Ammonium Sulfate Research Articles

Transcriptome analysis of the degradation process of organic nitrogen by two heterotrophic nitrifying and aerobic denitrifying bacteria.

The heterotrophic nitrification aerobic denitrification bacteria (HNDS) can perform nitrification and denitrification at the same time. Two HNDS strains, Achromobacter sp. HNDS-1 and Enterobacter sp. HNDS-6 which exhibited an amazing ability to solution nitrogen (N) removal have been successfully isolated from paddy soil in our lab. When peptone or ammonium sulfate as sole N source, no significant difference in gene expression related to nitrification and denitrification of the strains was found according to the transcriptome analysis. The expression of phosphomethylpyrimidine synthase (thiC), ABC transporter substrate-binding protein, branched-chain amino acid ABC transporter substrate-binding protein, and RNA polymerase (rpoE) in HNDS-1 were significantly upregulated when used peptone as N source, while the expression of exopolysaccharide production protein (yjbE), RNA polymerase (rpoC), glutamate synthase (gltD) and ABC-type branched-chain amino acid transport systems in HNDS-6 were significantly upregulated. This indicated that these two strains are capable of using organic N and converting it into NH4+-N, then utilizing NH4+-N to synthesize amino acids and proteins for their own growth, and strain HNDS-6 can also remove NH4+-N through nitrification and denitrification.

Hydrogel Effects on Soil Nitrogen Transformations in pH-Contrasting Soils

ABSTRACT Superabsorbent hydrogels (HGs) are three-dimensional, polymeric networks that have been shown to increase soil water holding capacity, but little is known about their effect on nitrogen (N) transformations in soil. The objective of this study was to determine the effect of two types of HGs (polyacrylate (TS) or cellulose-based (H30)) applied as soil amendment on pH, urea hydrolysis, nitrification, NH3 volatilization, and soil respiration in two soils receiving urea or ammonium sulfate. Separate studies with each HG in each of two soils (four studies) were conducted with an acidic sandy loam collected in Georgia (USA) and a basic sandy loam collected in the Veneto region of Italy. The results showed that the addition of TS increased the pH of the acidic soil, whereas H30 did not have a major effect on soil pH in either soil. In the acidic soil receiving urea, H30 increased nitrification, whereas TS decreased initial nitrification. Neither HG affected urea hydrolysis, N immobilization and NH3 volatilization in either soil, but both HGs increased soil respiration in the basic soil, possibly due to HG degradation by microorganisms. These results show that the use of HGs together with N fertilizers may affect soil pH, nitrification, and respiration.

Cost effective synthesis of sulfur and nitrogen co-doped graphene aerogel and application in binder free supercapacitor

Incorporating heteroatoms into graphene lattice results in enhanced electrical conductivity and electrochemically active sites and has significant importance in developing high-performance supercapacitors. In this study, sulfur and nitrogen co-doped graphene aerogel is synthesized via hydrothermal technique followed by a simple but effective freeze-thawing and ambient pressure drying process (referred to as SN-GA). The process requires low-cost raw materials and cost-effective equipment without the utilization of any special instrument that operates at ultra-low temperatures, under high pressure, or vacuum environment. Ammonium sulfate [(NH4)2SO4] and ethylenediamine are used as a source of sulfur and nitrogen and as a reducing agent. (NH4)2SO4 with different molarities (0, 12, 24, and 36 mM) are used to synthesize four different aerogel samples marked as GA, SN-GA1, SN-GA2, and SN-GA3. The electrode is prepared using an SN-GA2 sample, exhibiting an outstanding specific capacitance of 244 F g−1 at an applied current density of 1 A g−1 with almost 98.5% Coulomb efficiency. Furthermore, based on the SN-GA2 sample, the symmetrical supercapacitor is fabricated, displaying an energy density of 18.14 Wh kg−1 at a power density of 498.4 W kg−1. Hence, SN-GA2 renders a promising material for supercapacitor applications.

