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This paper presents a novel dispersive liquid–liquid microextraction (DLLME) method that employs solidified hydrophobic deep eutectic solvent (DES) with hydrophilic DES acting as the dispersant. The aim is to enrich polychlorinated biphenyls (PCBs) from water samples for subsequent determination by gas chromatography–mass spectrometry. The effects of both the hydrophobic DES as the extractant and the hydrophilic DES as the dispersant were thoroughly investigated. Optimization of the key factors influencing extraction efficiency was performed, and the method was subsequently validated. Specifically, a hydrophobic DES called DES2, prepared by combining thymol and decanoic acid in a molar ratio of 3:2, was selected as the extraction solvent. Meanwhile, a hydrophilic DES named DES6, prepared from choline chloride and acetic acid in a molar ratio of 1:2, was chosen as a dispersant. Under the optimal extraction conditions, the developed method exhibited excellent linearity over the concentration range of 0.01–5.0 µg/L, low limits of detection ranging from 3.0 to 5.1 ng/L, relative standard deviations less than 4.1%, and enrichment factors between 182 and 204 for PCBs. Finally, the effectiveness of the developed method was successfully demonstrated through residue determination of PCBs in water samples. [ABSTRACT FROM AUTHOR]

In this paper, the method for the fabrication of nanofibers based on poly(vinyl alcohol) (PVA) with controlled characteristics and surface morphology from binary solvent systems has been developed. Based on the Hildebrand–Scatchard theory of solubility, the calculated Teas diagrams, which take into account intermolecular interactions, made it possible to predict the formation of low-defect nanofibers based on PVA in systems of binary solvents with a higher proportion of hydrogen bonds. As a result of the findings, ethanol was determined to be a "inappropriate" solvent for the electrospinning PVA solution, whereas water and acetic acid displayed the properties of a "appropriate" solvent. The decrease in the volume of the unit cell with a slight decrease in the overall degree of crystallinity of the substance demonstrated the dependence of the change in the crystallization mechanism during the formation of PVA nanofibers on the transition from an individual aqueous polymer solution to the water/acetic acid binary solvent system. Compared with the results obtained during the PVA nanofibers fabrication from aqueous solution, the addition of 35% by weight of acetic acid to the aqueous solution of 8 wt% PVA allowed to lower the voltage from 30 to 26 kV and to increase the fiber fabrication yield by the increase in the flow rate from 0.2 to 0.3 mL/h. We confirmed that acetic acid has no effect on the chemical properties of PVA nanofibers however did change their lattice structure and reduce crystallinity of nanofibers. Such safe systems with controlled properties are suitable ones for biological active compounds encapsulation for drug delivery. [ABSTRACT FROM AUTHOR]

Several cottonseed varieties are cultivated in different countries. Each variety produces a different amount of gossypol as a natural toxic compound. The rising interest in cottonseed products (oil and feed) increases the demand for establishing simple methods for gossypol detection. Silica gel-based methods are ideal for its isolation, purification, and characterization. Silica gel-based methods are variants and can be used as simple methods for tracking plants' compounds. In this study, gossypol was isolated, characterized, and purified as gossypol acetic acid in the form of yellow crystals. Methods used for its characterization were TLC, preparative TLC, silica gel column, UV/IR spectrophotometer, and HPLC (robust spherical silica gel). A comparative study between its amount in both the Egyptian and Chinese varieties was performed. Under the experimental conditions, the Egyptian's cottonseed contains 8.705 gm/kg, while the Chinese's cottonseed contains 5.395 gm/kg. The TLC used in this study proved to be fast, accurate, and inexpensive. It can be used for gossypol acetic acid evaluation and quantification. Additionally, using TLC as a pre-purification step will give a pre-judgment for the sample's purity and quality. This step will protect the expensive HPLC silica gel-based column from any unexpected impurities. During each step, the silica gel itself could be simply removed by paper filtration. Collectively, the different silica gel-based methods as well as the other used methods are recommended for better Gossypol acetic acid isolation, purification, and characterization, as well as for maintaining HPLC columns. [ABSTRACT FROM AUTHOR]

Identifying key flavor compounds and their producing bacteria in sour bamboo shoots is crucial for flavor stabilization and industrial production. This study analyzed 15 traditional sour bamboo shoot samples from northern Guangdong to determine key flavor substances and microbial community. Results showed key flavor substances were acetic acid (RTC ≥ 50% in 10 samples), lactic acid (RTC ≥ 50% in 5 samples), and p-cresol (ROC ≥ 93%). Lactobacillus (ARA: 54.62%) was the dominant genus, significantly correlated with p-cresol (r = 0.80, p ≤ 0.01). Levilactobacillus (ARA: 3.33%) was positively correlated with lactic acid and p-cresol (r = 0.78, p ≤ 0.01; r = 0.66, p ≤ 0.01). Lentilactobacillus (ARA: 4.29%) was positively correlated with acetic acid (r = 0.85, p ≤ 0.01). Levilactobacillus was isolated, screened, identified, and its ability to produce key flavor substances was tested. Four strains of Levilactobacillus spicheri and their mixed strains produced lactic acid (10.12-16.62 g/kg), acetic acid (10.21-21.60 g/kg), and p-cresol (25.67-143.87 mg/kg). This is the first report of Levilactobacillus spicheri producing p-cresol., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome. RIFM staff are employees of the Research Institute for Fragrance Materials, Inc. (RIFM). The Expert Panel receives a small honorarium for time spent reviewing the subject work.

