Addition Of Urea Research Articles

Synthesis and Characterization of Nitrogen-Doped Activated Carbon for Lithium Battery Anode Applications

Nitrogen-dopped activated carbon was synthesized to see its effect on the characterization of the nitrogen surface functional groups, crystal size, and morphology of the resulting sample. Synthesis of nitrogen-doped activated carbon was carried out by varying the addition of Urea as a nitrogen doping source. Activated carbon compared its characteristics with variations in the concentration of added Urea to activated carbon, at 1:3 and 1:5. The FTIR results obtained were the presence of functional groups indicating the presence of nitrogen bonds in each sample. The crystallinity results showed that the samples were classified as crystalline and nitrogen doping influenced the size of the crystallinity of each sample. The morphology of nitrogen-doped activated carbon shows differences in the grain size of nitrogen-doped activated carbon. Crystallinity and morphology have been shown to affect battery anode performance. The more crystalline of anode material, the electrochemical properties are better. The smaller the grain size of the sample morphology, the stability of the battery cycle is to be great.

Preparation and evaluation of H2TiO3@attapulgite with high adsorption and selectivity for lithium ions

In this work, the Li2TiO3@attapulgite (LTO@A-C-3) was prepared using attapulgite as a binder and a dispersant, based on the preparation of urea doped Li2TO3(LTO-C-3) by the modified high-temperature solid phase (m-HTSP) method. Urea addition changed the stacking fault concentrations and the attapulgite increased the lattice oxygen content, facilitating the production of isolated surface hydroxyl groups. HTO@A-C-3 exhibited a relatively high equilibrium Li+ adsorption capacity (Qe) of 48.44 mg·g−1. The selective adsorption capacity of HTO@A-C-3 was 46.27 mg·g−1, and the separation factors (αMLi) of Li+ exceeded 100 in Na+, K+, Mg2+ and Ca2+ coexisting salt solutions. The adsorption capacity was maintained at 39.12 mg·g−1, and titanium dissolution loss was less than 2.42% after five cycles.

Urea addition during hydrolysis for increased ethanol yield from white sweet potato: a promising strategy

Bioethanol is mainly produced from corn worldwide, but many countries face challenges in producing sufficient corn for this purpose. White sweet potato (Ipomoea batatas Linneaus) has a lower nutritional value and less carotene pigment compared to other sweet potatoes, which may make it less desirable as a food source in some regions. However, the affordability of white sweet potato could make it an attractive option for bioethanol production in areas where corn is not readily available. This study investigated the use of white sweet potatoes powder (40 mesh sieve) as a feedstock for ethanol production using Saccharomyces cerevisiae yeast. Optimization of the fermentation process was carried out using response surface methodology (RSM). Results showed that an ethanol yield of 18% could be achieved by applying pH at 4.5 and urea concentration of 60 mg/L. These findings suggest that the addition of urea during hydrolysis of white sweet potato is a promising alternative method for bioethanol production which contained higher etnaol yield compated to the previous finding that utilized amyloglucosidase enzyme during hydrolysis.

Regulating surface condition of cotton-derived carbon towards enhanced lithium ion storage behavior

With the advancement of battery technology, graphite as a negative electrode material for commercial lithium-ion batteries (LiBs) is reaching the limit of its capacity, and mesoporous carbon with a larger capacity is regarded as its best alternative. In this paper, waste cotton is used as the carbon source, and KOH and urea are used as pore formers and pore size regulators to prepare uniform mesoporous materials (N-PCC800) with a pore size distribution of 2–5 nm. Compared with the traditional KOH pore-making method, the addition of urea can adjust the pore size upward, thereby increasing the effective number of pores for Li+ insertion. While optimizing the structure, urea can also be used as an additional nitrogen source for the material to enrich the content of heteroatoms and defects, thereby increasing the amount of Li+ adsorbed by porous carbon. As an anode material, N-PCC800 exhibits a stable discharge capacity (1086 mAh g−1 at 100 mA g−1) far exceeding that of graphite. At a current density of 1000 mA g−1, there is still a capacity of 596 mAh g−1 remaining after 1000 cycles, indicating its advantages in rate performance and cycle performance. The optimized pore size and higher nitrogen content endow the carbon material with higher Li+ storage performance, and further kinetic analysis indicates that the increased capacity comes from the increased Li+ insertion. This work proposes a new pore size optimization scheme to obtain high-capacity mesoporous carbon, which provides an effective scheme for the reuse of waste cotton and cotton products and helps achieve the goal of carbon neutrality.

