Decomposition Of Acid Research Articles

Porous BINAP-based polyaromatic polymers for the continuous base-free Ru-catalysed decomposition of aqueous formic acid

In this work, a Suzuki cross-coupling procedure towards highly porous BINAP-based polymeric Ru-catalyst materials with tunable specific surface areas (SSAs) were synthesized and their stability towards reducing conditions was investigated. After the removal of Pd impurities by an oxidative treatment with H2O2/HCl, P=O reduction and metal loading, the resulting catalysts were employed for the base-free ruthenium-catalyzed decomposition of aqueous formic acid to CO2 and H2 with TOFs of up to 134000 h−1 and TONs up to 920000.

Difference and similarity of coke from thermal decomposition or steam reforming of acetic acid

Polymerization/cracking and the reaction of intermediates with steam are the main routes by which the coke of very different properties might formed in steam reforming of acetic acid. This was investigated herein by conducting the steam reforming and decomposition of acetic acid on Ni/SBA-15 at 400, 550 and 700 °C, with particular focus on investigating the nature of resulting coke. Decomposition generated more coke than steam reforming at 400 °C (79.1% versus 24.6%), 550 °C (73.0% versus 45.6%) or 700 °C (39.0% versus 6.8%). More carbonaceous species like *CHx and *CC were the main intermediates, precursors of aromatic coke in decomposition, and their concentration on the catalyst surface let to serious coking at 550 °C, however, in steam reforming, oxygen-containing species like CO or C-O-C where the main intermediates precursors of coke. While larger outer diameter of carbon nanotube was formed in the reaction at 550 °C, smooth surface was formed at 700 °C.

Effect of elements availability on the decomposition and utilization of S-containing amino acids by microorganisms in soil and soil solutions

Effect of elements availability on the decomposition and utilization of S-containing amino acids by microorganisms in soil and soil solutions

Investigation of the decomposition performances of Cu-EDTA using pulsed streamer discharge

The decomposition of Cu-Ethylenediaminetetraacetic Acid (Cu-EDTA) using a pulsed streamer discharge in contact with liquid is reported under various experimental conditions, and the efficacy of OH radicals is investigated. The change in Cu-EDTA concentration was characterized using high-performance liquid chromatography. H2O2, NO2 −, NO3 −, and O3 were detected using water inspection test kits and an UV-visual spectrophotometer. The OH yield was estimated using a colorimetric method with disodium terephthalate. The results revealed that approximately 70% of the Cu-EDTA decomposed with an energy efficiency of 15 mmol kWh−1 in the Ar discharge, whereas the decomposition rate and energy efficiency in the air discharge were 80% and 16 mmol kWh−1, respectively, within 60 min of treatment. The decomposition in Ar was primarily driven by the OH generated during discharge, whereas a combined effect of O3 and OH was observed during air discharge. The discharge-generated OH was the dominant species in Cu-EDTA decomposition in this study.

Enhanced lignin and cellulose metabolism promote cell wall synthesis and growth of wild soybean HRA under alkali stress.

Soil salinization adversely threatens plant survival and food production globally. The mobilization of storage reserves in cotyledons and establishment of the hypocotyl/root axis (HRA) structure and function are crucial to the growth of dicotyledonous plants during the post-germination growth period. Here, we report the adaptive mechanisms of wild and cultivated soybeans in response to alkali stress in soil during the post-germination growth period. Diferences in physiological parameters, microstructure, and the types, amounts and metabolic pathways of small molecule metabolites and gene expression were compared and multi-omics integration analysis was performed between wild and cultivated soybean under sufcient and artifcially simulated alkali stress during the post-germination growth period in this study. Structural analysis showed that the cell wall thickness of wild soybean under alkali stress increased, whereas cultivated soybeans were severely damaged. A comprehensive analysis of small molecule metabolites and gene expression revealed that protein breakdown in wild soybean cotyledons under alkali stress was enhanced, and transport of amino acids and sucrose increased. Additionally, lignin and cellulose synthesis in wild soybean HRA under alkali stress were enhanced. verall, protein decomposition and transport of amino acids and sucrose increased in wild soybean cotyledons under alkali stress, which in turn, promotes HRA growth. Similarly, lignin and cellulose synthesis in wild soybean HRA enhanced, which subsequently, enhanced cell wall synthesis, thereby maintaining the stability and functionality of HRA under alkali stress. This study presents important practical implications for the utilization of wild plant resources and sustainable development of agriculture.

