H3PO4 Solution Research Articles

Temporary or permanent liquid superlubricity failure depending on shear-induced evolution of surface topography

The sensitivities to operation conditions may reduce the reliability and stability of liquid superlubricity and limit industrial application of the lubrication system. Here, we demonstrated that the superlubricity of Si3N4/glass sliding interface lubricated with H3PO4 solution degenerated as speed/load decreased or increased, which was temporary or permanent depending on the different shear-induced evolutions of substrate surface topographies. The smooth contacting surface produced in superlubricity stage could be maintained during the temporary superlubricity failure at decreased speed/load condition and the superlubricity was restored when speed/load was recovered. Differently, severe wear induced by high load/speed disabled the hydration lubricating layer and resulted in irreversible superlubricity degeneration. Finally, the relationship between the lubrication state of liquid superlubricity system and the sliding surface roughness was established.

Analysis of effect Magnesium Ammonium Phospate (MAP) Concentration on Struvite Morphology in A Vertical Reactor

Struvite was a white crystal known as Magnesium Ammonium Phosphate Hexahydrate (MgNH4PO4.6H2O). In industry, struvite was found in the pipes crust which the hot fluid through passes. Struvite is often used as fertilizer because it contains phosphate content. The one of benefits of struvite crystals is slow release fertilizer, so it can be more durable, which is good for the growth of the plants. The Precipitation technology is currently one of the most widely applied technologies in struvite formation. The process of forming struvite is carried out by using a vertical reactor. The process started by mixing the equimolar solutions of MgCl2, NH4OH, and H3PO4 with a concentration ratio of 1: 1: 1 and 1: 1: 2. The process was carried out with the condition at the 30°C while the air inlet rate was 1.25 liters/min. The pH of the solution is pH 9 and controlled using NaOH solution. The process was carried out in the steady state condition. Then the solution was filtered and solid was dried at room temperature for 48 hours. From this study, the concentration ratio of 1:1:2 was obtained the best composition of struvite compared to the others ratio. The solid was analyzed by using the SEM-EDX instrument. The morphology of struvite was formed an irregular pyramid-like crystal or commonly referred to as an authorhombic shape.

Simple Method for Detection of Potassium Iodate (KIO<sub>3</sub>) in a Kitchen Salt Using cassava starch <i>(Manihot esculent</i>a<i>)</i>

This research has been made a simple method for the detection of potassium iodate (KIO3) in a kitchen salt using cassava starch (Manihot esculenta). The process of making this test kits using acid solvent as the reagent, KIO3 solution, and indicator of cassava starch. The used cassava starch is in two conditions are dry starch for H2SO4 and wet starch for H3PO4. Based on the two solvents are then made a standard color series based on KIO3 levels of 10, 20, 30, 40, and 50 ppm. Validation of this method has analyzed using Spectrophotometer UV-Vis. From the results of this analysis obtained calibration curve of each standard with both solvent. Coefficients determination for linearity using H3PO4 and H2SO4 solution is 0.9874 and 0.9656. From that results from the H3PO4 solution applied to the detection of potassium iodate (KIO3) in a kitchen salt using cassava starch (Manihot esculenta) with a concentration in the range 30-40 ppm.

Inhibiting Properties of Hexamine as Corrosion Inhibitor for Zinc in H3PO4 Solutions: Kinetic, Adsorption and Synergic Effect Study

Inhibiting Properties of Hexamine as Corrosion Inhibitor for Zinc in H3PO4 Solutions: Kinetic, Adsorption and Synergic Effect Study

Current Regulation and Property Study of Porous Anodic Alumina Films with a Periodic Pore Structure.

Porous anodic alumina (PAA) films with periodically modulated pore diameters are prepared by cyclic anodization of Al in a 0.6 M H3PO4 solution at room temperature. Studies have demonstrated that the oscillating current signals have an important effect on the structures of PAA films. Scanning electron microscopy (SEM) images of the PAA film show that when the positive triangle wave current signal is applied, with the increase in the maximum current value, PAA gradually exhibits a symmetrically modulated pore diameter structure, and part of the pores generates slub-like branches. When the maximum current value is 60 mA, the effect of modulation on the pore diameter is the most obvious and the UV reflectance spectrum shows the lowest reflectivity. A sawtooth wave current signal will cause the generation of a V-shaped structure at the junction of adjacent oxide layers. This work provides important guidance for regulating the structure of PAA by changing the current signal.