Recovery of Rare Earth from Sedimentary Rare Earth Ore Using an Ammonium Sulfate Roasting and Leaching Process

Recovery of Rare Earth from Sedimentary Rare Earth Ore Using an Ammonium Sulfate Roasting and Leaching Process

Response of tomato to innovative organo-mineral fertilizers

Organo-mineral fertilizers (OMFs) with low organic carbon (Corg) content have been associated with higher mineral fraction nutrient use efficiency. However, the extraction of peat, which is typically used in these OMFs, from endangered ecosystems causes long-time stored Corg to mineralize and to be released back into the atmosphere as carbon dioxide (CO2). This study analyzes the replacement of peat in OMFs with biowaste materials. These materials, considered organic byproducts that microorganisms and other living things can decompose through composting and aerobic or anaerobic digestion, offer a viable opportunity. This study investigated three stabilized biowastes—green compost (GC) from pruning residues, municipal solid waste compost (MSWC), and manure-based vermicompost (VC)—as the organic matrices for granular OMFs. These matrices were impregnated with dissolved ammonium sulfate and urea and used to coat diammonium phosphate granules. Each biowaste OMF contained 7.5% Corg, 20% mineral N, and 10% mineral P2O5 (OMF20 − 10). Fertilizers with high nutrient concentrations have the advantage of requiring low application volumes, facilitating their application in the field. Biowaste OMFs were compared with peat OMFs with the same Corg-N-P2O5 concentration. Peat and MSWC were also used to create OMFs containing 7.5% Corg, 10% mineral N, and 5% mineral P2O5 (OMF10 − 5). A 75-day tunnel trial was conducted under semi-controlled conditions using tomato plants (Solanum lycopersicum L.) fertilized to an equivalent of 81 mg N kg−1 soil and 18 mg P kg−1 soil. Controls included no fertilization (N0P0) and mineral N and P fertilization (MFNP). The Soil Plant Analysis Development (SPAD) chlorophyll meter and the BBCH (from German Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie) scale as well as the number of shoots were measured over time, as berry and total aboveground yield, N and P uptakes, and N and P use efficiencies (NUE and PUE, respectively) were calculated at harvest. All treatments outperformed the control N0P0 in most indicators. Peat20 − 10 did not have more berry yield than other OMF20 − 10; however, the higher number of shoots indicated a higher potential yield in the event of prolonging the experiment. At the end of 75 days, VC20 − 10 and MSWC20 − 10 showed similar PUE to peat, suggesting that those materials can be used as replacements. In the case of OMF10 − 5, MSWC10 − 5 had yield and N and P uptakes like peat OMFs, confirming the potential use of MSWC as peat replacement even at different nutrient concentrations. This research provides reassuring evidence of the effectiveness of biowaste OMFs, offering a positive outlook for sustainable agriculture. However, their use is not recommendable for short growing seasons.

Applicability of Salting-Out Liquid-Liquid Extraction for New Fluorimetric Quantification of Omadacycline in Pharmaceutical Formulations and Biological Samples

Objective: A detectable innovative fluorimetric method was used to determine OMC in human plasma matrices, pharmaceutical tablets, and vials with high recovery rates and without biological interference. Method: The fluorimetric technique was used based on the interaction between 4-chloro7-nitrobenzofurazan (NBD-Cl) with a (2-ry amine group) in OMC with pH 8.0, which generates a fluorescent compound measured at 530 nm (exci 470 nm) following a 10-minute heating step at 80 oC. The plasma and milk samples were treated with ammonium sulfate as a salting-out procedure. Results: Omadacycline (OMC) was successfully determined in pharmaceutical, plasma, and milk samples with a linear range from 60.0 to 700.0 ng mL-1, with the lower limit of detection (LOD 5.18 ng mL-1) and limit of quantitation (LOQ 15.72 ng mL-1). Conclusion: This simple, reliable, and detectable fluorimetric method was successfully developed to determine omadacycline in pharmaceutical tablets, plasma samples, and milk with high recovery rates.

