Concentrations Of Phosphate Ions Research Articles

Efficient phosphate removal from water using ductile cast iron waste: a response surface methodology approach.

Water scarcity is a critical issue worldwide. This study explores a novel method for addressing this issue by using ductile cast iron (DCI) solid waste as an adsorbent for phosphate ions, supporting the circular economy in water remediation. The solid waste was characterized using XRD, XRF, FTIR, and particle size distribution. Wastewater samples of different phosphate ion concentrations are prepared, and the solid waste is used as an adsorbent to adsorb phosphate ions using different adsorbent doses and process time. The removal percentage is attained through spectrophotometer analysis and experimental results are optimized to get the optimum conditions using Design Expert V13. The pseudo-second order (PSO) kinetics model and Langmuir isotherm were fitted with the experimental results with maximum adsorption capacity (qmax = 0.28mg/g). The thermodynamic analysis indicated that this adsorption process was spontaneous based on the negative value of Gibbs free energy (∆G). Additionally, the positive values of enthalpy (∆H) indicated the endothermic nature of this adsorption system. It was able to reach the highest adsorption percentage of 98.9 (%) for phosphate ions from aqueous solutions using response surface methodology (RSM) with optimum conditions of 10mg/L phosphate ion concentration, pH = 8, normal room temperature, 9min adsorption, and 0.5g/L adsorbent dosage.

INVESTIGATION OF THE PHOSPHATE LOAD ON THE VOLGA RIVER BASIN IN THE AREA OF YAROSLAVL CITY

Excessive runoff of biogenic elements into natural watercourses as a result of anthropogenic activities leads to ecological balance violation in aquatic ecosystems, resulting in negative effect on aquatic organism vital activities and worsening the natural water quality due to activity of phytoplankton, especially blue-green algae. Nowadays eutrophication is one of the most serious environmental problems, especially in large rivers such as the Volga River.Since the Volga River flows through many agricultural areas and large cities, the influence of diffuse runoff from horticultural associations, as well as industrial and domestic runoff, on the river is significant. At the same time, the reservoir system built on the river also makes a significant contribution to the stagnation of water masses, which contributes to eutrophication.Currently, phosphates are recognized to be one of the main elements determining the eutrophication degree. Phosphorus for aquatic plants is the dominant component in mineral nutrition, therefore, significant deviations from the established standards of permissible concentrations lead to disastrous consequences for aquatic ecosystems.The purpose of this study was to monitor phosphate ion content in the Volga River and its tributaries in Yaroslavl city for a year and to find the dependence of the riverbed quantitative characteristics on dissolved phosphates content in them using the example of the Kotorosl River.The objects of the study were the Volga, Kotorosl, Tolgobolka, Nora, Dunayka, Uroch rivers, located in four districts of Yaroslavl city.The assessment of the dependence of the river morphometric parameters on the predisposition to phosphate accumulation was carried out on the Kotorosl River, as among of all the rivers represented in the Yaroslavl Region, it has a sufficiently large depth, a winding channel and a weak current, which makes it possible to assess the parameters of the channel at the inflow place to the Volga River.Based on the annual observation results, graphs of seasonal variability of phosphate concentrations in rivers by month of the year were constructed. The presented fluctuations in concentrations are of a wave nature.Correlation and regression analysis has been used to evaluate the relationship between the indicators of the Kotorosl riverbed and the phosphate content in the water column. According to the results of the work, the relationship between water section area and phosphate concentration in the river was revealed.The paper presents graphs of seasonal variability of phosphate ion concentrations in the Volga, Kotorosl, Dunayka, Tolgobolka, Nora, and Uroch rivers in Yaroslavl city. The morphometric parameters of the Kotorosl River at the place of its inflow to the Volga River were measured, and a correlation and regression analysis of the dependence of quantitative indicators of the riverbed and phosphate ions content in the water was carried out.