How a highly acidic SH3 domain folds in the absence of its charged peptide target.

Charged residues on the surface of proteins are critical for both protein stability and interactions. However, many proteins contain binding regions with a high net charge that may destabilize the protein but are useful for binding to oppositely charged targets. We hypothesized that these domains would be marginally stable, as electrostatic repulsion would compete with favorable hydrophobic collapse during folding. Furthermore, by increasing the salt concentration, we predict that these protein folds would be stabilized by mimicking some of the favorable electrostatic interactions that take place during target binding. We varied the salt and urea concentrations to probe the contributions of electrostatic and hydrophobic interactions for the folding of the yeast SH3 domain found in Abp1p. The SH3 domain was significantly stabilized with increased salt concentrations due to Debye-Huckel screening and a nonspecific territorial ion-binding effect. Molecular dynamics and NMR show that sodium ions interact with all 15 acidic residues but do little to change backbone dynamics or overall structure. Folding kinetics experiments show that the addition of urea or salt primarily affects the folding rate, indicating that almost all the hydrophobic collapse and electrostatic repulsion occur in the transition state. After the transition state formation, modest yet favorable short-range salt bridges are formed along with hydrogen bonds, as the native state fully folds. Thus, hydrophobic collapse offsets electrostatic repulsion to ensure this highly charged binding domain can still fold and be ready to bind to its charged peptide targets, a property that is likely evolutionarily conserved over 1 billion years.

Effects of different additions to Italian ryegrass (Lolium multiflorum Lam.) on silage quality

This research was carried out to determine the effects of different additions (urea and molasses) used with Italian ryegrass (Lolium multiflorum L.) silage on fermentation, in vitro gas production, microbiological properties, in vitro digestibility parameters, and relative fodder quality (RFQ) in silages made under laboratory conditions. The Italian grass (Lolium multiflorum L.) used in the study was chopped to an approximate size of 2–3.0 cm. Amounts of 0, 2, and 4% molasses and 0, 0.5, and 1% urea were added to the fresh material as a percentage of dry matter. Because of the urea, crude protein (CP) of Italian ryegrass silage increased, but the content of neutral detergent fibre (NDF), acid detergent fibre (ADF), and acid detergent lignin (ADL) decreased. While the addition of urea decreased the acetic acid and butyric acid concentrations of the silage, it increased the pH, lactic acid, and ammonia (NH3) content. Molasses addition increased in vitro gas production and organic matter digestibility (OMD); urea increased metabolic energy (ME) and the net energy lactation (NEL) values of silages. Urea and molasses both increased in vitro digestibility parameters, microbial protein production and synthesis, and relative fodder quality of the silage. As a result of the research, it was determined that urea and molasses could be used at contents of 1.5% and 4%, respectively, in Italian ryegrass silage.

Impact of Urea-Intercalated-Biochar on N-Release in Soil and Humified Soil Organic Matter

This research investigated the impact of urea-intercalated-biochar (ICB) on nitrogen release as well as on humified soil organic matter (SOM) distribution in highly weathered soil. Incubation studies were performed with a typical dystrophic red Ultisol and with 10 treatments: soil without amendment (control, CON), soil with three doses of biochar (BC75, BC145, and BC 290), and soil with ICB doses (ICB75, ICB145 and ICB 290). BC and ICB were characterized by 13C Nuclear Magnetic Resonance 13C-NMR CP/MAS spectroscopy and elemental analyses. N-extractable forms were periodically determined by Kjeldahl method and humic substances (HS) distribution was analyzed on the 28th day after incubation begins (DAI). Intercalation of urea in BC increased sample N content from 2.7 to 22 %, whereas that of C decreased from 40 % to 28 %. As a consequence, C: N decreased from 14.9 to 1.3. The 13C NMR spectra of BC and ICB were similar but relative abundance of major organic functional groups differs, for example, ICB presented a greater proportion of C=O groups due to the carbonyl group of urea and a greater proportion of N/O alkyl C, O-alkyl C, and anomeric C groups due to the addition of starch. There was a significant increase in the concentration of extractable N-NH4+ by addition of urea from the onset of incubation down late period and a significant difference (P > 0.05) was obtained between the ICB and BC over time. This could be as a result of the less accessible form of N in the biochar materials due to the pyrolysis process. There was no evidence of extractable N-NO3- ion until 14 DAI, significant difference in N-NH4+ concentrations at 28 DAI between the ICB and control was observed over time and the highest value recorded from ICB treated pots at 145 and 290 kg N ha-1.

