Na2HPO4 Solution Research Articles

Influence of Na-Al phosphate glass leachates in clays sorption behavior toward radionuclides

The article presents the results of the study of the sorption of 90Sr, 137Cs, 233U, 237Np, 239Pu,and 241Am radionuclides from model groundwater, model leachate of aluminophosphate glass and Na2HPO4 solutions of different concentrations on bentonite clays of Kamalinskoye (Krasnoyarsk Territory), Desyaty Khutor (Republic of Khakassia), and Dinozavrovoye (Republic of Kazakhstan) deposits. We determined that the presence of aluminophosphate glass leachate in the liquid phase reduced the sorption activity of the studied clays towards caesium. The distribution coefficients of strontium depend more on the clay properties than on the liquid phase composition. However, with increasing concentration of phosphate ion, we observed an increase in the strength of sorbed strontium retention by clay. The sorption of uranium, neptunium, plutonium and americium, increased in the presence of components leached from the aluminophosphate glass-like matrix, and the strength of their fixation by clay increased.

Development of a Novel Formulation of Bioactive Glass Based Calcium Phosphate Cement for Bone Grafting

AbstractParticulate bone grafting material can travel from the implantation site and diminish the magnitude of required bone formation response and hence its effectiveness. An easily prepared moldable graft that rapidly sets rigid in situ would alleviate this problem and in this study, such an injectable bone graft material is presented. By combining calcium phosphate (CP) salts with a bioactive glass (BG) mixed with a 2.5% Na2HPO4 solution a novel BG‐based calcium phosphate cement (CPC) is produced. Immersion in Tris buffer and simulated body fluid (SBF) solutions result in the rapid generation of octacalcium phosphate (OCP) and hydroxyapatite (HA) phases – a pre‐requisite for “bioactivity”. Cement‐conditioned media does not result in any cytotoxic potential with respect to MTT activity, DNA content, or alkaline phosphatase activity with an osteoblastic cell line. Application of the cement into standardized surgical defects in the minipig mandible results in short‐term, moderate irritation at 3 and 6 weeks and complete replacement of cement with new bone at 12 weeks.

A novel method to fabricate monetite granules for bone graft applications.

Monetite granules were reported to be able to balance osteoclastic resorption and new bone formation. However, to date, the dehydration of preset brushite has been the well-known method for preparing monetite granules. In the present study, for the first time, monetite granules could be prepared from the phase transformation of calcium sulfate dihydrate (CSD) granules through immersion in NaH2PO4 solution under hydrothermal conditions. CSD granules could be fully transformed into monetite granules at a reaction temperature of 125°C for 24 h. The obtained monetite granules were eight times more soluble in acetate buffer than in Tris-HCl buffer. Furthermore, monetite granules were two times more soluble in acetate buffer but comparable in Tris-HCl buffer compared to xenograft HA. The initial cytotoxicity test indicated that the novel monetite granules were nontoxic. In short, novel monetite granules were successfully prepared, exhibited better solubility in osteoclastic simulation than xenograft HA and were nontoxic.

Contradiction with enzymatic stoichiometry theory: Persistent low ratios of β-glucosidase to phosphomonoesterase following 10-year continuous phosphorus fertilization in three subtropical forests

The ratio of β-glucosidase (BG) to phosphomonoesterase (PME) activity (BG:PME) is often used to predict the intensity of microbial phosphorus (P) shortage, with lower BG:PME indicating stronger P shortage (enzymatic stoichiometry theory). Here, we demonstrated that 10-year continuous P fertilization as high as 150 kg P ha−1 yr−1 in the form of NaH2PO4 solution did not elevate the BG:PME up to the level of other terrestrial ecosystems. The BG:PME of primary, secondary, and planted forests were 0.094, 0.067, and 0.089, respectively in P-fertilized plots, which were much lower than global average (0.62 ± 0.04), despite the fact that Bray-extracted P contents were substantially elevated (more than 600 times). Thus, the findings of the current study suggest that BG:PME overestimates P shortage in our P-enriched forests, implying that the enzymatic stoichiometry theory may not be universally applicable.

