Addition Of Sulfate Research Articles

The effect of soil liming, nitrogen and potassium application on the growth, development and physiological parameters of Calendula officinalis L.

The effect of soil liming and the addition of different doses of nitrogen and potassium on the growth, development and operation of FAS pot marigold plants (Calendula officinalis L. abrikosovy jam variety was studied. Experimental options: option 1 (control); option 2 (lime 4.6 t/ha); option 3 (lime 4.6 t/ha, N70K140); option 4 (lime 4.6 t/ha, N100K200). The plants were grown at an illumination intensity of PAR 200 mmol/m2, with a photoperiod of 12 hours before the flowering stage. The results of the study showed that the application of lime and mineral fertilizers significantly increased the biomass, height, leaf area of plants and the intensity of photosynthesis, accelerated the development of plants compared with the control. At the same time, the greatest influence on plant productivity was exerted by the introduction of lime into the soil, which caused a maximum increase in the intensity of photosynthesis and the water use efficiency (WUE), an increase in the number of inflorescences and their mass. The addition of urea and potassium sulfate caused an additional increase in plant weight and leaf area. There was no significant effect of nitrogen and potassium addition on the chlorophyll content, stomatal conductance, transpiration intensity and WUE.

Enhanced dispersion of prussian blue via intercalation into layered double hydroxides for efficient solar seawater evaporation.

Prussian blue (PB) is favored for its photothermal absorption capability in solar vapor generation applications. However, the photothermal conversion efficiency of current PB-based devices is limited by the material's poor dispersion. Herein, we report a method of incorporating PB in the interlayers of layered double hydroxides (LDHs) to prevent its aggregation. The dispersion is further enhanced and stabilized by the addition of sodium dodecyl sulfate (SDS). The thermal and water stability of PB is improved due to the rigid structure of LDHs and interactions between layers and anions. Elemental analysis confirms that with the increase of molar ratio of Mg/Al and the introduction of SDS, concentrations of PB are decreased accordingly. As a result, the rate of solar vapor generation is increased by 35.9% for powders containing 50 mg of equivalent PB. Of note, converting this material into a three-dimensional structure of high rebound foam further enhances solar water evaporation rate, from 0.79 kg m-2 h-1 to 0.98 kg m-2 h-1, with only 20 mg of equivalent PB, increasing the corresponding photothermal conversion efficiency from 53.8% to 66.3%.

Electrodeposition of copper on niobium for cryocooler application

The electrodeposition of copper onto niobium using commercial acidic and alkaline electrolytes was tested. The continuous dense polycrystalline copper films were successfully obtained in aqueous alkaline-type bath containing copper sulphate, sodium hydroxide and sodium gluconate. The effect of benzotriazole and sodium lauryl sulphate additives on the morphology and crystal structure of the deposited copper was investigated by optical and scanning electron microscopy, and X-ray diffraction. No copper oxides were found in the grown films. Copper films had moderate adhesion properties that would be insufficient for cryocooler application. We are currently exploring different compositions of electrolyte baths for obtaining the coatings on niobium with improved adhesion.

Improved control of Taraxacum officinale with 2,4‐D in the field from ammonium sulphate additions

AbstractTaraxacum officinale G.H. Weber ex Wiggers (dandelion) is a common weed of cool‐season turfgrass with 2,4‐D as the most commonly used herbicide for its control. Hard water is known to antagonise 2,4‐D dimethylamine herbicide efficacy in greenhouse studies, and this antagonism is mitigated by adding the water conditioning agent ammonium sulphate (AMS) to spray mixtures. As greenhouse herbicide efficacy trials do not always provide similar control to field studies, this experiment was undertaken to determine how hard water and AMS influences 2,4‐D dimethylamine control of T. officinale in established lawns. Hard water was prepared to achieve 0, 275, 450 and 675 mg CaCO3 L−1. The 2,4‐D was applied at each hardness level with and without AMS at 20 g L−1 in eight separate field trials across three sites and two seasons. Regardless of water hardness level, 2,4‐D treatments with AMS added reduced T. officinale cover at 52 weeks after application (WAA) compared to those without AMS. Similarly, fewer T. officinale plants were recorded when adding AMS to 2,4‐D. Taraxacum officinale cover at 52 WAA was higher when applied in water with a hardness of 450 mg CaCO3 L−1 or more compared to applications in distilled water (0 mg CaCO3 L−1). When hard water antagonism occurred, the addition of AMS to the spray mixture reduced the antagonism. Based on this field experiment and consistent with greenhouse experiments, applicators should mix AMS at 20 g L−1 when applying 2,4‐D dimethylamine, especially in hard water.

