Phosphate Composites Research Articles

Using oxygen isotopes in phosphate to assess biological phosphorus cycling in a small and shallow freshwater lake system

AbstractReducing excess phosphorus (P) loads that cause eutrophication in aquatic systems is essential for meeting water quality standards. The oxygen isotopic composition of phosphate (δ18Op) is a powerful tool for tracking P sources and cycling in diverse natural ecosystems. Here, we use δ18Op distribution in a small freshwater body (a lagoon–lake system) with high biological activity. We report δ18Op values seasonally along the water flow path in lagoon–lake system adjacent to Lake Biwa, Japan. The δ18Op values of inflowing water originating as agricultural runoff were constant throughout the study period at +16.3‰ ± 0.2‰. The δ18Op values in the system were generally offset from temperature‐dependent isotopic equilibrium with the surrounding water, ranging from +11.1‰ to +17.8‰. The δ18Op values of the lake water approached equilibrium values in July and October, when dissolved inorganic P (DIP) retention rates were high, consistent with extensive biologically mediated phosphate cycling. A δ18Op two end‐member mixing model, involving inflowing P and biologically recycled P, suggests that P turnover rates in the lagoon–lake system were high during the productive seasons. In contrast, the longer lake water residence time in the non‐irrigation season (winter) allowed δ18Op values to deviate toward lower values relative to both equilibrium and agricultural source δ18Op values, suggesting that P metabolism was dominated by extracellular/ecto‐enzymatic hydrolysis of dissolved organic P under low DIP concentrations. This work highlighted the utility of δ18Op for understanding P dynamics in shallow lake ecosystems.

<i>In vivo</i> application of prevascularized bone scaffolds: A literature review

BACKGROUND: Despite expanding research, the development of materials for replacing bone defects remains an urgent problem in orthopedics and traumatology. Thus, one of the most important tasks is to create conditions for proper trophicity of the bone implant.
 AIM: To analyze modern approaches to bone scaffold vascularization and evaluate their adequacy in in vivo models.
 MATERIALS AND METHODS: The article presents a literature review dedicated to the methods of vascularization of bone scaffolds. A literature search was performed in PubMed, ScienceDirect, eLibrary, and Google Scholar databases from 2013 to 2023 using keywords, and 271 sources were identified. After exclusion, 95 articles were analyzed, and the results of 38 original studies and one literature review were presented.
 RESULTS: Regardless of the initial vascularization method of scaffolds, bone implants show distinct osteoinductive features and promote advanced bone tissue regeneration. Constructs based on solid polymers and calcium–phosphate compositions also perform osteoconductive functions. Mesenchymal stem cells are used as the main cell type, as well as vessel-type cells, which in cooperation also have a positive effect on bone-defect remodeling. Bone morphogenetic proteins are used for directed differentiation in the osteogenic direction, and vascular endothelial growth factor is used for differentiation in the vascular pathway.
 CONCLUSIONS: At present, no method for vascularization of scaffolds has been approved universally. In addition, no evidence supported the comparative effectiveness of vascularization methods, whereas animal model studies have demonstrated a positive effect of prevascularized patterns on the recovery rate of minor and critical defects.

Highly oxidation resistant and organic dispersible ligand functionalized MXene for triggering performance of lithium ion batteries

Two-dimensional (2D) MXenes are one of the leading members of materials science due to their exceptional dispersion in water, metal-like conductivity, and promising applications in interdisciplinary fields. However, the ease of oxidation and poor dispersion in organic solvents have hindered the advancement of MXenes for futuristic applications. In this study, we developed oxidation-resistant, organic dispersible, environmentally stable, and conductive Ti3C2Tx MXene (Tx = –OH, –O, –F, etc.) by surface modification with 2-Ethylhexyl phosphate (EHP) ligand via a simple condensation reaction at room temperature by optimizing the pH value. The EHP functionalized MXene (MXene-EHP) has excellent dispersion stability in most organic solvents due to EHP ligands favoring excellent compatibility with counterparts. The MXene-EHP/lithium iron phosphate (LiFePO4, LFP) composite was prepared and investigated as an efficient cathode in lithium ion batteries (LIBs). The surface modification with EHP has impeded the surface oxidation of the MXene in MXene-EHP and enhanced the compatibility with the LFP cathode and ionic diffusion in LIBs. MXene-EHP/LFP has delivered an excellent specific capacity of 150 mAh g−1 and 136 mAh g−1 at the initial cycle and after the 500th cycle at 1C rate, respectively in comparison to the bare LFP electrodes with a specific capacity of 118 mAh g−1 and 101 mAh g−1.