Functional and mechanistic assessment of plant-available soil phosphorus greatly improved the multisite diagnosis of maize yield response

Context or problemPlant-available soil phosphorus (P) is commonly assessed by chemical extractions with the purpose of diagnosing and advising fertilizer P application. However, for a given crop, this approach only poorly predicts yields obtained from several experimental sites. To solve this major drawback, a functional and mechanistic evaluation has been developed to mimic dominant processes involved in the absorption of phosphate ions. Objective or research questionIn this study, we investigated the predictive ability of a mechanistic approach to diagnose maize (Zea mays L.) yields, in comparison to the common Olsen's method (0.5 M bicarbonate solution). MethodsThe processes-based assessment consists of parameterizing relationships between amount of diffusible phosphate ions (Pr) at the solid-to-solution interface equilibrating the phosphate ions concentration in solution (CP) with time (t). We parameterized [Pr vs. (CP, t)] relationships for stored and archived soil samples (plough layer) of nine long-term field experiments (LTFEs) on increasing rates of P applications including the zero-P treatment (P0). LTFEs were located in different soils (Luvisol, Podzol, Arenosol, Calcosol) with large variations in physico-chemical properties. We also used LTFEs database of maize yields. ResultsThe CP values ranged from 0.02 to 3.86 mg P L−1 for 40 (LTFE×year of maize cropping) combinations. The (Pr=v×CPw×tp) equation closely described the [Pr vs. (CP, t)] datasets, with (v, w, p) parameters being soil specific. Maximum yields ranged from 5.5 to 14.7 t DM ha−1 depending on LTFEs and years. Yields decreased significantly only in P0, and did not differ for other P rates. The relationship between the relative maize yield and CP was sites-specific with CP thresholds to obtain a relative yield of 0.95 ranged from 0.07 to 0.88 mg P L−1 solution. Taking into account amounts of phosphate ions which balance CP by diffusion using (Pr=v×CPw×tp) equations, a single response curve is observed for the 9 LTFEs when the replenishment time is 1500 minutes (i.e. about one day). The critical CP thresholds closely correlated to the ability of the soil solid phase to buffer phosphate ions in solution. ConclusionsFor the 9 studied LTFEs on P fertilization, the [Pr vs. (CP, t)] relationships were more able to account for maize response curves than P extracted by Olsen method, improving the precision and reliability of the multisite diagnosis of maize yield response. Implications or significanceAs a result, P fertilization recommendations are more reliable regardless of soil type. Further progress could be gained by taking into account for the role of the soil layer beneath the plough layer.

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.

Correction: Relationship between Salivary Alkaline Phosphatase Enzyme Activity and The Concentrations of Salivary Calcium and Phosphate Ions.

In this article published in Cell J, Vol 17, No 1, 2015, on pages 159-162, the authors found that the affiliation of second author in address 2 was missed during the formatting of the paper. Therefore, we corrected it. The authors would like to apologize for any inconvenience.

Evaluation of antifungal activity of cerium oxide nanoparticles and associated cellular responses.

Cerium oxide nanoparticles (CeO2), as a metal oxide nanomaterial, are increasingly used for various industrial and biomedical applications. Although their cytotoxicity to bacteria and the associated mechanisms have attracted particular attention, the mechanisms behind their antifungal effects have remained unclear. This study investigated the antifungal properties of CeO2, focusing on Aspergillus oryzae. CeO2 inhibited fungal spore germination on solid substrates, and the effect was fungistatic rather than fungicidal. CeO2 inhibited fungal growth, especially under UV irradiation, and induced reactive oxygen species (ROS) production. Tocopherol reduced the intracellular ROS levels and the growth-inhibitory effects of CeO2, suggesting that ROS are involved in these growth-inhibitory effects. Transcriptomic analysis revealed upregulated expression of genes related to phospholipases and phosphate metabolism. CeO2 affected phosphate ion concentration in the medium, potentially influencing cellular responses. This research provided valuable insights into the antifungal effects of CeO2 application, which differ from those of conventional photocatalysts like TiO2.

