Acidic Products Research Articles

EFFECT OF STATIC PHYSICAL ACTIVITY ON CENTRAL HEMODYNAMICS AND ARTERIAL DISTENSIBILITY IN ADOLESCENT ATHLETES INVOLVED IN SWIMMING AND CROSS-COUNTRY SKIING

The purpose of the paper is to compare arterial distensibility in endurance sports atheletes (track and field athletes and swimmers), in whom adaptation to muscle activity is formed in interaction with various environmental factors. Materials and methods. Qualified athletes (adolescents aged 13–17) performed a 5-minute isometric handgrip exercise, corresponding to 20 % of the maximum compression force. The authors assessed athletes’ hemodynamics, arterial elasticity and cardiac parameters using the SphygmoCor technology. Results. At rest, swimmers demonstrated increased systolic blood pressure, lower values of heart rate, augmentation index and relative systole duration. Immediately after load, swimmers showed an increase in blood pressure, augmentation pressure, and left ventricular contractility as a consequence of sympathoadrenal system activation during exercise. In skiers the answers were reduced. After 20-minute recovery, diastolic pressure and augmentation index in swimmers dropped below the baseline. It was probably due to the vasodilatory effect of acidic metabolic products washed out after exercise from isometrically contracted ischemic forearm muscles. Conclusion. The characteristic aspects of aquatic training influence background hemodynamic parameters, arterial distensibility and responsiveness to local isometric load.

Exploring the impact of fermentation on bioactive compounds in two different types of carrot pomace

This study assessed the fermentation process of black and orange-colored carrot pomaces utilizing three varieties of lactic acid bacteria: Lactobacillus plantarum, Lactobacillus casei, and Lactobacillus acidophilus. The fermentation process influenced the titratable acidity and lactic acid production, with L. plantarum resulting in the highest increases, particularly noticeable in orange-colored carrot pomace (OCP). Initially, citric acid levels increased, while ascorbic acid levels decreased in all cultures. Black carrot pomace (BCP) fermented by L. casei exhibited the highest phenolic content (611.42 mg GAE/100 g dw) and antioxidant activity on day 3. The total phenolic content of OCP was the highest on day 3 with both L. casei and L. plantarum. The phenolic acid profiles varied by carrot type, with BCP being rich in neochlorogenic and chlorogenic acids, and OCP in gallic and p-coumaric acids. High anthocyanin content was found in OCP, especially cyanidin derivatives, peaking with L. casei. Similarly, OCP showed increased levels of both α-carotene and β-carotene on day 3 with L. casei. Carotenoid analysis revealed that BCP contained only α-carotene, with the highest level observed after 4 days of fermentation with L. plantarum. This study demonstrates that selective fermentation with lactic acid bacteria can alter the phytochemical profile of carrot pomaces, potentially enhancing the nutritional quality in various food applications.

Stability of Nano-Emulsified Cannabidiol in Acidic Foods and Beverages.