Separation of siderite from calcite by differential reaction with dilute ethanoic acid: mineralogical and isotopic (δ13C, δ18O) effects

ABSTRACT A simple procedure is described for the separation of siderite, from mixtures of siderite and calcite, for carbon and oxygen isotope analysis based on the selective decomposition of calcite by reaction with stoichiometric excess ethanoic acid. Artificial mixtures, prepared from two naturally occurring materials (concretionary siderite containing approximately equal quantities of low-Mg and high-Mg siderite, and low-Mg calcite), are used to test the selectivity of calcite removal, investigate the potential for differential acid decomposition of siderites of differing geochemical composition, and assess the effect of separation procedures on the isotopic composition of recovered carbonate. Acidification results in complete removal of calcite and only minor (< 2 wt %) siderite decomposition. Isotopic effects are limited with minimal difference between untreated (experimental control) and acid-treated materials. Discrepancies are attributed to preferential decomposition (greater reactivity) of (low δ13C, δ18O) high-Mg over (high δ13C, δ18O) low-Mg siderite in moderately acidic solvents. Observed departures from true isotopic compositions are insignificant for most geochemical applications when compared with other sources of uncertainty associated with the interpretation of siderite stable-isotope data sets in natural systems.

Topological defects induced by N incorporation-evaporation strategy promote the metal-support interaction over Pd/NC for catalytic formic acid dehydrogenation

Hydrogen (H2) production from formic acid (FA) decomposition is considered to be the application pattern of clean energy with board prospects. However, in precious metal-based catalysts, the weak metal-support interaction always leads to the reduction of exposure and utilization of active centers. Herein, N incorporation-evaporation strategy was employed to generate more topological carbon defects to deposit Pd nanoparticles (Pd NPs). The results demonstrate that topological defects are able to promote the electron transfer at the Pd-carbon interface, resulting in enhanced metal-support interaction. The Pd/NC800 catalyst with numerous topological defects exhibits significant activity (turnover frequency of 1251 h−1) and stability under mild conditions because of highly dispersed Pd centers with a modulated electronic state. The mechanism of enhancing metal-support interaction through topological defects was discussed through theoretical calculations, and it was found that the optimal topological configuration is the 5–8-5 defect induced by pyrrolic N. This work casts a new light on understanding the interaction between carbon configurations and active metals.

Alkaline amino acid modification based on biological phytic acid for preparing flame-retardant and antibacterial cellulose-based fabrics

Cellulose-based fabrics have significant advantages, but their application scenarios are limited due to their flammability. This work used biomass phytic acid and protein decomposition products, alkaline amino acids (arginine, lysine, histidine) to prepare alkaline amino acid flame retardants (PALA, PALL, PALH), and they were utilized to endow Lyocell fabrics with flame-retardant and antibacterial properties. When the weight gain was about 16.0 wt%, PALA exhibited better flame-retardant effect, and the limited oxygen index value of PALA-Lyocell reached 47.1 %. In the cone calorimetry test, PALA showed the best flame-retardant efficiency in reducing flame growth index with a 92.0 % decrease in peak heat release rate. The results of thermogravimetric analysis coupled with Fourier Transform Infrared spectroscopy (TG-FTIR) and char residues indicated that the flame-retardant property of alkaline amino acid flame retardants was formed through the combined action of gas and condensed phases. In the antibacterial test, PALA had the highest antibacterial rate against Staphylococcus aureus at 97.2 %. Mechanical property, handle feeling, and whiteness results had indicated that alkaline amino acid based flame retardants had little effect on the physical properties of Lyocell fabrics. This work confirms alkaline amino acid based flame retardants have functions of flame-retardant and antibacterial properties, providing reference for the practical value of biomass in cellulose-based fabrics.