Enhanced visible light photocatalytic activity of octopod Ag3PO4 microcrystals with high index crystal faces.

Novel octopod shaped Ag3PO4 microcrystals were successfully fabricated by a simple ion exchange method under the conditions of a hot water bath using [Ag(NH3)2]+ solution and Na2HPO4 solution as the precursors. Meanwhile, sphere and cube shaped Ag3PO4 microcrystals were also prepared followed by changing reaction materials as well as temperature. The surface morphology, microstructure and photocatalytic performance were investigated on the three different shaped crystals respectively. Compared to sphere and cube counterparts, the obtained octopod shaped Ag3PO4 crystals possess 8 symmetric feet with sharp tips and exhibit higher photocatalytic activity and better cycle stability. After further exploring its formation process, UV-vis diffusion reflectance properties as well as photocurrent transient response, it was found that the Ag3PO4 octopod had exposed high index crystal faces, and possessed a narrow band gap as well as high photoexcited transient charge separation efficiency. The results show that the improved photocatalytic activity of octopod shaped Ag3PO4 is mainly due to the synergistic action of the strong light absorption capacity and high carrier separation efficiency. These results highlight the tremendous practical application of octopod Ag3PO4 microcrystals in visible light photocatalysis.

Effect of phosphate post-treatment on corrosion behavior of cerium-based conversion coated Mg-4.0Y-4.0Zn-0.5Zr-0.2Ca (wt.%) alloys

The present study aims to investigate the effect of cerium-based conversion coating and phosphate post-treatment on the corrosion behavior of Mg-4.0Y-4.0Zn-0.5Zr-0.2Ca (wt.%) alloy (WZ44) in chlorinated solution. In this regard, as-cast and forged WZ44 alloy was subjected to cerium salt bath treatment at ambient followed by NaH2PO4 solution at 85 °C. The morphological evolution and chemical composition of the composite coating were examined using field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), two and three-dimensional surface topography, and X-ray photoelectron spectroscopy (XPS) reveal the formation of complex phase mixture of CeO2, Ce2O3, CePO4, Mg(OH)2, and unknown hydrated compounds. The as-prepared cerium conversion coating possesses nodular CeO2 precipitates with abundant mud-cracks features originating due to hydrogen evolution and film dehydration-induced tensile stress. However, phosphate treatment develops a relatively smoother and compact coating with minimum surface roughness and conversion of nodular CeO2 precipitates into CePO4, albeit with few fine cracks. The tape adhesion and scratch test disclose that coating delamination predominant in cerium conversion coated specimens was reduced drastically by phosphate treatment with ∼16–23 % improvement in scratch hardness. Corrosion in terms of mass loss and potentiodynamic polarization (PDP) highlights that phosphate treatment improves the corrosion rate by ∼25–65 % compared to blank. Electrochemical impedance spectroscopy (EIS) demonstrates that coating (Rcoat) and polarization resistance (RP) at the film-metal interface was substantially increased to ∼953 Ω cm2 and ∼729 Ω cm2 for phosphate-treated specimens with a progressive increase in semicircular capacitive loop diameter indicating surface passivation. Overall, a duplex coating strategy with cerium salt bath followed by phosphate treatment can essentially develop a compact double-layer that effectively minimizes severe corrosion of WZ44 alloy in a 0.1 M NaCl electrolyte.