(Invited) The Effect of Surfactants on Vanadium Electrochemistry in Porous Carbon Electrodes

We present a study of vanadium electrochemistry in porous electrodes with and without sodium dodecyl sulfate (SDS) additives present. Carbon paper and felt electrodes are compared. Carbon felt electrodes are the de facto standard in flow batteries. There are significant differences in the electronic conductivity of these media. The carbon paper has a much higher conductivity than the felt, which has an electronic conductivity similar to the ionic conductivity of the electrolytes used. The latter fact motivates an extension of available theory for polarization curve fitting to explicitly include both electronic and ionic contributions in the porous electrode. We demonstrate agreement between our model and an existing model evaluated at the limit where electrode conductivity is significantly greater than electrolyte conductivity. Our model uses the product of the electrode surface area per volume ratio and the heterogeneous electron transfer rate constant, and the Damköhler number as fitting parameters for carbon paper and felt electrodes. We discuss the effect of SDS additives on kinetics in the context of the cation hydration shell for the vanadium ions. To this point, we apply Marcus-Hush-Chidsey formalism to our porous electrode model to quantify reorganization energies obtained through polarization curve fitting. This work was supported as part of the Breakthrough Electrolytes for Energy Storage (BEES2), an Energy Frontier Research Center funded by the United States. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0019409.

Yield and grain quality of oat (Avena sativa L.) varieties grown on typical chernozems

Purpose. To determine the yield potential and grain qua­lity of varieties of oat (Avena sativa L.) as a function of the nutritional and climatic conditions. Methods. Field, laboratory (grain quality determination) and statistical methods were used in the research. Results. Using different fertilization systems, seven oat varieties were studied, of which the most productive were ‘Ayvori’, ‘Lehin Nosivskyi’ and ‘Zakat’. The greatest increase in yield due to the use of fertilizers in 2022–2023 (1.24–2.73 t/ha with average increases of 0.32–2.83 t/ha) was observed for the cultivation of the ‘Ayvori’ variety. Additional increases due to the introduction of sulphur, compared to the options where only nitrogen, phosphorus and potassium were used, were observed for the varieties ‘Neptun’ – 0. 26–0.39 t/ha; ‘Lehin Nosivskyi’ – 0.47–0.49; ‘Svitanok’ – 0.23–0.66; ‘Zakat’ – 0.39–0.64; ‘Zubr’ – 0.41–0.54; ‘Albatros’ – 0.58–0.78; ‘Ayvori’ – 0.34–0.66 t/ha. The average yield of the control varieties in 2021–2023 was as follows 2.28 t/ha – ‘Neptun’; 2.64 – ‘Lehin Nosivskyi’; 2.50 – ‘Svitanok’; 2.70 – ‘Zakat’; 2.71 – ‘Zubr’; 2.60 – ‘Albatros’; 2.81 t/ha – ‘Ayvori’. Increasing the rate of nutrient application to the soil helped to improve grain quality. Thus, with the addition of N30P30K30 + N30 BBCH32, the protein content in the grain was within 10.2–10.8%; N60P60K60 + N30 ВВСН32 – 10.4–11.2; N90P90K90 + N30 ВВСН32 – 11.0–11.8; N120P120K120 + N30 BBCH32 – 11.4–12.4%. The addition of sulphur to the fertilization system resulted in a more efficient use of nitrogen and therefore an increase in the protein content of the grain of 1.3–1.8% compared to the options where the rate of macronutrients was the same for all varieties. The content of albumins and globulins was higher in the grain of the control variant (17.0–19.3 and 20.1–21.6% respectively) and did not vary significantly between varieties. The amount of reserve proteins – prolamins and glutelins – increased (from 28.4–30.2 to 34.8–36.2%) with an increase in fertilizer rate, especially with the introduction of N120P120K120S45 + N30. Conclusions. All investigated oat varieties are highly productive and give yields in the range of 3.33–5.54 t/ha, depending on the fertilizer rate. The variety ‘Neptun’ is slightly lower in yield than the others, but has grain with a significant content of biologically valuable protein fractions. The application of sulphur­containing fertilizers increases yield, improves grain quality and allows a more efficient use of nitrogen, which makes it possible to reduce the basic rate of addition of macronutrients to the soil.