Properties and reaction mechanism of phosphoric acid activated metakaolin geopolymer at varied curing temperatures

Reaction mechanism of phosphoric activated metakaolin is studied by techniques of calorimetry, ICP-OES, FTIR and NMR taking curing temperature and [H3PO4] as variables. A two-stage curing method including pre-curing at 40 °C for 24 h and second curing at 60/80 °C for another 24 h effectively mitigates thermal-cracking of the obtained silico-aluminate phosphate (SAP) samples, whose maximum compressive strength reaches 120 MPa. Dealumination of metakaolin in H3PO4 solution produces low aluminate-containing silicate units and subsequently condensation of silicate tetrahedrons occurs. Higher temperature and H3PO4 concentration accelerate the two processes. After complete reaction, AVI structure from metakaolin disappears and the dissolved Al preferably forms AlVI-O-P units. During reaction, metastable P-O-P intermediate appears in SAPs with higher P/Al ratio and finally transforms into Al-O-P structure upon PO43− consumption. Phosphate units as P(OAl)x(H2O)4-x are connected with Si or Al structure units. Major structural units of the SAPs include Al-O-P, Si-O-P, Si-O-Si, and Si-O-Al.

Adsorption and corrosion of renewable inhibitor of Pomelo peel extract for mild steel in phosphoric acid solution

Pomelo peel extract (PPE) was evaluated as green and renewable corrosion inhibitor for mild steel in 1.0 mol/L H3PO4 solution. The inhibition behaviour was studied using mass loss, potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) measurements. The chemical structure of PPE was investigated using Fourier transform infrared (FT-IR) and ultraviolet-visible (UV–vis) spectroscopy. The corrosion morphology of mild steel was analysed via scanning electron microscopy (SEM). The adsorption thermodynamics and kinetics was discussed. The results show that PPE confers an acceptable long-term effect (inhibition efficiency of 95.0% and 92.8% for corroding 23 h and 224 h in the presence of 5.0 g/L PPE inhibitor) and functions as a mixed inhibitor. The adsorption of PPE on mild steel simultaneously follows the Langmuir, El-Awady and Temkin isotherms at 35, 45 and 55 °C. PPE is mixed adsorption dominated with physical adsorption at room temperature or with higher PPE concentrations. PPE possesses many polar functional groups such as hydroxyl, carbonyl and hetero-aromatic rings. The inhibition mechanism is closely related to these polar groups, as is the surface coverage of steel.

Tribology and in-vitro biological characterization of samaria doped ceria stabilized zirconia ceramics

Samaria doped ceria stabilized zirconia (SmCSZ) ceramic discs were prepared through powder metallurgy technique and sintered in an air atmosphere. Near full dense sintered discs were tested using a pin on disk wear testing machine to evaluate tribological properties. The Low-Temperature Degradation (LTD) behaviour of SmCSZ was assessed using a hydrothermal aging study. The bioactivity was studied through a simulated body fluid immersion test, and the cytotoxic behaviour was evaluated by culturing osteoblast-like (MG63) cells on the surface of samples. It was observed that SmCSZ samples shown better tribological properties compared to undoped ceria stabilized zirconia (CSZ). The accelerated aging revealed no monoclinic phase transformation (no degradation) in SmCSZ even after 200 h of study, indicating its high resistance to LTD. The chemical treatment of samples with 5 M H3PO4 solution enhanced the bioactivity, and the cell culture study showed that the cells are metabolically active and proliferating on the surface of SmCSZ.