Development of environmentally-friendly modified bioadsorbents for water treatment

As a result of scientific research, it was found that synthesized pure sorbents based on a composite of Fe3O4 nanoparticles and AlgBT have an increased adsorption capacity due to the inclusion of double hydroxides and an alginate matrix. The processes of complex formation occur according to the principle of maximum inheritance of the structural features of the original coordination compounds, which make it possible to predict and implement the hypothetical structures of new compounds. All this significantly improves the adsorption capacity of the developed adsorbents with respect to phosphate ions. Modified sorbents with a clay basis are therefore a particularly intriguing field. The current research constructed and described modified sorbents, and then conducted tests in the laboratory to determine how well they absorbed phosphate. This study used spectroscopic techniques (SEM, FTIR, X-ray diffraction, and XRD analytical methods) to examine the structure and physicochemical characteristics of improved ecologically friendly sorbents based on alginates, bentonite, and nanoparticles. The alginate core may be physically and chemically modified and can take part in a variety of phosphate anion adsorption methods thanks to the active COOH and OH groups that are present there. The sorption efficiency was established for a modified Fe3O4NPs@AlgBT. Equilibrium in the system sorbent-an aqueous solution of Na2HPO4 is established in 10 hours after the start of sorption, while two-thirds of all sobbed anions pass into the solid phase during the first two hours. The limiting sorption of phosphate ions on modified Fe3O4NPs@AlgBT reaches 410 mg/g, which makes it possible to offer it as an effective sorbent for industrial wastewater treatment

Influence of the Chemical Composition of Ceria Conversion Coatings, Sealed in Solution of NaH2PO4 and Ca(NO3)2, on the Corrosion Behavior of Aluminum.

The corrosion-protective influence of eco-friendly ceria conversion coatings deposited on Al-1050 alloy, additionally treated in mixed NaH2PO4 and Ca(NO3)2 solution, was studied. The main aim of this work was to investigate how the obtained mixed systems of coatings eliminates the negative role of cracks and pores on the surface formed after deposition only of ceria coating. For this purpose, the growth structure, main components and corrosion resistance of the so formed protective systems were investigated by SEM, EDS, XRD, XPS and electrochemical (PDP, Rp, etc.) methods. The results obtained show that the basic components of the conversion layers (before and after exposure in model corrosion media) are characterized by Al2O3, Al(OH)3, CePO4 and Ca5(PO4)3(OH). Based on these results, the optimal conditions of immersion treatment(s) of Al substrate are established. At these regimes, the relationship of co-deposited Ce3+, PO43+ and Ca2+-containing components of the conversion layers determine the maximum values of their polarization resistance-a basic criterion for corrosion protection of Al. This effect is related to the formation of fill out of the defects of the conversion coatings and additional Ca5(PO4)3(OH), CePO4 AlPO4 and Al(OH)3 deposits, leading to the decrease of the corrosion rate.

Restorative Dental Resin Functionalized with Calcium Methacrylate with a Hydroxyapatite Remineralization Capacity.

The ability of dental materials to induce the mineralization of enamel like hydroxyapatite (HA) is of great importance. In this article, a novel kind of dental restorative material characterized by a mineralization ability was fabricated by photopolymerization. Calcium methacrylate (CMA) was introduced into the classical bisphenol A-glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) dental resin formulation. This functional dental resin (BTCM) was calcium-rich and can be prepared simply by one-step photopolymerization. The influence of CMA on the photopolymerization kinetics, the dental resin's mechanical properties, and its capacity to induce dynamic in situ HA mineralization were examined. Real-time FTIR, compression modulus, scanning electron microscopy, X-ray spectroscopy, MTT assay, and cell attachment test were carried out. The obtained data were analyzed for statistical significance using analysis of variance (ANOVA). Double bond conversion could be completed in less than 300 s, while the compression modulus of BTCM decreased with the increase in CMA content (30 wt%, 40 wt%, and 50 wt%). After being soaked in Ca(NO3)2 and Na2HPO4 solutions alternatively, dense HA crystals were found on the surface of the dental resin which contained CMA. The amount of HA increased with the increase in CMA content. The MTT results indicated that BTCM possesses good biocompatibility, while the cell adhesion and proliferation investigation demonstrated that L929 cells can adhere and proliferate well on the surface of BTM. Thus, our approach provides a straightforward, cost-effective, and environmentally friendly solution that has the potential for immediate clinical use.