Prebiotic Chemistry of Phosphite: Mild Thermal Routes to Form Condensed-P Energy Currency Molecules Leading Up to the Formation of Organophosphorus Compounds.

The in-fall of meteorites and interstellar dust particles during the Hadean-Archean heavy bombardment may have provided the early Earth with various reduced oxidation state phosphorus compounds and minerals, including phosphite (HPO32-)([Pi(III)]). The ion phosphite ([Pi(III)])has been postulated to be ubiquitous on the early Earth and consequently could have played a role in the emergence of organophosphorus compounds and other prebiotically relevant P species such as condensed P compounds, e.g., pyrophosphite ([PPi(III)]) and isohypophosphate ([PPi(III-V)]). In the present study, we show that phosphite ([Pi(III)]) oxidizes under mild heating conditions (e.g., wet-dry cycles and a prebiotic scenario mimicking a mildly hot-evaporating/drying pool on the early Earth at 78-83 °C) in the presence of urea and other additives, resulting in changes to orthophosphate ([Pi(V)]) alongside the formation of reactive condensed P compounds (e.g., pyrophosphite ([PPi(III)]) and isohypophosphate ([PPi(III-V)])) through a one-pot mechanism. Additionally, we also show that phosphite ([Pi(III)]) and the condensed P compounds readily react with organics (nucleosides and organic alcohol) to form organophosphorus compounds.

Nonlinear Transient Permeability in pH-Responsive Bicontinuous Nanospheres

We demonstrate the construction of pH-responsive bicontinuous nanospheres (BCNs) with nonlinear transient permeability and catalytic activity. The BCNs were assembled from amphiphilic block copolymers comprising pH-responsive groups and were loaded with the enzymes urease and horseradish peroxidase (HRP). A transient membrane permeability switch was introduced by employing the well-known pH-increasing effect of urease upon conversion of urea to ammonia. As expected, the coencapsulated HRP displayed a transiently regulated catalytic output profile upon addition of urea, with no significant product formation after the pH increase. This transient process displayed a nonlinear "dampening" behavior, induced by a decrease in membrane permeability as a result of significant local ammonia production. Furthermore, the catalytic output of HRP could be modulated by addition of different amounts of urea or by altering the buffer capacity of the system. Finally, this nonlinear dampening effect was not observed in spherical polymersomes, even though the membrane permeability could also be inhibited by addition of urea. The specific BCN morphology therefore allows to optimally control catalytic processes by pH changes in the nanoreactor microenvironment compared to bulk conditions due to its unique permeability profile.

The inhibition of high ammonia to in vitro rumen fermentation is pH dependent.

Ammonia is an important rumen internal environment indicator. In livestock production, feeding a large amount of non-protein nitrogen to ruminants will create high ammonia stress to the animals, which increases the risk of ammonia toxicity. However, the effects of ammonia toxicity on rumen microbiota and fermentation are still unknown. In this study, an in vitro rumen fermentation technique was used to investigate the effects of different concentrations of ammonia on rumen microbiota and fermentation. To achieve the four final total ammonia nitrogen (TAN) concentrations of 0, 8, 32, and 128 mmol/L, ammonium chloride (NH4Cl) was added at 0, 42.8, 171.2, and 686.8 mg/100 mL, and urea was added at 0, 24, 96, and 384 mg/100 mL. Urea hydrolysis increased, while NH4Cl dissociation slightly reduced the pH. At similar concentrations of TAN, the increased pH of the rumen culture by urea addition resulted in a much higher free ammonia nitrogen (FAN) concentration compared to NH4Cl addition. Pearson correlation analysis revealed a strong negative correlation between FAN and microbial populations (total bacteria, protozoa, fungi, and methanogens) and in vitro rumen fermentation profiles (gas production, dry matter digestibility, total volatile fatty acid, acetate, propionate, etc.), and a much weaker correlation between TAN and the above indicators. Additionally, bacterial community structure changed differently in response to TAN concentrations. High TAN increased Gram-positive Firmicutes and Actinobacteria but reduced Gram-negative Fibrobacteres and Spirochaetes. The current study demonstrated that the inhibition of in vitro rumen fermentation by high ammonia was pH-dependent and was associated with variations of rumen microbial populations and communities.

