Phosphoric Acid Treatment Research Articles

Treatment of Crude Phosphoric Acid Using Activated Carbon-Based Nanocomposites Integrated with Catalytic Wet Peroxide Oxidation

Treatment of Crude Phosphoric Acid Using Activated Carbon-Based Nanocomposites Integrated with Catalytic Wet Peroxide Oxidation

Mechanical and tribological characterization of vacuum pressurized impregnation (VPI) treated bamboo fiber-reinforced polymer (FRP) composites with jute mat layer under fretting wear conditions

ABSTRACT The study explored the performance of VPI-treated bamboo fiber reinforced FRP laminated composites, focusing on fretting wear and mechanical behavior with various chemical treatments. FTIR analysis revealed that NaOH treatment effectively removed hemicelluloses and lignin, with peak shifts at 3330, 2918, and 1420 cm−1, while tannic acid induced peak shifts at 1640 and 1500 cm−1, indicating cellulose interactions. Phosphoric acid treatment reduced intensity at 3340 and 2890 cm−1, suggesting cellulose depolymerization. TGA showed varied weight loss profiles, reflecting thermal property modifications. XRD analysis indicated changes in crystalline structure, and SEM revealed structural alterations. Tensile strengths at 0.5% weight were 216 ± 3.0 MPa for alkaline-treated bamboo fiber composite (A-BFC), 256 ± 0.01 MPa for tannic acid-treated bamboo fiber composite (T-BFC), and 281 ± 3.0 MPa for phosphoric acid-treated bamboo fiber composite (P-BFC). Fretting wear analysis demonstrated that P-BFC withstood loads up to 45N, with wear resistance improving with increased fiber content. dynamic mechanical analysis (DMA) highlighted that P-BFC exhibited the highest initial storage modulus and a tan δ peak of 69°C, compared to T-BFC and A-BFC, both at 68°C. The wear rate decreased with higher bamboo fiber content and load, showcasing the potential of VPI-treated bamboo fiber composites for applications requiring enhanced strength and wear resistance.

Influence of magnesium content and phosphoric acid treatment on cadmium adsorption onto sugarcane leaf biochar

Influence of magnesium content and phosphoric acid treatment on cadmium adsorption onto sugarcane leaf biochar

Production of Porous Biochar from Cowdung and its Application

Porous activated carbon (PAC) powder is prepared from solid bio-waste - cow dung samples (CD). UV- Spectroscopy confirms the absorption rate of activated porous biochar at different concentration solutions(in ppm).The activation process is carried out by phosphoric acid and sodium hydroxide treatment followed by calcination at different temperature condition. XRD pattern confirms the amorphous phase formation with graphitic nature for different precursor utilization. SEM analysis shows the uniform and hierarchical porous network formation and aggregated particle with tiny. X- ray analysis confirms the formation of graphitic carbon and porous morphology for sample activated at increased calcination temperature. The elemental composition of as prepared carbon samples is determined by SEM and confirms the formation major carbon content existence. The obtained product is observed for the dye removal process wherein the specific amount of PAC is added to the Methylene Blue(MB) dye solutions and the absorption rate is observed through uv-spectroscopy.

Inducing hydrophobicity in stainless steel 304 by mechanical texturing and chemical functionalization

This study investigates the impact of combined texturing by micromachining and chemical functionalization on the wetting behavior and water condensation on stainless steel 304. The transition from Wenzel to Cassie-Baxter or impregnated Cassie-Baxter regimes is investigated. Understanding this transition is critical for advancing surface engineering, as it enables precise control over wetting behavior for various applications. Herein, we report on the wire EDM (wEDM) machining on stainless steel 304 to produce two distinct microstructure patterns with directional canals or pyramidal structure, and their performance in water condensation. These patterns significantly impact water condensation performance. wEDM is employed to create surface roughness, followed by phosphoric acid treatment and chemical functionalization with trichloro-1H,1H,2H,2H-perfluorooctyl silane. Contact angle measurements reveal a synergistic effect between groove direction and silane coating, leading to hydrophobic surfaces and dropwise water condensation. Specimens with directional canals exhibit a contact angle of 150°, while specimens with pyramidal structures exhibit 151o. Roll-off angle experiments showcased distinct behavior among specimens featuring canals or pyramidal structures. Specimens with canals exhibit notably lower roll-off angles compared to both flat surfaces and those with pyramidal patterns, leading to a dependence of roll-off angles on the orientation of canals. In humid environments, micromachined specimens exhibit superior water condensation capability compared to untreated SS304 surfaces. Chemically functionalized grooved specimens present larger condensate droplet diameters than flat surfaces. An enhancement in water condensation and a sevenfold higher latent heat transfer coefficient is reported. Specimens with chemical functionalization achieve corrosion protection with an efficiency reaching 82.9%.

