Solubilization of aluminum phosphate by specific Penicillium spp.

The solubilization of hardly soluble aluminum phosphate （AlPO4） by specific Penicillium spp. isolated from wheat rhizospheric soils was investigated in Pikovskaya agar and liquid medium, respectively. Most of the Penicillium isolates except P. sirnplicissimum AP 11 and P. variabile AP 15 developed clear transparent zone around the colony margin in plate assays. Results of broth assays show that the Penicillium isolates can efficiently solubilize aluminum phosphate in Pikovskaya liquid medium, and vary in their capabilities to release soluble phosphate from aluminum phosphate. All the isolates exhibit different abilities to lower the pH and increase the titratable acidity in the broth compared to the control. HPLC analysis shows that most of the isolates except the species of P. aurantiogriseum can excrete different concentrations of organic acids, including gluconic acid, citric acid, oxalic acid, malic acid and tartaric acids, in the broth. The release of soluble phosphate by the isolate P. oxalicum AP2, which is the best solubilizer of aluminum phosphate among the isolates, is accompanied by a significant drop of pH and an obvious rise of titratable acidity during 7 d of aluminum phosphate-solubilizing experiments. The effects of temperature, initial pH, concentration of aluminum phosphate and shaking speed on aluminum phosphate solubilization by P. oxalicum AP2 were also investigated, and the maximum contents of soluble phosphate released are recorded at temperature 30 ℃, initial pH 6, aluminum phosphate concentration 20 g/L, and shaking speed 160 r/min.

Characterization and Catalytic Activity of Titanium-containing Aluminum Phosphate Prepared by Sol-gel and Nonuniform Precipitation for O-Alkylation of Catechol with Ethanol

Three titanium-containing aluminum phosphate catalysts with a general formula Al 0.77 Ti 0.23 PO 4 were prepared by the sol-gel method at room temperature(APTS), and a nonuniform precipitation procedure at room temperature(APTR) and under reflux(APTF), respectively. The structural features and the surface properties of the three catalysts were determined by means of the physical adsorption of nitrogen at liquid N 2 temperature, XRD, UV-Vis, NH 3-TPD and IR of adsorbed pyridine. The vapor phase O-alkylation of catechol with ethanol over the prepared catalysts was studied. It was found that the activity and the selectivity of these catalysts are greatly dependent on the preparation method, and catalyst APTF shows the highest activity and selectivity. The characterization evidence indicates that the weak Brnsted acid sites were more effective for the reaction.

Influence of deposition voltage on phase, microstructure and antioxidation property of cristobalite aluminum phosphate coatings

Cristobalite aluminum phosphate (C-AlPO_4) coatings were prepared by a hydrothermal electrophoretic deposition process on SiC-coated C/C composites. Phase compositions and microstructures of the as-prepared coatings were characterized by XRD and SEM analyses. The influence of deposition voltage on the phase, microstructure and antioxidation property of the cristobalite aluminum phosphate coatings was investigated. Results show that the as-prepared coatings are composed of cristobalite aluminum phosphate crystallites. The thickness and density of cristobalite aluminum phosphate coatings are improved with the increase of deposition voltage. The deposition amount and bonding strength of the cristobalite aluminum phosphate coatings also increase with the increase of deposition voltage. The deposition mass per unit area of the coatings and the square root of the deposition time at different hydrothermal voltages satisfy linear relationship. The antioxidation property of the coated C/C composites is improved with the increase of deposition voltage. Compared with SiC coatings prepared by pack cementation, the multilayer coatings prepared by pack cementation with a later hydrothermal electrophoretic deposition process exhibit better antioxidation property. The as-prepared multi-coatings can effectively protect C/C composites from oxidation in air at 1 773 K for 37 h with a mass loss rate of 0.53%.