Hydrothermal preparation of cubic sodium zirconium phosphate crystals

NASICON type material NaZr2(PO4)3 is considered to be the ideal solid electrolyte choice for solid-state Na batteries due to its excellent low thermal expansion and Na ion conductivity. However, the often-prepared solid-state reaction method requires a high reaction temperature and produces other polymerized phosphates and environmentally unfriendly substances. This paper’s hydrothermal method quickly prepared NaZr2(PO4)3 crystals with cubic morphologies at a low temperature. The effects of different concentrations of NaH2PO4 solution and different hydrothermal times on the preparation of the powders were explored. XRD, SEM, TEM and IR tests characterized the as-prepared samples. The results show that the NaZr2(PO4)3 crystals synthesized by the hydrothermal method have good crystallinity and a clean surface, with a standard cubic morphology and a size distribution between 400 nm and 750 nm. This indicates that the hydrothermal method is an effective synthesis one.

CERAMIC MATERIALS OF A GIVEN PHASE COMPOSITION BASED ON HYDROXYAPATITE POWDER TREATED IN SOLUTIONS OF AMMONIUM, SODIUM AND POTASSIUM DIHYDROPHOSPHATES

Powders of hydroxyapatite (HA) Ca10(PO4)6(OH)2 treated in 0.25M aqueous solutions of ammonium NH4H2PO4, sodium NaH2PO4 and potassium KH2PO4 dihydrophosphates for 1 hour under stirring were used for ceramics production. According to the XRD data, there was no changes in the phase composition of the powders after such treatment. After firing in the range of 900 – 1100 ?С, the phase composition of ceramics based on HA Ca10(PO4)6(OH)2 powder treated with an aqueous solution of NH4H2PO4 included ?-tricalcium phosphate ?-Ca3(PO4)2 and HA Ca10(PO4)6(OH)2; The phase composition of ceramics based on HA Ca10(PO4)6(OH)2 powder treated with NaH2PO4 aqueous solution included sodium-substituted tricalcium phosphate Ca10Na(PO4)7 and HA Ca10(PO4)6(OH)2; the phase composition of ceramics based on HA Ca10(PO4)6(OH)2 powder treated with an aqueous solution of KH2PO4 included potassium-substituted tricalcium phosphate Ca10K(PO4)7 and HA Ca10(PO4)6(OH)2. The formation of biphasic ceramics occurred due to a decrease in the molar ratio Ca/P of HA powder after treatment in aqueous solutions of ammonium NH4H2PO4, sodium NaH2PO4 and potassium KH2PO4 dihydrophosphates. HA-particle surface adsorption of cations and anions from the solution, slight dissolution of HA in solutions of dihydrophosphates with acidic pH, as well as ion exchange of cations and anions of HA for cations and anions from solutions, were possible processes providing change in the ratio of cations and anions in the HA powder. The resulting ceramic composites contain biocompatible phases, and can be recommended for the creation of bone implants.

An economic and eco-friendly method for the recovery of ellagic acid from waste pomegranate peel via thermal hydrolysis assisted extraction and liquid-liquid extraction

In the present study, a low-cost and environmentally-friendly method for the recovery of ellagic acid (EA) from waste pomegranate peel (WPP) was developed. Thermal hydrolysis assisted extraction (THAE) method was designed to efficiently prepare EA at low economic and environmental costs by the simultaneous extraction and hydrolysis of EA and its derivatives using NaH2PO4 solution as extraction solvent, which could be reused at least 5 times after simple post-treatments. Ethyl acetate was chosen as liquid-liquid extraction (LLE) solvent to directly recover EA from THAE extract and regenerate NaH2PO4 solution. After a series of optimization of operation parameters, the recovery rates of EA in the THAE and LLE processes reached ∼94% and 96%, respectively. As all of the solvents used above belong to cheap, eco-friendly, and edible solvents, this proposed method provides a good way to get safe and inexpensive EA-rich extract (with a purity of ∼89%), which could be used as natural ingredient in food, cosmetic, and medicinal industries, as well as starting materials for the preparation of pure EA.

The study of self-regulating α-TCP based composite by micro/nano scaled silk fibroin and α-CSH on physicochemical and biological properties of bone cement.