BEHAVIOR OF LANDFILLED STABILIZED FLY ASH TREATED BY DIFFERENT TREATMENT METHODS FOR THE PAST 27 YEARS

Municipal solid waste incineration (MSWI) fly ash (FA) contains toxic substances and hence, direct landfilling of MSWI FA is prohibited in Japan Complying with Japan's stringent Waste Disposal and Public Cleansing Law, which demands adherence to landfill disposal and effluent standards, is crucial for ensuring environmental safety. To address the issue, various treatment methods including treatment by chemical, phosphoric acid, and melting and solidification can be used to stabilize the MSWI FA through the immobilization of heavy metals. However, the long-term stability of these treatment methods has not been thoroughly investigated. Therefore, the purpose of this study is to evaluate the long-term effectiveness of these three treatment methods for MSWI FA respectively, both independently and in conjunction with compost. This study involves the monitoring of changes in the concentration of heavy metals, including lead (Pb), cadmium (Cd), total-chromium (T-Cr), copper (Cu), and zinc (Zn), that have been leached over a period of 27 years. This study aims to conduct a detailed analysis of the impact of various treatment methods on the concentration levels of these individual heavy metals. Notably, the results suggest that independently, phosphoric acid treatment outperforms chelate treatment in the long run, but when combined with compost, both treatments exhibit enhanced efficacy, suggesting a promising approach for immobilizing heavy metals.

Primary and residual impacts of phosphoric acid modified biochar on growth and concentrations of essential and non-essential elements in lettuce and second crop arugula

The study aimed to explore how phosphoric acid-modified rice husk biochar (PBC) affects the growth and concentrations of essential and non-essential elements in two crops: lettuce as the primary crop and arugula as the secondary crop. The treatments consisted of a no P fertilized control and 250 mg P kg−1 sourced either from PBC, triple super phosphate (TSP) or phosphoric acid (PA). When subjected to phosphorus (P) sources, both lettuce and arugula exhibited a noteworthy rise in their dry weights compared to the control plants. PBC treatments significantly increased P concentration in both plants. Although the PBC treatment decreased lettuce nitrogen (N) concentration, it had no impact on arugula N concentration. Phosphorus treatments resulted in a decrease in lettuce K concentration, whereas it increased in arugula. Calcium (Ca), magnesium (Mg) and sulfur (S) concentrations in both plants were not affected by P sources. The zinc (Zn) concentrations of the plants notably decreased with P treatments. Moreover, P treatments led to a reduction in manganese (Mn) concentration specifically in arugula. PBC significantly increased the silicon (Si) concentrations of lettuce plants. The application of PA significantly increased the vanadium (V) concentration in arugula. Phosphoric acid treatments resulted in an increase in the plant bromine (Br) concentrations. To conclude, PBC may serve as an alternative P source, potentially being as effective as or even more effective than other P sources in influencing plant nutrition, without causing an undesirable elevation of non-essential elements in plants.

Comparing specific capacitance in rice husk-derived activated carbon through phosphoric acid and potassium hydroxide activation order variations

This manuscript investigates the influence of the chemical activation step order and process parameters on the specific capacitance of activated carbon derived from rice husk. The chemical activation was performed either before or after the carbonization step, using phosphoric acid (H3PO4) and potassium hydroxide (KOH) as activating agents. For activation before carbonization, the carbonization process was conducted at various temperatures (600, 750, 850, and 1050 °C). On the other hand, for activation after carbonization, the effect of the volume of the chemical agent solution was studied, with 0, 6, 18, 21, 24, and 30 mL/g of phosphoric acid and 0, 18, 30, 45, 60, and 90 mL/g of 3.0 M KOH solution. The results revealed that in the case of chemical activation before carbonization, the optimum temperature for maximizing specific capacitance was determined to be 900 °C. Conversely, in the case of chemical activation after carbonization, the optimal volumes of the chemical agent solutions were found to be 30 mL/g for phosphoric acid (H3PO4) and 21 mL/g for potassium hydroxide (KOH). Moreover, it was observed that utilizing phosphoric acid treatment before the carbonization step leads to an 21% increase in specific capacitance, attributed to the retention of inorganic compounds, particularly silica (SiO2). Conversely, when rice husks were treated with KOH after the carbonization step, the specific capacitance was found to be doubled compared to treatment with KOH prior to the carbonization step due to embedding of SiO2 and KHCO3 inorganic constituents. This study provides valuable insights into the optimization of the chemical activation step order and process parameters for enhanced specific capacitance in rice husk-derived activated carbon. These findings contribute to the development of high-performance supercapacitors using rice husk as a sustainable and cost-effective precursor material.