Pyrogenic transformation of the phosphate state of permafrost forest soils of Central and Southern Yakutia

For the first time, the phosphate state of permafrost forest post-pyrogenic polycyclic soils of Central and Southern Yakutia, formed respectively in arid and humid climates, was studied and evaluated. These soils with a polycyclic profile, formed in the transaccumulative facies of this regions of the permafrost zone, contain, in addition to the modern one, 2–3 buried humus horizons with abundant inclusion of black charcoal. These pyrogenic humus horizons are characterized by an increased content of humus, total nitrogen and phosphorus soluble in iron oxalates, exchange bases, as well as fractions of physical clay and silt compared to neighboring mineral horizons of the soil profile. At the same time, the brown soil of Southern Yakutia, formed under less severe and humid climatic conditions, compared with those of the pale soil developed under cryoarid conditions of Central Yakutia, was more biogenic, and the total content of phosphorus here was 98.0–427.2, whereas in the second soil – only 11.0–257.1 mg P2O5/100 g of soil. Organophosphates predominated in the composition of the total phosphorus of burozem, amounting to 51.8–81.3%, and in pale soil – mineral forms of phosphorus, which accounted for 52.2–78.8%. The fractional composition of mineral phosphates of both types of permafrost soils was mainly dominated by phosphates of one and a half oxides (Al-P and Fe-P), totaling 43.3–94.3%, and among the latter – Fe-P, which accounted for 34.8–87.4% of the total amount of all fractions of mineral phosphates. It is assumed that the high content of iron phosphates, and in some cases occluded aluminum-iron phosphates in the studied permafrost soils, is due to the manifestation of both cryogenic and biogenic pyrogenic ferruginization in their genesis.

Direct inkjet writing of polylactic acid/β-tricalcium phosphate composites for bone tissue regeneration: A proof-of-concept study.

There is an ever-evolving need of customized, anatomic-specific grafting materials for bone regeneration. More specifically, biocompatible and osteoconductive materials, that may be configured dynamically to fit and fill defects, through the application of an external stimulus. The objective of this study was to establish a basis for the development of direct inkjet writing (DIW)-based shape memory polymer-ceramic composites for bone tissue regeneration applications and to establish material behavior under thermomechanical loading. Polymer-ceramic (polylactic acid [PLA]/β-tricalcium phosphate [β-TCP]) colloidal gels were prepared of different w/w ratios (90/10, 80/20, 70/30, 60/40, and 50/50) through polymer dissolution in acetone (15% w/v). Cytocompatibility was analyzed through Presto Blue assays. Rheological properties of the colloidal gels were measured to determine shear-thinning capabilities. Gels were then extruded through a custom-built DIW printer. Space filling constructs of the gels were printed and subjected to thermomechanical characterization to measure shape fixity (Rf) and shape recovery (Rr) ratios through five successive shape memory cycles. The polymer-ceramic composite gels exhibited shear-thinning capabilities for extrusion through a nozzle for DIW. A significant increase in cellular viability was observed with the addition of β-TCP particles within the polymer matrix relative to pure PLA. Shape memory effect in the printed constructs was repeatable up to 4 cycles followed by permanent deformation. While further research on scaffold macro-/micro-geometries, and engineered porosities are warranted, this proof-of-concept study suggested suitability of this polymer-ceramic material and the DIW 3D printing workflow for the production of customized, patient specific constructs for bone tissue engineering.

Atomic layer deposition for tuning the surface chemical composition of nickel iron phosphates for oxygen evolution reaction in alkaline electrolyzers