Evaluation of spent coffee grounds as a nutrient source for turfgrass systems

The growing popularity of cold-brewed coffee has resulted in large amounts of localized spent coffee grounds (SCG) generated from production plants. Spent coffee grounds offer many favorable agronomic properties, but also contain caffeine, tannins and phenolic compounds that may be deleterious to plant growth. There is a growing body of research examining the effects of SCG on plants, but little of which pertains to use in turfgrass systems. The objective of this two-year field study was to evaluate the feasibility of using SCG as an agronomic source of nutrients for turfgrass. Field studies were conducted over two years to characterize performance of ‘Riley’s Super Sport’ (Celebration®) bermudagrass (Cynodon dactylon) receiving multiple nutrient source treatments including fresh and composted SCG, as well as synthetic, natural organic, and bridge fertilizers, some which included SCG. Soils were analyzed at the conclusion of the study to determine whether SGC provided long-term effects of on soil pH and/or nutrient concentrations. Our results demonstrated that although SCG possesses between 2.3-2.9% N and a favorable C:N ratio, direct SCG applications over two seasons did not produce responses typical of a fertilizer when applied as a topdressing. However, when combined with poultry litter, the SCG-containing organic fertilizer GeoJava produced improved turf quality relative to other organic and synthetic commercial fertilizers in our study, including Milorganite, ammonium sulfate, and URI-PEL S.R. Further, despite the acidic nature of SCG, their repeated application over multiple years did not result in any long-term changes to soil pH. Although early on, SCG treatments caused mild and transient phytotoxicity, these effects were not observed when it was applied in combination with the manure used in GeoJava.

A bioinspired doxorubicin-carried albumin Nanocage against aggressive Cancer via systemic targeting of tumor and lymph node metastasis

Cancer metastasis and recurrence are obstacles to successful treatment of aggressive cancer. To address this challenge, chemotherapy is indispensable as an essential part of comprehensive cancer treatment, particularly for subsequent therapy after surgical resection. However, small-molecule drugs for chemotherapy always cause inadequate efficacy and severe side effects against cancer metastasis and recurrence caused by lymph node metastases. Here, we developed doxorubicin-carried albumin nanocages (Dox-AlbCages) with appropriate particle sizes and pH/enzyme-responsive drug release for tumor and lymph node dual-targeted therapy by exploiting the inborn transport properties of serum albumin. Inspired by the protein-templated biomineralization and remote loading of doxorubicin into liposomes, we demonstrated the controlled synthesis of Dox-AlbCages via the aggregation or crystallization of doxorubicin and ammonium sulfate within albumin nanocages using a biomineralization strategy. Dox-AlbCages allowed efficient encapsulation of Dox in the core protected by the albumin corona shell, exhibiting favorable properties for enhanced tumor and lymph node accumulation and preferable cellular uptake for tumor-specific chemotherapy. Intriguingly, Dox-AlbCages effectively inhibited tumor growth and metastasis in orthotopic 4T1 breast tumors and prevented postsurgical tumor recurrence and lung metastasis. At the same time, Dox-AlbCages had fewer side effects than free Dox. This nanoplatform provides a facile strategy for designing tumor- and lymph node-targeted nanomedicines for suppressing cancer metastasis and recurrence.

Oil-Coated Ammonium Sulfate Improves Maize Nutrient Uptake and Regulates Nitrogen Leaching Rates in Sandy Soil

Ammonium sulfate (AS) has been utilized in agriculture; however, there is a dearth of research on its application in maize cultivation subsequent to the implementation of nitrification inhibitors or coating treatments. This study aimed to analyze the impacts of various combinations of AS fertilizers on soil nutrients, plant nutrient uptake, yield, and fertilizer utilization efficiency in maize cultivation to establish an optimal and stabilized disposal method for AS. A completely randomized design was employed with five treatments (AU, the control using urea; AS, treatment using ammonium sulfate; ASN, treatment using ammonium sulfate with a nitrification inhibitor; ASG, treatment using oil-coated ammonium sulfate; and ASD, treatment using oil–humic acid-coated ammonium sulfate). The results show the following: (1) Compared with AU and AS, ASN, ASG, and ASD decreased the leaching rates of total nitrogen (TN), ammonium nitrogen (NH4+-N), and nitrate nitrogen (NO3−-N), and more residual N had accumulated in the soil. The first-order kinetic equation Nt = N0(1 − e−kt) could better fit the process of N accumulation and release, and the N-release rate constant was in the order of AU > CK > AS > ASG > ASN > ASD. (2) Compared with the AU and AS treatments, the plant dry weight, grain dry weight, spike width, spike length, and yields of maize increased by 8.85–11.08%, 12.98–14.15%, 2.95–3.52%, 5.50–5.65%, and 43.21–51.10%, respectively, under the ASG treatment. A path analysis revealed the main decision coefficient of the effective spike number on the maize yield. Furthermore, the accumulation levels of N, P, and K within above-ground plants significantly increased under the ASG treatment compared with those under the AU and AS treatments. N, P, and K partial factor productivity under the ASG treatment increased by 47.12%, 47.15%, and 73.40% on average, while grain N, P, and K balance increased by 50.45%, 47.10%, 55.61% on average, compared with the AU and AS treatments. Therefore, the ASG treatment exhibited the optimal slow-release effect on nutrients and achieved excellent performance in enhancing the production and efficiency of maize.