Bacterial cellulose (BC) is a remarkable biomacromolecule with potential applications in food, biomedical, and other industries. However, the low economic feasibility of BC production processes hinders its industrialization. In our previous work, we obtained candidate strains with improved BC production through random mutations in Gluconacetobacter. In this study, the molecular identification of LYP25 strain with significantly improved productivity, the development of chestnut pericarp (CP) hydrolysate medium, and its application in BC fermentation were performed for cost-effective BC production process. As a result, the mutant strain was identified as Gluconacetobacter xylinus. The CP hydrolysate (CPH) medium contained 30 g/L glucose with 0.4 g/L acetic acid, whereas other candidates known to inhibit fermentation were not detected. Although acetic acid is generally known as a fermentation inhibitor, it improves the BC production by G. xylinus when present within about 5 g/L in the medium. Fermentation of G. xylinus LYP25 in CPH medium resulted in 17.3 g/L BC, a 33 % improvement in production compared to the control medium, and BC from the experimental and control groups had similar physicochemical properties. Finally, the overall process of BC production from biomass was evaluated and our proposed platform showed the highest yield (17.9 g BC/100 g biomass)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Bacterial cellulose (BC) has been widely applied in various fields due to its excellent physicochemical properties, but its high production cost remains a challenge. Herein, the present study aimed to utilize the hydrolysate of vinegar residue (VR) as the only medium to realize the cost-effective production of BC. The BC production was optimized by the single-factor test. The treatment of 6 % VR concentration with 3 % acid concentration at 100 °C for 1.5 h and 96 U/mL of cellulase for 4 h at 50 °C obtained a maximum reducing sugar concentration of about 32 g/L. Additionally, the VR hydrolysate treated with 3 % active carbon (AC) at 40 °C for 0.5 h achieved a total phenol removal ratio of 86 %. The yield of BC reached 2.1 g/L under the optimum conditions, which was twice compared to the standard medium. The produced BC was characterized by SEM, FT-IR, XRD, and TGA analyses, and the results indicated that the BC prepared by AC-treated VR hydrolysate had higher fiber density, higher crystallinity, and good thermal stability. Furthermore, the regenerated BC (RBC) fibers with a tensile stress of 400 MPa were prepared successfully using AmimCl solution as a solvent by dry-wet-spinning method. Overall, the VR waste could be used as an alternative carbon source for the sustainable production of BC, which could be further applied to RBC fibers preparation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

We evaluated the suitability of Komagataeibacter europaeus, a vinegar production organism adept at synthetic media growth, as a host for heterologous gene expression. Cryptic plasmids (pGE1 and pGE2 derivatives) from K. europaeus strain KGMA0119 were employed as vectors for heterologous gene expression. The focus was placed on the groES promoter as a potential inducible switch. The groES promoter was fused with the EGFP gene and introduced into a pGE1 derivative to assess its suitability. Ethanol, acetic acid, and heat stresses were examined under various conditions for induction. EGFP transcription surged 600-fold when late logarithmic phase K. europaeus cells, cultured at 30 °C, endured heat stress at 40 °C, coupled with 20% acetic acid and 30% ethanol stress after an additional 6-hour cultivation. This robust induction system was then applied to express two proteins, Tth pol from the thermophilic bacterium Thermus thermophilus strain M1 and UPV230, a restriction enzyme from the acid-tolerant microorganism Ureaplasma parvum, known to cause vaginal infections and miscarriages. Both Tth pol and UPV230 were successfully expressed in K. europaeus cells and purified. The recovery of Tth pol from K. europaeus cells (480 µg protein per liter culture) was approximately half that from E. coli (960 µg protein per liter culture). In contrast, UPV230 recovery from K. europaeus cells (640 µg protein per liter culture) was nearly 10 times higher than that from Escherichia coli (66 µg protein per liter). The data highlights the potential of acetic acid bacteria as a host for producing acidophilic proteins. The shift in recognition from a 6-base sequence to a 4-base sequence of UPV230 was observed, accompanied by a change in structure as the pH transitioned from acidic pH to near-neutral pH., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Shinsuke Fujiwara reports financial support was provided by Japan Agency for Medical Research and Development (AMED) JP23fk0108677. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Traditional bran vinegar brewing unfolds through natural fermentation, a process driven by spontaneous microbial activity. The unique metabolic activities of various microorganisms lead to distinct flavors and qualities in each batch of vinegar, making it challenging to consistently achieve the desired characteristic flavor compounds. Therefore, identifying the critical microbial species responsible for flavor production and designing starter cultures with improved fermentation efficiency and characteristic flavors are effective methods to address this discrepancy. In this study, 11 core functional microbial species affecting the fermentation flavor of Sichuan shai vinegar (Cupei were placed outside solarization and night-dew for more than one year, and vinegar was the liquid leached from Cupei) (SSV), were revealed by combining PacBio full-length diversity sequencing based on previous metagenomics. The effects of environmental factors and microbial interactions on the growth of 11 microorganisms during fermentation were verified using fermentation experiments. Ultimately, the microbial community was strategically synthesized using a 'top-down' approach, successfully replicating the distinctive flavor profile of Sichuan shai vinegar (SSV). The results showed that the interaction between microorganisms and environmental factors affected microorganism growth. Compared with traditional fermentation, the synthetic microbial community's vinegar-fermented grains (Cupei) can reproduce the key flavor of SSV and is conducive to the production of amino acids. In this study, the key flavor of SSV was reproduced through rational design of the synthetic microbial community. This achievement holds profound significance for the broader application of microbiome assembly strategies in the realm of fermented foods., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Copyright of Journal of Hebei University of Science & Technology is the property of Hebei University of Science & Technology, Journal of Hebei University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Crude oil gasification bacteria, including fermenting bacteria, hydrocarbon-oxidizing bacteria, reducing bacteria, and methanogenic bacteria, participate in multi-step reactions involving initial activation, intermediate metabolism, and the methanogenesis of crude oil hydrocarbons. These bacteria degrade crude oil into smaller molecules such as hydrogen, carbon dioxide, acetic acid, and formic acid. Ultimately, they convert it into methane, which can be utilized or stored as a strategic resource. However, the current challenges in crude oil gasification include long production cycles and low efficiency. This paper provides a summary of the microbial flora involved in crude oil gasification, the gasification metabolism pathways within reservoirs, and other relevant information. It specifically focuses on analyzing the factors that affect the efficiency of crude oil gasification metabolism and proposes suggestions for improving this efficiency. These studies deepen our understanding of the potential of reservoir ecosystems and provide valuable insights for future reservoir development and management. [ABSTRACT FROM AUTHOR]