Transition metal phosphates are promising catalysts for the oxygen evolution reaction (OER) in alkaline medium. Herein, Fe-doped Ni phosphates are deposited using plasma-enhanced atomic layer deposition (PE-ALD) at 300 °C. A sequence of f Fe phosphate PE-ALD cycles and n Ni phosphate PE-ALD cycles is repeated x times. The Fe to Ni ratio can be controlled by the cycle ratio (f/n), while the film thickness can be controlled by the number of cycles (x times (n+f )). 30 nm films with an Fe/Ni ratio of ∼10% and ∼37%, respectively, are evaluated in 1.0 M KOH solution. Remarkably, a significant difference in OER activity is found when the order of the Ni and Fe phosphate PE-ALD cycles in the deposition sequence is reversed. A 20%–45% larger current density is obtained for catalysts grown with an Fe phosphate PE-ALD cycle at the end compared to the Ni phosphate-terminated flavour. We attribute this to a higher concentration of Fe centers on the surface, as a consequence of the specific PE-ALD approach. Secondly, increasing the thickness of the catalyst films up to 160 nm results in an increase of the OER current density and active surface area, suggesting that the as-deposited smooth and continuous films are converted into electrolyte-permeable structures during catalyst activation and operation. This work demonstrates the ability of PE-ALD to control both the surface and bulk composition of thin film electrocatalysts, offering valuable opportunities to understand their impact on performance.

The Prevalence of Nephrolithiasis and Associated Risk Factors Among the Population of the Riyadh Province, Saudi Arabia.

Background and objective Kidney stones, also referred to as nephrolithiasis or renal calculi, is a condition where crystal depositions are formed within the kidney and ideally excreted from the body via the urethra with no pain; however, larger calculi may cause significant pain and require further medical assistance. The vast majority of patients who develop renal calculi form calcium stones, which are either a composition of calcium oxalate or calcium phosphate. Other types include uric acid, struvite, and cysteine. While kidney stones are one of the most significant diseases among the Saudi population, which require an acute emergency intervention to prevent serious long-term complications,there are limited studies published regarding this condition inSaudi communities. In light of this, we performed this study to assess the prevalence, incidence, and risk factors of kidney stones among the population of Riyadh, Saudi Arabia. Methods This was a cross-sectional studyconducted in Riyadh, Saudi Arabia between Augustand October 2023, aiming to estimate the prevalence and risk factors of nephrolithiasis among residents of the Riyadh province. Data were collected through an electronic questionnairein both Arabic and Englishand distributed via social media in addition to barcode handouts in various selected venues in Riyadh. The questionnaire involved 12 questions categorized into three sections. The first section obtained demographical information while the second sectioncollected data about the past medical history of the participants. Lastly, the third section aimedto assess the prevalence of nephrolithiasis among participants or any history of the condition among their families. Results Atotal of 1,043 participants were surveyed, of whom 533 were males (51.1%). The prevalence of kidney stones was reported in 98 individuals (9.4%) overall. Individuals in the age groups of 36-50, 51-60, and >60 years showed significantly more renal stone prevalence than those in younger age groups (p<0.001). The prevalencewas found to be higher in participants who were smokers, diabetic, hypertensive, and those who suffered from inflammatory bowel disease (IBD), gout, chronic kidney disease (CKD), hyperthyroidism, and hyperparathyroidism. Participants who took calcium supplements or had a positive family history of renal stones were found to have a higher prevalence of renal stones as well. However, only hypertension, gout, and family history showed any statistical significance (p<0.05). Conclusions A direct correlation was observed between hypertension, gout, positive family history, and aging and an increased prevalence of kidney stones among theinhabitants of the Riyadh province. Therefore, we encourage the local authorities to raise awareness of kidney stones and their related risk factors among the general public. Moreover, further local studies need to be conducted to gain deeper insights into kidney stone prevalence, especially pertaining to associated comorbiditiesand the pattern of the disease itself.

The Structural, Thermal and Morphological Characterization of Polylactic Acid/Β-Tricalcium Phosphate (PLA/Β-TCP) Composites upon Immersion in SBF: A Comprehensive Analysis.

Biocomposite films based on PLA reinforced with different β-TCP contents (10%, 20%, and 25%wt.) were fabricated via solvent casting and immersed in SBF for 7, 14, and 21 days. The bioactivity, morphological, and thermal behavior of composites with immersion were studied using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) microanalysis, weight loss (WL), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and gel permeation chromatography (GPC). This broad analysis leads to a deeper understanding of the evolution of the polymer-filler interaction with the degradation of the biocomposites. The results showed that β-TCP gradually evolved into carbonated hydroxyapatite as the immersion time increased. This evolution affected the interaction of β-TCP with PLA. PLA and β-TCP interactions differed from PLA and carbonated hydroxyapatite interactions. It was observed that β-TCP inhibited PLA hydrolysis but accelerated the thermal degradation of the polymer. β-TCP retarded the cold crystallization of PLA and hindered its crystallinity. However, after immersion in SBF, particles accelerated the cold crystallization of PLA. Therefore, considering the evolution of β-TCP with immersion in SBF is crucial for an accurate analysis of the biocomposites' degradation. These findings enhance the comprehension of the degradation mechanism in PLA/β-TCP, which is valuable for predicting the degradation performance of PLA/β-TCP in medical applications.