Correction to: The Influence of Phosphate Ion Concentrations on the Properties of Wollastonite-Apatite-Based Cements

Correction to: The Influence of Phosphate Ion Concentrations on the Properties of Wollastonite-Apatite-Based Cements

The Influence of Phosphate Ion Concentrations on the Properties of Wollastonite-Apatite-Based Cements

The Influence of Phosphate Ion Concentrations on the Properties of Wollastonite-Apatite-Based Cements

Synthesis of graphene oxide-choline chloride in order to remove phosphate ion from aqueous samples: study of mechanism, isotherm and adsorption kinetics

In this study, a graphene oxide-choline chloride adsorbent was used as a highly efficient and environmentally friendly material for removing phosphate ions from aqueous samples. Graphene oxide was synthesized using the Hummers method and then modified with choline chloride to create the graphene oxide-choline chloride adsorbent. The synthesized adsorbent was characterized using Fourier transform infrared spectrophotometry (FT-IR), Field Effect Scanning Electron Microscopy (FESEM), and Energy-dispersive X-ray spectroscopy (EDX). It was then applied to remove phosphate ions at different pH levels and stirring times. The results of this study showed that the maximum removal efficiency of phosphate ions was achieved at pH 5, with an adsorbent amount of 0.015 g and a stirring time of 30 minutes. Furthermore, it was observed that the adsorption of phosphate ions on the adsorbent surface followed the Langmuir isotherm (monolayer adsorption), with a maximum adsorption capacity of 217.4 mg/g. The examination of absorption kinetics also revealed that the absorption of phosphate ions followed pseudo-second-order kinetics, and an increase in temperature favored the progress of the reaction.

Hydrogen Sulfide Delivery to Enhance Bone Tissue Engineering Cell Survival.

Though crucial for natural bone healing, local calcium ion (Ca2+) and phosphate ion (Pi) concentrations can exceed the cytotoxic limit leading to mitochondrial overload, oxidative stress, and cell death. For bone tissue engineering applications, H2S can be employed as a cytoprotective molecule to enhance mesenchymal stem cell (MSC) tolerance to cytotoxic Ca2+/Pi concentrations. Varied concentrations of sodium hydrogen sulfide (NaSH), a fast-releasing H2S donor, were applied to assess the influence of H2S on MSC proliferation. The results suggested a toxicity limit of 4 mM for NaSH and that 1 mM of NaSH could improve cell proliferation and differentiation in the presence of cytotoxic levels of Ca2+ (32 mM) and/or Pi (16 mM). To controllably deliver H2S over time, a novel donor molecule (thioglutamic acid-GluSH) was synthesized and evaluated for its H2S release profile. Excitingly, GluSH successfully maintained cytoprotective level of H2S over 7 days. Furthermore, MSCs exposed to cytotoxic Ca2+/Pi concentrations in the presence of GluSH were able to thrive and differentiate into osteoblasts. These findings suggest that the incorporation of a sustained H2S donor such as GluSH into CaP-based bone graft substitutes can facilitate considerable cytoprotection, making it an attractive option for complex bone regenerative engineering applications.

Physicochemical and FT-IR analyses of some freshwater and inflow wastewater-treated effluents in the Eastern Cape Province of South Africa

Monitoring changes occurring in water bodies is a tool to make a sound decision on water quality management. This work investigates water quality parameters and metabolites in the Bloukrans, Buffalo, Swartkops and Tyhume Rivers in the Eastern Cape Province of South Africa. The water physicochemical parameters assessed include the dissolved oxygen, oxidation-reduction potentials, temperature, Hydrogen ion concentration, salinity, conductivity, turbidity and total dissolved solids measured with a pre-calibrated Hanna Multiparameter instrument on-site. Chemical oxygen demand, phosphate, chloride, ammonium, sulphate and nitrate ions were measured in the laboratory with a UVmini spectrophotometer. FT-IR analysis of extracted metabolites was done on a Perkin Elmer FT-IR spectrometer. The result shows that upstream river samples have lower COD values and below the detection level in some. The concentrations of phosphate, chloride, ammonium, sulphate and nitrate ions were above the recommended values in the wastewater effluents, midstream and downstream river samples. FT-IR peaks similar to vinylidene, saturated aliphatic aldehydes, aryl aldehydes, primary amines, hydantoin amides, halogen, and organofluorides were common in the wastewater effluent samples and the receiving rivers. Grahamstown treated wastewater effluents and its receiving Bloukrans River were distinguished with absorption peaks of urethane and aromatic aldehydes. Absorption peaks of sulphonyl halides were present only on the spectra of treated wastewater effluents of Alice and the receiving downstream Tyhume River. Multivariate analysis shows correlations between the water samples from different geographical locations and treated wastewater effluents. It is concluded that the quality of the rivers was very poor and more efforts are needed to make the treated wastewater conform to the acceptable standard for a sustainable aquatic ecosystem.