Effect of aluminum phosphate gel on prevention of early rebleeding after ligation of esophageal variceal hemorrhage

BACKGROUND Liver cirrhosis is the main cause of portal hypertension.The leading cause of death in patients with liver cirrhosis is its most common complication,esophageal variceal bleeding(EVB).Endoscopic variceal ligation(EVL)is recommended by many guidelines to treat EVB and prevent rebleeding;however,esophageal ulcers occur after treatment.Delayed healing of ulcers and unhealed ulcers lead to high rebleeding and mortality rates.Thus,the prevention of early postoperative rebleeding is of great significance in improving the quality of life and prognosis of patients.AIM To evaluate the efficacy of aluminum phosphate gel(APG)plus a proton pump inhibitor(PPI)in the prevention of early rebleeding after EVL in patients with EVB.METHODS The medical records of 792 patients who were diagnosed with EVB and in whom bleeding was successfully stopped by EVL at Shenzhen People’s Hospital,Guangdong Province,China from January 2015 to December 2020 were collected.According to the study inclusion and exclusion criteria,401 cases were included in a PPI-monotherapy group(PPI group),and 377 cases were included in a PPI and APG combination therapy(PPI+APG)group.We compared the incidence rates of early rebleeding and other complications within 6 wk after treatment between the two groups.The two-sample t-test,Wilcoxon rank-sum test,and chisquared test were adopted for statistical analyses.RESULTS No significant differences in age,sex,model for end-stage liver disease score,coagulation function,serum albumin level,or hemoglobin level were found between the two groups.The incidence of early rebleeding in the PPI+APG group(9/337;2.39%)was significantly lower than that in the PPI group(30/401;7.48%)(P=0.001).Causes of early rebleeding in the PPI group were esophageal ulcer(3.99%,16/401)and esophageal varices(3.49%,14/401),while those in the PPI+APG group were also esophageal ulcers(5/377;1.33%)and esophageal varices(4/377;1.06%);such causes were significantly less frequent in the PPI+APG group than in the PPI group(P=0.022 and 0.024,respectively).The early mortality rate within 6 wk in both groups was 0%,which was correlated with the timely rehospitalization of all patients with rebleeding and the conduct of emergency endoscopic therapy.The incidence of adverse events other than early bleeding in the PPI+APG group(28/377;7.43%)was significantly lower than that in the PPI group(63/401;15.71%)(P<0.001).The incidence of chest pain in the PPI+APG group(9/377;2.39%)was significantly lower than that in the PPI group(56/401;13.97%)(P<0.001).The incidence of constipation in the PPI+APG group(16/377;4.24%)was significantly higher than that in the PPI group(3/401;0.75%)(P=0.002)but constipation was relieved after patients drank more water or took lactulose.In the PPI and PPI+APG groups,the incidence rates of spontaneous peritonitis within 6 wk after discharge were 0.50%(2/401)and 0.53%(2/377),respectively,and those of hepatic encephalopathy were 0.50%(2/401)and 0.27%(1/377),respectively,presenting no significant difference(P>0.999).CONCLUSION PPI+APG combination therapy significantly reduces the incidence of early rebleeding and chest pain in patients with EVB after EVL.

Electrical Properties of NASICON-type Structured Li1.3Al0.3Ti1.7（PO4）3 Solid Electrolyte Prepared by 1,2-Propylene glycol-assisted Sol-gel Method

Lithium-ion conductor Liz.3Alo.3Ti1.7（P04）3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol （1,2-PG）-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning elec- tron microscopy, electrochemical impedance spectroscopy, and chronoamperornetry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solu- tion is obtained without the precipitation of Ti4＋ and A13＋ with PO43- Well crystallized Lil.3Alo.3Til.7（PO4）3 can be prepared at much lower temperatures from 850 ~C to 950 ~C within a shorter synthesis time compared with that prepared at a temperature above 1000 ~C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 ℃ with an activation energy as low as 36.6 k J/tool for the specimen pre-sintered at 700 ℃ and sintered at 850 ℃. The high conductivity, good chemi- cal stability and easy fabrication of the Li1.3Al0.3Ti1.7（PO4）a provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.

Preparation of Novel Scorzalite Imitated Phosphate Pigments

Novel phosphate pigments imitated with Scorzalite,FeAl2(PO4)2(OH)2,were prepared from iron and aluminum nitrate solutions,ascorbic acid,and phosphoric acid with pH adjustments(pH 5,7,9).The obtained precipitates were heated at 300,500,and 700°C for 1 h.The precipitates and their thermal products were estimated with X-ray diffraction(XRD),Infrared(IR)spectra,ultraviolet-visible(UV-Vis)reflectance spectra,and L*a*b*color space.The precipitated sample was not clearly colored,but it turned orange to red when heated.Samples prepared at low pH showed higher whiteness than samples prepared at high pH.The theoretical amount of ascorbic acid was sufficient to completely reduce iron during the adjustment.This study showed the possibility of novel inorganic phosphate red pigment.