Oxygen Isotope Analysis of Nanomole Phosphate Using PO3- Fragment in ESI-Orbitrap-MS.

The oxygen isotope composition of phosphate is a useful tool for studying biogeochemical phosphorus cycling. However, the current Ag3PO4 method is not only tedious in PO43- extraction and purification but also requires a large-sized sample at the micromole level, thereby limiting its application. Here, we present an approach to measuring the oxygen isotope composition, δ18O, of dissolved phosphate at the nanomole level using electrospray ionization Orbitrap mass spectrometry (ESI-Orbitrap-MS). We compared the reproducibility of δ18O measurements using the H2PO4- ions (m/z = 97 and 99 for H2P16O4- and H2P18O16O3-, respectively) and using the PO3- fragment ions (m/z = 79 and 81 for P16O3- and P18O16O2-, respectively) generated by source fragmentation and by higher-energy collisional dissociation, respectively. The results demonstrate that phosphate δ18O can be more reliably measured by the PO3- ions than by the H2PO4- ions. PO3- generated by source fragmentation at 40 V achieved the highest reproducibility for δ18O based on precision tests. Furthermore, the mass spectrum for a 50:50 μM mixed solution of phosphate and sulfate revealed that PO3- ions resulting from source fragmentation at 40 V are the predominant species in the Orbitrap analyzer. Notably, P16O3- ions (m/z: 79) are not interfered with by 32S16O3- (m/z: 80) ions. This is in contrast to the case for 1H2P16O4- ions, which share the same m/z value with 1H32S16O4- ions and exhibit much lower signal intensity than HSO4- ions. Using the PO3- fragment method and six phosphate standards with a wide range of δ18O values, we obtained a calibration line with a slope of 0.94 (R2 = 0.98). The overall uncertainty for ESI-Orbitrap-MS phosphate δ18O measurement was 0.8‰ (n = 30; 1 SD). With much room for improvement, the PO3- fragment method presents a better approach to measuring the phosphate oxygen isotope composition, applicable to nanomole sample sizes in a liquid phase.

Single large enterolith in a cat with chronic inflammatory enteropathy

AbstractA 3‐year‐old, male, neutered, domestic shorthair cat with a history of chronic intermittent vomiting, diarrhoea and constipation was referred for abdominal ultrasound of a mid‐abdominal mass identified on palpation. Findings included a densely shadowing structure within the distal ileum with severe local muscularis thickening, mild diffuse small intestinal muscularis thickening, and an enlarged right ileocolic lymph node. Abdominal radiographs showed the structure to be most consistent with an enterolith. Enterolithiasis is a rare condition in companion animals, but common in horses and selected populations of human patients. Enterectomy was performed, and histopathology results of intestinal biopsies were consistent with chronic inflammatory enteropathy. Chemical analysis of the enterolith revealed a predominantly calcium phosphate composition. At the 3‐month follow‐up, the cat had gained weight and showed marked improvement in gastrointestinal signs. Screening for underlying structural intestinal disease may be beneficial in cats diagnosed with enteroliths.

Regional heterothermies recorded in the oxygen isotope composition of harbour seal skeletal elements

Regional heterothermy is a strategy used by marine mammals to maintain a high and stable core body temperature, but its identification needs in situ measurements difficult to set up in extant wild organisms and inapplicable to extinct ones. We have analysed the oxygen isotope composition of bioapatite phosphate (δ18Op) from one permanent tooth and from thirty-six skeletal elements of one adult male harbour seal (Phoca vitulina) from the Baie de Somme (Hauts-de-France, France). We propose that the observed intra-skeletal δ18Op variability reflects tissue temperature heterogeneities typical of the pinniped regional heterothermy strategy. Our δ18Op data indicate that bone hydroxylapatite from harbour seal autopod skeletal elements (metacarpals, metatarsals, and phalanxes) mineralises at a lower temperature than that of the bone from the axial skeleton (e.g. vertebrae, ribs, and girdle bones). The results suggest that it is possible to locate a history of regional heterothermies in amphibious marine vertebrates using the δ18Op values of their mineralised tissues. This enables direct evaluation of the thermophysiology of both modern and fossil Pinnipedia from their skeletons opening perspectives on understanding their thermal adaptation to the marine environment in the fossil record. In addition to thermophysiology, oxygen isotope data from the permanent teeth of Pinnipedia, which are formed during the in utero phase from body fluid of the mother and at a stable temperature, could be valuable for locating the geographical areas inhabited by existing Pinnipedia females during their gestation period.