Nutrient Potential Leachability in a Sandy Soil Amended with Manure-Based Fertilisers

The application of manure-based fertilisers (MBFs) is considered an important practice for achieving agricultural sustainability. However, the potential losses of nutrients to the environment need to be thoroughly evaluated. This study aimed to assess nutrients’ potential leachability from a sandy soil, fertilised with MBFs produced by mixing manure from one single animal species with N- or P-mineral fertilisers, to achieve target N:P ratios (1:1, 2:1 and 0.5:1). MBFs were prepared by combining pig slurry, cattle slurry or poultry manure with N- and P-mineral fertilisers, or slurry-derived materials, obtained by solid–liquid separation. A leaching experiment was set-up in soil columns treated with MBFs, for 59 days, with seven leaching events. Poultry manure application to soil led to higher potential N leaching, while pig slurry induced higher P leaching. All 2:1 MBFs decreased P leaching, relative to the original manure, with the higher reduction (52%) being observed for pig slurry with urea. The addition of urea to poultry manure also diminished its potential for N leaching. The behaviour of P-enriched materials, pig slurry solid fraction and both 0.5:1 MBFs obtained with phosphoric acid addition showed a higher risk of P leaching, while the use of superphosphate as a P-mineral source decreased the risk of P leaching. Concluding, it is possible to use specific MBFs, enriched with N and P from mineral sources, and have lower N and P leaching potential, reducing the risks associated with manure soil application, while increasing their interest as alternative fertilisers.

Enhanced enzymatic saccharification and ethanol production of corn stover via pretreatment with urea and steam explosion

Enhancing the degradation of lignocellulosic structure is essential for the efficient use of corn stover. This study investigated the effects of using urea combined with steam explosion on the enzymatic hydrolysis and ethanol production of corn stover. The results demonstrated that 4.87% urea addition and 1.22 MPa steam pressure were optimal for ethanol production. The highest reducing sugar yield (350.12 mg/g) was increased by 116.42% (p < 0.05), and the corresponding degradation rates of cellulose, hemicellulose, and lignin in pretreated corn stover were increased by 40.26%, 45.89% and 53.71% compared with the untreated corn stover (p < 0.05). Moreover, the maximal sugar alcohol conversion rate was approximately 48.3%, and the ethanol yield reached 66.5%. In addition, the key functional groups in corn stover lignin under combined pretreatment were identified. These findings offer new insights into corn stover pretreatment and can help develop feasible technologies to enhance ethanol production.

Addition of formaldehyde releaser imidazolidinyl urea and MOPS buffer to urine samples enables delayed processing for flow cytometric analysis of urinary cells: A simple, two step conservation method of urinary cells for flow cytometry.

Kidney diseases are a major health concern worldwide. Currently there is a large unmet need for novel biomarkers to non-invasively diagnose and monitor kidney diseases. Urinary cells are promising biomarkers and their analysis by flow cytometry has demonstrated its utility in diverse clinical settings. However, up to date this methodology depends on fresh samples, as cellular event counts and the signal-to-noise-ratio deter over time. Here we developed an easy-to-use two-step preservation method for conservation of urine samples for subsequent flow cytometry. The protocol utilizes a combination of the formaldehyde releasing agent imidazolidinyl urea (IU) and MOPS buffer, leading to gentle fixation of urinary cells. The preservation method increases acceptable storing time of urine samples from several hours to up to 6 days. Cellular event counts and staining properties of cells remain comparable to fresh untreated samples. The hereby presented preservation method facilitates future investigations on flow cytometry of urinary cells as potential biomarkers and may enable broad implementation in clinical practice.