In this paper, MFe2O4 nanoparticles (M = Ca, Mg) are synthesized by sol– gel method using different stabilizer (acetic acid, pectin and β- carrageenan). The stability of the formed gel is studied extensively by determining the affective conditions (type of stabilizer, molar ratio of stabiliser: M(OH)2:Fe(OH)3, time, and temperature) on the preparation process. The most stabilized gel obtained using β-carrageenan for both Ca, Mg with (1.2·10-2:1:2), (1.37·10-2:1:2) molar ratios, respectively, during 72 h at 25°C. The obtained gel is calcinated and analysed using DTA, XRD and IR spectroscopy. The results show that the calcium ferrite is formed at 493.2°C by orthorhombic lattice cell with particle size of 13.01 nm and the magnesium ferrite is formed at 621.4°C by cubic crystal phase with particle size of 15.93 nm. [ABSTRACT FROM AUTHOR]

The total synthesis of laurolitsine was achieved for the first time. This reaction was accomplished in 14 steps with a 2.3% yield (this was calculated using 3-hydroxy-4-methoxybenzaldehyde as the starting material) starting from two simple materials, 3-hydroxy-4-methoxybenzaldehyde and 2-(3-hydroxy-4-methoxyphenyl)acetic acid, and the longest linear sequence consisted of 11 steps. The key steps included an electrophilic addition reaction in which a nitro group was reduced to an amino group using lithium tetrahydroaluminum and a Pd-catalyzed direct biaryl coupling reaction. In this paper, many of the experimental steps were optimized, and an innovative postprocessing method in which 2-(3-(benzyloxy)-4-methoxyphenyl)ethanamine is salted with oxalic acid was proposed. [ABSTRACT FROM AUTHOR]

Organo chemo sensors were used to detect fluoride ions in water samples and were synthesized by mixing two compounds in a 1:1 ratio with constant stirring for two hours using a stirrer with the addition of acetic acid and ethanol. The products were checked for a single spot using TLC paper. The experiment was taken further for the detection of fluoride ions by making a solution of chemo sensor and water sample at a 1:2 ratio and checked using a spectrophotometer and colorimeter. The values of absorbance were then compared with the standard solution containing fluoride ions. The formation of H - F bonding between the chemo sensors and fluoride ions in the water samples was confirmed. The results indicate the presence of fluoride ions in terms of ppm in the different water samples taken. [ABSTRACT FROM AUTHOR]

In this work, an innovative fiber-optic sensor for measuring total acidity (TA: expressed as the % w/v of acetic acid) in beverages was developed. For this purpose, we relied on the kinetic principles of heterogeneous solid-phase reactions (slow reactions due to diffusion processes) to develop a novel pH-sensitive fluorescent membrane calibration method for the quantification of TA. In the proposed calibration method, a linear relationship between TA and the protonation rate of a pH-sensitive fluorescent membrane with a pKa ≥ 9 (Paper-FM) is established. Paper-FM was synthesized by the covalent immobilization of the pH-probe Nile Blue on a porous paper membrane. In addition, a 3D-printed interface was designed to implement Paper-FM into a 0.5 mm diameter optical fiber. The fiber-optic sensor developed in this work was tested by analyzing 21 vinegar samples of different origins, and the results were successfully validated with a reference titration method. The results presented in this work show that our fiber-optic sensor allows a direct, simple, and fast (15 s response time) quantification of TA in vinegar samples. In addition, it is environmentally friendly, because, unlike titration methods, it does not generate toxic waste, is reversible, and is extremely stable (a 0.9 mm diameter circle of Paper-FM allows at least 50 consecutive measurements). [Display omitted] • A pH-fluorescent membrane was designed and implemented into a fiber-optic device. • A novel calibration strategy of a fluorescent pH-membrane was developed. • The total acidity of real food samples was successfully determined. • The fiber-optic sensor is reversible and reusable. • The fiber-optic sensor is environmentally friendly as it does not generate waste. [ABSTRACT FROM AUTHOR]

In this study, UiO-66-NH2 nanoparticles were synthesized via a hydrothermal method, using acetic acid and hydrochloric acid as modulators to optimize the specific surface area and pore width. Oxytetracycline (OTC) was chosen as the test compound to evaluate the adsorption efficiency of UiO-66-NH2.The material was thoroughly characterized under varying conditions, and the adsorption mechanism was systematically explored through adsorption kinetics, isotherms, and thermodynamic analyses. The results demonstrated that UiO-66-NH2 exhibited a high OTC adsorption capacity, achieving a maximum of 312.5 mg g−1 under optimal conditions. XRD, TGA, and BET analyses revealed that acetic acid and hydrochloric acid significantly improved the crystallinity and thermal stability of UiO-66-NH2, increasing the specific surface area from 8.023 m2 g−1 to 998.663 m2 g−1 and reducing the pore width from 18.783 nm to 2.129 nm. FTIR, XPS, adsorption kinetics, and isotherm studies indicated that the main forces driving OTC adsorption by CMC-Fe were hydrogen bonding, π–π stacking, weak electrostatic interactions, and pore filling. Cyclic adsorption experiments further demonstrated the excellent reusability of UiO-66-NH2. In summary, the use of acetic acid and hydrochloric acid significantly increased the specific surface area of UiO-66-NH2, exposing more adsorption sites and playing a critical role in pollutant removal. [ABSTRACT FROM AUTHOR]