467 Enhancing Cell Infiltration and Controlled Growth Factor Release for a Customized 3D-Printed Bone Graft Composite

OBJECTIVES/GOALS: Annually, 1.5 million global patients receive maxillofacial reconstruction. The gold standard, involving bone particulate, lacks reproducibility. To improve this, we have developed a custom 3D-printable, porous cover-core design. This study optimizes the hydrogel core properties and growth factor (GF) release for enhanced bone regeneration. METHODS/STUDY POPULATION: Different ratios of Methacrylated Gelatin (GelMa), Methacrylated Alginate (AlgMa) and tricalcium phosphate (α²-TCP) were combined to optimize cell viability, GF sequestration and mechanical stability. Material characterization was performed using a rheometer to determine the viscoelastic properties of the blends. Release from disks loaded with FGF-containing PLGA microparticles was quantified with an ELISA kit. Furthermore, scanning electron microscopy (SEM) was conducted to quantify hydrogel porosity. In vitro studies were performed using NIH 3T3 murine fibroblasts in Corning Transwells while immunofluorescent, metabolic and osteogenic studies were performed in 96 well plates to investigate cell infiltration, cell adhesion, viability and differentiation, respectively. RESULTS/ANTICIPATED RESULTS: By adjusting the AlgGelMa ratio, we manipulated matrix properties. GelMa possesses excellent durability and cell adhesion due to intrinsic RGD-binding motifs. AlgMa enhanced swelling by 30%, growth factor sequestration by 50% in 24hrs, and matrix storage modulus without increasing the loss modulus which could cause cell migration away from the hydrogel. Varying the AlgGelMa ratio lowered pH, promoted cell infiltration, and reduced fibronectin accumulation. The addition of β-TCP is anticipated to improve cell differentiation towards an osteogenic lineage due to improved elastic modulus, calcium and phosphate ion concentration improving mineral deposition. DISCUSSION/SIGNIFICANCE: These findings suggest through the use of this composite, early cell infiltration can be increased and promoted due to FGF release, leading to increased osteointegration. Our porous cover-core design ensures efficient clot integration and early cell infiltration, enhancing osteointegration through FGF release.

Targeting initial tumour-osteoclast spatiotemporal interaction to prevent bone metastasis.

Bone is the most common site of metastasis, and although low proliferation and immunoediting at the early stage make existing treatment modalities less effective, the microenvironment-inducing behaviour could be a target for early intervention. Here we report on a spatiotemporal coupling interaction between tumour cells and osteoclasts, and named the tumour-associated osteoclast 'tumasteoclast'-a subtype of osteoclasts in bone metastases induced by tumour-migrasome-mediated cytoplasmic transfer. We subsequently propose an in situ decoupling-killing strategy in which tetracycline-modified nanoliposomes encapsulating sodium bicarbonate and sodium hydrogen phosphate are designed to specifically release high concentrations of hydrogen phosphate ions triggered by tumasteoclasts, which depletes calcium ions and forms calcium-phosphorus crystals. This can inhibit the formation of migrasomes for decoupling and disrupt cell membrane for killing, thereby achieving early prevention of bone metastasis. This study provides a research model for exploring tumour cell behaviour in detail and a proof-of-concept for behaviour-targeting strategy.