Introduction: Food and beverage products containing cannabidiol (CBD) is a growing industry, but some CBD products contain Δ9-tetrahydrocannabinol (Δ9-THC), despite being labeled as "THC-free". As CBD can convert to Δ9-THC under acidic conditions, a potential cause is the formation of Δ9-THC during storage of acidic CBD products. In this study, we investigated if acidic products (pH ≤ 4) fortified with CBD would facilitate conversion to THC over a 2-15-month time period. Materials and Methods: Six products, three beverages (lemonade, cola, and sports drink) and three condiments (ketchup, mustard, and hot sauce), were purchased from a local grocery store and fortified with a nano-emulsified CBD isolate (verified as THC-free by testing). The concentrations of CBD and Δ9-THC were measured by Gas Chromatography Flame Ionization Detector (GC-FID) and Liquid Chromatography with tandem mass spectrometry (LC-MS/MS), respectively, for up to 15 months at room temperature. Results: Coefficients of variation (CVs) of initial CBD concentrations by GC-FID were <10% for all products except ketchup (18%), showing homogeneity in the fortification. Formation of THC was variable, with the largest amount observed after 15 months in fortified lemonade #2 (3.09 mg Δ9-THC/serving) and sports drink #2 (1.18 mg Δ9-THC/serving). Both beverages contain citric acid, while cola containing phosphoric acid produced 0.10 mg Δ9-THC/serving after 4 months. The importance of the acid type was verified using acid solutions in water. No more than 0.01 mg Δ9-THC/serving was observed with the condiments after 4 months. Discussion: Conversion of CBD to THC can occur in some acidic food products when those products are stored at room temperature. Therefore, despite purchasing beverages manufactured with a THC-free nano-emulsified form of CBD, consumers might be at some risk of unknowingly ingesting small amounts of THC. The results indicate that up to 3 mg Δ9-THC from conversion can be present in a serving of CBD-lemonade. Based on the previous studies, 3 mg Δ9-THC might produce a positive urine sample (≥15 ng/mL THC carboxylic acid) in some individuals. Conclusion: Consumers must exert caution when consuming products with an acidic pH (≤4) that suggests that they are "THC-Free," because consumption might lead to positive drug tests or, in the case of multiple doses, intoxication.

Photochemical Aerobic Upcycling of Polystyrene Plastics.

Although the introduction of plastics has improved humanity's everyday life, the fast accumulation of plastic waste, including microplastics and nanoplastics, have created numerous problems with recent studies highlighting their involvement in various aspects of our lives. Upcycling of plastics, the conversion of plastic waste to high-added value chemicals, is a way to combat plastic waste that is receiving increased attention. Herein, we describe a novel aerobic photochemical process for the upcycling of real-life polystyrene-based plastics into benzoic acid. A new process employing a thioxanthone-derivative, in combination with N-bromosuccinimide, under ambient air and 390 nm irradiation is capable of upcycling real-life polystyrene-derived products in benzoic acid in yields varying from 24-54%.

CO2 electrolysis to multi-carbon products in strong acid at ampere-current levels on La-Cu spheres with channels

Achieving satisfactory multi-carbon (C2+) products selectivity and current density under acidic condition is a key issue for practical application of electrochemical CO2 reduction reaction (CO2RR), but is challenging. Herein, we demonstrate that combining microenvironment modulation by porous channel structure and intrinsic catalytic activity enhancement via doping effect could promote efficient CO2RR toward C2+ products in acidic electrolyte (pH ≤ 1). The La-doped Cu hollow sphere with channels exhibits a C2+ products Faradaic efficiency (FE) of 86.2% with a partial current density of −775.8 mA cm−2. CO2 single-pass conversion efficiency for C2+ products can reach 52.8% at −900 mA cm−2. Moreover, the catalyst still maintains a high C2+ FE of 81.3% at −1 A cm−2. The channel structure plays a crucial role in accumulating K+ and OH- species near the catalyst surface and within the channels, which effectively suppresses the undesired hydrogen evolution and promotes C–C coupling. Additionally, the La doping enhances the generation of *CO intermediate, and also facilitates C2+ products formation.

Ripening-related gene expression analysis revealed the molecular impact of 1-MCP application on apricot fruit softening, color, aroma, and antioxidant capacity

Apricot (Prunus armeniaca L.) is globally the third most cultivated stone fruit, prized for its flavourful and nutritious fruit. However, its climacteric nature impacts postharvest behaviour, shortening shelf-life. While the role and interaction of key genes and proteins involved in the ripening process of this species have been extensively studied over the years, research on ethylene suppressors like 1-methylcyclopropene (1-MCP) and cold storage is still limited. Fruit samples from 10 genotypes were collected at commercial maturity from the CEBAS-CSIC research centre and divided into three groups: control (T0), one application of 1-MCP at harvest (T1), and two applications of 1-MCP at harvest and after seven days of cold storage (T2). The study aimed to assess the effects of these treatments on fruit quality traits, such as skin color, soluble solids, acidity, firmness, and ethylene production, after various cold storage periods (10, 20, and 30 days) at 1°C, followed by 48 hours at 20°C. Cold storage combined with 1-MCP effectively reduced fruit softening and ethylene production, with varying impacts on fruit quality traits depending on the genotype. '906–12' and 'Goldrich' were identified as the most contrasting genotypes in terms of ethylene production and fruit softening. Additionally, the application of 1-MCP reduced the expression of genes responsible for fruit softening, coloration and some organoleptic characteristics while enhancing those promoting antioxidant activity during ripening. This study sheds light on the molecular processes involved in apricot fruit ripening and highlights the potential of this approach for enhancing postharvest preservation.