In this paper, Bi2212 superconducting thin films were prepared with metal acetate as salt source and a mixture of acetic acid and N,N-dimethylformamide (DMF) as solvent. The volatilization process of the solvent was regulated by changing the ratio of the mixed solvent, which in turn achieved the regulation of the surface morphology and crystallinity of the Bi2212 superconducting films. The mechanism of the mixed solvents on the crystallinity and surface quality of Bi2212 superconducting films was systematically investigated. The results showed that the Bi2212 superconducting films were all (00 l) epitaxial growth. The grain size of Bi2212 increased continuously with the increase of the proportion of acetic acid in the solvents. The grain size of the largest grain size was 43.8 nm when the proportion of acetic acid was 80 %. However, the high proportion of acetic acid in the mixed solvents reduced the surface quality of Bi2212 thin films. The minimum surface roughness was 15.0 nm at 40 % acetic acid. All the samples exhibited good superconducting properties. This work provides a research basis for the systematic preparation of multicomponent oxide thin films. [ABSTRACT FROM AUTHOR]

Three new molecular cobaloxime complexes with the general formula [ClCo(dpgH)2L] (1–3), where L1 = N-(4-pyridylmethyl)-1,8-naphthalimide, L2 = 4-bromo-N-(4-pyridylmethyl)-1,8-naphthalimide, L3 = 4-piperidin-N-(4-pyridylmethyl)-1,8-naphthalimide, have been synthesized and characterized by UV-Vis, multinuclear NMR, FT-IR and PXRD spectroscopic techniques. The crystal structures of all complexes have also been reported. The electrocatalytic activity of complexes is investigated under two catalysis conditions: (i) homogeneous conditions in acetonitrile using acetic acid (AcOH) as a proton source and (ii) heterogeneous conditions upon immobilization onto the surface of activated carbon cloth (CC). Complex 3 exhibited high electrocatalytic HER activity under both homogeneous and heterogeneous conditions. It catalyses proton reduction to molecular hydrogen in acetonitrile solution at a lower overpotential (640 mV) with a high turnover frequency (TOF) of 524.57 s−1 and demonstrates good stability in acidic conditions. Furthermore, catalytic (working) electrodes are prepared by immobilizing the complexes onto the surface of activated carbon cloth (CC) for electrocatalytic HER under heterogeneous conditions. An impressive HER performance was again obtained with catalytic electrode 3@CC in 1.0 M KOH, achieving a current density of −10 mA cm−2 at an overpotential of 262 mV. Chronoamperometric (CA) studies showed no significant decay of the initial current density for 10 h, indicating the excellent stability of 3@CC. Additionally, UV-Vis and NMR spectral studies of the recovered catalyst after electrocatalysis revealed no structural changes, demonstrating its robustness under reaction conditions. [ABSTRACT FROM AUTHOR]

Glass durability is one of the properties that can be affected by surface treatments such as coatings or chemical attacks. These treatments can be used to reduce the quantities of potentially toxic elements contained in glass that may be released in solution. Five surface treatments were selected: three different coatings (SnO2, TiO2, SiO2) and two acidic attacks (SO2 dealkalization and acid polishing). These treatments were performed on five glass compositions (soda-lime, borosilicate, barium silicate, opal, and lead crystal). Their effects on alteration rates and mechanisms were investigated through a single protocol (acetic acid 4%, 70 °C) simulating accelerated aging conditions for containers of beverages or food. The data collected over 1.3 years showed significant reduction of lead leaching with all treatments except acid polishing. The best reduction factor was obtained with SO2 dealkalization, which also demonstrated beneficial effects towards the retention of Ba by reducing the diffusion of alkalis. [ABSTRACT FROM AUTHOR]

Copyright of China Fiber Inspection / Zhongguo Xian-Jian is the property of China Fiber Inspection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work focuses on the use of the deep eutectic solvent composed of choline chloride and acetic acid (1 : 2) in the pretreatment of the perennial energy crop Miscanthus, commonly called silvergrass. The pretreatment time and temperature were optimized to achieve a maximum of the glucan and minimum of the lignin contents in the pretreated biomass. In the optimization approach, the maximal glucan recovery in the pretreated solid was also considered. The performed optimization resulted in conditions (2 h 52 min and 150 °C), at which a pretreated biomass contained 74.1 wt% and 9.5 wt% of glucan and lignin respectively, and a glucan recovery was as high as 87.0 wt%. Furthermore, the biocompatibility of deep eutectic solvent was evaluated by using enzymatic hydrolysis washed and unwashed pretreated biomass produced at optimal conditions. The enzymatic hydrolysis of washed biomass resulted in higher glucan and xylan conversion than those achieved from unwashed biomass, deeming the step of biomass washing necessary. This was confirmed by the fractal kinetics modelling that confirmed higher accessibility of glucan for washed biomass than for unwashed Miscanthus sample. [ABSTRACT FROM AUTHOR]

In this paper, a two‐step process is described for the chemoselective synthesis of highly fluorescent polycyclic chromeno[4,3,2‐ij]isoquinoline‐3‐carbonitriles using a sequential nucleophilic addition reaction involving 4‐chloro‐3‐vinyl coumarins, α,α‐dicyanoolefins and ammonium acetate as a source of nitrogen. In this process, it is believed that ammonium acetate is converted into ammonia and acetic acid during the reaction. Ammonia is the source of nitrogen, and the acid produced can catalyze the progress of the reaction. Single‐crystal X‐ray analysis was performed to confirm the structure of one of the typical products. In addition, the photophysical characteristics of the product 3 a were investigated through absorption and emission spectroscopy. This analysis reveals that the new heterocyclic system has impressive fluorescence characteristics. Several advantages of the presented synthetic strategy can be found in its simplicity, readily available starting materials, high‐efficiency products, highly chemoselective route, metal‐free catalyst, and ability to purify products by washing them with EtOH (96 %), a technique called GAP (Group‐Assisted‐Purification) chemistry. [ABSTRACT FROM AUTHOR]