Case study: enhancing methane production and polylactic acid decomposition in mesophilic anaerobic digestion system with hydrogen enrichment

Case study: enhancing methane production and polylactic acid decomposition in mesophilic anaerobic digestion system with hydrogen enrichment

Effects of concentrated CO2 on the performance of a PBI/H3PO4 high temperature proton exchange membrane fuel cell

In this study, the impact of mimic reformate of formic acid decomposition on the anode polarization of HT-PEMFC is investigated under various operating conditions of the anode, including different concentrations of CO2, N2, CO, and humidification. Polarization curve and EIS measurements indicate that there is no significant difference (less than 5 mV when i < 0.4A/cm2) between the same concentrations of CO2 and N2 up to 75 vol%. No significant poisoning of the anode by CO2 (up to 75 vol%) has been observed, suggesting that the addition of concentrated CO2 acts more as a diluent than a poison. Upon separating the polarization effects, it is found that the oxygen reduction reaction (ORR) is a crucial step limiting the fuel cell performance, with cathodic activation losses reaching as high as 70 % at 0.8A/cm2. However, with 1 vol% CO in a H2/CO2 1/1 mixture, a significant poisoning effect on the fuel cell is observed. DRT (distribution of relaxation times) analyses reveal two peaks related to CO in high-frequency regions above 100 Hz associated with the anode polarization, with the peak integration being five times larger than in pure hydrogen. Humidification doesn't improve the voltage or mitigate CO poisoning. A one-dimensional flux model that includes the anode polarization is developed to analyze the polarizations for both cathode and anode under different concentrations of diluents, well describing the experimental results. When i < 0.8 A/cm2, the predicted values from the model closely match the measured values (within 5–10 mV). Calculations suggest that the anode polarization cannot be ignored, especially when the anode is fed with diluted gases.

Effect of water on formic acid and formaldehyde decomposition on the TiO2 (110) surface

The catalytic and photocatalytic performance of TiO2 in air pollutant degradation is significantly influenced by the adsorption of water. Here, we explore the molecular mechanism of formic acid and formaldehyde decomposition and their interaction with water on the TiO2 (110) surface, employing density functional theory (DFT) calculations and reactive molecular dynamics (RMD) simulations. RMD simulations indicate that due to the competitive adsorption of water at the surface Ti site, formic acid predominantly exists in a monodentate dissociative adsorption form on the TiO2 (110) surface. Moreover, on the TiO2 (110) surface, water molecules inhibit the adsorption and dissociation of formic acid, but they facilitate that of formaldehyde, forming methanediol (*CH2OHO) and dioxymethylene (*CH2O2). DFT calculations suggest that the formation pathway of *CH2OHO or *CH2O2 is energetically favorable, but the formation of formate is difficult. This contrasts with the adsorption of formaldehyde on the anatase surface, where formate species are formed.

Synthetic nanoarchitectonics with ultrafast Joule heating of graphene-based electrodes for high energy density supercapacitor application

This study presents a novel approach for the development of high-performance supercapacitor (SC) electrodes using the Flash Joule Heating (FJH) method. Here, we report a direct and rapid synthesis of graphene-based electrodes via FJH. The technique involves microwave-assisted decomposition of citric acid and urea to form CNDs as precursors, followed by Flash Joule Heating (FJH) leading to the formation of graphene in seconds. The scalability of this method paves the way for the rapid production of graphene-based SC electrodes. Based on the characterisation using XRD, Raman, SEM and TEM, the FJH-treated CNDs yielded graphene on carbon fibre cloth with well-defined morphologies leading to superior electrochemical performance in supercapacitors. The FJH processed electrodes exhibited exceptional electrochemical performance with a specific capacitance of 279 F g⁻¹ at 1 A g⁻¹, significantly outperforming unflashed and low current flash processed electrodes. This exceptional performance can be attributed to the formation of high-quality, few-layered graphene with enhanced electrical conductivity and efficient ion transport properties. Moreover, a Symmetric supercapacitor is also assembled which demonstrated a specific capacitance of 106.5 F g⁻¹ at 1 A g⁻¹. It also exhibited an impressive energy density of 44.4 W h kg−1 at a power density of 1000 W kg⁻¹. This work demonstrates the feasibility of FJH as a rapid, scalable and cost-effective technique for the production of high-performance graphene-based electrodes for supercapacitor applications.

Formation of Products of Incomplete Destruction (PID) from the Thermal Oxidative Decomposition of Perfluorooctanoic Acid (PFOA): Measurement, Modeling, and Reaction Pathways.