Research on the Use of Organic Fertilizer Instead of Chemical Fertilizer and Its Effect on the Morphological and Yield in Fennel Plant

Objective: Organic manures can be used as an alternative method to replace chemical fertilizers for sustainable agricultural production. Sheep manure and vermicompost are the most important alternative applications. These manures can increase soil fertility, plant productivity, and quality. Fennel (Foeniculum vulgare L.) has been used as a medicinal and aromatic plant throughout human history, and it is widely used as a food additive, pharmacological substance, and medicinal application. Materials and Methods: This study was conducted to determine the effect of different organic applications (sheep manure (SM) and vermicompost manure (VM)-10, 15, and 20 t/ha) and chemical fertilizer (Ammonium sulfate (AS)-40, 80, and 120 kg/ha) with a control (no fertilizer or manure) on the morphology, yield, and essential oil, and fixed oil yield of fennel. Results: The results of the study showed that significant statistical differences were found only in plant height and the fixed oil yield of fennel. The fruit yield ranged from 90.14 kg/da to 122.72 kg/da, and the 80 kg/ha ammonium sulfate (AS-2) and 10 t/ha sheep manure (SM-1) applications had the highest values. Essential oil yield and fixed oil yield changed between 2.57-3.85 L/da and 16.18-36.90 L/da, respectively. The result of the study suggested that applications of SM-1 had the highest thousand fruit weight, fruit yield, essential oil yield, and fixed oil yield compared to other applications. PCA analysis showed the relationships among the examined properties, and component 1 and component 2 revealed 61.50% of the total variation of the valuables. Conclusion: Sheep manure application (SM-1) can be used for the high fruit, essential oil, and fixed oil yield of fennel for sustainable agriculture.

Purification and structural analysis of tannase from novel bacteria of Bacillus cereus strain KMS3-1 isolated in marine sediment

Tannases are a family of esterases that catalyze the hydrolysis of ester and depside bonds of hydrolyzable tannins to release small compounds such as glucose. In this work, tannase production from Bacillus cereus strain KMS3-1 was purified and characterized. The standard methods, such as ammonium sulfate precipitation followed by gel filtration chromatography, were used to purify the enzyme tannase from KMS3-1. With 40% enzyme recovery, the purification process yielded a 1.93-fold increase in specific activity. Analysis using SDS-PAGE confirmed a molecular weight of about 40 kDa. Circular dichroism analysis revealed the secondary structure composition α-helix (12.03%), indicating a dominant role of β-turns (38.4%). A pH of 6.0 and a temperature between 50 and 60 °C were ideal for enzyme activity. Tannic acid has an enzyme Km value of 3.0 x 10−3 M and a Vmax of 4.45 U/mL. Surfactants, metal ions, organic solvents, and inhibitors significantly influence the enzyme activity. Cytotoxicity assays revealed the non-toxic nature of the purified enzyme on Vero cells and rat animal models. These results explore and contribute to a better understanding of tannase enzyme properties and their potential applications in the food and beverage industries.

Interactive effects of ammonium sulfate and lead on alfalfa in rare earth tailings: Physiological responses and toxicity thresholds

Ion-adsorption rare earth ore contains significant levels of leaching agents and heavy metals, leading to substantial co-contamination. This presents significant challenges for ecological rehabilitation, yet there is limited understanding of the toxicity thresholds associated with the co-contamination of ammonium sulfate (AS) and lead (Pb) on pioneer plants. Here, we investigated the toxicity thresholds of various aspects of alfalfa, including growth, ultrastructural changes, metabolism, antioxidant system response, and Pb accumulation. The results indicated that the co-contamination of AS-Pb decreased the dry weight of shoot and root by 26 %–77 % and 18 %–92 %, respectively, leading to irregular root cell morphology and nucleus disintegration. The high concentration and combined exposures to AS and Pb induced oxidative stress on alfalfa, which stimulated the defense of the antioxidative system and resulted in an increase in proline levels and a decrease in soluble sugars. Structural equation modeling analysis and integrated biomarker response elucidated that the soluble sugars, proline, and POD were the key physiological indicators of alfalfa under stresses and indicated that co-exposure induced more severe oxidative stress in alfalfa. The toxicity thresholds under single exposure were 496 (EC5), 566 (EC10), 719 (EC25), 940 (EC50) mg kg−1 for AS and 505 (EC5), 539 (EC10), 605 (EC25), 678 (EC50) mg kg−1 for Pb. This study showed that AS-Pb pollution notably influenced plant growth performance and had negative impacts on the growth processes, metabolite levels, and the antioxidant system in plants. Our findings contribute to a theoretical foundation and research necessity for evaluating ecological risks in mining areas and assessing the suitability of ecological restoration strategies.