Assessment of the influence of mineral fertilisers on the phosphate regime of meadow chernozem carbonate soil and yield of sunflower and winter wheat

The relevance of the study lies in the need to maintain optimal levels of mobile phosphorus in carbonate soils to support healthy plant growth and development, as it can be converted into less mobile forms in such soils. The purpose of the study was to assess the impact of various long-term fertilisation strategies on the content of various forms of phosphorus in the soil to improve this availability. The research was conducted in 2019-2022 as a stationary experiment in a separate division of the National University of Life and Environmental Sciences of Ukraine “Agronomic Experimental Station” in Kyiv Oblast on meadow chernozem carbonate low-humus coarse-sawn light loamy soil in a five-field crop rotation, where the influence of different levels of fertiliser saturation (no fertiliser, minimum, average, and optimal) on soil phosphate status and yield of Etana winter wheat variety and Sumiko sunflower hybrid was investigated. Soil samples were taken from the 0-20 and 20-40 cm layers, and the group and fractional composition of phosphates was determined using the Chang-Jackson method and the content of mobile phosphates using the Chirikov and Machigin methods. According to the analysis of the group and fractional composition of soil phosphates, it was found that in meadow chernozem carbonate low-humus coarse-sawn light loamy soil, the content of iron phosphates prevails among all fractions during long-term fertilisation. The results showed an increase in the content of aluminium phosphates in the 0-20 cm surface layer of the soil of two variants with long-term fertilisation, and an increase in the content of the second fraction of soluble calcium phosphates (Ca-PII), with the minimum saturation (N27P18K20) with the highest available phosphate fraction for plants (Ca-PI) is observed. The content of mobile phosphates was maximal at optimal fertiliser saturation (N81P54K62) and was 4.8 and 8.5 mg/100 g of soil, the aftereffect of organic fertilisers positively affected the accumulation of mobile phosphates in the soil. The highest yield of winter wheat (7.55 t/ha) and sunflower (4.28 t/ha) was obtained with optimal fertiliser saturation, the lowest – without the use of fertilisers, where it was 4.45 t/ha for winter wheat and 2.23 t/ha for sunflower. The results of the study can be used to develop more sustainable and effective strategies for using phosphorus in soils, which can help preserve soil resources and prevent possible contamination of water sources due to excessive phosphorus intake

Efficient removal of uranium from acidic mining wastewater using magnetic phosphate composites

Uranium mining operations produce large volumes of acidic uranium mining wastewater, necessitating the development of environmentally friendly and recyclable materials for efficient uranium removal and recovery. The current study successfully produced hydroxyapatite (HAP-L) and magnetic phosphate composites (CaFeP-1, CaFeP-2, and FePO4) through a combination of mixing, ultrasonication, hydrothermal precipitation, and calcination methods. The research explores the influence of various parameters such as pH, solid–liquid ratio, contact time, initial uranium concentration, co-existing ions, and recyclability on the uranium removal efficiency of these materials. The findings indicate exceptional uranium adsorption capacities, with CaFeP-1 exhibiting the highest capacity among the materials, especially in acidic environments. Moreover, CaFeP-1 displays strong resistance to interference from other ions and can be recycled multiple times while maintaining high removal rates. Treatment of acidic uranium mining wastewater by CaFeP-1 results in pH adjustment and the reduction of uranium and other ion concentrations, making it a promising solution for comprehensive remediation of acidic uranium mining wastewater. The U(VI) removal mechanism by CaFeP-1 was validated through XRD, FT-IR, and XPS results. The U(VI) removal was attributed to processes such as dissolution-precipitation, surface complexation, and ion exchange. The formation of sodium uranyl phosphate hydrate was identified as a new product following U(VI) abatement by CaFeP-1. In summary, CaFeP-1 shows great potential for the effective treatment of acidic uranium mining wastewater.