A novel self-hardening α-tricalcium phosphate (α-TCP) bone cement complexed with different content of α-calcium sulfate hemihydrate (α-CSH) and micrometer hydroxyapatite mineralized silk fibroin (HA-SF) using micro/SF as curing liquid has been investigated in this work, which was capable of tunable setting time, degradation, mechanical property and ability to anti-washout. After addition 0 ∼ 25% α-CSH to the α-TCP cement with SFFs as curing liquid, it shortened the setting time of the modified composite to 10 ∼ 30min. Furthermore, the addition of SFFs improved the compressive strength of the composite from 5.41MPa to 9.44MPa. The composites with both Na2HPO4 and SFFs as curing liquid showed good anti-collapse performance. The weight loss ratio of bone cement was -0.18 ∼ 12.08% in 4weeks when the content of α-CSH in α-TCP/α-CSH was between 0 ∼ 25wt%. During the degradation of α-CSH, the amorphous α-TCP were deposited as hydroxyapatite to formed a plate-like products on the surface of composite. Compared to the composite with Na2HPO4 solution as the curing liquid, alkaline phosphatase (ALP) activity of the composites using SFFs as curing liquid were maintained at high levels on the 14th day especially when the Ca/P ratio was 1.7. This study provides a theoretical basis for the regeneration of bone defects guided by bone cement materials.

A mild closed-loop process for lithium–iron separation and cathode materials regeneration from spent LiFePO4 batteries

The recycling and reusing of waste LiFePO4 batteries significantly promote sustainable development and environmental protection. In this study, an innovative process of iron-lithium separation and cathode materials regeneration from used LiFePO4 batteries is proposed. The spent LiFePO4 powder was put into NaH2PO4 and H2O2 combined treatment solution for an oxidation leaching reaction. Under the optimal condition, excellent lithium–iron separation was achieved, with 98.65% leaching of lithium and only 0.028% leaching of iron. The selective separation of lithium ion can be efficiently achieved during the leaching process. Li+ from the leachate was precipitated into Li3PO4 by evaporation crystallization, and the saline solution, after precipitation, was converted into a leaching agent by adding H3PO4 for reusing. The regenerated LiFePO4 from recovered FePO4 displays excellent rate capability and long-term cyclic stability. Through the synergistic effect of NaH2PO4 and H2O2, this work achieves efficient and mild separation of iron-lithium while maintaining the raw material olivine structure, regenerating LiFePO4 cathode material with good electrochemical properties, avoiding the cost of wastewater treatment and forming a stable closed loop.

Preparation of micro-calcite powder using fine-bubble assisted carbonation as toothpaste material

ABSTRACTIntroduction: Calcite (CaCO3) is typically used in commercial toothpaste with particle size ranges from 1-12 μm. In the latest study, calcite was synthesized by using Ca(OH)2 precursor from natural resources However, the resulting particle size does not match the size of the toothpaste filler. This study aims to prepare micro-calcite via fine-bubble assisted carbonation as toothpaste material. Methods: The calcite powder was prepared from Ca(OH)2 analytical grade powder utilizing the fine-bubble carbonation process with the Ca(OH)2 concentration and initial pH variation. The study was started by making a Ca(OH)2 suspension with a concentration of 0.25, 0.5, 0.75, 1 and 1.25 M using 2.000 ml methanol as a solvent. 0.5 M NaH2PO4 solutions were utilized to adjust the initial pH of 0.5 M Ca(OH)2 suspension into 8, 9, and 10. The suspensions were aerated using CO2 fine-bubble for two hours to produce CaCO3 samples. All precipitated CaCO3 particles were characterized by PSA, Zeta-Potential, and FTIR measurements. Results: The calcite phase was identified from the FTIR transmittance. Aragonite or vaterite phase was not observed in the samples. PSA result shows the size of CaCO3 particles from samples 0.25 M to 1.25 M are as follows 3.03, 3.23, 2.79, 3.70, 0.99 μm respectively. Meanwhile, the particle sizes of CaCO3 in samples with a pH of 8, 9 and 10 are 3.00, 2.03 and 2.50 μm respectively. The zeta potential shows the value ranges from -23.2 mV to -11.9 mV, indicating fair dispersion ability. Conclusion: The fine bubble assisted carbonation method in this study helps in producing calcite in micron size that could be used as alternative fillers for toothpaste.Keywords: calcite, fine-bubble, carbonation, particle size, toothpaste