Microwave-enhanced sulfate roasting for lithium extraction from lepidolite: A comprehensive study

Currently, the sulfate method used for roasting lepidolite to extract lithium presents several issues, including high energy consumption and low recovery efficiency. To address these limitations, we have employed microwave external fields to enhance lithium extraction and modified the roasting process. Microwave-enhanced roasting reduces heating time from 43 to 20 min, significantly lowering energy consumption compared to conventional roasting. Experimental results reveal that the optimal conditions are ferrous sulfate: potassium sulfate: calcium oxide: ore = 2:0.6:0.1:1, roasting temperature at 775 °C, and roasting time of 2 h, resulting in a lithium leaching efficiency of 95.9%. The study of dielectric properties shows that the addition of sulfate improves the microwave absorption characteristics of lepidolite, facilitating rapid heating in the microwave field. Additionally, uniform microwave heating reduces sample melting and adhesion, leading to looser clinker and improved lithium leaching efficiency. The microwave-enhanced sulfate roasting technology holds significant importance for the study of lithium extraction from lepidolite.

Understanding the Impact of Peripheral Substitution on the Activity of Co Phthalocyanine in Sulfur Reduction Catalysis

AbstractCatalytic materials are effective in promoting sulfur utilization in lithium‐sulfur batteries. Co phthalocyanine (CoPc) presents a unique planner single‐molecular structure with a highly active Co‐N4 center for sulfur reduction catalysis. The high flexibility of phthalocyanines offers rich opportunities for electronic structure modulation toward enhanced catalytic activities. To guide future design and screening, this study aims to understand the impact of peripheral substitution, the most common method to obtain CoPc derivatives, by examining two typical substituents: the electron‐withdrawing nitro and electron‐donating amino groups. Co tetranitrophthalocyanine (CoTnPc) presents a significantly higher activity in promoting the liquid‐solid transition process than Co tetraaminophthalocyanine (CoTaPc). Substitution alters the stable binding geometry of Li2S4 by influencing the electrostatic potential and Li─bond, making the Co─S bond energetically favorable with the bridging S atoms on CoTnPc. CoTnPc also enables a greater electron donation from the S 3pz orbital to the singly occupied Co 3 orbital, significantly weakening the bridging S─S bond to enhance the reactivity of Li2S4 for the subsequent liquid‐solid transition. A framework of theoretical calculation is tested, providing descriptors for the screening of related materials. The potential of CoPc derivatives is demonstrated by pouch cells with CoTnPc under high sulfur loading and limited electrolyte addition.

Enhanced removal of bisphenol S in ozone/peroxymonosulfate system: Kinetics, intermediates and reaction mechanism

The degradation process of bisphenol S (BPS) in ozone/peroxymonosulfate (O3/PMS) system was systematically explored. The results showed that the removal efficiency of BPS by O3 could be significantly improved with addition of PMS. Compared with ozonation alone, the pseudo-first-order constant (kobs) was increased by 2–5 times after adding 400 μM PMS. In O3/PMS system, accelerated removal of BPS was observed under neutral and alkaline conditions. The removal efficiency of BPS reached 100% after 40 s of reaction at pH 7.0, with the kobs of 0.098 s−1. Moreover, Cu2+ had a catalytic effect on the O3/PMS system, because it could catalyze the decomposition of ozone and PMS to produce •OH and SO4•-, respectively. Electron paramagnetic resonance illustrated that •OH and SO4•- were the reactive species in O3/PMS system. Twelve intermediates were identified by mass spectrometry, and the degradation reactions in O3/PMS system mainly included hydroxylation, sulfate addition, polymerization and β-scission. Finally, the toxicity of the products was evaluated by the EOCSAR program. Our results introduce an efficient method for BPS removal and would provide some guidance for the development of O3-based advanced oxidation technology.