Characterization, bioactivity, antibacterial and cytotoxicity of inexpensive soda-lime-silica glass/tetracalcium phosphate composites

Composite biomaterials were created by sintering soda-lime-silica glass powder and tetracalcium phosphate powder. Sintering of the samples at 1200 °C/2h led to the formation of wollastonite, calcium phosphate, and cristobalite before soaking in simulated body fluid (SBF). However, after soaking for two weeks in SBF the hydroxyapatite, wollastonite, and cristobalite phases appeared with relatively intense in hydroxyapatite phase on sample surfaces. The microstructure shows micro-scale particles on the sample surface after soaking in SBF. The bulk densities and porosities were within 1.82453–1.9672 g/cm3 and 15.0621–34.1657 % respectively whereas compressive strength values were between 42.79 and 111.26 MPa. Since the increase of the porosity in the direction of high addition of phosphate portion while strengths were high in opposite values. The biocompatibility in SBF increases with increasing the SLS glass portion and the SEM micrographs show fine spherical crystals, within 20–200 nm, of hydroxyapatite phase on composite surfaces. The FTIR spectrum after soaking in SBF indicates the presence of phosphate bands in all samples and the intensity of these bands increases as the SLS glass percentage increases. The degradation of composite samples decreases in the direction of an increase in the phosphate portion which led to a decrease in the porosity and an increase in both density and strength. Pseudomonas aeruginosa and Staphylococcus aureus, the two examined bacteria, both showed the establishment of growth inhibition zones in the disk diffusion assay. All samples were shown to be biocompatible by the cytotoxicity test conducted on the human normal fibroplast cell line (BJ1). In light of this, the cytotoxicity analysis demonstrated that the highest soda-lime-silica glass sample (SLP55), which has potential uses in the dental and bone fields, was entirely safe for use with the human normal fibroplast cell line (BJ1).

Post-consumer high density polyethylene/zirconium phosphate and aluminum hydroxide composites: Assessment of physico-mechanical and flame retardancy properties

Regarding environmental preservation, the upcycling of plastics from petroleum source is a consistent alternative. This work intended to investigate melting extruded composites of post-consumer HDPE (rHDPE) filled with pristine zirconium phosphate (ZrP), aluminum hydroxide [Al(OH)3] and aluminum hydroxide modifying-zirconium phosphate [ZrPOct/Al(OH)3]. Physico-mechanical and flame retardancy were assessed. FTIR revealed that rHDPE brought some degree of oxidative degradation probably from its cleaning process and/or processing. By nuclear magnetic resonance at time domain, rHDPE showed three relaxation domains. Fillers induced the lowering of rHDPE relaxation time owing to polymer/filler by hydrogen bonds. Diffraction pattern of rHDPE/Al(OH)3 and rHDPE/ZrPOct/Al(OH)3 indicated better fillers’ dispersion. Fillers changed rHDPE crystallinity degree and thermal stability but rheologic properties were invariable. For all composites, elastic modulus increased (up to 17%) indicating stiffening. Yield strength did not change but stress and strain at break decreased. For the composites, SEM/EDS showed better dispersion and distribution of ZrP and ZrPOct/Al(OH)3 particles. It was assumed that ZrP and ZrPOct/Al(OH)3 greatly increased the flame retardancy. The work corroborates the importance of polymers’ upcycling, and it is in consonance with the objectives of 2030 Agenda released by United Nations.

Unlocking the synergetic potential of cobalt iron phosphate and multiwalled carbon nanotube composites towards supercapacitor application

Exploring non-toxic, multiple oxidation state iron phosphate (Co3Fe4(PO4)6) anchored MWCNTs with blossomed micro platelets surface architecture as a supercapacitive electrode and design of a large-scale (10 × 4 cm2) symmetric device powering a DC fan.