Influence of the anodization conditions and chemical treatment on the formation of alumina membranes with defined pore diameters

Porous anodic aluminum oxide membranes were fabricated via two-step anodization of aluminum in 0.3 M H2C2O4, 0.3 M H2SO4 and 0.17 M H3PO4 solutions. The parameters of the oxide film such as: pore diameter (Dp), interpore distance (Dc), porosity (P) and pore density (ρ) can be completely controlled by the operating conditions of the anodization. Additionally, the pore diameters and pore density can be controlled via a chemical treatment (pore opening/widening process). The effect of anodizing conditions such as the applied voltage, type of electrolyte and purity of the substrate on the rate of porous oxide growth are discussed. The obtained results were compared with the theoretical predictions and data that has been reported in the literature. The influence of the duration of chemical etching on the structural features of the oxide membranes was studied. On the based on qualitative and quantitative FFT analyzes and circularity maps, it was found that the nanostructures of anodized aluminum have the maximum order under certain specified conditions. The presence of alloying elements affects not only the rate of oxide growth but also the morphology of the anodic aluminum oxide. The rate of oxide growth depends on the electrolyte type and temperature. During chemical treatment of the oxide films pore diameter increases with the pore widening time and the highest pore widening was observed in phosphoric acid solution.

Purification of precursors of calcium orthophosphates synthesis by co-precipitation method

The purification of the synthesis precursors of calcium phosphates from the toxic microimpurities Cu(II), Cd(II), As(III) and Pb(II) by co-precipitation with a part of the target product was studied. It was found that a maximum extraction of Cu(II), Cd(II) and As(III) from the CaCl2 solutions was achieved in the acidic and alkaline media. When precipitating calcium phosphates from the H3PO4 solutions, the following patterns regarding the degree of co-precipitation of the microimpurities with increase of pH were observed: the degree of co-precipitation of Cd(II) decreases rapidly, whereas the degree of the co-precipitation of As(III) goes through the maximum and Cu(II) is removed completely. Pb(II) ions are also completely removed in both CaCl2 and H3PO4 solutions. It was shown that in order to purify the CaCl2 solution, it is necessary to add at least 15 g of H3PO4 per 1 dm3 of the solution and then adjust pH to the value of 2.5 to 3.0 by neutralizing the solution with ammonia. In order to remove the impurities from the phosphoric acid solution, it is recommended to carry out the co-precipitation in two following stages: firstly, the ions of Cd(II), Cu(II) and Pb(II) are removed at pH of 6.0–6.5, which requires at least 4 g of CaCl2 per 1 dm3 of the acid, and then the arsenic residues are removed at pH of 8.0–8.25, which requires at least 13 g of CaCl2 per 1 dm3 of the solution.

Thermal and Mechanical Properties a Membrane of the Mixing PVA Nanocomposite and Limestone Hydroxyapatite

Synthesis and characterization of membranes from a mixture of PVA nanocomposites and limestone hydroxyapatite have been carried out. The limestone is crushed, sieved with a size of 200 mesh. The synthesis of hydroxyapatite was carried out by heating limestone powder using a furnace at a temperature of 600 °C for 4 hours. Furthermore, limestone was dissolved with distilled water and 0.3M H3PO4 solution using a magnetic stirrer with stirring at 300 rpm for 1 hour. The pH of the solution was made 10 by adding 1 M NH4OH periodically. The solution was aged for 24 hours and the precipitate was dried using an oven at 120 °C for 5 hours. The hydroxyapatite powder was characterized by FTIR to see the functional groups and XRD characterization to see the hexagonal hydroxyapatite phase. The characterization results obtained that the main groups of hydroxyapatite compounds were calcium hydroxide (CaO), phosphate (PO4 3-), and hydroxyl (OH−) groups with a crystal size of 86.27 nm. Limestone hydroxyapatite was mixed with a solution of PVA-chitosan with a composition variation of 0%, 1%, 2%, 3%, and 4% weight using a magnetic stirrer at 40°C for 3 hours using the sol-gel method. The membrane obtained was characterized by DSC to determine its thermal properties and UTM to determine its mechanical properties. The maximum melting point obtained in the mixture (98: 2) % was 195.51°C and the highest tensile strength was at the percentage of 1% with a modulus of elasticity of 22.28 M.Pa and tensile strength of 13.23 M.Pa.

