Hospital (DMCH) eclampsia unit during August 2004 to January 2005 in order to determine whether 8 g of magnesium sulphate heptahydrate is sufficient in controlling convulsion and preventing recurrences in lighter Bangladeshi women instead of 10 g of magnesium sulphate (MgSO4) as loading dose that is now being used. One hundred consecutive eclamptic patients who were eligible for magnesium sulphate therapy were assigned by lottery to receive either 8 g of magnesium sulphate heptahydrate (MgSO4. 7H₂O) (group A) or 10 g of magnesium sulphate (group B). The two groups were well-balanced and comparable on important characteristics. Result: The results show that there was no significant difference between the two groups with respect to recurrent convulsion, time needed to regain consciousness and maternal and perinatal morbidities and mortalities. Conclusion: The results reveal that 8 g magnesium sulphate heptahydrate is as effective as 10 g MgSO4 (as loading dose) in management of eclamptic convulsion of Bangladeshi women. If 8 g of magnesium sulphate heptahydrate can be used, it will be more economic, painful intramuscular injections will be avoided and the risk of toxicity will be reduced

Bioflocculant produced by Bacillusvelezensis and its potential application in brewery wastewater treatment

This study was designed to evaluate the potential of bioflocculant producing strains isolated from wastewater sludge. According to the Plackett–Burman design, the response surface revealed glucose, magnesium sulfate, and ammonium sulfate as critical media components of the nutritional source, whereas the central composite design affirmed an optimum concentration of the critical nutritional source as 16.0 g/l (glucose), 3.5 g/l magnesium sulfate heptahydrate (MgSO4.7H2O), and 1.6 g/l ammonium sulfate ( (NH4)2SO4), yielding an optimal flocculation activity of 96.8%. Fourier Transformer Infrared Spectroscopy (FTIR) analysis confirmed the presence of hydroxyl, carboxyl and methoxyl in the structure of the bioflocculant. Additionally, chemical analysis affirmed the presence of mainly a polysaccharide in the main backbone of the purified bioflocculant with no detection of protein. Energy Dispersive X-ray analysis affirmed the presence of chlorine, phosphorous, oxygen and chlorine as representatives of elemental composition. Thermogravimetric (TGA) analysis revealed over 60% weight was retained at a temperature range of 700 °C. The purified bioflocculant remarkably removed chemical oxygen demand, biological oxygen demand and turbidity in brewery wastewater. This study suggested that the bioflocculant might be an alternate candidate for wastewater treatment.

Corrosion mechanism and damage characteristic of Q235B steel under the effect of stray current in NS4 simulated soil solution

Dynamic direct current (DC) may cause severe electrochemical corrosion on buried steel pipelines near urban rail transits. In this paper, the corrosion behavior of Q235B steel under dynamic DC interference was carried out in NS4 simulated soil solution (NS4 solution) including potassium chloride (KCl), sodium bicarbonate (NaHCO3), calcium chloride (CaCl2), Magnesium sulfate heptahydrate (MgSO4.7 H2O) and deionized water. The electrochemical corrosion behaviors of Q235B steel in NS4 solution were studied by means of potentiodynamic polarization (Tafel curve) and electrochemical impedance spectroscopy (EIS) techniques. Dynamic DC was simulated by four types of applied current according to the leakage current rule of rail trains arriving at and departing from the platform. The results of Tafel curves showed that Q235B steel exhibits a decrease in corrosion resistance with increasing applied current density, and anodic reaction exhibited active dissolution controlled by charge transfer. EIS results indicated that Nyquist plots of samples included double capacitive arcs and exhibited Warburg impedance characteristics caused by the concentration gradient. Weightlessness measurement showed that the average corrosion rates of four types of samples were 1.0, 1.4, 2.0, and 2.5 g.cm−2. d−1, respectively. In addition, the corrosion morphology indicated that samples featured in pitting corrosion, which was correlated to applied dynamic DC values and counts, and corrosion products were Fe3O4 and Fe (OH)3. Finally, the study shows that corrosion of buried steel pipelines is related to rail train arriving types and counts.

Medium for the Production of Bacillus-Based Biocontrol Agent Effective against Aflatoxigenic Aspergillus flavus: Dual Approach for Modelling and Optimization.

One of the leading limiting factors for wider industrial production and commercialization of microbial biopesticides refers to the high costs of cultivation media. The selection of alternative sources of macronutrients crucial for the growth and metabolic activity of the producing microorganism is a necessary phase of the bioprocess development. Gaining a better understanding of the influence of the medium composition on the biotechnological production of biocontrol agents is enabled through bioprocess modelling and optimization. In the present study, after the selection of optimal carbon and nitrogen sources, two modelling approaches were applied to mathematically describe the behavior of the examined bioprocess—the production of biocontrol agents effective against aflatoxigenic Aspergillus flavus strains. The modelling was performed using four independent variables: cellulose, urea, ammonium sulfate and dipotassium phosphate, and the selected response was the inhibition-zone diameter. After the comparison of the results generated by the Response Surface Methodology (RSM) and the Artificial Neural Network (ANN) approach, the first model was chosen for the further optimization step due to the better fit of the experimental results. As the final investigation step, the optimal cultivation medium composition was defined (g/L): cellulose 5.0, ammonium sulfate 3.77, dipotassium phosphate 0.3, magnesium sulfate heptahydrate 0.3.