Preparation Of Phosphate Research Articles

Preparation of porous iron hydroxy phosphate by phosphate slag and its application for adsorbing heavy metal Pb2+

Porous iron hydroxy phosphate was prepared by hydrothermal purification, ball milling modification, hydrothermal crystallization and high temperature roasting of phosphating slag, and was used to treat lead-containing wastewater. The adsorbent was characterized by XRD, SEM, FTIR and TG, and the effect of the amount of adsorbent and the pH value of the system on the adsorption performance of PIHP was investigated. The results showed that when the amount of PIHP added was 0.5g, the removal rate of pb2+ could reach 91% after 120min. When the amount of PIHP added was 0.2 g and the pH of the system was 2.15, the removal rate of pb2+ after 120min could reach 95%. This research has opened up a new direction for the resource utilization of phosphating slag.

Research on Preparation of Nano-porous Lithium Iron Phosphate for Lithium-ion Battery Electrode Materials

Citric acid, nitric acid, ferrous phosphate and lithium carbonate as raw materials, the precursor Fe3(PO4)2 were synthesized by precipitation method, and nano-porous lithium iron phosphate (LiFePO4) was prepared by modified sol-gel method. The influence of pH to purity and yield of precursor Fe3(PO4)2 and sintering temperature to purity of LiFePO4 were studied. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy techniques (TEM) were used to character the phase and morphology of nano-porous lithium iron phosphate (LiFePO4).

Low temperature preparation of α-tricalcium phosphate up-converted luminescence nano phosphor

In this work, fluorescent α-tricalcium phosphate (α-TCP: Yb3+,Er3+) was successfully prepared by the thermal transformation of amorphous calcium phosphate (ACP) precursor. β-cyclodextrin (β-CD) was used for preparation of ACP precursor and played an important role in designing its special structure. Due to the new low temperature preparation of α-tricalcium phosphate, the obtained microsphere has a uniform distribution with rational strength (15.0 Mpa). Futhermore, the two ions (Yb3+,Er3+) were doped into α-tricalcium phosphate (α-TCP), the obtained phosphor can emit exhibit bright green luminescence under the excitation of a 980 nm laser diode. The α-TCP: Yb3+,Er3+ may have great potential in the fields of in vivo bio-imaging and a drug delivery system.

Synthesis of magnesium phosphate nanoflakes and its PCL composite electrospun nanofiber scaffolds for bone tissue regeneration.

This study describes the preparation of nano-magnesium phosphate (nMP) flakes by one step microwave irradiation method. The synthesized nMP was incorporated with polycaprolactone (PCL), hyperbranched polyglycerol (HPG) and nano-hydroxyapatite (nHA) to fabricate as composite electrospun nanofibrous scaffold for bone tissue engineering applications. The electrospun nanofibers were analyzed by scanning electron microscope, XRD, FTIR, DSC, TGA, and wettability measurement. The nanofibers were smooth, randomly oriented, and surface decorated with nMP. The water contact angle was 32±1° (initial contact angle), which reduces to 0° after 1min for HPG and nMP containing nanocomposites, while the contact angle of PCL is 104±5°. The nanocomposite scaffolds exhibited higher swelling, biomineralization, and breakages during PBS immersion. The scaffolds were non-cytotoxic to MG63 osteosarcoma cells and hMSCs with higher viability after 72h. They allowed good adhesion and spreading of these cells when compared to PCL and PCL/nHA electrospun nanofibers. These results indicated that HPG with surface decorated nMP electrospun nanocomposite scaffold can be a promising material for bone tissue engineering applications.

(NaPO3)6-assisted formation of dispersive casein-amorphous calcium phosphate nanoparticles: An excellent platform for curcumin delivery

Although much effort has been focused on the preparation of stable amorphous calcium phosphate (ACP) nanoparticles, the poor dispersity of ACP nanoparticles in aqueous solution remain an unresolved problem. In this work, hexametaphosphate ((NaPO3)6) was used as a green dispersant to disperse casein-stabilized ACP (casein-ACP) nanoparticles in aqueous solution. Characterization of casein-ACP nanoparticles by X-ray diffraction (XRD) proved that the casein-induced amorphous structures could maintained for at least 3 months at room temperature. Moreover, the effects of (NaPO3)6 solutions for dispersing casein-ACP nanoparticles in water was studied and their ability to stabilize aqueous casein-ACP dispersions was demonstrated by digital photos. A typical anticancer drug, curcumin (Cur), was employed to evaluate the drug loading abilities and drug release behaviors of prepared nanoparticles. The results showed that the resultants have high drug loading capacity and favorable pH-responsive drug release properties. Furthermore, this drug delivery system showed an excellent ability to damage A549 cells, indicated that the as-prepared casein-ACP-(NaPO3)6 nanoparticles are promising for the applications in drug delivery.