Высокотемпературная коррозия сталей в растворах кислот. Ч. 3. Ингибиторная защита сталей азотсодержащими гетероциклическими органическими соединениями и неорганическими окислителями. Обзор

The literature and patent data on the protection of steels in high-temperature acid solutions by nitrogen-containing heterocyclic organic compounds and inhibitors of oxidative type were summarized. Composite inhibitors based on substituted triazoles can provide effective protection of low-carbon and chromium-nickel steels in these environments (200 °С). The mechanism of the protective action of these inhibitors is based on the ability of substituted triazoles to form on the steel surface in acid solutions the protective layers chemically bonded to the metal surface. Often these protective layers are basically composed of a polymer complex compound containing triazole molecules and Fe cations (in the case of nickel-chromium steels — Ni and Cr). It is noted that oxidizing additives can be used to protect steels which are in high-temperature acidic media at a passive state. Using the example of corrosion of chromium-nickel steel in H3PO4 solutions (130 °C), it is shown that additives of oxidants (Cu(II) and NO3–) stabilize the passive state of the metal in this medium, preventing the possibility of its active dissolution. Based on analysis of the literature data, a conclusion was made about the prospects of using compositions based on nitrogen-containing heterocyclic compounds for protecting steels in high-temperature acidic environments. These compositions are superior in important technological parameters to mixed inhibitors based on unsaturated organic compounds.

ATI CP Grade 7 Titanium

Abstract ATI CP Grade 7 Titanium is an unalloyed titanium grade that contains 0.12–0.25% Pd. This palladium-containing alloy extends the range of application of commercially pure (CP) titanium in HCl, H3PO4, and H2SO4 solutions. ATI CP Grade 7 Titanium is used in applications requiring excellent corrosion resistance in chemical processing or storage applications where the media is mildly reducing or fluctuates between oxidizing and reducing. It can be used in continuous service up to 425 °C (795 °F) and in intermittent service up to 540 °C (1000 °F). This datasheet provides information on composition, physical properties, elasticity, tensile properties and bend strength. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: Ti-175. Producer or source: ATI.

Modification of Activated Carbon from Elaeis Guineensis Jacq Shell with Magnetite (Fe3O4) Particles and Study Adsorption-Desorption on Ni(II) Ions in Solution

Activated carbon coated with magnetite (ACA-Fe3O4) was synthesized in this study. Activated carbon was synthesized using an Elaeis Guineensis Jacq (EGJ) as a raw material followed by physical and chemical activation. Physical activation is carried out by heating at a temperature of 700°C and followed by a reaction with H3PO4 solution as chemical activation. Furthermore, the activated carbon was reacted with a mixture of FeCl3 and FeSO4 solution then followed by the addition of NaOH solution up to a pH of 10. Characterization with X-Ray Diffraction (XRD) and Scanning Electron Microscopy - Energy Dispersive X-Ray (SEM-EDX) on ACA-Fe3O4 was done to confirm that magnetite has succeeded to coating on ACA. Brunauer-Emmett-Teller Surface Area Method (SBET) confirmed that pore volume and average pore diameter increase with the presence of magnetite. Optimum conditions for Ni(II) ion adsorption with ACA-Fe3O4 was under conditions of 0.5 grams adsorbent, 25 mL of Ni(II) ion solution 100 ppm, and contact time of 1 hour with the acquisition of 99.11%. Adsorption process more suitable with pseudo-second-order and Langmuir adsorption isotherm pattern. Desorption of Ni(II) ion of 70.84% using HCl.

Electrical Conductivity and Water Effects in Phosphoric Acid Solutions for Doping of Membranes in Polymer Electrolyte Fuel Cells