Collagen films with improved wet state mechanical properties by mineralization

Collagen films have weak wet mechanical properties due to poor water resistance. Herein, two mineralization processes were designed to improve the mechanical properties of collagen fibers under wet conditions for use as packaging materials. One scheme (S1) involved preparing carboxymethyl chitosan amorphous calcium orthophosphate (CMCS-ACP) nanoparticles, dispersing them in an aqueous solution and then immersing the collagen film in the dispersion to introduce the inorganic phase. Another scheme (S2) introduced the inorganic phase by alternately soaking in a CaCl2 and a Na2HPO4 solution. S1 introduced an amorphous inorganic phase and enhanced the wet tensile strength of collagen films from 2.71 MPa (Control) to 4.08 MPa (1.0%C-A). S2 introduced a large number of inorganic phases, which did not significantly enhance the wet tensile strength of the film, but reduced its swelling ratio from 176.15% to 112.87%. The amorphous inorganic phase from S1 did not destroy the triple helix structure of the collagen film, whereas the direct calcium phosphate deposition from S2 greatly damaged the original structure of the collagen film, resulting in poorer mechanical properties from 2.71 MPa (Control) to 1.55 MPa (N3).

Disodium Phosphate Dodecahydrate Salt Hydrate-Based Approach for Thermal Energy Storage Systems

Salt hydrates, classified as inorganic phase change materials, are used in thermal energy storage (TES) systems. Due to their superior properties such as higher thermal conductivity and better thermal energy storage density, non-flammability and availability in wide temperature ranges at a reasonable cost than organic PCMs, salt hydrates are preferable PCMs. Disodium phosphate dodecahydrate (Na2HPO4·12H2O) have a favourable melting point and melting enthalpy for room temperature energy storage applications but supercooling, phase segregation, formation of lower hydrates, and corrosion to storage vessels are frequent limits to its employment, just as they are for other salt hydrates. These issues are addressed using various intensification techniques such as an aqueous saturated salt solution of Na2HPO4 (both non-gel and gel-based) instead of pure salt hydrate and using suitable nucleating, and gelling agents. Further, the intensification is done via the incorporation of solution in an open cell polyurethane (PU) foam. DSC analysis of PU-based PCM composite confirmed its melting temperature and melting enthalpy at about 35oC and 167.343 J/g recommends for its applications between 30oC- 40oC. Thermal performance observation, in a model system, shows the PU-Gel based PCM to be more efficient with a temperature difference of about 10oC- 14oC for repeated thermal cycles as compared to normal PU foam and PU-Salt based PCM.

Effects of a mineralization-promoting peptide on the physical and chemical properties of mineral trioxide aggregate