Elemental Sulfur and Organic Matter Amendment Drive Alkaline pH Neutralization and Mineral Weathering in Iron Ore Tailings Through Inducing Sulfur Oxidizing Bacteria.

Mineral weathering and alkaline pH neutralization are prerequisites to the ecoengineering of alkaline Fe-ore tailings into soil-like growth media (i.e., Technosols). These processes can be accelerated by the growth and physiological functions of tolerant sulfur oxidizing bacteria (SOB) in tailings. The present study characterized an indigenous SOB community enriched in the tailings, in response to the addition of elemental sulfur (S0) and organic matter (OM), as well as resultant S0oxidation, pH neutralization, and mineral weathering in a glasshouse experiment. The addition of S0 was found to have stimulated the growth of indigenous SOB, such as acidophilic Alicyclobacillaceae, Bacillaceae, and Hydrogenophilaceae in tailings. The OM amendment favored the growth of heterotrophic/mixotrophic SOB (e.g., class Alphaproteobacteria and Gammaproteobacteria). The resultant S0 oxidation neutralized the alkaline pH and enhanced the weathering of biotite-like minerals and formation of secondary minerals, such as ferrihydrite- and jarosite-like minerals. The improved physicochemical properties and secondary mineral formation facilitated organo-mineral associations that are critical to soil aggregate formation. From these findings, co-amendments of S0 and plant biomass (OM) can be applied to enhance the abundance of the indigenous SOB community in tailings and accelerate mineral weathering and geochemical changes for eco-engineered soil formation, as a sustainable option for rehabilitation of Fe ore tailings.

Sodium sulfate addition increases the bioresource of biologically active sulfated polysaccharides from Antrodia cinnamomea

Fungal sulfated polysaccharides (SPS) have been used in the pharmaceutical industry. In this study, sodium sulfate was employed as an elicitor to induce stress on the mycelia of Antrodia cinnamomea for the biosynthesis of SPS with high sulfate content. Sodium sulfate treatments increased the yield of SPS to 4.46 % and increased the sulfate content to 6.8 mmol/g of SPS. SPS were extracted from A. cinnamomea cultured with 500 mM sodium sulfate; these SPSs are denoted as Na500. Na500 exhibited the highest sulfate content and dose-dependent inhibitory activity against LPS-induced production of macrophage interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and interleukin 1β (IL-1β). Mechanistically, Na500 hindered the phosphorylation of transforming growth factor-β receptor II (TGFRII), extracellular signal-regulated kinases (ERK), and protein kinase B (AKT) expression. A purified 7.79 kDa galactoglucan, Na500 F3, augmented the anti-inflammation activity by inhibiting LPS-induced TGFβ release. Additionally, Na500 F3 restrained the LPS-induced phosphorylation of p-38, ERK, AKT, and TGFRII in RAW264.7 cells. Na500 F3 impeded the proliferation of lung cancer H1975 cells by inhibiting the phosphorylation of focal adhesion kinase, ERK, and Slug. The anti-inflammation and anticancer properties of Antrodia SPS contribute to its health benefits, suggesting its utility in functional foods.