Prevotella enterotype associates with diets supporting acidic faecal pH and production of propionic acid by microbiota

Metabolism of dietary fibres by colon microbiota plays an important role for human health. Personal data from a nutrition study (57 subjects) were analysed to elucidate quantitative associations between the diet, faecal microbiome, organic acid concentrations and pH. Ratios of the predominant acids acetate, butyrate and propionate ranged from 1:0.67:0.27 to 1:0.17:0.36. Pectin-rich diets resulted in higher faecal acetate concentrations. Negative correlation between faecal pH and BSS was observed. Higher faecal pH and lower acid concentrations were related to the higher abundance of amino acid degrading Clostridium, Odoribacter and Eubacterium coprostanoligenes, which are weak carbohydrate fermenting taxa. Propionic acid correlated especially to high abundance of Prevotella and low abundance of proteobacteria. The acetate to propionate ratio of the Prevotella enterotype was about half of that of the Bacteroides enterotype. Based on the results we suggest the measurement of faecal pH and organic acid composition for research and diagnostic purposes.

Occurrence of Sphingomonas olei with elemental S oxidation capability in sodic soil: Potential role in sodicity reclamation and plant growth promotion

The success of the sodic soil reclamation using elemental S (S°) depends on the population of the native S° oxidizers. Augmenting the native flora of the sodic soils with effective S° oxidizers can enhance the success of the sodic soil reclamation. Present study reports for the first time the S° oxidation potential of the Sphingomonas olei strain 20UP7 isolated from sodic soils with pHs 9.8 and ECe 3.6 dS m–1. Inoculation with S. olei strain 20UP7 caused 13.0–24.2 % increase in S° oxidation in different sodic soils (pHs 9.1–10.5). It improved the concentration of the Ca2+, Mg2+, PO43– and declined the HCO3– and total alkalinity of the soil solution. This isolate also showed appreciable P and Zn solubilization, indole acetic acid, ammonia, and titratable acidity production in the growth media. It tended to the formation of biofilm around sulphur particles. The PCR amplification with gene–specific primers showed the occurrence of soxA, soxB, and soxY genes with a single band corresponding to length of 850, 460, and 360 base pairs, respectively. The integration of the S. olei strain 20UP7 with S° caused 21.7–25.4 % increase in the rice and wheat yield compared to the soil treated with S° alone. This study concludes that the S. olei, native to high saline–sodic soils can be utilized for improving the sodicity reclamation and plant growth promotion using elemental S based formulations.

Poly(dl-lactide) Polymer Blended with Mineral Phases for Extrusion 3D Printing-Studies on Degradation and Biocompatibility.

A promising therapeutic option for the treatment of critical-size mandibular defects is the implantation of biodegradable, porous structures that are produced patient-specifically by using additive manufacturing techniques. In this work, degradable poly(DL-lactide) polymer (PDLLA) was blended with different mineral phases with the aim of buffering its acidic degradation products, which can cause inflammation and stimulate bone regeneration. Microparticles of CaCO3, SrCO3, tricalcium phosphates (α-TCP, β-TCP), or strontium-modified hydroxyapatite (SrHAp) were mixed with the polymer powder following processing the blends into scaffolds with the Arburg Plastic Freeforming 3D-printing method. An in vitro degradation study over 24 weeks revealed a buffer effect for all mineral phases, with the buffering capacity of CaCO3 and SrCO3 being the highest. Analysis of conductivity, swelling, microstructure, viscosity, and glass transition temperature evidenced that the mineral phases influence the degradation behavior of the scaffolds. Cytocompatibility of all polymer blends was proven in cell experiments with SaOS-2 cells. Patient-specific implants consisting of PDLLA + CaCO3, which were tested in a pilot in vivo study in a segmental mandibular defect in minipigs, exhibited strong swelling. Based on these results, an in vitro swelling prediction model was developed that simulates the conditions of anisotropic swelling after implantation.