Optimum phosphate ion removal from aqueous solutions using roller kiln industrial solid waste

Water scarcity is the most imperative predicament that concerns the population. In this research, a roller kiln (RK) industrial solid waste was used in the adsorption of phosphate ions from aqueous solutions thus converting a waste to wealth through aiding in serving as a water treatment application. The RK waste was produced from an Egyptian factory with a flow rate of million tons/day. Surface characterization for this solid waste was performed including transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infra-red (FTIR), zeta potential (ZP), and particle size distribution (PSD). Based on the kinetics and isotherm studies, the pseudo first order (PFO) kinetic model and Freundlich isotherm model were the best-fitted models with the experimental data as well as the Dubinin–Radushkevich isotherm model indicated that the adsorption type was physical. The attained experimental results were then optimized to attain the experimental conditions at which the optimum adsorption percentage was achieved using response surface methodology (RSM). The optimum percentage removal of phosphate ions 99.5 (%) was achieved at the following experimental conditions; pH 8, temperature = 25 °C, contact time = 9 min, initial phosphate ion concentration = 10 mg/L and adsorbent dose 0.5 = g/L.

Growth, Biomass Production, Pollutant Removal Capacity of Chlorella Vulgaris Cultivated in Water Polluted with Phosphates, Nitrates, Cadmium and Lead Ions; A Possible Strategy for Bioremediation, Carbon Dioxide Utilization and Simultaneous Biodiesel Productivity

The main objective of the work reported herein was to study the possibility of simultaneous use of microalgae for bioremediation and biodiesel production. Determination of optimum nitrate and phosphate concentrations for the maximum algal growth in the presence of heavy metal ions in the growth media was the other objective. In this regard, Chlorellavulgaris, a microalga, was cultivated separately for 30 days at ~28 °C in the presence and absence of known cadmium, lead, phosphate ion concentrations in growth media containing an optimum nitrate ion concentration. The concentrations of these ions in the growth media, dry algal biomass and extractable algal-oil percentage after 30 days of their growth were determined. According to the study, the optimum total nitrate and total phosphate concentrations required for the maximum algal growth were 200 mg L-1 and 10 mg L-1, respectively. The maximum tolerable Pb2+ and Cd2+ concentrations were 8 mg L-1 and 2.5 mg L-1, respectively. The results revealed that Chlorellavulgaris has a high capacity for both removing these ions (> 70%) from the growth medium, and generating algal biomass, simultaneously. Moreover, the algal biomass generated under these harsh conditions yields algal-oil (~41% in terms of dry algal biomass) that is free from these ions.

Effect of Precursor Solution on Sedimentation of Alkaline-earth Phosphates at Different Temperatures

Kinetic study of sedimentation of alkaline-earth phosphates-magnesium phosphate (MP), calcium phosphate (CP), strontium phosphate (SP) and barium phosphate (BP) precipitates was carried out by varying reactant concentration approach involving turn-wise variation of precursor metal ions (Mg2+, Ca2+, Sr2+ and Ba2+) and phosphate ion (PO43-) concentrations, and monitoring the settling of the precipitate formed in a precipitate sedimentation measurement apparatus. A pseudo-rate order equation, associated with the approach of varying reactant concentration, was linearized, and the dependence of precipitate sedimentation on precursor concentration, established therewith. Whereas MP precipitate gave positive order-sedimentation increased with increase in concentrations of precursor solutions, orders of CP, SP and BP precipitates were negative-sedimentation decreased with increase in concentrations of precursor solutions. Inter-particle attraction and repulsion associated with high solid concentration, volume of precipitate particles formed as well as chemical interactions of precipitate with the mother solution might have caused these effects.

The influence of polylactide/hydroxyapatite composite material crystallinity on the polymer structure degradation rate