Mineral trioxide aggregate (MTA) has been used widely in dentistry due to its sealing ability and biocompatibility. Delayed setting time is one of the major limitations of MTA. Various additives have been studied to further improve the properties of MTA with varied degrees of success. In this study, we have investigated the effect of a calcium phosphate mineralization promoting-peptide (MPP3) on the physical and chemical properties of MTA in comparison with Na2HPO4. Based on the reported effects of MPP3 on calcium-phosphate mineralization reaction, our hypothesis was that MPP3 may also show beneficial effects on the calcium-silicate mineralization system of MTA. Na2HPO4 was used for comparison since its setting accelerant effect on MTA has been well documented. The cements were prepared by mixing with distilled water, 0.40 mM MPP3 solution, 15% Na2HPO4 solution, and a combination of MPP3 and Na2HPO4 solution. Initial and final setting times were measured via Vicat needle. Microhardness values were measured via Vickers indenter at 1,3,7, and 28 days after hydration. Compressive strength after setting was measured via universal testing machine. Morphological and compositional analyses were performed via FESEM imaging, XRD and Raman spectroscopy. The microhardness data was evaluated via repeated-measures ANOVA. Setting time and compressive strength data were evasluated via one-way ANOVA. Initial setting time was reduced to ∼3 min in the Na2HPO4 containing groups but remained at ∼5 min in the control and MPP3 groups. Final setting times were significantly reduced in all groups compared to the control group. The reduction in the final setting times in the Na2HPO4 containing groups were significantly higher compared to the MPP3 group. Microhardness was significantly higher in the MPP3 group at all time points. No statistically significant difference in compressive strength was observed among the groups. FESEM analysis showed presence of ettringite crystals in the MPP3 group, and NaBiO3 crystals in the Na2HPO4 containing groups. XRD analysis showed a broadening of peaks at 2θ = 32° in the Na2HPO4 containing groups, possibly due to presence of NaBiO3. Raman spectroscopy showed statistically higher ettringite content in the MPP3 containing groups. Our findings indicate that MPP3 is a beneficial additive to eliminate some of the drawbacks associated with MTA with no detrimental effects on mechanical properties and without resulting in phases that potentially cause discoloration, such as NaBiO3. We propose that the reduced final setting time and increased microhardness by MPP3 may be associated with the increased ettringite content. Future studies, where wider range of MPP3 concentrations are studied may help elucidate and optimize the beneficial effects of MPP3 observed in this study.

Effect of Pulsed Electric Field on the Electrodialysis Performance of Phosphate-Containing Solutions.

A comparative analysis of mass transfer characteristics and energy consumption was carried out for the electrodialysis recovery of PV from of NaH2PO4 solutions and multicomponent (0.045 M NaxH(3-x)PO4, 0.02 M KCl, 0.045 M KOH, 0.028 M CaCl2, and 0.012 M MgCl2, pH 6.0 ± 0.1) solution in conventional continuous current (CC) and pulsed electric field (PEF) modes. The advantages of using PEF in comparison with CC mode are shown to increase the current efficiency and reduce energy consumption, as well as reduce scaling on heterogeneous anion-exchange membranes. It has been shown that PEF contributes to the suppression of the "acid dissociation" phenomenon, which is specific for anion-exchange membranes in phosphate-containing solutions. Pulse and pause lapse 0.1 s-0.1 s and duty cycle 1/2 were found to be optimal among the studied PEF parameters.

Study of strontium-doped tricalcium silicate/hydroxyapatite composite cement prepared through sol–gel process

A composite cement made of strontium containing tricalcium silicate and hydroxyapatite (SrC3S/HAp) was prepared and studied through a two-stage sol–gel method. The elemental components are 75 wt% of strontium-doped tricalcium silicate (SrC3S) and 25 wt% of hydroxyapatite (HAp). According to previous studies, the SrC3S has good mechanical properties and hydraulic conductivity, and the HAp has good biocompatibility. Therefore, the 75SrC3S-25HAp powder with 10 wt% of NaH2PO4 solution was mixed to prepare the slurry material. This slurry was measured for the working time and setting time at 37 °C under saturated vapor pressure. The material properties were evaluated in terms of crystal structures, surface morphologies, and mechanical properties. The in vitro testing was conducted to determine the ion release rate and curing behavior under a simulated body fluid environment. Finally, the L929 murine fibroblast cells were cultured to study the biocompatibility of the material. The results indicated that the operating time was 15.2 min, and the setting time was 43.6 min. After being soaked into simulated body fluid for14 days of the experiment, the compressive strength of 75SrC3S-25HAp remained 22.1 MPa, and the release of calcium and strontium ions was 501.4 ppm and 49.5 ppm, respectively. The cell viabilities were higher than 70% in various concentrations. These results suggest the 75SrC3S-25HAp has excellent potential for bone cement application.