Paper Waste Hydrolysis with Stepwise Sulfuric Acid Catalyst

The need for paper results in a lot of paper waste. Paper waste, which is lignocellulosic, can be hydrolyzed using an acid catalyst to produce various cellulose degradation products. In this study, the effect of the sulfuric acid catalyst addition method on the waste paper hydrolysis process was investigated. The addition of the catalyst was carried out in three types. The Type-1 method was sulfuric acid addition in the 0th minute. The Type-2 method was sulfuric acid addition in the 0th and 30th minutes. The Type-3 method was sulfuric acid addition every 10 minutes. The results showed that the lowest residual mass of waste paper hydrolyzed was produced using the Type-3 method. This showed that the Type-3 method, sulfuric acid addition every 10 minutes, had an effect on the residual mass of the hydrolyzed sample. The Type-3 method was the most effective type of sulfuric acid catalyst addition compared to other types. On the other hand, variations in the concentration of the sulfuric acid catalyst affect the residual mass of the waste paper hydrolyzed sample, where higher sulfuric acid concentration will lower residual mass. The catalyst concentration of 2% sulfuric acid with The Type-3 addition method resulted in the highest conversion which was 38.27%.

Increased monocarbonate formation during long-term hydration of CAC-limestone binder by calcium sulfate addition – A temperature-dependent XRD study

The long-term hydration of a mix with and without gypsum addition was investigated at 10, 23 and 40 °C by QXRD analysis. In addition, thermodynamic modelling was performed on all systems using GEMS to determine the stable phase composition and the influence of water loss during hydration. The results show that the formation of conversion-sensitive phases such as CAH10 is accelerated at 10 °C and hindered at 23 and 40 °C by the addition of gypsum. Moreover, at all different temperatures, monocarbonate forms next to AH3 as the main hydrate phase and the final phase composition is reached after at least 14 d (at 23 °C and 40 °C already after 2 d). Formation of low amounts ettringite only occurs at 10 and 23 °C during the entire storage time. At 40 °C, however, ettringite is not observed, which is probably due to water loss in the mix until 2 d.

A highly sensitive micelle-enhanced synchronous spectrofluorimetric determination of the recently approved co-formulated drugs, bilastine and montelukast in pharmaceuticals and human plasma at nanogram levels.

In this study, the simultaneous determination of bilastine and montelukast, two recently approved co-formulated antihistaminic medications, was accomplished using a quick, sensitive, environmentally friendly, and reasonably priced synchronous fluorescence spectroscopic approach for the first time. Enhancement of the method's sensitivity down to nanogram levels was achieved by the addition of sodium dodecyl sulfate (1.0% w/v) as a micellar system. According to the results, bilastine and montelukast's fluorescence was measured at 255.3 and 355.3nm, respectively, using Δλ of 40.0nm and distilled water as a green diluting solvent. With respect to the concentration ranges of bilastine (5.0-300.0ng/ml) and montelukast (50.0-1000.0ng/ml), the method showed excellent linearity (r ≥ 0.9998). The results showed that the suggested method is highly sensitive, with detection limits of 1.42 and 13.74 ng/ml for bilastine and montelukast, respectively. Within-run precisions (intra- and interday) per cent relative standard deviations (RSD) for both analytes were <0.59%. With high percentage recoveries and low percentage RSD values, the designed approach was successfully applied for the simultaneous estimation of the cited medications in their dosage form and human plasma samples. To evaluate the green profile of the suggested method, an analytical GREENNESS metric approach (AGREE) and green analytical procedure index (GAPI) metric tools were used. These two methods for evaluating greenness confirmed that the developed method met the highest number of green requirements, recommending its use as a green substitute for the routine analysis of the studied drugs. The proposed approach was validated according to ICHQ2 (R1) guidelines.

The Effect of Sulfur and Cutting Height on the Growth Characteristics of Sorghum Crop (Buhooth 70)