Optical and Dielectric Properties of Multiphase Phosphate Obtained from Phosphoric Acid Treatment of Bauxite Residue

Optical and Dielectric Properties of Multiphase Phosphate Obtained from Phosphoric Acid Treatment of Bauxite Residue

Efficacy of phosphorus loaded oyster shell in heavy metal removal: A combined study on adsorption behavior, structure characterization and comparative mechanism

This study presents a comprehensive evaluation of unmodified and modified oyster shells (OS, MP-OS, MC-OS) as adsorbents for removing heavy metals (Cd2+ and Pb2+) from water. The modifications involved phosphoric acid treatment (MP-OS) and dipotassium phosphate calcination (MC-OS), aiming to enhance the adsorption capabilities of the shells. Experimental results demonstrated that MC-OS exhibited the highest adsorption capacity due to its optimal pore structure and surface properties. The kinetic and isotherm studies revealed that the adsorption process is predominantly governed by chemical adsorption, with notable contributions from physical adsorption mechanisms. Morphological and surface analyses, including SEM, XRD, and FTIR, highlighted significant changes in the shells post-modification, contributing to their enhanced adsorption performance. The study also compared the environmental and economic aspects of these modified shells with other adsorbents like hydroxyapatite and reed biochar. The findings suggest that modified oyster shells, particularly MC-OS, are highly effective, eco-friendly, and economically viable for heavy metal remediation in water, with potential applications in soil decontamination. This research offers valuable insights into the utilization of fishery waste for environmental management, demonstrating the effectiveness of chemical modification in transforming natural biowastes into potent adsorbents.

A novel carbon-based solid acid catalyst with high acidity for the hydration of α-pinene to α-terpineol: Effect of graphite crystallite size and synergistic effect of defects

This work, for the first time, highlights that small-sized graphite crystallite and highly defective carbon-based catalysts can effectively increase the −SO3H density of the catalysts and modulate the surface electronic properties of the catalysts, which further facilitates the α-pinene hydration reaction. Hydrothermal phosphoric acid modulation of graphite crystallite size and defects in carbon-based catalysts systematically revealed the correlation between −SO3H density, catalytic activity, graphite crystallite size, and defects in biomass carbon. The characterization results demonstrate that small-size graphite crystallites and high structural defects provide more sp2 hybridized carbon edges, contributing to the catalyst's increase of −SO3H density. The −SO3H group density of the catalyst increased from 0.89 to 1.20 mmol/g after hydrothermal phosphoric acid treatment. The catalyst has the highest efficiency in the α-pinene hydration to α-terpineol among the reported catalysts, in which 87.06 % of α-pinene was converted and reached a maximum α-terpineol selectivity (55.38 %) time only 22 h. Density functional theory calculations show that the lattice defects of graphite crystallites in catalysts lead to the polarization of the electron cloud around the catalyst, which further leads to the reduction of electrostatic resistance between α-pinene and the active catalytic sites. The apparent activation energy of hydration by the catalyst is 1.74 times lower than that of conventional biomass carbon-based solid acids. The reduction of graphite crystallite size is considered a critical step in improving the selectivity of α-terpineol attributed to the effective reduction of α-terpineol adsorbed on the catalyst.

Effect of Phosphate Treatment on the Corrosion Resistance of Nd–Fe–B Anisotropic Magnetic Powder

Anisotropic Nd–Fe–B hydrogenation disproportionation desorption recombination powder with high corrosion resistance was prepared by phosphoric acid treatment. The treated samples baked at temperatures higher than 250 °C exhibited high corrosion resistance. In addition, the change ratio of coercivity before and after the anticorrosion test was within 5%. Microstructural observations indicated the formation a uniform phosphate layer with a small amount of Nd oxide at high baking temperature.