The thermal decomposition of perfluorooctanoic acid (PFOA) under oxidative conditions was investigated using air (O2) and N2O as oxidants over temperatures ranging from 400 to 1000 °C in an α-alumina reactor. In the presence of air, PFOA was found to decompose into perfluorohept-1-ene (C7F14) and perfluoroheptanoyl fluoride (C7F14O) in addition to HF, CO, and CO2. At temperatures above 800 °C, both C7F14 and C7F14O were no longer detected. A comprehensive analysis of the reaction mechanisms through quantum chemical analysis and kinetic modeling in combination with experimental observations was utilized to identify key reaction pathways. Quantum chemical analysis led to the conclusion that oxygen atoms are crucial in decomposing perfluoroalk-1-enes, especially the stable perfluorohept-1-ene (C7F14). Under oxidative conditions, it was found that significant quantities of C2F6 and CF4 were formed. Further quantum chemical analysis suggests that the O atoms facilitate the formation of volatile fluorinated compounds (VFCs) such as tetrafluoromethane (CF4) and hexafluoroethane (C2F6), particularly at higher temperatures. By elucidating these key reactions, an improved understanding of the potential formation products of incomplete combustion (PICs) or products of incomplete destruction (PIDs) is made.

Effects of Various Flavors of Baijiu on the Microbial Communities, Metabolic Pathways, and Flavor Structures of Dongbei Suancai.

This study aimed to assess the effects of Chinese Baijiu with different flavors as supplementary material on microbial communities and flavor formation during inoculated fermentation of Chinese Dongbei Suancai. The results showed that the addition of Fen flavor Baijiu significantly increased the relative abundance of Candida, Luzhou flavor Baijiu increased the relative abundance of Pedobacter and Hannaella, while Maotai flavor Baijiu increased the Chryseobacterium and Kazachstania. A total of 226 volatile metabolites were detected in Suancai fermented when adding different flavors of Baijiu. Furthermore, the significantly upregulated metabolites (p < 0.01) of Suancai after adding Baijiu increased by 328.57%, whereas the significantly downregulated metabolites decreased by 74.60%. Simultaneously, the addition of Baijiu promoted the synthesis and decomposition of amino acids and short-chain fatty acids in the early and middle stages of fermentation. Further, Maotai flavor Baijiu improved the diversification of metabolic pathways in the late stage of Suancai fermentation. The E-nose response showed that sulfur-organic, broad-alcohol, sulfur-chlor was the principal differential flavor in Suancai caused by adding Baijiu with different flavors. Simultaneously, Fen flavor Baijiu and Luzhou flavor Baijiu accelerated the formation of the Suancai flavor. These results indicated that Baijiu with different flavors had significant effects on the flavor formation of inoculated fermented Suancai.

Antibiotics affect the pharmacokinetics of n-butylphthalide in vivo by altering the intestinal microbiota.

N-butylphthalide (NBP) is a monomeric compound extracted from natural plant celery seeds, whether intestinal microbiota alteration can modify its pharmacokinetics is still unclear. The purpose of this study is to investigate the effect of intestinal microbiota alteration on the pharmacokinetics of NBP and its related mechanisms. After treatment with antibiotics and probiotics, plasma NBP concentrations in SD rats were determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The effect of intestinal microbiota changes on NBP pharmacokinetics was compared. Intestinal microbiota changes after NBP treatment were analyzed by 16S rRNA sequencing. Expressions of CYP3A1 mRNA and protein in the liver and small intestine tissues under different intestinal flora conditions were determined by qRT-PCR and Western Blot. KEGG analysis was used to analyze the effect of intestinal microbiota changes on metabolic pathways. Compared to the control group, the values of Cmax, AUC0-8, AUC0-∞, t1/2 in the antibiotic group increased by 56.1% (P<0.001), 56.4% (P<0.001), 53.2% (P<0.001), and 24.4% (P<0.05), respectively. In contrast, the CL and Tmax values decreased by 57.1% (P<0.001) and 28.6% (P<0.05), respectively. Treatment with antibiotics could reduce the richness and diversity of the intestinal microbiota. CYP3A1 mRNA and protein expressions in the small intestine of the antibiotic group were 61.2% and 66.1% of those of the control group, respectively. CYP3A1 mRNA and protein expressions in the liver were 44.6% and 63.9% of those in the control group, respectively. There was no significant change in the probiotic group. KEGG analysis showed that multiple metabolic pathways were significantly down-regulated in the antibiotic group. Among them, the pathways of drug metabolism, bile acid biosynthesis and decomposition, and fatty acid synthesis and decomposition were related to NBP biological metabolism. Antibiotic treatment could affect the intestinal microbiota, decrease CYP3A1 mRNA and protein expressions and increase NBP exposure in vivo by inhibiting pathways related to NBP metabolism.