The preparation and performance analysis of zirconium-modified aluminum phosphate-based high-temperature(RT-1500℃)resistant adhesive for joining alumina in extreme environment

High-temperature-resistant adhesives are critical materials in the aerospace field.The zirconium-modified aluminum phosphate-based adhesives developed in this work had the advantage of adjustable thermal expansibility,achieving a high matching of coefficient of thermal expansion(CTE)with alumina.The introduction of zirconium can significantly improve the thermal stability of the adhesive matrix,and the Zr/Al ratio substantially affects the various reaction processes inside the adhesive,especially the types of zirconium-containing compounds.Most of the zirconium-containing compounds in the A7Z3 adhesive were ZrO_(2) only when the mass ratio of zirconium hydroxide to aluminum hydroxide was 3:7,which was the key reason why it had the highest CTE.The room-temperature bonding strength of A7Z3 after heat treatment at 1500℃reached 67.2 MPa.After pretreatment at 1500℃,the high-temperature bonding strength of A7Z3 was greater than 50 MPa in the range of(room temperature)RT-1000℃.After 40 thermal cycles between RT and 1500℃,the bonding strength still reached 10 MPa.Physical bonding occurred at temperatures below 1000℃,while chemical bonding dominated above 1000℃based on the generation of Al5BO9 and mullite at the interfaces.

Preparation of a SiC/Cristobalite-AlPO_4 Multi-layer Protective Coating on Carbon/Carbon Composites and Resultant Oxidation Kinetics and Mechanism

In order to improve the oxidation resistance of carbon/carbon （C/C） composites,a SiC/C-AlPO4 multi-layer coating was fabricated on the C/C composites by a simple and low-cost method.The internal SiC bonding layer was prepared by a two-step pack cementation process and the external C-AlPO4 coating was deposited by hydrothermal electrophoretic deposition process.Phase compositions and microstructures of the as-prepared multi-layer coating were characterized by X-ray diffraction （XRD）,scaning electron microspocy （SEM） and energy dispersive spectrometer （EDS）.Anti-oxidation properties,oxidation behavior and the failure behavior of the coated composites were investigated.The results indicate that the multi-layer coating exhibits obviously two-layer structure.The inner layer is composed of β-SiC,α-SiC phase with a scale of silicon phase.The outer layer is composed of cristobalite aluminum phosphate （C-AlPO4） crystallites.The SEM observation shows the good bonding between the inner and outer layers.The multi-layer coating displays an excellent oxidation resistance in air in the temperature range from 1573 to 1773 K,and the corresponding oxidation activation energy of the coated C/C composites is calculated to be 117.2 kJ/mol.The oxidation process is predominantly controlled by the diffusion of O2 through the C-AlPO 4 coating.The failure of the multi-layer coating results from the generation of the microholes that may be left by the escape of the oxidation gases.

Combined quantitative microscopy on the microstructure and phase evolution in Li1.3Al0.3Ti1.7(PO4)3 ceramics

Lithium aluminum titanium phosphate(LATP)is one of the materials under consideration as an electrolyte in future all-solid-state lithium-ion batteries.In ceramic processing,the presence of secondary phases and porosity play an important role.In a presence of more than one secondary phase and pores,image analysis must tackle the difficulties about distinguishing between these microstructural features.In this study,we study the phase evolution of LATP ceramics sintered at temperatures between 950 and 1100℃by image segmentation based on energy-dispersive X-ray spectroscopy(EDS)elemental maps combined with quantitative analysis of LATP grains.We found aluminum phosphate(AlPO4)and another phosphate phase((Lix)PyOz).The amount of these phases changes with sintering temperature.First,since the grains act as an aluminum source for AlPO4 formation,the aluminum content in the LATP grains decreases.Second,the amount of secondary phase changes from more(Lix)PyOz at 950℃to mainly AlPO4 at 1100℃sintering temperature.We also used scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)to study the evolution of the LATP grains and AlPO4,and LATP grain size increases with sintering temperature.In addition,transmission electron microscopy(TEM)was used for the determination of grain boundary width and to identify the amorphous structure of AlPO4.