Changes in solubility and chemical speciation of potassium, calcium, and silicon in wood ash by acid treatment

ABSTRACT This study investigated the relationship between the solubility and the chemical speciation of plant nutritional elements (K, Ca, and Si) in wood ash treated with a dilute solution of sulfuric acid or phosphoric acid. The diluted acid solutions were added to fly ash (FA) collected from a power plant, and the untreated and acid-treated FAs were analyzed for their contents of K, Ca, and Si. The crystalline phases of the untreated and acid-treated FAs were identified using X-ray diffraction (XRD), and the Si species were determined using X-ray absorption near-edge structure (XANES) spectroscopy. Sulfuric acid and phosphoric acid treatments did not affect the solubility of K in FA. Water soluble and citrate soluble K in FA were decreased by the addition of these acids. The water soluble Ca content in FA treated with phosphoric acid did not show a significant change compared to that in the untreated FA, but it increased up to 65 times in FA treated with sulfuric acid. It is suggested that CaCO3, which was the main Ca species in the untreated FA, was transformed into syngenite and gypsum by the sulfuric acid treatment. Hydrochloric acid soluble Si in the acid-treated FA decreased compared to that in the untreated FA. In contrast, the NaOH-soluble Si fraction, a method for selectively extracting silica gel, increased especially in the phosphoric acid-treated FA. The results of XANES analysis showed that the FA samples treated with 10–30% sulfuric acid or 10–30% phosphoric acid had a lower degree of Si polymerization than the untreated FA, which corresponded generally to the increased Si solubility in FAs. However, FA treated with 30% sulfuric acid had lower soluble Si despite a lower degree of polymerization than FA, which was attributed to a lower pH. These results suggest that the change in solubility of Si in the acid-treated FA was influenced by the degree of polymerization and the decrease in pH. From the viewpoint of a fertilizer use of FA, sulfuric acid-treated ash, which consists of both water soluble Ca and citrate soluble Ca, is suitable for Ca fertilizer, and phosphoric acid-treated ash, which has high NaOH-soluble Si, is suitable for Si fertilizer

Synthesis of Novel White Pigment by Phosphoric Acid Treatment of Zinc Oxide

Synthesis of Novel White Pigment by Phosphoric Acid Treatment of Zinc Oxide

Study on the Phosphogypsum Proportion in Foamed Concrete Based on Concrete Strength and Carbon Emission

The production of concrete will produce a lot of carbon dioxide and pollute the environment. Phosphogypsum is a solid waste generated during wet phosphoric acid treatment, and the use of phosphogypsum blending instead of cement in concrete production can effectively reduce carbon dioxide emissions. Then, experiments were conducted for six concrete groups with different phosphogypsum content as 0%~50% to test the strength in 3 days, 7 days, and 28 days. The results show that as the curing day rise, the compressive strength of concrete increases, meanwhile, with the increment of phosphogypsum content, the 28-day strength decreases significantly. The analysis for the consideration of the balance in carbon emission and the strength evolved, and results could be concluded that although the decrement of 28-day strength as well as the carbon dioxide emissions with the increasing phosphogypsum content in concrete, different trends were found. As the strength and emissions vary, a suggested range of content for phosphogypsum in concrete can be found. Based on these results, the proportion of phosphogypsum in concrete is proposed to achieve the purpose of energy saving and emission reduction and improve the utilization rate of phosphogypsum.

A facile method of resource recovery from bauxite residue by phosphoric acid treatment

A facile method of resource recovery from bauxite residue by phosphoric acid treatment

Room temperature phosphorescence based on nitrogen-phosphorus co-doped carbonized polymer dots for information encryption

Carbonized polymer dots (CPDs) are proposed as a novel room temperature phosphorescence (RTP) materials that widely used in optoelectronic devices, bioimaging, especially in the field of information encryption and anti-counterfeiting due to their unique optical properties. However, achieving RTP emission under matrix-free conditions requires reasonable structural design to prevent the quenching of triplet excitons, which is very challenging. Herein, we proposed a facile, rapid and effective strategy to prepare matrix-free nitrogen and phosphorus co-doped CPDs (named Arg-CPDs) via microwave assisted heating treatment of arginine (Arg) and phosphoric acid. The Arg-CPDs exhibit bright blue fluorescence in aqueous solution and yellow green RTP emission in solid state, and the RTP emission is visible to the naked eye for about 4 s after switching-off the UV lamp. The phosphorescence lifetime of Arg-CPDs was 149 ms and 667 ms in ambient conditions and low temperature (77 K), respectively, which shown that the typical phosphorescent properties. Moreover, potential applications of the Arg-CPDs in the fields of information protection and encryption are demonstrated. This study provides a facile strategy for the preparation of matrix-free CPDs-based RTP materials toward the information security and their successful application in information security.