Efeito de nitrogênio e enxofre no perfil de ácidos graxos de cártamo

ABSTRACT Nutritional management is one of the most important factors determining plant growth and improving the quality characteristics of a crop. This study aimed to investigate the application of doses of sulphur from different fertilizer sources (S0: control - no sulphur application); S1: 25 kg ha−1 - sulphur phosphate composites; S2: 50 kg ha−1 - sulphur phosphate composites; S3: 25 kg ha−1 - elemental sulphur; S4: 50 kg ha−1 - elemental sulphur; S5: 25 kg ha−1 - zinc sulphate; S6: 50 kg ha−1 - zinc sulphate) and nitrogen fertilizers (0, 40 and 80 kg ha−1 - urea fertilizer) on the profile of fatty acids, in Carthamus tinctorius L. seeds. The application of high levels of sulphur significantly reduced the amount of ash. The highest percentage of oil was achieved from plants grown with S4N80 and S3N40. The highest amounts of stearic and oleic acid were recorded with the use of S6N80. The linolenic acid content was affected by both sulphur and nitrogen doses, and the highest amount was recorded using S4N80 and S6N40, respectively. The application of S4N80, S6N80 and S3N80 in the studied area could significantly improve the oil quality.

Design Polyaniline/α-Zirconium Phosphate Composites for Achieving Self-Healing Anti-Corrosion of Carbon Steel.

The rupture of a micro/nano container can trigger the release of repair agents and provides the coating with a self-healing and anti-corrosion effect. However, the defect and inhomogeneity of the coating, produced by the rupture of the micro/nano container, may weaken its anti-corrosion performance. This study reports a rare protection mechanism, which optimizes the space occupying of zirconium phosphate, and the de-doping peculiarity of polyaniline without the rupture of the micro/nano container. Polyaniline/α-zirconium phosphate composites were constructed through in situ oxidation polymerization. Repair agents were added in the form of doped acids. According to the different repair agents in polyaniline/α-zirconium phosphate composites (citric ion, tartaric ion and phytic ion), the performance and protection mechanism of the composites were researched. Polyaniline/α-zirconium phosphate coating (with phytic ion) shows an excellent self-healing anti-corrosive effect, due to the large spatial structure and abundant chelating groups of the precipitation inhibitor. Considering the anti-corrosive application, the developed polyaniline/α-zirconium phosphate composite has a far-reaching influence on marine development.

Mechanical strength enhancement of CaZr4P6O24 ceramics with multi-walled carbon nanotubes additions

Multi-walled carbon nanotubes/calcium zirconium phosphate composite (MWCNTs/CZP) ceramics were successfully synthesized by co-precipitation to improve the mechanical strength of CZP ceramics sintered at 1100 ℃ under an argon atmosphere. The impact of the different weight percentages of MWCNTs (ranging from 0.1 to 1.0 wt%) on the structure, morphological, and mechanical strength of CZP was investigated. Microstructural analysis revealed the grain size was reduced and the surface morphology and densification were improved by the addition of MWCNTs compared to pure CZP ceramics. The flexural strength and modulus of 0.5 MWCNTs/CZP composite were measured at 91.76 MPa and 21.98 GPa, respectively, further revealing that MWCNTs had significant effects on densification and mechanical strength of CZP ceramics.

One-pot synthesis of novel mesoporous FeOOH modified NaZrH(PO4)2·H2O for the enhanced removal of Co(II) from aqueous solution.

One-pot synthesis of a novel mesoporous hydroxyl oxidize iron functional Na-zirconium phosphate (FeOOH-NaZrH(PO4)2·H2O) composites was firstly characterized and investigated its Co(II) adsorption from aqueous solution. Compared to NaZrH(PO4)2·H2O (65.7 mg⋅g-1), the maximum Co(II) adsorption capacity of FeOOH-NaZrH(PO4)2·H2O was improved to be 95.1 mg⋅g-1. BET verified the mesoporous structures of FeOOH-NaZrH(PO4)2·H2O with a larger pore volume than NaZrH(PO4)2·H2O. High pH values, initial Co(II) concentration, and temperature benefited the Co(II) adsorption. Kinetics, isotherms, and thermodynamics indicated an endothermic, spontaneous chemisorption process. FeOOH-NaZrH(PO4)2·H2O has a better Co(II) adsorption selectivity than that of NaZrH(PO4)2·H2O. In particular, FeOOH-NaZrH(PO4)2·H2O exhibited an outstanding reusability after ten cycles of tests. The main possible mechanism for adsorbents uptake Co(II) involved in ion exchange, electrostatic interaction, and -OH, Zr-O bond coordination based on FTIR and XPS analysis. This work presents a feasible strategy to prepare novel modified zirconium phosphate composites for extracting Co(II) from solutions and providing a new insight into the understanding of Co(II) adsorption in the real nuclear Co(II)-containing wastewater.