Wet preparation of calcium phosphates from aqueous solutions

Wet preparation of calcium phosphates from aqueous solutions

Preparation, crystallization features and electro-magnetic properties of phosphate based glass-ceramics as solid electrolyte for lithium-ion batteries

In the present study, the effect of Fe2O3/Al2O3 replacement on the crystallization characteristics of lithium aluminum phosphate glasses with a new composition of 12Li2O–(18–X) Al2O3–X Fe2O3–70 P2O5 (X = 0, 9 and 18 mol%) was investigated. The strength of glasses structure were decreased with incorporation of iron into the glass network instead of aluminum; this is evident from reduce the glass transition temperature, Tg, of the specimens. X-ray diffraction patterns evidenced the formation of Al(PO3)3, ALPO4, (Al0.5, Fe0.5)(PO3)3, and LiFe(P3O9) phases after the controlled heat-treatment process. It also showed that the Al(PO3)3 crystal structure can accept considerable amount of iron to form aluminum iron metaphosphate solid solution. A significant decrease in the grain microstructure of the glass-ceramics was observed as Al2O3 replaced by Fe2O3in the glasses. The magnetic properties of the prepared glass-ceramics were determined at the room temperature by using vibrating sample magnetometer (VSM). The magnetic hysteresis loops of the crystallized glasses have paramagnetic behavior, and their magnetic parameters were dramatically improved by adding of Fe2O3 instead of Al2O3. The evolution of electrical properties in glass-ceramic as a function of Fe2O3/Al2O3 ratio was correlated with the type and size of the phases formed. The substitution of Al2O3 by Fe2O3 resulted in improving the conductivity of the glass-ceramics. The results gave excellent indications for use the prepared glass-ceramic as solid electrolyte materials.

Enzymatic Synthesis of 2‐Deoxyribose 1‐Phosphate and Ribose 1 Phosphate and Subsequent Preparation of Nucleosides

α‐Ribose‐1‐phosphate (Rib‐p) and 2‐deoxy‐α‐ribose‐1‐phosphate (dRib‐p) are key intermediates in nucleoside metabolism and are important starting compounds for the enzymatic synthesis of various modified nucleosides. To date, chemical and enzymatic methods allowed the preparation of these compounds in rather low yields (11–37 %). This prevents their widespread use for the enzymatic synthesis of biologically active and practically important nucleosides. Here we propose to use 7‐methyl‐2′‐deoxyguanosine (7‐Me‐dGuo) and 7‐methylguanosine (7‐Me‐Guo) for the preparation of dRib‐p and Rib‐p. In this paper, we present the effective preparation of Rib‐p and dRib‐p starting from readily prepared 7‐methylguanosine derivatives via their irreversible enzymatic phosphorolysis in the presence of purine nucleoside phosphorylase. Rib‐p and dRib‐P are obtained in nearly quantitative yields (HPLC analysis) and 74–96 % yields after their isolation and purification, which is much higher than previously reported.

Preparation, characterization and bioactivities of nano anhydrous calcium phosphate added gelatin–chitosan scaffolds for bone tissue engineering

Gelatin, chitosan and nano calcium phosphate based composite scaffold with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the physico chemical, mechanical and osteogenic properties of 3D porous scaffold by incorporation of dihydrogen calcium phosphate anhydrous (DCPA) nanoparticles into biopolymer matrix with variation in composition in the prepared scaffolds. Scaffolds were prepared from the slurry containing gelatin, chitosan and synthesized nano DCPA particle using lyophilization technique. DCPA nano particles were synthesized using calcium carbonate and phosphoric acid in water–ethanol medium. XRD pattern showed phase pure DCPA in synthesized nanopowder. Scaffolds were prepared by addition of DCPA nanoparticles to the extent of 5–10 wt% of total polymer into gelatin–chitosan solution with solid loading varying between 2.5 and 2.75 wt%. The prepared scaffold showed interconnected porosity with pore size varying between 110 and 200 micrometer. With addition of DCPA nanoparticles, average pore size of the prepared scaffolds decreased. With increase in nano ceramic phase content from 5 wt% to 10 wt% of total polymer, the compressive strength of the scaffold increased. Scaffold containing 10 wt% DCPA showed the highest average compressive strength of 2.2 MPa. Higher cellular activities were observed in DCPA containing scaffolds as compared to pure gelatin chitosan scaffold suggesting the fact that nano DCPA addition into the scaffold promoted better osteoblast adhesion and proliferation as evident from MTT assay and scanning electron microscopic (SEM) investigation of osteoblast cultured scaffolds. A higher degree of lamellopodia and filopodia extensions and better spreading behavior of osteoblasts were observed in FESEM micrographs of MG 63 cultured DCPA containing scaffold. The results demonstrated that both mechanical strength and osteogenic properties of gelatin–chitosan scaffold could be improved by addition of anhydrous dihydrogen calcium phosphate nanoparticles into it.