Influence of Phosphoric Acid Etching on Bond Strength for Calcium Silicate-Based Sealers

IntroductionThis study evaluated the microtensile bond strength of calcium silicate-based sealers and epoxy resin-based sealer, depending on the use of phosphoric acid (PA) etching before immediate resin restoration. MethodsExposed dentin surfaces of extracted human third molars were randomly assigned to 3 groups depending on sealer type (AH Plus [Dentsply DeTrey], CeraSeal [Meta Biomed Co.], and EndoSeal MTA [Maruchi]). Half of the samples were treated with PA for 30 seconds, and the other half were cleaned with water. Completely untreated specimens were used as controls. Self-etching adhesive (Clearfil SE Bond, Kuraray) was applied and composite resin (Tetric N-Ceram, Ivoclar Vivadent) was used to create build-ups. After 24 hours, the microtensile bond strength was measured (EZ Test, Shimadzu Co.). The failure mode was determined by light microscopy and scanning electron microscopy. One-way analysis of variance with the Bonferroni correction was used to analyze the data (P < .05). ResultsThe bond strength of the water-washed dentin surfaces in the calcium silicate-based sealer groups did not differ significantly from those of the control surfaces but the PA-pretreated surfaces exhibited relatively low-bond strength. The AH Plus-treated group had lower bond strength than the control group when no PA treatment was applied, but PA treatment restored the bond strength. The adhesive failure mode was most frequently found in the AH Plus group without PA etching. ConclusionsWhen a water-soluble calcium silicate-based sealer is used, sufficient bond strength can be obtained by washing with water alone, with no need for PA use.

Effect of phosphoric acid treatment on the physical properties of zinc telluride thin films

Zinc Telluride (ZnTe) films were prepared by the closed space sublimation (CSS) method. The effect of chemical treatments with concentrated phosphoric acid, on the optical, electric and structural properties of the films was studied. Zinc-blend structure of the polycrystalline nature of the films was confirmed by x-ray diffraction (XRD) spectra. The energy dispersive x-ray (EDX) shows an increase in Te ratio on the surface of the film as exposed to phosphoric acid. In addition, the dc electrical resistivity of the films was dropped considerably. The refractive index, thickness, and thickness irregularity of the films were determined by fitting of the optical transmittance spectra in the wavelength range 400 to 2500 nm. The effect, of treatment, on the optical parameters is also reported.

Improved contact quality for silver-free silicon heterojunction solar cells by phosphoric acid treatment

Electroplating technology is considered as a promising alternative to low-temperature sintered silver pastes for the purpose of significantly reducing the cost of silicon heterojunction (SHJ) solar cells (SCs). However, achieving excellent contact quality between the plated grid and indium tin oxide (ITO) remains a big challenge to satisfy the requirements for fabrication and high performance. In this work, phosphoric acid (H3PO4) is used to modify the ITO surface to improve the contact quality of the plated grid/ITO and enhance the performance of SHJ SCs. It is found that the phosphate groups are adsorbed on the ITO surface to form a dipole layer after H3PO4 treatment. The wettability of H3PO4-treated ITO is substantially improved, resulting in a pinhole-free electroplated nickel (Ni) seed layer. Moreover, the work function of ITO rises by approximately 0.2 eV, which reduces the contact potential barrier between the ITO and the metal electrode. The contact resistivity (ρc) between the plated grid and H3PO4-treated ITO is reduced to approximately 0.4 mΩ·cm2, compared to 1.5 mΩ·cm2 of the control sample. In addition, the metal grid formed on the H3PO4-treated ITO exhibits a better uniformity. Finally, the SHJ cell with H3PO4 treatment process receives a remarkable power conversion efficiency (PCE) of 23.19%, which is approximately 1% (absolute) higher than that of the control device. Therefore, we demonstrate that modifying ITO by H3PO4 is a promising way to improve the contact quality for the electroplating metallization in SHJ SCs.