A field experiment was conducted during the 2022 season at the Research Center of the College of Agricultural Engineering Sciences - University of Baghdad, with the aim of studying the effect of agricultural sulfur levels and cutting heights, as well as their interaction, on the growth characteristics of sorghum (Variety Buhooth 70). The experiment included four levels of agricultural sulfur (0, 1, 2, and 3 tons S ha-1) and three cutting heights (10, 15, and 20 cm). The experiment was conducted according to a randomized complete block design (RCBD) with split-plots arrangement, with three replications and two cuts. Samples were taken at the beginning of the flowering stage, and the following characteristics were studied: plant height, stem diameter, leaf number, leaf area, nodes, and internodes. The results indicated a significant effect of agricultural sulfur addition on all studied characteristics. The treatment with the highest sulfur level (3 tons S ha-1) and both the first and second cuts recorded the highest mean for plant height, stem diameter, leaf number, leaf area, nodes, and internodes, with values of (200.6 cm, 0.737 cm, 8.46, 1434 cm2, 8.08) for the first cut respectively, and (242.7 cm, 1.8 cm, 13.44, 4243 cm2, 8.389) for the second cut respectively. Cutting height also had a significant effect on most of the study’s characteristics, but only in the second cut. The treatment with a cutting height of 20 cm showed the highest mean for plant height, stem diameter, leaf number, and leaf area, with values of (244.6 cm, 1.627 cm, 12.82, 3974 cm2) respectively. The interaction between the two study factors also had a significant effect in the second cut, with the combination of 3 tons S ha-1 and 20 cm cutting height showing the highest mean for plant height and stem diameter, reaching (286.8 cm, 2.213 cm) respectively.

Influence of sulfur ions on the glass-forming ability and structure of silicate-phosphate glasses

The aim of the study was to analyze the structure of two groups of glasses: first sulfur-free from the SiO2-P2O5-K2O-MgO system and second sulfur-containing from the SiO2-P2O5-K2O-MgO-SO3 system with various network formers content in the form of P2O5 and SiO2. The sulfur speciation in the sulfur-bearing glasses was also determined. The sulfur-containing glasses were obtained under reducing conditions. The bulk composition of the glasses was confirmed by X-Ray Fluorescence Spectroscopy. The amorphous nature of the samples was verified using XRD analysis. The structure of the materials was studied with the 29Si and 31P MAS NMR and XAS spectroscopic techniques. It was found that the addition of sulfur increased the ability of glasses with higher amounts of P2O5 to form. XAS spectra demonstrate that S-bearing glasses contain sulfur in the reduced form as S2-. The 31P and 29Si MAS NMR spectra did not detect P-S and Si-S linkages.

Synergistic effect of sodium dodecyl sulfate (SDS) and oleic acid (OA) on gelation and lubrication performance

In this paper, it was found that with the addition of sodium dodecyl sulfate (SDS, a hydrophilic surfactant) and oleic acid (OA, a lipophilic surfactant) in a solvent with a proper composition ratio, a stable gel could be obtained via a simple ultrasonic treatment. The synergistic gelation of OA–SDS was verified in a series of solvents with different polarities, such as white oil (WO), LB-2000, n-hexane, polyalphaolefin (PAO10), and deionized water. The Fourier transform infrared (FTIR) analysis confirms that the gelation of OA–SDS is highly related to the ion exchange reaction between them. However, the xerogel of OA–SDS gelator in deionized water and WO (OSW) exhibited remarkably different morphologies, indicating that the gelation is based on different molecular assembly processes, which is governed by the orientation of the two surfactant molecules in liquid media. Further characterizations of OSW gel presented that the synergistic effect between OA and SDS not only existed in gelation, but also in enhancing the mechanical and thermal stability of WO, and endowing the OSW gel with reliable friction reduction and antiwear performances under variable working conditions. Subsequently, the lubrication mechanism was proposed based on rheological analysis and the morphological and compositional analysis of wear surfaces. This study provides a novel idea for the molecular design of lubricating gelators with wide adaptability to solvent polarity and working conditions.

Role of WSOCs and pH on Ammonium Nitrate Aerosol Efflorescence: Insights into Secondary Aerosol Formation.