Introduction Assessment of biological characteristics of polylactide/hydroxyapatite (PLLA/HA) biodegradable materials is requiered to specify indications for the use of PLLA/HA composite implants in clinical practice.The present study was aimed to measure the kinetics of calcium and phosphate release from PLLA and its dependence on polymer structure crystallinity. Material and methods Four types of biodegradable materials were studied in vitro. Samples of type 1 and type 3 made of crystalline PLLA after annealing contained 25 % and 50 % of HA mass fraction, respectively. Samples of type 2 and type 4 made of amorphous PLLA (without annealing) contained 25 % and 50 % of HA mass fraction, respectively. In every group, 6 samples were tested. The samples were incubated in an aqueous medium at 37 °C for 52 weeks. The rate of PLLA degradation was assessed by the accumulation of lactate monomer in the hydrolysate. The concentrations of calcium ions and phosphate ions were determined for assessment the HA hydrolysis rate. The degree of crystallinity of the polymer matrix was evaluated by scanning calorimetry.Results The hydrolysis of PLLA and HA in the samples was not simultaneous. The PLLA was hydrolyzed first followed by HA hydrolysis. By the moment of complete hydrolysis of PLLA, there was only 15 % of hydrolyzed HA. The release of calcium ions occurred from the sixth week of incubation for all tested samples, that of phosphate ions from the third week. The total amount of the released calcium ions and phosphate ions decreased in the line: material 3 > material 4 > material 1 > material 2. Calcium ions in the hydrolysates were detected up to 42 weeks of incubation, phosphate ions up to the 52nd week.Conclusion Higher crystallinity of PLLA achieved by annealing results in increased rate of hydrolysis of HA from PLLA matrix. Biological activity of PLLA/HA implants can be determined by degree of polymer crystallinity and saturation with HA.

Kinetics of Phosphate Ions and Phytase Activity Production for Lactic Acid-Producing Bacteria Utilizing Milling and Whitening Stages Rice Bran as Biopolymer Substrates.

A study evaluated nine kinetic data and four kinetic parameters related to growth, production of various phytase activities (PEact), and released phosphate ion concentration ([Pi]) from five lactic acid bacteria (LAB) strains cultivated in three types of media: phytate (IP6), milling stage rice bran (MsRB), and whitening stage rice bran (WsRB). Score ranking techniques were used, combining these kinetic data and parameters to select the most suitable LAB strain for each medium across three cultivation time periods (24, 48, and 72 h). In the IP6 medium, Lacticaseibacillus casei TISTR 1500 exhibited statistically significant highest (p ≤ 0.05) normalized summation scores using a 2:1 weighting between kinetic and parameter data sets. This strain also had the statistically highest levels (p ≤ 0.05) of produced phosphate ion concentration ([Pi]) (0.55 g/L) at 72 h and produced extracellular specific phytase activity (ExSp-PEact) (0.278 U/mgprotein) at 48 h. For the MsRB and WsRB media, Lactiplantibacillus plantarum TISTR 877 performed exceptionally well after 72 h of cultivation. It produced ([Pi], ExSp-PEact) pairs of (0.53 g/L, 0.0790 U/mgprotein) in MsRB and (0.85 g/L, 0.0593 U/mgprotein) in WsRB, respectively. Overall, these findings indicate the most promising LAB strains for each medium and cultivation time based on their ability to produce phosphate ions and extracellular specific phytase activity. The selection process utilized a combination of kinetic data and parameter analysis.

Pengukuran Anion Anorganik Secara Simultan dalam Sampel Air Tanah dan Air Ledeng Menggunakan Kromatografi Ion

Ion chromatography is an advanced and highly sensitive form of ion exchange chromatography that can effectively detect ion species, whether organic or inorganic ions. This research study utilized ion chromatography with a suppressed conductivity detection system to separate and measure the concentration of fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate ions in groundwater and tap water samples. The eluent solution used in this separation contained 6.0 mmol/L Na2CO3 and 0.25 mmol/L NaHCO3, which was crucial in ensuring the accuracy and selectivity of the detections. The samples were collected in 3 sub-districts in Ternate City, and the study's findings shed light on the water quality in the area.

The First Application of Palladium–Phosphorus Catalysts in the Direct Synthesis of Hydrogen Peroxide: Reasons for the Promoting Action of Phosphorus

The main reasons for the promoting effect of phosphorus on the properties of Pd–P/ZSM-5 palladium catalysts in the direct synthesis of H2O2 from H2 and O2 under mild conditions are considered based on data from X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and inductively coupled plasma mass spectrometry (ICP MS). It is shown that the introduction of phosphorus into the composition of the catalyst affects the dispersity, the electronic state of palladium in the surface layer, and the surface concentration of phosphate and phosphite ions. An increase in the H2O2 yield is favored by an increase in the dispersion of Pd–P-catalysts, inhibition of the side process of H2O2 decomposition by surface phosphate and phosphite ions, and a decrease in the solubility of hydrogen in solid solutions of phosphorus in palladium.