In this study, UiO‐66 was employed for the first time as an adsorbent to separate phenolic acid analogues, specifically 4‐hydroxyisophthalic acid and salicylic acid, from impurities. Synthesized in‐house, UiO‐66 was shown to exhibit high selectivity towards 4‐HIPA/4‐HBA and SA/4‐HBA when a molar equivalent of acetic acid modulator to terephthalic acid was set at 44. The adsorption capacities for 4‐HBA, 4‐HIPA, and SA were determined to be 56.34, 55.02, and 60.34 mg/g, respectively. Furthermore, it was observed that after six regeneration cycles, the adsorption capacity for 4‐HBA remained nearly unchanged, whereas those for 4‐HIPA and SA decreased by 5.6% and 2.6%, respectively. FTIR and XPS analyses revealed that all three compounds were adsorbed at the same dominant Zr cluster site on UiO‐66, primarily through hydrogen bonding and electrostatic interaction. Dynamic adsorption experiments revealed that 4‐HBA was the first to elute, maintaining the residual contents of 4‐HIPA and SA below 0.1 wt%. Compared to traditional separation techniques, this paper provided a simple and effective method to purify industrial grade 4‐hydroxybenzoic acid. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to examine the shear bond strength (SBS) of repair material to conventionally, subtractive‐, and additive‐manufactured denture bases after different surface treatments. Materials and Methods: Disk‐shaped test specimens (N = 300) were prepared from denture base materials produced by one conventional (Procryla), one subtractive (Yamahachi), and one additive (Curo Denture) method. The test specimens were randomly divided into five groups (n = 10) and exposed to a variety of surface treatments—Group A: no surface treatment; Group B: grinding with silicon carbide paper; Group C: sandblasting; Group D: erbium: yttrium‐aluminum‐garnet laser; and Group E: plasma. Repair was performed with autopolymerizing acrylic resin (Meliodent). Surface roughness analyses were performed with a profilometer. Scanning electron microscopy was used to examine one specimen from each subgroup. SBS was evaluated on a universal testing machine. Failure types were observed under a stereomicroscope. Results: Surface roughness values were significantly higher in all test materials in Group D than in the other groups (p < 0.001). For conventional resin, the SBS values were higher in Group C than in Groups A, D, and E (p < 0.001). For CAD/CAM material, Groups B and C had significantly greater SBS increases compared with Group E (p < 0.001). For 3D material, Group D showed higher SBS than all groups except Group C (p < 0.001). Conclusions: For SBS, sandblasting was most effective in the conventional group, whereas laser treatment was the most effective in the additive‐manufactured group. For the subtractive group, surface treatments other than plasma exhibited similar SBS. Clinical Significance: In repairing fractured prostheses, any degree of roughening suitable for the material content may provide an SBS benefit. [ABSTRACT FROM AUTHOR]

Mole fraction solubilities are reported for (2-nitrophenyl)acetic acid dissolved in 1-pentanol, 1-heptanol, 1-octanol, 2-butanol, 3-methyl-1-butanol, 2-pentanol, 4-methyl-2-pentanol, cyclopentanol, 2-ethoxyethanol, 2-propoxyethanol, 2-isopropoxyethanol, 1,4-dioxane, methyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, tert-butyl acetate, pentyl acetate, methyl butyrate, dimethyl adipate and propanenitrile at 298.15 K. Solubilities were determined using a spectrophotometric method of chemical analysis. Experiment-based Abraham model solute descriptors are calculated for the molecular, monomeric form of (2-nitrophenyl)acetic acid by combining our experimental values with the published solubility data obtained from the published paper by Zhou and co-workers. The calculated solute descriptors describe the observed solubility data to within an overall standard deviation of 0.10 log units. [ABSTRACT FROM AUTHOR]

Both of sulfone compounds and isoqunoline derivatives are important compounds. In this paper, Isoquinoline C1 and C3 Sulfone compounds have been synthesized by electrochemical means using isoquinoline N‐Oxides and some sodium benzenesulfinate as reactants, inexpensive and easily available sodium iodide as electrolytes, and a mixture of acetonitrile, water and acetic acid as reaction solvents. By using the method, a series of isoquinoline sulfone compounds have been synthesized in high yields. The reaction does not need oxidants and catalysts, and the reaction conditions are mild, environmentally friendly, efficient and suitable. In addition, we also carried out ALS enzyme inhibition experiments on the synthesized isoquinoline sulfone compounds, six of the isoquinoline sulfone compounds synthesized herein were found to inhibit ALS enzyme at a high rate, four of them inhibited ALS enzyme at a rate comparable to that of the commercialized herbicides Halosulfuron and Broadstrike, and the other two compounds also inhibited ALS enzyme at a rate higher than that of Halosulfuron and Broadstrike. Therefore, it is possible to find lead compounds with good herbicidal activity potential from these 6 compounds. [ABSTRACT FROM AUTHOR]

Acetic acid (AA) is an organic acid and has been widely used as food preservative and a dietary spice in vinegar form. In addition to its therapeutic uses in its vinegar form, AA attenuates inhibitory effects of stress in plants. However, in some plant species toxic effects of AA have been found. Therefore, in this study, 0, 2.5 and 5 mM concentrations of AA were applied to 2-day-old barley (Hordeum vulgare L. cv. Bornova-92) seedlings for 2 days in order to investigate the possible toxic effects of AA. After treatments, seedlings were grown in AA-free conditions for 2 days to recover. AA inhibited root and shoot growth; decreased water content, fresh weight, chlorophyll, pheophytin, and carotenoid contents. However, anthocyanin and flavonoid contents, as well as the levels of UV-absorbing compounds and UV-B marker increased in the leaves of AA-treated plants. AA increased hydrogen peroxide (H2O2) content in shoots and induced cell death in roots. Soluble carbohydrate content decreased in roots of AA-treated plants while insoluble carbohydrate content increased. Our results demonstrate that AA in young barley seedlings can exhibit its toxic effects through oxidative stress, which induced antioxidative response in the form of molecules with antioxidative activities. These effects persisted for 2 days after the removal of AA. [ABSTRACT FROM AUTHOR]