Nitrogen fertilizers affecting the efficiency of mineral and organic phosphorus fertilizers in tropical soils cultivated with maize

Most conventional phosphorous (P) fertilizers are highly soluble, which favors P retention in the solid phase of the soil, and this condition hinders P availability to plants. Alternative P fertilizers, such as organominerals and struvite, have a slow release of nutrients into the soil, which in turn favors P uptake by plants; nevertheless, soil acidification caused by nitrogen (N) fertilizers can reduce P availability in the soil. In his study, we assessed the effect of N fertilizers on P availability for maize (Zea mays) grown in tropical soils with alternative P fertilizers. An experiment was set up in columns under greenhouse conditions with maize in two cultivation cycles in two soils with contrasting textures (medium and clayey textures), two N fertilizers (calcium nitrate - CN - and ammonium sulfate - AS), three P fertilizers (triple superphosphate - TSP -, organomineral - OM - and struvite - ST), and a control treatment (without addition of P and N fertilizers). At 45 days after emergence, we measured the biomass production and the N and P contents in plants to calculate fertilization efficiency as well as the soil P content. AS promoted the highest aboveground N accumulation, whereas the highest efficiency was obtained with CN. The alternative P sources did not differ in terms of P availability when combined with both N sources. Soil textures were sensitive to fertilizer combination. Further studies are needed to assess struvite interaction with other elements in the soil and the P release kinetics to plants.

Optimization of the production of Exopolysaccharide (EPS) from biofilm-forming bacterial consortium using different parameters

Bacterial cells produce a variety of exopolysaccharide (EPS) throughout their life cycle. EPS plays a crucial role in the formation of biofilms and the control of environmental processes in microbial communities. The bacterial community benefits from biofilms in several ways, including nutrient compartmentation and storage, environmental stress resistance and synergism. The generation of EPS by consortium-associated bacteria, which involves a variety of microorganisms, is versatile and efficient for use in industrial and environmental processes, such as biotechnology and pollution degradation. The qualitative and quantitative chemical characteristics of the consortium's EPS are mostly determined by the type of culture utilized, nutrient type, temperature, and pH. The main goal of the study was to find out how EPS biosynthesis works in a bacterial consortium culture. To achieve maximum EPS regeneration, pH, temperature, carbon, and nitrogen sources were optimized. A consortium of three bacterial strains i.e. Klebsiella pneumonia strain, Pseudomonas aeruginosa strain and Burkholderia cepacian strain that were distinguished by their capacity to produce biofilms were developed as part of the study. The maximum total EPS production was detected after 8 days of incubation at pH 7.5 (15.5g/L) and a temperature of 35 °C (12.60g/L). The optimum EPS production was identified as 17.84g/L and 21.07g/L when ammonium sulfate and glucose were employed as nitrogen and carbon supplements, respectively. The protein concentration of the EPS was 3067µg/mL, which was more than the carbohydrate (263.10µg/mL) and DNA (7.60µg/mL) content. The total protein/carbohydrate ratio of the EPS detected in the present study was 11.65, which was much higher than in prior investigations. FTIR analysis of EPS confirmed the functional groups of carbohydrates, proteins, lipids and DNA, viz., C=O, COOH, NH, OH, CH and OCH3. The study's findings revealed that enhancing the consortium's EPS molecules involves lowering biofilm-related infections and improving the efficacy of antimicrobial treatments in wastewater.