Development of a flow photocatalytic reactor for the photodecomposition of Ga(III) complexes and recovery of free Ga(III) radioisotopes

This report describes the development and application of a flow photocatalytic reactor for the effective photodecomposition of organic compounds and the recovery of a targeted metal ion; specifically, we describe the decomposition of a gallium-ethylenediaminetetraacetic acid (Ga-EDTA) complex. The system includes a scrubber, which increases the amount of dissolved oxygen in the solution before entering the photocatalytic reactor. First, the decomposition efficiency of the developed reactor is evaluated using dimethyl sulfoxide (DMSO). The decomposition of DMSO is accelerated upon introducing oxygen from the scrubber into the flowline. Second, we employ this system for the decomposition of Ga-EDTA and evaluate the recovery of a Ga radioisotope (RI), which can serve as a probe in positron emission tomography for medical diagnoses. The byproducts generated during Ga-EDTA photodecomposition are monitored by capillary electrophoresis, and the released Ga3+ concentrations are determined by inductively coupled plasma atomic emission spectroscopy for the stable isotope of Ga and with a scintillation detector for RI-Ga. After 30 min under ultraviolet irradiation, 54 % of the RI-Ga released during the photodecomposition of RI-Ga-EDTA was recovered.

Prehydrated Electrons Activated by Continuous Electron Transfer Stemmed from Peracetic Acid Homolysis Mediated by Diamond Surface Defects for Enhanced PFOA Destruction.

Research on the use of peracetic acid (PAA) activated by nonmetal solid catalysts for the removal of dissolved refractory organic compounds has gained attention recently due to its improved efficiency and suitability for advanced water treatment (AWT). Among these catalysts, nanocarbon (NC) stands out as an exceptional example. In the NC-based peroxide AWT studies, the focus on the mechanism involving multimedia coordination on the NC surface (reactive species (RS) path, electron reduction non-RS pathway, and singlet oxygen non-RS path) has been confined to the one-step electron reaction, leaving the mechanisms of multichannel or continuous electron transfer paths unexplored. Moreover, there are very few studies that have identified the nonfree radical pathway initiated by electron transfer within PAA AWT. In this study, the complete decomposition (kobs = 0.1995) and significant defluorination of perfluorooctanoic acid (PFOA, deF% = 72%) through PAA/NC has been confirmed. Through the use of multiple electrochemical monitors and the exploration of current diffusion effects, the process of electron reception and conduction stimulated by PAA activation was examined, leading to the discovery of the dynamic process from the PAA molecule → NC solid surface → target object. The vital role of prehydrated electrons (epre-) before the entry of resolvable electrons into the aqueous phase was also detailed. To the best of our knowledge, this is the first instance of identifying the nonradical mechanism of continuous electron transfer in PAA-based AWT, which deviates from the previously identified mechanisms of singlet oxygen, single-electron, or double-electron single-path transfer. The pathway, along with the strong reducibility of epre- initiated by this pathway, has been proven to be essential in reducing the need for catalysts and chemicals in AWT.

Effect of Annealing Temperature on Thermal Behaviour and Crystallinity of Zinc Oxide Supported Magnesium Aluminate (ZnO/MgAl2O4) Via Green Synthesis One Pot Fusion