Effect of Particle Size and Citric Acid Concentration on the Yield and pH of Butterfly Flower (Clitoria ternatea L.) Extract

This research aimed to determine the effect of differences in butterfly pea flower particle size and citric acid concentration on butterfly pea flower extraction, including yield and pH value analysis. The results showed that the particle size of butterfly pea flowers and the concentration of citric acid affected the yield. pH analysis showed that only treatments with different concentrations of citric acid affected the pH of butterfly pea flower extract. The highest yield in the treatment (7.52) and the highest pH (4,74). The above treatment can only be used for acidic food products, and citric acid can be replaced with food additives that lower the pH value but do not affect the taste so that it can be applied to all types of food.

Abstract 4158: Non-invasive mapping of acidosis and extracellular lactosis for assessing tumor invasion in vivo

Abstract Tumor cells typically display a hyperglycolytic metabolic phenotype characterized by increased lactate production, known as the Warburg effect. This drift in oxidative metabolism often results in a more acidic microenvironment. This adverse microenvironment represents a unique metabolic signature in cancer cells with more invasive phenotypes. However, to date, there are no effective methods available to evaluate cancer progression and metastatic potential in vivo. To bridge this gap, we have developed a molecular imaging technique (CEST-MRI) that can track extracellular pH (pHe; acidoCEST) and extracellular lactate levels (shiftCEST) simultaneously to discern different cancer phenotypes. In this study we have generated and selected in vivo two PyMT derived murine breast cancer cell lines, a parental and a G6 metastatic. We first characterized the cell’s metabolism by analyzing key biomarkers with qPCR, Western Blot and microscopy, and confirmed their distinct metabolic profiles with Seahorse and RNA Sequencing. Notably, the metastatic PyMT exhibited a more active metabolism, aligning with the invasive phenotype observed by spheroid invasion assay. Herein, we combined the injection of iopamidol and shift reagent (SR) to perform quasi-simultaneous acidoCEST and shiftCEST. First, we assessed the approach in vitro by introducing iopamidol and SR into phantoms containing the individual contrast agents, and the combination in pure water and cells supernatants at different pHe and lactate levels. We performed LDH assays to cross-validate the extracellular concentrations and monitored the pH with a micro pH meter (Mettler-Toledo). In vivo, the cells were injected orthotopically in the 4th mammary fat pad of C57BL/6N mice. Hybrid shift/acidoCEST sequences were optimized and acquired following the injection of the iopamidol+SR solution. Preclinical shift/acidoCEST enabled the simultaneous and accurate determination of extracellular acidosis and lactosis, revealing increased acidification in the metastatic models despite lower lactate secretion. Metastatic tumors exhibited a negative correlation between tumor volume and pHe, indicating the significance of acidity in mutagenesis and invasion. In contrast, no correlation was observed for the parental non-metastatic tumor. Additionally, the metastatic tumors had lower levels of lactate than the parental tumors, which could be attributed to their higher mitochondrial activity, reflecting a diverted metabolic fitness. In summary, our study highlights the efficacy of shift/acidoCEST as a reliable method for non-invasive metabolic imaging, enabling the simultaneous detection of extracellular acidity and lactate production by MRI. This research introduces a unique platform for assessing the metabolic aggressiveness of cancer, emphasizing the significance of acidity and lactate production as crucial biomarkers in cancer invasion. Citation Format: Anais Choffart, Remy Chiaffarelli, Max Zimmermann, Laura Kuebler, André Martins. Non-invasive mapping of acidosis and extracellular lactosis for assessing tumor invasion in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4158.