The thermodynamics of enhanced dope stability of cellulose solution in NaOH solution by urea

The addition of urea in pre-cooled alkali aqueous solution is known to improve the dope stability of cellulose solution. However, its thermodynamic mechanism at a molecular level is not fully understood yet. By using molecular dynamics simulation of an aqueous NaOH/urea/cellulose system using an empirical force field, we found that urea was concentrated in the first solvation shell of the cellulose chain stabilized mainly by dispersion interaction. When adding a glucan chain into the solution, the total solvent entropy reduction is smaller if urea is present. Each urea molecule expelled an average of 2.3 water molecules away from the cellulose surface, releasing water entropy that over-compensates the entropy loss of urea and thus maximizing the total entropy. Scaling the Lennard-Jones parameter and atomistic partial charge of urea revealed that direct urea/cellulose interaction was also driven by dispersion energy. The mixing of urea solution and cellulose solution in the presence or absence of NaOH are both exothermic even after correcting for the contribution from dilution.

Dissolved biochar fractions and solid biochar particles inhibit soil acidification induced by nitrification through different mechanisms

Biochar can inhibit soil acidification by decreasing the H+ input from nitrification and improving soil pH buffering capacity (pHBC). However, biochar is a complex material and the roles of its different components in inhibiting soil acidification induced by nitrification remain unclear. To address this knowledge gap, dissolved biochar fractions (DBC) and solid biochar particles (SBC) were separated and mixed thoroughly with an amended Ultisol. Following a urea addition, the soils were subjected to an incubation study. The results showed that both the DBC and SBC inhibited soil acidification by nitrification. The DBC inhibited soil acidification by decreasing the H+ input from nitrification, while SBC enhanced the soil pHBC. The DBC from peanut straw biochar (PBC) and rice straw biochar (RBC) decreased the H+ release by 16 % and 18 % at the end of incubation. The decrease in H+ release was attributed to the inhibition of soil nitrification and net mineralization caused by the toxicity of the phenols in DBC to soil bacteria. The abundance of ammonia-oxidizing bacteria (AOB) and total bacteria decreased by >60 % in the treatments with DBC. The opposite effects were observed in the treatments with SBC. Soil pHBC increased by 7 % and 19 % after the application of solid RBC and PBC particles, respectively. The abundance of carboxyl on the surface of SBC was mainly responsible for the increase in soil pHBC. Generally, the mixed application of DBC and SBC was more effective at inhibiting soil acidification than their individual applications. The negative impacts of dissolved biochar components on soil microorganisms need to be closely monitored.

High-Gravity Fermentation for Bioethanol Production from Industrial Spent Black Cherry Brine Supplemented with Whey

By-products from different industries could represent an available source of carbon and nitrogen which could be used for bioethanol production using conventional Saccharomyces cerevisiae yeast. Spent cherry brine and whey are acid food by-products which have a high organic matter content and toxic compounds, and their discharges represent significant environmental and economic challenges. In this study, different combinations of urea, yeast concentrations, and whey as a nutrient source were tested for bioethanol production scale-up using 96-well microplates as well as 7.5 L to 100 L bioreactors. For bioethanol production in vials, the addition of urea allowed increasing the bioethanol yield by about 10%. Bioethanol production in the 7.5 L and 100 L bioreactors was 73.2 g·L−1 and 103.5 g·L−1 with a sugar consumption of 81.5% and 94.8%, respectively, using spent cherry brine diluted into whey (200 g·L−1 of total sugars) supplemented with 0.5 g·L−1 urea and 0.5 g·L−1 yeast at 30 °C and a pH of 5.0 after 96 h of fermentation for both systems. The results allow these by-products to be considered low-economic-value alternatives for fuel- or food-grade bioethanol production.

Globally nitrogen addition alters soil microbial community structure, but has minor effects on soil microbial diversity and richness

Globally increasing nitrogen (N) deposition is recognized as an important regulator of soil microbial communities. However, how N enrichment affects soil microbial diversity, richness and community structure remains unclear at the global scale. Here, by focusing on high-throughput amplicon sequencing data from field experiments using N fertilizers only, we conducted a meta-analysis of a global dataset assessing the responses of microbial diversity (Shannon index), richness (Chao1, OTU richness) and community structure to N addition. Our results showed that N addition significantly reduced soil bacterial diversity (−2.3%), and such effect was significant in cropland (rather than grassland and forest) and with urea addition (rather than ammonium nitrate). However, there was no significant effect of N addition on soil fungal diversity and microbial (bacterial or fungal) richness. Moreover, N addition shifted microbial community structure likely due to the microbial adaptation to N-excess, but had no significant effect on microbial beta-diversity. Model-selection analysis further showed that the change in soil pH was the most important factor regulating the responses of soil bacterial diversity and richness to N addition. Overall, our results contribute to an in-depth understanding of the effects of N addition on soil microbial diversity and community structure in terrestrial ecosystems at the global scale.