Zinc oxide-supported magnesium aluminate (ZnO/MgAl2O4) was synthesized by the one-pot fusion method, consuming magnesium nitrate, aluminum nitrate, and citric acid as starting precursors. The samples prepared were annealed at temperatures ranging from 700 to 900°C to study the influence of annealing temperature on thermal behaviour and crystalline properties. The thermal behaviour of ZnO/MgAl2O4 was characterized by thermogravimetric analysis (TGA), while the structural properties and crystalline phase of ZnO/MgAl2O4 were analysed by X-ray diffraction (XRD). The TGA results show that there were three stages of decomposition in the sample. The first stage indicates the removal of water content from the sample; the second stage indicates the decomposition of citric acid; and the third stage represents the crystallization phase formation at a temperature range of 800- 950°C. The percentage of citric acid decomposition increases with increasing annealing temperatures up to 800°C. However, the decomposition rate gradually reduces at annealing temperatures between 850 and 900°C. XRD analysis results suggest that microstructured ZnO/MgAl2O4 with high crystallinity can be obtained at the highest annealing temperature. It can be concluded that the result of thermal behaviour represented by the decomposition stage is corroborated with structural and crystalline properties at increasing annealing temperatures.

Soil nitrogen and phosphorus regulate decomposition of organic nitrogen compounds in the rothamsted experiment

The effects of long-term N and P fertilisation on soil organic nitrogen (SON) turnover are unclear. We sampled soils fertilised by N and/or P since 1843 at Rothamsted Research to investigate the effects of long-term N and P fertilisation on high- or low-molecular-weight SON decomposition and gross N mineralisation. Short-term assays with added 14C-labelled proteins, peptides, and amino acids and gross organic N mineralisation were measured, and the microbial communities and functions were also assessed in parallel. Long-term N fertilisation increased the contents of soil extractable organic N and peptides but decreased organic N-hydrolysing enzyme activities (N-acetyl-β-D-glucosaminidase and leucine aminopeptidase). Fertilisation with P and N accelerated and reduced the decomposition of 14C-labelled organic N compounds, respectively. The decomposition of peptides and amino acids, as labile SON components, was mainly regulated by soil P content because microbial biomass and activity were more sensitive to P fertilisation than to N fertilisation. Gross NH4+/NO3− production and consumption were accelerated by 41%–60% under N fertilisation but remained unchanged under P fertilisation compared to the unfertilised treatment. Metagenomic sequencing showed that N fertilisation increased microbial diversity and enriched functional genes associated with organic N decomposition, compared to the unfertilised treatment. P fertilisation had no effect on the abundance of these functional genes. In agricultural practices, it is essential to comprehensively consider the interaction between N and P fertilisation to optimise the cycling and utilisation of SON.

Hepatoprotective effects and mechanisms of l-theanine and epigallocatechin gallate combined intervention in alcoholic fatty liver rats.

Chronic excessive alcohol consumption can lead to alcoholic fatty liver, posing substantial health risks. l-Theanine (LTA) and epigallocatechin gallate (EGCG) in tea exert antioxidant and hepatoprotective effects. However, the combined effects of LTA and EGCG on rats with alcoholic fatty liver, and the underlying mechanisms of such effects, remain unclear. In this study, Sprague Dawley (SD) rats were fed with alcohol for 6 weeks to induce alcoholic fatty liver. Subsequently, for another 6 weeks, the rats were administered LTA (200 mg kg-1 day-1), EGCG (200 mg kg-1 day-1), or a combination of LTA with EGCG (40 mg kg-1 day-1 l-Thea +160 mg kg-1 day-1 EGCG), respectively. The combined use of LTA and EGCG for alcoholic fatty liver disease had more significant effects than their individual administration. This combination reduced the activity of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) as well as the levels of hepatic triglyceride (TG), malondialdehyde (MDA), and reactive oxygen species (ROS) in the rats. The combined intervention also increased hepatic superoxide dismutase (SOD) and glutathione peroxidase activity. Reductions in hepatic fat accumulation and inflammatory responses were observed. The mechanism underlying these effects primarily involved the inhibition of fatty acid synthesis and the alleviation of lipid peroxidation through the downregulation of the mRNA and protein expression of TNF-α, SREBP1c, and CYP2E1 and the upregulation of the mRNA and protein expression of ADH1, ALDH2, Lipin-1, PPARαPPARα, AMPK, and PGC-1α, thereby promoting the oxidative decomposition of fatty acids and reducing the synthesis of cholesterol and glucose. l-Theanine and EGCG appear to be able to alleviate alcoholic fatty liver by modulating lipid metabolism and ameliorating oxidative stress, indicating their potential as natural active ingredients in anti-alcoholic fatty liver food products. © 2024 Society of Chemical Industry.