A method to improve sensitivity of Ferrous ammonium sulfate - Benzoic acid - Xylenol orange (FBX) aqueous radiation dosimeter

Ferrous ammonium sulfate - Benzoic acid - Xylenol orange (FBX) solution is known for its dosimetry properties in the dose range applicable in radiation oncology. Several attempts at improving its dose sensitivity have been reported in literature. The current work explores a novel method to improve the dose response of the system in the range 0–10 Gy with the original standard composition of the solution. Value of the sensitivity of the dosimeter was found to be 7.471/Gy with excellent linearity using the developed method. This is 115 times higher than the sensitivity obtained using the conventional methods.

Production of a new chitinase from Nocardiopsis halophila TN-X8 utilizing bio-waste from the blue swimming crab: enzyme characterization and immobilization.

In accordance with the framework of the Circular Blue Bioeconomy in the Mediterranean region, the objective of this study was to evaluate the biotransformation of blue swimming crab (Portunus segnis) residues obtained from the port of Sfax by an extracellular chitinase produced by Nocardiopsis halophila strain TN-X8 isolated from Chott El Jerid (Tozeur, Tunisia). From the analysis of multiple extremophilic Actinomycetota, it was determined that strain TN-X8 exclusively utilized 60g/L of raw blue swimming crab as its carbon and energy source, achieving a chitinase activity of approximately 950 U/mL following a 6-day incubation period at 40°C. Pure chitinase, designated as ChiA-Nh30, was obtained after heat treatment, followed by ammonium sulfate fractionation and Sephacryl® S-200 column chromatography. The maximum ChiA-Nh30 activity was observed at pH 3 and 75°C. Interestingly, compared with cyclohexamidine, ChiA-Nh30 showed a good antifungal effect against four pathogenic fungi. Furthermore, when using colloidal chitin as substrate, ChiA-Nh30 demonstrated a higher degree of catalytic efficiency than the commercially available Chitodextrinase®. In addition, ChiA-Nh30 could be immobilized by applying encapsulation and encapsulation-adsorption techniques. The kaolin and charcoal used acted as excellent binders, resulting in improved ChiA-Nh30 stability. For the immobilized ChiA-Nh30, the yield of N-acetyl-D-glucosamine monomers released from 20% (w/v) blue swimming crab residues increased by 3.1 (kaolin) and 2.65 (charcoal) times, respectively.

Detection, Optimization, Characterization, and Cytotoxic Effect of Vaginolysin Extracted from Gardnerella Vaginalis Isolated from Iraqi Women Who Had Abortions

Objective: The goal of this study is the detection of the gen that responsible for production the vaginolysin toxin, discovered the optimal condition for produce vaginolysin, purification and characterization of the toxin and show the cytotoxic effect of vaginolysin on VK2cell and HeLa cell. Methods: Among 592 specimens isolated from pregnant women suffering from vaginal inflammation and threatened with abortion(these women is suffering from strong pain in the cervical region), only 62 of isolates identified as G vaginalis. From Baghdad teaching hospital. detection of the gen that responsible for production the vaginolysin toxin. study of the optimal condition to produce vaginolysin. the purification of the toxin by using ammonium sulfate, ion exchange chromatography and gel filtration, toxin characterization of pH and temperature activity and stability, the study of cytotoxic effect of vaginolysin on VK2 and HeLa cells. Result: The optimal condition to produce the toxin is pH level in 4, best temperature is 37 0C, the best media is TSB broth , and the best hours is 24hr. . The best range for precipitation saturation ratio 50%. ion exchanges have specific activity 4 mg. gel filtrations show an increase in the specific activity of purified toxin (10U/mg). the characterization done by pH and temperature,Vaginolysin was active in 0.5 U/ mL at pH 7, and stable in pH 7 activity, the best temperature for vaginolysin activity is 0.5 U/mL at 37°C and maximum stability was recorded at 37°C . the cytotoxic effect of the toxin on VK2 cell observed the viability ratio 69.98%, at higher toxin concentration, while the result for HeLa cell viability ratio 38.77%, at higher toxin concentration. Conclusion: vaginolysin cause lysis of vaginal cell and cervical cell may lead to abortion, the killing ratio increase by increasing the concentration of the toxin and the effect of the toxin on HeLa cell is more than on VK2 cell.