Assessment of carbon dioxide emissions in road transport, using exhaust gas cleaning technology, in the Republic of Kazakhstan

Approaches are presented for calculating carbon dioxide (CO2) emissions generated by the use of exhaust gas purification technology based on urea catalysts. To reduce harmful substances in the exhaust gases for diesel-fueled automobile engines, the need for SCR technology is justified. It is shown that the main source of emissions is diesel freight transport, while it is advisable to carry out calculations from 2010, and not from 2005, as a number of foreign experts insist. The working scheme of the integrated cleaning system of diesel engines of passenger cars has been developed. An integrated cleaning system for automotive engines has been developed. Additional emissions are very small and account for less than one percent of the CO2 emissions generated from the operation of all road transport. According to the results of the calculations, it was obtained that the share of emissions from the use of urea additives is very small to the emissions of СО2 formed during direct combustion of fuel.

Salinity and high pH reduce denitrification rates by inhibiting denitrifying gene abundance in a saline-alkali soil

Denitrification, as the main nitrogen (N) removal process in farmland drainage ditches in coastal areas, is significantly affected by saline-alkali conditions. To elucidate the effects of saline-alkali conditions on denitrification, incubation experiments with five salt and salt-alkali gradients and three nitrogen addition levels were conducted in a saline-alkali soil followed by determination of denitrification rates and the associated functional genes (i.e., nirK/nirS and nosZ Clade I) via N2/Ar technique in combination with qPCR. The results showed that denitrification rates were significantly decreased by 23.83–50.08%, 20.64–57.31% and 6.12–54.61% with salt gradient increasing from 1 to 3‰, 8‰, and 15‰ under 0.05‰, 0.10‰ and 0.15‰ urea addition conditions, respectively. Similarly, denitrification rates were significantly decreased by 44.57–63.24% with an increase of the salt-alkali gradient from 0.5 to 8‰. The abundance of nosZ decreased sharply in the saline condition, while a high salt level significantly decreased the abundance of nirK and nirS. In addition, the increase of nitrogen concentration attenuated the reduction of nirK, nirS and nosZ gene abundance. Partial least squares regression (PLSR) models demonstrated that salinity, dissolved oxygen (DO) in the overlying water, N concentration, and denitrifying gene abundance were key determinants of the denitrification rate in the saline environment, while pH was an additional determinant in the saline-alkali environment. Taken together, our results suggest that salinity and high pH levels decreased the denitrification rates by significantly inhibiting the abundance of the denitrifying genes nirK, nirS, and nosZ, whereas increasing nitrogen concentration could alleviate this effect. Our study provides helpful information on better understanding of reactive N removal and fertilizer application in the coastal areas.

Application of Dairy Effluents to Pastures Affects Soil Nitrogen Dynamics and Microbial Activity

The use of farm dairy effluents (FDE) has become a promising alternative to increase pasture yield while reducing the environmental impact of waste accumulation into streams, but other environmental implications should be considered. The present study aimed to assess the effect of application of either raw FDE or lagoon-stored FDE compared to dissolved urea or a non-amended control on N2O emission, soil N dynamics, functional microbial activity, and the yield and N-use efficiency of a fescue pasture. The normalized N application rate of 200 kg N ha−1 was divided into four seasonal events in a greenhouse experiment. Similar fescue forage production with FDE or urea positioned FDE application to soil as an alternative disposal. The repeated application of raw effluent delivered more organic C to the soil which induced an increase in enzyme activities, a shift in the catabolic activity of the soil microbial community, and greater N mineralization potential. On the other hand, urea addition decreased the functional activity of the soil microbial community. However, N2O emissions were greater for the raw effluent, so lagoon-stored effluent is an alternative to manage FDE under these conditions, avoiding urea addition and enhancing soil metabolic activity.