ZIDOVUDINE: STRUCTURAL MODIFICATIONS AND THEIR IMPACT ON BIOLOGICAL ACTIVITIES AND PHARMACOKINETIC PROPERTIES

Zidovudine was the first drug approved for the treatment of Acquired Immuno Deficiency Syndrome (AIDS). Its chemical name is azidothymidine (AZT). AZT use is associated with bone marrow toxicity. Shorter half-life and inability to penetrate the blood-brain barrier are the pharmacokinetic problems of this important drug molecule. Various modifications have been carried out in the structure of AZT. These include modification of hydroxyl and azido group, thymidine ring, preparation of phosphate and phosphonate derivatives, attachment of polymers and synthesis of hybrid molecules. Some of these changes produced compounds with significantly increased activity and less toxicity. This review highlights the various structural modifications of AZT and their influence on biological activities and pharmacokinetic properties.

Evaluation of the effectiveness of selected phosphate preparations in the equalization of subclinical hypophosphataemia of dairy cows

Evaluation of the effectiveness of selected phosphate preparations in the equalization of subclinical hypophosphataemia of dairy cows

Preparation of calcium manganese phosphate by mechanochemical synthesis of manganese and hydroxyapatite

Biocompatible hydroxyapatite (HA), with chemical formula Ca5(PO4)3(OH), is widely used in dentistry and orthopedics. Inorganic additions of metal ions into HA structure can significantly influence physicochemical properties of HA-based ceramics. Calcium manganese phosphate (Ca19Mn2(PO4)14) was successfully synthesized by mechanochemical method where the manganese was added to HA with 5, 10, 15, and 20 wt%. The mechanochemical process was investigated by using Fourier-transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), and differential thermal analysis (DTA). The compacted circular disc samples heat-treated at 1200 °C were also investigated using field emission scanning electron microscopy (FE-SEM) where fine agglomerates with small grain size were found. Sample densification improved with increasing sintering temperature. Calcium manganese phosphate (Ca19Mn2(PO4)14), beta-tricalcium phosphate (β-Ca3(PO4)2), and manganese oxide (Mn2O3) phases were formed and increases with increasing sintering temperature. The electrochemical behaviors and corrosion rate were investigated by potentiodynamic polarization, which confirms low corrosion rate that calculated by weight loss test of HA/Mn sample in Hank’s solution. With increasing Mn content, Vicker’s hardness and contact angle of the 1200-°C sintered materials decrease.

Рівень мінералізації щелеп у хворих з дисбалансом естрогенів за даними комп’ютерної томографії