Modulating Pt‐N/O Bonds on Co‐doped WO3 for Acid Electrocatalytic Hydrogen Evolution with Over 2000 h Operation

AbstractDeveloping durable electrocatalysts with high performance for hydrogen evolution reaction (HER) in acid conditions is of prime challenge for hydrogen production. Durability is of important prerequisite for catalyst application. Herein, this work constructs the Co‐doped WO3 loaded with Pt nanoparticles under ammonia treatment (Pt/N‐CoWO3) with the Pt‐N/O‐W interaction, which shows excellent activity and stability for acidic hydrogen production at industrial current density. The electronic structure of Pt species is modulated with enhanced Pt‐N/O bonding by Co doping, hence reinforcing the metal‐support interaction, and greatly enhancing the stability of the catalyst under high current density in acidic media. The resultant Pt/N‐CoWO3 catalyst exhibits the overpotentials of only 94 and 108 mV at high current densities of 1 and 2 A cm−2, respectively. More impressively, Pt/N‐CoWO3 delivers a record operation for acid electrocatalytic hydrogen evolution over 2000 h at 1 A cm−2, denoting its potential for catalyst applications at the industrial current density. This work opens a new avenue for developing Pt‐loading acidic HER catalysts for long‐term operation at ampere‐level current densities in acid conditions.

Grafting Ultra‐fine Nanoalloys with Amorphous Skin Enables Highly Active and Long‐lived Acidic Hydrogen Production

AbstractLarge‐scale deployment of proton exchange membranes water electrolysis (PEM‐WE) requires a substantial reduction in usage of platinum group metals (PGMs) as indispensable electrocatalyst for cathodic hydrogen evolution reaction (HER). Ultra‐fine PGMs nanocatalysts possess abundant catalytic sites at lower loading, but usually exhibit reduced stability in long‐term operations under corrosive acidic environments. Here we report grafting the ultra‐fine PtRu crystalline nanoalloys with PtxRuySez “amorphous skin” (c‐PtRu@a‐PtxRuySez) by in situ atomic layer selenation to simultaneously improve catalytic activity and stability. We found that the c‐PtRu@a‐PtxRuySez‐1 with ~0.6 nm thickness amorphous skin achieved an ultra‐high mass activity of 26.7 A mg−1Pt+Ru at −0.07 V as well as a state‐of‐the‐art durability maintained for at least 1000 h at −10 mA cm−2 and 550 h at −100 mA⋅cm−2 for acid HER. Experimental and theoretical investigations suggested that the amorphous skin not only improved the electrochemical accessibility of the catalyst surface and increasing the intrinsic activity of the catalytic sites, but also mitigated the dissolution/diffusion of the active species, thus resulting in improved catalytic activity and stability under acidic electrolyte. This work demonstrates a direction of designing ultra‐fine PGMs electrocatalysts both with high utilization and robust durability, offers an in situ “amorphous skin” engineering strategy.

Grafting Ultra-fine Nanoalloys with Amorphous Skin Enables Highly Active and Long-lived Acidic Hydrogen Production.

Large-scale deployment of proton exchange membranes water electrolysis (PEM-WE) requires a substantial reduction in usage of platinum group metals (PGMs) as indispensable electrocatalyst for cathodic hydrogen evolution reaction (HER). Ultra-fine PGMs nanocatalysts possess abundant catalytic sites at lower loading, but usually exhibit reduced stability in long-term operations under corrosive acidic environments. Here we report grafting the ultra-fine PtRu crystalline nanoalloys with PtxRuySez "amorphous skin" (c-PtRu@a-PtxRuySez) by in situ atomic layer selenation to simultaneously improve catalytic activity and stability. We found that the c-PtRu@a-PtxRuySez-1 with ~0.6 nm thickness amorphous skin achieved an ultra-high mass activity of 26.7 A mg-1 Pt+Ru at -0.07 V as well as a state-of-the-art durability maintained for at least 1000 h at -10 mA cm-2 and 550 h at -100 mA⋅cm-2 for acid HER. Experimental and theoretical investigations suggested that the amorphous skin not only improved the electrochemical accessibility of the catalyst surface and increasing the intrinsic activity of the catalytic sites, but also mitigated the dissolution/diffusion of the active species, thus resulting in improved catalytic activity and stability under acidic electrolyte. This work demonstrates a direction of designing ultra-fine PGMs electrocatalysts both with high utilization and robust durability, offers an in situ "amorphous skin" engineering strategy.