Abstract Fuel cells (FCs) are among the more efficient solutions to limit the emission of greenhouse gases. Based on the conversion of the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electrical energy, a typical FC produces a voltage of 0.7 V under load. The potential is highly increased by placing the cells in series to obtain a stacked cell. Among the types of FCs, the polymer electrolyte membrane FCs (PEMFCs) are developed mainly for transport applications, because of their low impact on the environment, high power density and light weight compared with other types of FCs. Phosphoric acid (H3PO4) doped polybenzimidazole (PBI) membranes are widely used as efficient electrolytes. The performance of a (high temperature, 130–200 °C) HT-PEMFC depends mainly on the amount of H3PO4 in the solid polymer membrane. The strong autoprotolysis of H3PO4 is responsible for the high proton conductivity also in the anhydrous state. In this study, the H2OH3PO4 system is investigated in the temperature range 60–150 °C with varying water vapour activity at constant atmospheric pressure. Main purpose is to gain more insights into the kinetics of the equilibria in the H2O-H3PO4 system, which influence the fuel cell performance. Density, water content, electrical conductivity and activation energy are determined by exposing H3PO4 solutions for sufficiently long periods to controlled gas atmosphere in order to reach near-equilibrium conditions. The coexistence of ortho- and pyrophosphoric acid is analysed and higher condensed species are also considered. A new setup fully made in quartz is designed and developed to mix the phosphoric acid solutions in a climate chamber. The experimental results are compared to literature data to validate the developed setup and the methodology.

Application of ultrafiltration ceramic membrane for separation of oily wastewater generated by maritime transportation

This article addresses the applicability of the ultrafiltration ceramic membrane for separation of oily wastewaters generated during maritime transportation. The UF experiments were performed in a cross-flow system using a pilot-scale installation. The membrane used had a separation cut-off equal to 8 kDa and an active area of 0.0038 m2. The experiments were conducted in a wide range of temperature (303 and 323 K), tangential flow rate (2.9–8.2 m/s) and transmembrane pressure (0.28–0.40 MPa). The excellent separation properties of the ceramic UF membrane have been confirmed. It allowed to obtain a high-quality, oil-free permeate with the turbidity at the level of about 0.2 NTU. However, wastewaters caused the intensive membrane fouling, which significantly decreased the process performance. Most often, the permeate flux was stabilized after about 100 min of the process running and the steady-state flux at 30% of its maximum value was obtained. The effects of wastewater pre-filtration and feed pH on the UF process performance have been studied. It was found that the pre-filtration of oily wastewaters adversely affects the permeate flux. For analyzing the fouling mechanisms, Hermia’s model was used. Importantly, different ways of membrane rinsing were applied. Regardless of the degree of membrane contamination, the effective membrane cleaning was achieved using 1–3 wt% NaOH and H3PO4 solutions.

Multiphase phosphate cements from steel slags

The use of industrial waste in the synthesis of phosphate ceramics opens the door to new ways of production and marketing of this kind of product, as well as contributing to the reduction of the environmental impact of industrial waste. In the present study, chemically bonded phosphate ceramics (CBPC) were synthesized from steel slags (electric arc furnace slag (EAF), basic oxygen furnace slag (BOF), and ladle furnace basic slag (LF) and aqueous solutions of H3PO4. A chemical analysis was performed of the steel slags, which were selected through standard sampling before being ground and milled to obtain the appropriate granulometry. In the evaluated slags, iron oxides and calcium oxides, present both in their free state and in compounds with other elements, were identified as the elements with the greatest presence and potential to form CBPC. Design of experiments (DOE) was applied to form multiphase cements, in order to make the variables present in the obtainment of cements workable, thereby allowing the formation reactions of cement to be better understood. The cements obtained were analyzed through XRD, SEM-EDS, FTIR, XPS, and mechanical compressive strength tests. The synthesized cement exhibited mainly vitreous structure for the iron phosphate phases (Fe(H2PO4)2) or (FeHPO4), and mainly crystalline structure for the calcium phosphate phases, present as dihydrogen phosphate of calcium hydrate (Ca(H2PO4)2·xH2O) and brushite (CaHPO4·2H2O). Compression strength between 10 and 19 MPa was recorded for the different compositions evaluated, with short setting times.