Objective. To increase the effectiveness of the prevention of caries and non-carious dental lesions in patients with estrogen imbalance.Materials and methods. To quantify the density of the bone tissue of the jaws by the method of computed tomography of the structures, an X-ray attenuation scale, called the Hounsfield scale, was used. A Planmeca ProMax 3Ds cone beam computed tomograph was used. To process the results, Planmeca Romexis® software was used. To confirm the imbalance of estrogen, all patients underwent a study on the level of estrogen (estradiol) in the body. For an indirect study of the degree of osteoporosis (bone destruction), we determined the level of serum acid phosphatase. For the study, 3 groups of patients were selected: a comparison group (20 patients) – patients who had not received additional treatment, main group 1 (20 patients) – patients who underwent general therapy with complex calcium preparations, main group 2 (20 patients) – patients who underwent general therapy with complex preparations of calcium and aminobisphosphonates.Results. At the beginning of the study, all groups showed significant demineralization of bone tissue. After 6 months in thecomparison group, the Hounsfield index remained almost unchanged and amounted to 1497±63, which indicates the absence of dynamics in this group. In the main group 1, the Hounsfield index was 1571±44, which is only 5.28% better than the initial result. In the main group 2, the Hounsfield index was 1701±48, which is 13.05% more than the initial result. At the beginning of the study, all groups showed a significant increase in the level of acid phosphatase. So, the indicators in the comparison group, the main group 1, and in the main group 2 were 6.75±0.29, 6.81±0.56, 6.79±0.73, respectively (norm 0–5.5 IU/l). After 6 months of treatment in the comparison group, the level of acid phosphatase remained almost unchanged and amounted to 6.79±0.24, which indicates the absence of dynamics in this group. In the main group 1, the level of acid phosphatase was 4.93±0.26, which is only 27.6 % less than the initial result. In the main group 2, the level of acid phosphatase was 2.43±0.18, which is 64.2 % less than the initial result.Conclusions. The use of complex therapy using calcium phosphate preparations with vitamin D3 and aminobisphosphonates lasting 6 months increases bone mineralization by 13.05 %. The use of complex therapy using calcium phosphate preparations with vitamin D3 and aminobisphosphonates lasting 6 months reduces the activity of acid phosphatase by 64.2 %. The proposed treatment complex helps to reduce the destruction of bone tissue and stimulates the restoration of mineralization of bone tissue and hard tissues of teeth.Key words: tooth mineralization, osteoporosis, estrogen dysfunction, Hounsfield index.

Magnesium phosphate based cement with improved setting, strength and cytocompatibility properties by adding Ca(H2PO4)2·H2O and citric acid

Inorganic phosphate cements have become prevalent as bone filling materials in clinical applications, owing to beneficial properties such as self-setting, biodegradability and osteoconductivity. However, the further development of phosphate cements with higher strength and improved cytocompatibility is expected. In this paper, we reported the preparation of a novel magnesium phosphate based cement (MPBC), which has similar compositions with magnesium phosphate cement (MPC) but Ca(H2PO4)2·H2O and citric acid were additionally added to modulate the performance. The physicochemical and biological properties of MPBC were investigated, the influences of the added Ca(H2PO4)2·H2O and citric acid on the performances of MPBC were analyzed, and the differences of performance between MPBC and MPC were discussed. Experimental results show that the setting time and compressive strength of MPBC were effectively enhanced by the addition of citric acid. In vitro biological degradation indicates that about 15 wt% of MPBC was reduced in 4 weeks. Compared with MPC, MPBC has weaker alkalinity and less dissolution of phosphate, leading to better suitability for cell proliferation and adhesion. These results suggest that as a bone filling material, MPBC shows better performance than MPC in many key indicators and has promising application prospects.

Facile Preparation of Semiconductor Silver Phosphate Loaded on Multi-walled Carbon Nanotube Surface and Its Enhanced Catalytic Performance

A series of colloidal Ag3PO4 sphere loaded onto multi-walled carbon nanotube (CAPS-MWCNT) photocatalysts containing different mass ratio of MWCNT for the removal of RhB and phenol from waste water were synthesized. The photocatalysts were characterized by X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, thermogravimetry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy. By SEM and TEM test, the obtained Ag3PO4 form precipitated and colloidal method present different structure morphology and this showed an important effect on the photocatalytic activity. The CAPS-MWCNT photocatalysts were applied to the removal of Rhodamine B (RhB) and phenol from waste water; and the results indicated that CAPS-MWCNT sample can exhibit the high adsorption and photodegradation efficiency under visible light irradiation. For RhB, the removal efficiency of CAPS-MWCNT-4 reaches 99.8% within 50 min, of which adsorption efficiency is 76.5% within the former 30 min; for phenol, the removal efficiency of CAPS-MWCNT-4 reaches 90.6% within 110 min, of which adsorption efficiency is 14.2% within the former 30 min. The experiment results show that CAPS-MWCNT-4 has the highest removal efficiency for RhB while it presents an excellent reusability for removing phenol from waste water. The present work illustrates a new train for the design and synthesis of stable and high efficiency catalysts, applicable for the removal of various organic pollutants by adsorption and photodegradation.

Preparation of Calcium Phosphate Coated Simvastatin-Loaded PLGA Microspheres Dispersed Alginate Hydrogel Beads as a Controlled Drug Delivery Carrier

Simvastatin (SIM) is widely used as a cholesterol-lowering drug known to affect bone formation in vivo and its sustainable administration into localized area is of particular interest. We reported previously that sustained SIM release from poly (lactic-co-glycolide) (PLGA) microspheres could maintain relatively low concentration in the bone defect area, resulting in the improved bone regeneration effect. The aim of this study was to determine the release characteristics of SIM from calcium phosphate coated SIM-loaded PLGA Microspheres (CSPMs) dispersed into an alginate hydrogel bead (with different drug release profiles), since we speculated that further sustainable SIM release would be more effective related to stimulate the formulation of BMP-2, resulting in the promoted bone regeneration.