Evaluation and Validation of Simple and Quick Methods of Lime Rate Determination under Acid Soil-Affected Areas of West Shewa Zone, Ethiopia

Liming acid soils is one of the available intervention options to amend soil acidity and increase crop production and productivity. The selection of a lime requirement determination easy and cheap method that is suitable to the soil conditions in a particular area is a pressing issue. Three lime requirement (LR) estimation methods i.e. (Exchangeable acidity, laboratory pH, and portable pH/Artikilee 3000) methods with one control treatment were tested in acid soils of the dhumuga learning watershed. A field study was conducted to verify the lime requirement (LR) by using portable pH methods and investigate the wheat response to lime. The treatments were laid out in an RCBD design with two farmers’ replications. The result showed that there a was significant (p&lt;0.05) yield response to the liming. The highest grain yield of 5512.3kg ha 1 was obtained from lime treated with the pH method statistically at par with Exchangeable acidity and article 3000 methods. LR rates estimated by the Exchangeable acidity method were lower than those estimated by laboratory pH and portable pH/ Artikilee 3000. However, both methods (laboratory pH and portable pH/ Artikilee 3000) overestimated the lime requirements of the study soil. The exchangeable acidity method was lower than the LR estimated with the article 3000 method by an average of 38 %, which indicates article 3000 methods overestimated the LR for the present study area, while exchangeable acidity methods were found to be reliable estimation LR. Lime rates determined with the three lime testing methods (pH method, Portable pH or Artikilee 3000 and exchangeable acidity) gave yield advantages of 31.94, 24.93 and 20.45%, respectively over the non-limed treatment. From the results of this study, it was concluded that the exchangeable acidity method gives a more reliable estimation of the lime requirements of acid soils of the study area.

Sorption Treatment of Aqueous and Organic Media to Remove Tributyl Phosphate and Acidic Products of Its Decomposition

Sorption Treatment of Aqueous and Organic Media to Remove Tributyl Phosphate and Acidic Products of Its Decomposition

Effect of the initial pH of the culture medium on the nutrient consumption pattern of Bifidobacterium animalis subsp. lactis Bb12 and the improvement of acid resistance by purine and pyrimidine compounds.

During fermentation, the accumulation of acidic products can induce media acidification, which restrains the growth of Bifidobacterium animalis subsp. lactis Bb12 (Bb12). This study investigated the nutrient consumption patterns of Bb12 under acid stress and effects of specific nutrients on the acid resistance of Bb12. Bb12 was cultured in chemically defined medium (CDM) at different initial pH values. Nutrient consumption patterns were analyzed in CDM at pH 5.3, 5.7, and 6.7. The patterns varied with pH: Asp+Asn had the highest consumption rate at pH 5.3 and 5.7, while Ala was predominant at pH 6.7. Regardless of the pH levels (5.3, 5.7, or 6.7), ascorbic acid, adenine, and Fe2+ were vitamins, nucleobases, and metal ions with the highest consumption rates, respectively. Nutrients whose consumption rates exceeded 50% were added individually in CDM at pH 5.3, 5.7, and 6.7. It was demonstrated that only some of them could promote the growth of Bb12. Mixed nutrients that could promote the growth of Bb12 were added to three different CDM. In CDM at pH 5.3, 5.7, and 6.7, it was found that the viable cell count of Bb12 was the highest after adding mixed nutrients, which were 8.87, 9.02, and 9.10 log CFU ml-1, respectively. The findings suggest that the initial pH of the culture medium affects the nutrient consumption patterns of Bb12. Specific nutrients can enhance the growth of Bb12 under acidic conditions and increase its acid resistance.