In this study, metal-doped niobates and perovskites were obtained by a solid-state reaction. The solids were evaluated in the esterification of glycerol in the presence of acetic acid to produce valuable esters of glycerol. The structural features of the solids indicated the ZnNb2O6, Pb2.8Nb2O7.8 and CuNb2O6 columbite main phases and La2MnFeO6 double-perovskite. Density functional theory (DFT) studies of Pb2.8Nb2O7.8 clearly confirmed the existence of a robust orthorhombic structure and its electronic properties were correlated with the Nb and Pb interactions. The morphological and elemental analyses also indicated that not all surface elements, as well as morphology, were crucial for catalytic properties. All solids were active and selective toward triacetin formation upon glycerol esterification with acetic acid. The catalytic performance depends mainly on the availability of the surface and its structural stability, as well as defects formation. Recyclability studies indicated that the La2MnFeO6 double-perovskite was an efficient catalyst, achieving glycerol conversion of 68% and triacetin selectivity of 25% up to 4 cycles of use in the reaction. The structural defects near the Mn4+/Mn3+ surface sites resulted in the diffusion of anions and an increased concentration of oxygen vacancies contributed to the stable performance of the solid in glycerol ester production. [ABSTRACT FROM AUTHOR]

This paper investigates a straightforward method of powder surface modification to increase the efficiency of acetic acid small molecules adhering to the surface of SiC powder. This method involves pretreating the SiC powder with diluted sulfurcontaining solutions and enhancing the reaction between acetic acid and silica hydroxyl groups on the surface of SiC powder in a closed solvothermal environment. X-ray photoelectron spectroscopy analysis showed that acetic acid formed chemical bond with SiC surface silicon hydroxyl groups under the action of sulfur-containing catalyst and solvothermal method; thermogravimetric analysis results showed that acetic acid formed stable adsorption on the SiC powder surface. The modified powder's zeta potential value reached 60.8 mV at pH=10.8, and the dispersion stability was significantly improved. Compared with the original powder, the viscosity of the slurry formulated with the modified powder was less than 60 mPa.s at 47 vol% solid content, and the rheological properties of the slurry were improved. [ABSTRACT FROM AUTHOR]

Hydrogen, as a promising energy carrier, can be extracted from renewable biomass derived acetic acid (HAc). Ni-based catalysts supported on solid solution of Sm2−xPrxO3±δ were prepared using a coprecipitation method and evaluated in auto-thermal reforming (ATR) of HAc for hydrogen production. The results revealed that Pr species infiltrated the Sm2O3 lattice and formed a solid solution structure with oxygen vacancy defects, in which the redox process of Sm3+ + Pr3+ Sm2+ + Pr4+ enhanced oxygen mobility, facilitating gasification of the coking precursor and suppressing carbon deposition. DFT analysis also confirmed that Pr doping into the Sm2−xPrxO3±δ solid solution significantly lowered the energy barrier by 112 kJ mol−1 for formation of oxygen vacancies. Additionally, the interaction between Ni0 and Sm2−xPrxO3±δ effectively improved the dispersion of Ni0 metal particles, inhibiting sintering of Ni species. Consequently, the NSP10 catalyst (Ni0.80Sm1.72Pr0.24O3.74±δ) exhibited outstanding catalytic performance for hydrogen production: the conversion of HAc approached 100%, while the hydrogen yield remained stable at 2.75 mol-H2/mol-HAc. [ABSTRACT FROM AUTHOR]

MOF-74 or M2(dhtp) (M = metal ions, dhtp = 2,5-dihydroxyterephthalic acid), as a typical class of metal–organic frameworks (MOF), have garnered considerable interest due to their abundant unsaturated metal sites. However, environmental and economic limitations caused by the extensive use of organic solvents in traditional syntheses hinder their industrial applications. Although water as a green solvent is considered to be the best candidate solvent, water-based MOFs often have poor crystallinity and long synthesis time, and controlling the particle size is difficult. Herein, a water-based strategy is proposed to synthesize high-quality MOF-74–Co with controllable particle sizes in a rotating packed bed (RPB) reactor using high-gravity technology. MOF-74–Co could be rapidly prepared in the RPB, and shows a smaller and more uniform particle size, higher crystallinity, and larger specific surface area, as compared to the counterpart prepared in a traditional stirred tank reactor. Further adopting acetic acid as a modulator, the as-prepared MOF-74–Co has the highest BET surface area (1599 m2 g−1) in the reported literature so far and simultaneously possesses a high space–time yield (293 kg m−3 day−1). High-quality MOF-74–Zn and MOF-74–Ni can also be prepared, proving the generality of this strategy. Furthermore, the small-sized MOF-74–Co-78 nm exhibits a faster adsorption rate and a larger saturation adsorption capacity (298 mg g−1) for CO2 compared with large-sized samples. This study not only advances the field of green synthesis of MOFs but also paves the way for efficient manufacturing processes in MOF-74 synthesis for CO2 adsorption. [ABSTRACT FROM AUTHOR]