Efflorescence of ammonium nitrate (AN) aerosols significantly impacts atmospheric secondary aerosol formation, climate, and human health. We investigated the effect of representative water-soluble organic compounds (WSOCs) (sucralose (SUC), glycerol (GLY), and citric acid (CA) on AN:WSOC aerosol efflorescence using vacuum Fourier transform infrared spectroscopy. Combining efflorescence relative humidity (ERH) measurements, heterogeneous nucleation rates, and model predictions, we found that aerosol viscosity, correlating with molecular diffusion, effectively predicted ERH variations among the AN:WSOC aerosols. WSOCs with higher viscosity (SUC and CA) hindered efflorescence, while GLY with a lower viscosity showed a minor effect. At a low AN:CA molar ratio (10:1), CA promoted ERH, likely due to CA crystallization. Increasing the droplet pH inhibited AN:CA aerosol efflorescence. In contrast, for AN:SUC and AN:GLY aerosols, efflorescence is pH-insensitive. With the addition of trivial sulfate, AN:SUC droplets exhibited two-stage efflorescence, coinciding with ammonium sulfate and AN efflorescence. Given the atmospheric abundance, the morphology, phase, and mixing state of nitrate aerosols are significant for atmospheric chemistry and physics. Our results suggest that AN:WSOCs aerosols can exist in the amorphous phase in the atmosphere, with efflorescence behavior depending on the aerosol composition, viscosity, pH, and the cation and anion interactions in a complex manner.

Molecular Cloning, Characterization, and Application of Organic Solvent-Stable and Detergent-Compatible Thermostable Alkaline Protease from Geobacillus thermoglucosidasius SKF4.

Several thermostable proteases have been identified, yet only a handful have undergone the processes of cloning, comprehensive characterization, and full exploitation in various industrial applications. Our primary aim in this study was to clone a thermostable alkaline protease from a thermophilic bacterium and assess its potential for use in various industries. The research involved the amplification of the SpSKF4 protease gene, a thermostable alkaline serine protease obtained from the Geobacillus thermoglucosidasius SKF4 bacterium through polymerase chain reaction (PCR). The purified recombinant SpSKF4 protease was characterized, followed by evaluation of its possible industrial applications. The analysis of the gene sequence revealed an open reading frame (ORF) consisting of 1,206 bp, coding for a protein containing 401 amino acids. The cloned gene was expressed in Escherichia coli. The molecular weight of the enzyme was measured at 28 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The partially purified enzyme has its highest activity at a pH of 10 and a temperature of 80°C. In addition, the enzyme showed a half-life of 15 h at 80°C, and there was a 60% increase in its activity at 10 mM Ca2+ concentration. The activity of the protease was completely inhibited (100%) by phenylmethylsulfonyl fluoride (PMSF); however, the addition of sodium dodecyl sulfate (SDS) resulted in a 20% increase in activity. The enzyme was also stable in various organic solvents and in certain commercial detergents. Furthermore, the enzyme exhibited strong potential for industrial use, particularly as a detergent additive and for facilitating the recovery of silver from X-ray film.

Rheological and Aging Characteristics of Polymer-Modified Asphalt with the Addition of Sulfur

Crosslinking agents, notably sulfur, are used in asphalt binder modification to facilitate chemical bonding between polymer chains and the asphalt binder. Despite some prior research indicating the benefits of sulfur crosslinking in enhancing polymer-modified asphalt’s (PMA) stability, there is a lack of comprehensive understanding regarding its impact on rheological properties and its anti-aging potential. This study addresses these gaps by thoroughly investigating the effects of varying the sulfur content (ranging from 0.03% to 0.5% by total weight of binder) on PMA’s rheological properties. The research assesses the effectiveness of sulfur in enhancing PMA’s resistance to aging using various methods, including the Glover-Rowe parameter, FTIR analysis, and the examination of the dynamic modulus and phase angle master curves. The results indicated that the addition of sulfur, particularly up to 0.3%, bumps the high-temperature performance grade by one level, and significantly improves elasticity, allowing the PMA to support heavier traffic without experiencing rutting, all while maintaining resistance to low-temperature cracking. Furthermore, PMA with sulfur demonstrated an increase in resistance to aging, reducing the aging potential by approximately 15% with the best sulfur formulation. This enhanced durability can reduce the frequency of maintenance activities, leading to cost savings, reduced roadwork emissions, and prolonged pavement life.