UTILIZATION OF COFFEE GROUNDS AS ACTIVATED CARBON FOR RHODAMINE B ADSORBENT

Research on the use of coffee grounds activated carbon as an adsorbent to reduce the content of Rhodamine B dye has been carried out. The activated carbon used is chemically activated by immersion using 1 M H3PO4 solution for 24 hours then burned at 500ËšC for 45 minutes, while physically activated it is carried out by burning at 500ËšC for 45 minutes. The results of the study which showed the characteristics published in SNI 06-3730-1995, the optimum conditions of Rhodamine B adsorption on both activated carbon at pH 7 and contact time at 15 minutes. Rhodamine B adsorption isotherms on chemically and physically activated carbon using Langmuir adsorption isotherm models with adsorption capacities are 1.6943 mg/g and 1.5936 mg/g, respectively. Chemical and physics activated coffee grounds activated carbon were applied to reduce Rhodamine B from sarung waste in Samarinda. Decrease of Rhodamine B levels in 25 mL of waste samples containing Rhodamine B 14.1860 mg/g with 1 gram of adsorbent were 89.1125% and 60.7923%, respectively.
 
 Keywords: Activated carbon, Spent coffee grounds, Rhodamine B, Adsorption

Nanostructure of Anodic Porous Alumina Fabricated By Galvanostatic Anodizing in Etidronic Acid

Galvanostatic and potentiostatic anodizing processes of aluminum leads to the formation of large-scale porous alumina. It is previously reported that self-ordered porous alumina measuring above 500 nm in cell diameter can be fabricated via two-step anodizing in etidronic acid at higher voltage more than 200 V. On the other hand, extremely little has been reported on the growth behavior and their nanostructure during galvanostatic anodizing in etidronic acid. Herein, we investigate the nanostructural characterization of the porous alumina film formed via galvanostatic anodizing in etidronic acid under various operating conditions. Electropolished aluminum specimens were anodized at a constant current density of 0.005-500 Am-2 in 0.03-3 M etidronic acid solutions at 273-333 K. After anodizing, the porous alumina film was dissolved in a 0.20 M CrO3/0.51 M H3PO4 solution at 353 K, and the aluminum dimple array, which corresponded to the bottom shape of porous alumina, was exposed to the surface. The anodized specimens were examined by field-emission scanning electron microscopy (FE-SEM). The cell size (interpore distance) of the porous alumina was calculated using image analysis software. Typical voltage-time curves for the formation of anodic porous alumina were obtained during galvanostatic anodizing in etidronic acid: The voltage linearly increased, gradually decreased, and then reached plateau value. However, excess current density caused oxide burning with unstable oscillation in the voltage-time curve, and non-uniform porous alumina was formed on the aluminum surface. The plateau voltage greatly increased with the current density at each operating temperature, and various porous alumina films with different nanostructures were successfully fabricated by anodizing at a wide voltage range measuring 7-218 V. Figure 1 shows the changes in the average, maximum, and minimum cell sizes with the anodizing voltage under various operating conditions. The cell sizes are directly proportional to the anodizing voltage with proportionality constants of 2.5 (average), 3.5 (maximum), and 0.7 (minimum), respectively. Figure 1

The Effects of H3PO4 Treatment on Li/Mn-Rich Layered Li1.2-X[Mn0.55Ni0.15Fe0.10]O2(1-x)F2x Cathode Materials for Li-Ion Batteries

In this study, sol-gel synthesized Li/Mn-rich layered Li1.2-x[Mn0.55Ni0.15Fe0.10]O2(1-x)F2x was studied as an alternative to commercial NMC and LiCoO2 batteries due to greater theoretical capacity ~250 mAh g-1, increased safety, and lower-cost. Despite these advantages, MNF cathodes show experimentally lower capacity and decay, voltage fading, and poor rate capability [1]. To address these problems, the creation of a Li3PO4-coating with a H3PO4 solution treatment was investigated. Treatment has resulted in increased initial discharge capacity for the first 3 cycles at 0.1C and increased cell retention for the following 97 cycles at 0.33C compared to untreated MNF551510. As alternatives to the classic NMC and LiCoO2 arise, H3PO4 treatment can be a useful technique to enhance electrochemical performance of novel cathode materials.Powder X-ray diffraction was used to determine the phase of the material as well as the amount of lithium carbonate contamination before and after Li3PO4-coating. Furthermore, scanning electron microscopy (SEM) was performed to analyze the effects of Li3PO4-coating on the morphology of the particle. For electrochemical analysis, galvanostatic charge-discharge cycling and cyclic voltammetry (CV) were completed.