Preparation of Copper Phosphate from Naturally Occurring Phytic Acid as an Advanced Catalyst for Oxidation of Aromatic Benzyl Compounds

Both direct oxidation of aromatic benzyl compounds to aromatic ketones and utilization of naturally occurring chemicals to prepare functional catalysts are highly attractive. Herein, copper phosphate was successfully synthesized by using naturally occurring phytic acid as the phosphorus source. The obtained copper phosphate showed excellent performance for the direct oxidation of aromatic benzyl compounds to aromatic ketones with N-hydroxyphthalimide (NHPI) as the radical promoter using O2 as the oxidant. Additionally, the synthesized copper phosphate was stable in the reaction system and could be used at least four cycles without considerable decrease in catalytic performance. This work provides a new way to prepare efficient heterogeneous catalysts using naturally occurring chemicals for the highly efficient oxidation of aromatic benzyl compounds to aromatic ketones.

Improvements in the preparation of phosphate for oxygen isotope analysis from soils and sediments.

In contrast to the successful preparation of phosphate for oxygen isotope analysis from water samples, there are still a series of problems for similar analyses from soils and sediments. Here, we improved and optimized the methods of silver phosphate preparation for oxygen isotope analysis from soils and sediments. During our preparations, organic matter was removed by sodium hypochlorite and XAD-2 resin, while the impurities of elemental silver and its oxide were removed by rapid microprecipitation and ammonium phospho-molybdate and magnesium ammonium phosphate. The total organic carbon and total nitrogen in the prepared silver phosphates from soils and sediments were 0.226±0.033% and 0.030±0.0059% (n = 7), 0.217±0.053% and 0.034±0.0120% (n = 9), respectively, indicating a high removal efficiency of organic matter. We confirmed that adding citric acid during rapid microprecipitation would introduce the impurity of elemental silver, which could be removed by ammonia recrystallization. The pH range of solutions for rapid microprecipitation was optimized at 7.0‒7.5. Results of X-ray Diffraction and stable oxygen isotope analyses showed that the improved method could obtain high pure silver phosphate from soil and sediment samples without oxygen isotope fractionation. This improved procedure provides a foundation for biogeochemical studies on phosphorus in soil and lacustrine environments by using phosphate oxygen isotopes.

Preparation and evaluation of clindamycin phosphate loaded chitosan/alginate polyelectrolyte complex film as mucoadhesive drug delivery system for periodontal therapy

In this study, Clindamycin phosphate loaded adhesive polyelectrolyte complex films for local periodontal therapy were prepared with alginate and chitosan. The thickness, drug content, structure, swelling, adhesion and in vitro drug release with release kinetics of formulations were evaluated. The effects of the varying concentration and molecular weight of polymers used and the volume of the polymer solutions on the characteristics of the films were investigated. Increasing the concentration of sodium alginate in total content of polymer mixture caused to higher adhesiveness. Chitosan molecular weight also affected to adhesiveness of complex films. The release rate of drug and release kinetics was affected from the complexation. The best complexation was obtained with the three times higher concentration and volume of alginate in combination with low molecular weight chitosan. Thus polyelectrolyte films that have delayed release together with high swelling ability and adhesiveness and high drug content were formed. Due to the heterogeneous structure of complex film, the release profiles of the formulations fitted to the anomalous transport mechanism. 3D structure of the drug loaded complex film was analyzed by Micro-CT imaging in this study and it was showed that using this method would be very advantageous for further studies about the investigation of complexation than the other imaging methods in order to determine the volume and the size of the formed complexes within the structure at the same time.

Preparation and characterization of nanoscale flaky iron phosphate from phosphating slag

Nanoscale flaky FePO4·2H2O was prepared in PTFE lined reactors by hydrothermal recrystallization method. Explored effects of different hydrochloric acid concentrations on purity, particle size, crystal structure and micromorphology. The addition of hydrochloric acid improved the purity of the iron phosphate in the phosphating slag. During the acidity increasing, average particle size decreased, crystal orientation changed twice. At the concentration of hydrochloric acid was 8wt.%, iron phosphate crystal has the best crystallinity, morphology changed into flake with 58.8 nm thickness.