This experiment aimed to evaluate the effects of chitosan administration to total mixed ration (TMR) silage on ruminal fermentation characteristics and degradability by using both in vitro and in sacco methods. The completely randomized design (CRD) used in this study included five treatments and six replications. The treatments consisted of TMR silage with distilled water as control (SA), TMR with 1% acetic acid (SB), 0.5% chitosan in 1% acetic acid diluent (SC), 1% chitosan in 1% acetic acid diluent (SD), and 1.5% chitosan in 1% acetic acid diluent (SE). The variables observed were ruminal fermentation parameters, methane production and in sacco nutrient degradability. Results revealed that adding 1--1.5% chitosan (SD and SE treatments) reduced (P < 0.05) total protozoa, total gas production, methane production, the percentage of acetic acid, and the ratio of acetic acid to propionic acid, while it increased (P < 0.05) the proportion of propionic acid. The addition of chitosan (SE treatment) decreased (P < 0.05) the degradation of dry matter, but it increased (P < 0.05) the degradability of organic matter and crude protein, as determined by in sacco analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Defects were introduced in MIL-125 to narrow the forbidden band width. • Improved the surface acidity of material for efficient degradation of mixed VOCs. • Revealed the catalytic mechanism using in situ DRIFTS spectroscopy and GC–MS. In this paper, the effect of three monocarboxylic acids on MIL-125 synthesis was systematically investigated and the results were discussed in detail. X-ray diffractometry (XRD) and nitrogen adsorption–desorption curves indicated that small molecule acids (acetic acid, propionic acid and butyric acid) affected the morphology of MIL-125 and induced lamellar pores and structural defects in the crystals. Thermogravimetric measurements confirmed the presence of acid-regulated defective metal–organic frameworks (MOFs). Electrochemical tests and density function theory calculations indicated that acid modulation could change the forbidden bandwidth of the material. The acid modification strategy effectively promoted the transfer of photogenerated electrons and enhanced the adsorption and activation of O 2 and H 2 O molecules, generating reactive radicals. The modified MOFs also showed excellent performance in the removal of mixed toluene and chlorobenzene. The degradation pathways of the mixture were analyzed by in situ infrared (IR) and gas chromatography-mass spectrometry (GC–MS). The mixture was converted to chlorophenolic intermediates in the presence of reactive oxygen species, further decomposed to form ethers and ethanol, and finally formed small molecules such as carbon dioxide and water. A feasible method was provided for the preparation of photocatalysts for the treatment of mixed VOCs. [ABSTRACT FROM AUTHOR]

Objectives. Development of a domestic technology for producing environmentally friendly non-phthalate plasticizers, lubricants and transformer fluids based on neopentyl glycol (NPG), an oxo-synthesis product.Methods. The methodology of the work was to study the kinetic laws of NPG esterification with acetic and 2-ethylhexanoic acids under self-catalysis conditions with an 8-fold molar excess of monocarboxylic acids. The production of NPG esters was carried out by azeotropic esterification in the presence of solvents—benzene and m-xylene. The resulting diesters were isolated from the reaction mass by vacuum rectification. The purity of the obtained NPG diesters was no less than 99.7 wt %. Analysis of the qualitative and quantitative composition of reaction samples was carried out using infrared spectroscopy, gas chromatography–mass spectrometry and gas–liquid chromatography.Results. The paper presents the results of kinetic studies on NPG esterification of with acetic and 2-ethylhexanoic acids. It compares the reaction rates and reactivity of the acids used. Under the given conditions, NPG diesters were produced, and some of their physicochemical properties were determined. This enabled the data obtained to be used for the development of industrial technology in the production of NPG diesters.Conclusions. It was established that with an eightfold molar excess of acid under self-catalysis conditions, a yield of NPG diacetate equal to 95% is achieved within 20–22 h at an optimal process temperature of 100–110℃; NPG di(2-ethylhexanoate)—within 26–28 h at 160–170℃. The activation energies and pre-exponential factors for the formation of NPG mono- and diesters with acetic and 2-ethylhexanoic acids were established. The paper presents the kinetic models of esterification.

In this paper, the change characteristics of DOM (dissolved organic matter) and acid production characteristics of anaerobic fermentation in waste activated sludge(WAS) pretreated with rhamnolipid (RL) were studied. The results showed that RL at the dose of 80 mg/gTS could significantly promote the disintegrating of EPS (extracellular polymers) and cell wall in WAS, and a large number of proteins and carbohydrates were dissolved. Three dimensional fluorescence parallel factor analysis showed that the addition of RL enhanced the dissolution and biodegradability of humus-like substances. LC-OCD (Liquid chromatography – organic carbon detection) analysis showed that RL promotes the dissolution of biodegradable components such as Biopolymer, Building Blocks and LMW Neutrals, and ensures the increase of VFA (volatile fatty acids) production in the process of anaerobic fermentation. Under the RL dose of 80 mg/gTS, the maximum VFA production of WAS was obtained at 108 h of anaerobic fermentation, which was 2699.39 mg/L. Acetic acid and propionic acid were the main components in the WAS fermentation broth pretreated by RL. The concentration of butyric acid increased with the increase of RL dose. The RL dose can significantly affect the composition of VFA in WAS fermentation broth. [ABSTRACT FROM AUTHOR]

A phosphine, base and additive free cross-coupling of arylboronic acid is reported via C–O bond cleavage of acetic anhydride using a switchable ferrocene functionalized n-heterocyclic carbene (NHC) palladium complex. The novel redox active catalytic system afforded the corresponding arylketones with good to excellent yields. [ABSTRACT FROM AUTHOR]

We report in this paper a Pd(II)‐catalyzed migratory gem‐fluorolactonization of ene‐carboxylic acids. Reaction of 4‐methylenealkanoic acid derivatives with Selectfluor in the presence of Pd(OAc)2 (1.0 mol %) at room temperature affords fluorolactones in good to excellent yields. 2‐(2‐Methylenecycloalkanyl)acetic acids are transformed to bridged fluorolactones under identical conditions. One C−C, one C−O and one tertiary C−F bond were generated along the gem‐disubstituted carbon‐carbon double bond in this operationally simple transformation. Trapping experiments indicates that the reaction is initiated by a 5‐exo‐trig oxypalladation followed by Pd oxidation, regioselective ring‐enlarging 1,2‐alkyl/Pd(IV) dyotropic rearrangement and C−F bond forming reductive elimination cascade. Post‐transformations of these fluorolactones taking advantage of the electrophilicity of the 1‐fluoroalkylcarboxylate function are also documented. [ABSTRACT FROM AUTHOR]