Major drivers of soil acidification over 30 years differ in paddy and upland soils in China

Elevated nitrogen (N) fertilization has largely increased crop production in China, but also increased acidification risks, thereby threatening crop yields. However, natural soil acidification due to bicarbonate (HCO3) leaching and base cation (BC) removal by crop harvest also affect soil acidity whereas the input of HCO3 and BC via fertilizers and manure counteract soil acidification. Insights in rates and drivers of soil acidification in different land use types is too limited to support crop- and site-specific mitigation strategies. In this study, we assessed the historical changes in cropland acidification rates and their drivers for the period 1985–2019 at 151 sites in a typical Chinese county with the combined nutrient and soil acidification model VSD+. VSD+ could well reproduce long-term changes in pH and in the BC concentrations of calcium, magnesium and potassium between 1985 and 2019 in non-calcareous soils. In paddy soils, the acidity production rate decreased from 1985 onwards, mainly driven by a pH-induced reduction in HCO3 leaching and N transformations. In upland soils, however, acidity production was mainly driven by N transformations and hardly changed over time. Crop BC removal by harvesting played a minor role in both paddy and upland soils, but its relative importance increased in paddy soils. The acidity input was partly neutralized by HCO3 input from fertilizers and manure, which decreased over time due to a change from ammonia bicarbonate to urea. Soil buffering by both BC and aluminium release decreased in paddy soils due to a reduction in net acidity production, while it stayed relatively constant in upland soils. We conclude that acidification management in paddy soils requires a focus on avoiding high HCO3 leaching whereas the management in upland soils should focus on balancing N with recycling organic manure and crop residues.

Electrosynthesis of peracetic acid using in-situ generated H2O2 enabled by carbon-based bifunctional electrodes

Electrosynthesis of peracetic acid (PAA) using in-situ generated H2O2 is a sustainable route to bypass the complexity and hazards of current industrial production routes of PAA. However, efficient electrochemical operation requires advancements in both electrocatalytic H2O2 production and the subsequent oxidation of acetic acid. Herein, we report a bifunctional carbon electrode for PAA electrosynthesis, which features metal-free carbon catalysts structured on a hierarchical array-like graphene substrate. With such a three-dimensional architecture to maximise active site utilisation and enhance mass transfer, this carbon electrode exhibits acidic H2O2 production performance comparable to metal-based counterparts. Moreover, the same electrode activates OH· from H2O2 by virtue of its surface functional group, facilitating strong oxidation of acetic acid to PAA. In a flow electrolyser that couples H2O2 production and acetic acid oxidation, the bifunctional electrode achieved continuous production of industrially relevant concentrations of PAA at high rates and low energy consumption. Our work highlights the critical role of electrode design for the decentralised synthesis of PAA, providing new insights for the electrification of the chemical industry towards a sustainable future.

TGA and NMR relaxation measurement of nonmesoporous silica to investigate the amount of hydrolysis product in acetylsalicylic acid adsorbed on silica

This study investigated a crucial surface property of silica that contributes to the chemical stability of acetylsalicylic acid (ASA) physically adsorbed on silica. Hydrophilic nonmesoporous types of silica were selected, and the number of hydroxyl groups on silica (N(OH)) was evaluated using thermogravimetric analysis (TGA). The ASA-containing silica was stored at 40 °C in drying conditions, and the amount of ASA degradation was quantified based on salicylic acid. From the scatterplots between the number of hydroxyl groups per unit weight (specific surface area (SSA) × N(OH)) and the amount of ASA degradation, it was clarified that in ASA adsorbed on silica, the ASA chemical stability was determined by the formula (the SSA × N(OH)). In addition, a time-domain nuclear magnetic resonance measurement verified the N(OH) result by estimating the interaction between the silica surface and water in an aqueous silica suspension. The N(OH) result was found to be reasonable.