Evaluation of nanoparticle-enhanced silane and vinyl ester coatings for protecting concrete from ammonium sulfate

Inferior quality of concrete surface layers can lead to significant deterioration of concrete infrastructure due to the infiltration of fluids and deleterious substances from the surrounding environment. Concrete structures such as foundations, abutments, flatwork, and underground tanks in agricultural and mining zones, as well as slabs in factories producing ammonium-based fertilizers, are highly susceptible to ammonium sulfate attack, which is known as the most aggressive sulfate deterioration driven by acid-sulfate reactions. Coatings are an effective strategy for protecting such concrete structures to restore its performance and prolong its service life. Therefore, this study aimed at investigating the performance of nano-based coatings as superficial treatments for concrete elements exposed to aggravated exposures of ammonium sulfate. Silane (hydrophobic agent) and vinyl ester (membrane-forming polymer) were used as base resins, in which nano-clay and nano-calcium carbonate particulates were dispersed at different dosages (0, 2.5, and 5 %). In addition, a colloidal silica solution was used as a surface treatment. The durability of coated concrete specimens was evaluated under two ammonium sulfate exposures: full immersion and combined with cyclic environmental conditions (freezing-thawing and wetting-drying cycles). Degradation of concrete specimens was monitored by visual assessment and quantified in terms of mass and length changes over time. In addition, the deterioration mechanisms and coatings’ performance were studied by thermal, mineralogical, and microstructural tests. The results showed that colloidal silica could not adequately protect concrete specimens from these exposures. Conversely, silane nanocomposites improved the durability of concrete under both exposures and superior performance was generally observed for concrete specimens coated with vinyl ester nanocomposites.

Process and kinetics of ammonium sulfide removal of zinc, nickel and cobalt from manganous sulfate electrolyte

In producing electrolytic manganese and manganese-based lithium batteries, Manganous sulfate solution serves as a crucial intermediate material. During the preparation of manganese sulfate solution by acid leaching, the removal of impurities such as zinc, nickel, and cobalt ions by sulfide precipitation is essential for obtaining high-quality metallic manganese and high-purity manganese sulfate. The results show that when the temperature is 45 °C, the pH is 5.60, the ammonium sulfide dosage is 40 %, the time is 5 min, and the rotation speed is 650 rpm, the sulfidation rates of zinc, nickel and cobalt are 99.07 %, 89.30 %, and 87.70 % respectively. At this time, the loss rate of manganese in the solution after sulfide impurity removal is 11.45 %, and the manganese-impurity ratio is 80.00. Response surface methodology analysis revealed that temperature, pH, and ammonium sulfide concentration significantly affected the manganese loss rate. After process optimization, at a temperature of 32.70 °C, a pH of 5.20, and an ammonium sulfide concentration of 32.73 %, the manganese loss rate decreased to 6.05 %, while the removal rates of Ni, Co, and Zn were 75.35 %, 60.80 %, and 99.51 %, respectively. In the Manganous sulfate electrolyte with or without ammonium sulfate, the sulfide precipitation processes of zinc, nickel and cobalt ion are all first-order reactions, and the reaction order is zinc > nickel > cobalt. More importantly, the density functional theory (DFT) calculation results also confirmed the formation sequence of zinc sulfide > nickel sulfide > cobaltous sulfide, which supported the experimental results well. This study will lay the foundation for process optimization and mechanism elucidation of impurity ions in ammonium sulfate electrolyte precipitated by ammonium sulfate

L-Asparaginase producing ability of Aspergillus species isolated from tapioca root soil and optimized ideal growth parameters for L-Asparaginase production

This research was designed to isolate the predominant L-asparaginase-producing fungus from rhizosphere soil of tapioca field and assess the suitable growth conditions required to produce maximum L-asparaginase activity. The Aspergillus tubingensis was identified as a predominant L-asparaginase producing fungal isolate from 15 isolates, and it was characterized by 18S rRNA sequencing. The L-asparaginase-producing activity was confirmed by pink color zone formation around the colonies in modified Czapek Dox agar plate supplemented with 1% L-Asparagine. The optimal growth conditions required for the L-asparaginase production by A. tubingensis were optimized as pH 6.0, temperature 30 °C, glucose as carbon source, 1.5% of L-Asparagine, ammonium sulphate as nitrogen source, rice husk as natural L-Asparagine enriched source, and 8 days of the incubation period. The L-Asparaginase activity from A. tubingensis was excellent under these optimal growth conditions. It significantly used rice husk as an alternative to synthetic L-Asparagine. As a result, this may be considered a sustainable method of converting organic waste into valuable raw material for microbial enzyme production.