In pKa computational determination, the challenge in exploring and fostering new methodologies and approaches goes in parallel with the amelioration of computational performances. In this paper a "ready to use methodology" has been compared to other strategies, such as the re‐shaping in solvation cavity (Bondi radius re‐shaping), wanting to assess its reliability in predicting the pKa of a broad list of carboxylic acids. Thus, the functionals B3LYP and CAM‐B3LYP have been selected, using SMD as continuum solvation model. Exploiting our previous results, two water molecules were made explicit on the reaction centre. Data show that our model (CAM‐B3LYP/2H2O) is capable to accurately predict pKa, leading to mean absolute error (MAE) values lower than 0.5. Noteworthy, good results were achieved in computing the pKa of substituents bearing nitro and cyano groups. Focusing on B3LYP, eventually remarkable outputs were obtained only when Bondi correction was applied to the complex with two water molecules. Hence, massive outcomes were obtained in foreseeing the trichloro and trifluoro acetic acid pKa. These findings demonstrated that no complex level of theory nor external factor is required to accurately predict carboxylic acids pKa, with MAE well below 0.5 units. [ABSTRACT FROM AUTHOR]

As one of the most common pollutants in wastewater, heavy metals seriously threaten human health and survival, and among the current removal methods, the adsorption method has attracted the most attention because of its simple and safe operation. Zeolite is a substance with a unique spatial structure, cheap cost, and environmental friendliness. Zeolite is a substance with a unique spatial structure, cheap cost, and environmental friendliness. Due to its size and high surface area‐to‐volume ratio, zeolite exhibits excellent adsorption and ion exchange properties and is a promising adsorbent. In this paper, the modified zeolite chitosan composite film was prepared by solution method by dissolving chitosan in acetic acid solution as the solvent, and the effects of zeolite content, modifier type, initial pH, pore‐making agent, adsorption time, adsorption temperature, initial concentration, and feeding amount were studied. The optimal conditions for Pb2+ adsorption were 40% modified zeolite content, 293 K in 100 mg/L solution, a feeding amount of 1 g/L, pH = 5.5, and a removal rate of 96.6% in 24 h. The isotherm is consistent with the Langmuir adsorption model, which is manifested as single‐molecule chemical adsorption, and the highest saturated adsorption capacity is 139.6 mg/g. After five cycles, it still has a greater than 90% initial adsorption effect. Highlights: Chitosan‐modified zeolite composite membranes are inexpensive.After adsorption, the sorbent is easy to recover. [ABSTRACT FROM AUTHOR]

Summary: The Batch Stirred Tank Reactor (BSTR) has been commonly used for decades in the chemical process industries and even on a pilot plant or laboratory scale whenever expensive and delicate raw materials and products such as pharmaceuticals or fragile transition metal complexes are involved. This research article describes the details of isothermal BSTR and subsequ ent experimental validation of the rate law discovered in the previous paper of this series on the electron transfer reaction between Co(II) and chlorate ions in acetic acid solution. A Series of tests were performed to evaluate the efficiency of the BSTR at multiple temperatures and illustrate the differences between the theoretical and experimental conversion of potassium chlorate through relative error. The experimental conversions are calculated with the design equation. Theoretical and experimental conversions are correlated and proportional to the initial concentrations of the reactant and electron transfer reaction among the reactants. Based on the parameters of the design equation, a set with average parameters was chosen and tested over BSTR. The model was then validated for different temperatures and conversions. A design equation for the BSTR has been written and applied for the conversions of 25%, 50%, 75%, and 95%. The time interval is going to be predicted by the model to achieve the desired conversions. The percent relative error between predicted and experimental conversions clearly shows the model's predictability, power, and reliability. The precision of the observed rate constant for the electron transfer reaction is found to be 2.2023 × 10-2 %. [ABSTRACT FROM AUTHOR]

• Decreasing percentage of droplet diameter is introduced to state the fluctuation of generated droplet diameters. • Estimated formulas are presented based on experimental data. • Time evolution of EHD modes detected during experiments were physically stated. • Influence of effective parameters on droplet diameter and EHD modes are stated. The paper is an experimental investigation of the effect of process parameters like applied voltage, volume flow rate and distance between two electrodes through dimensionless numbers in the electrospray process, droplet diameter in particular. In addition, this study attempts to present new estimated formulas based on experimental data to ease primary evaluations of droplet diameter before any performing electrospray applications in order to reduce time and cost spending. For this purpose, a high-speed camera was used to have clear evidence of the influence of the parameters on the diameter of liquid droplets generated from acetic acid and their electrohydrodynamic (EHD) modes. In this study, the time evolution of EHD modes detected during experiments and the reasons for EHD mode geometric shapes were physically stated. The results show that decreasing the distance between two electrodes producing an electric field causes a reduction in the voltage to meet desired droplet diameter (needed minimum droplet diameter) and a switch of EHD modes occurs in lower voltages. This paper also demonstrates that the percentage of decreasing droplet diameter during the electrospray process has the extremum which can change based on changing effective parameters. Furthermore, a quick estimation for calculating minimum droplet diameter in dripping, spindle, and cone-jet modes based on experimental data is presented because it was observed the decreasing percentage of droplet diameters in each EHD mode is approximately constant unexpectedly whereas all effective parameters of the electrospray process in this research tested. Finally, another equation was also driven to calculate the decreasing percentage of droplet diameter based on dimensionless numbers, Weber and Electric Capillary numbers, using experimental data to acquire appropriate means for the primary forecast of the trend of droplet diameter production being useful for various of electrospray processes such as drug delivery, powder production, encapsulation, thin films, and electrospinning. [ABSTRACT FROM AUTHOR]

• Introduced acetic acid into the leaching process of ion-adsorption type rare earth ore. • The kinetics of rare elements leaching followed internal diffusion. • Acetic acid increases the leaching efficiency of rare earth elements. • HAc-Ac- buffer system inhibits the leaching efficiency of aluminum. The leaching process of rare earth (RE) from ion-adsorption type rare earth ore (IATREO) using ammonium salt or magnesium salt as leaching agents presents challenges to inefficient leaching of RE elements and simultaneous leaching of ion-exchangeable phase aluminum (Al). This paper introduced acetic acid (HAc) into the leaching process of IATREO, to enhance the leaching of RE elements and inhibit the leaching of ion-exchangeable phase Al. The results show that RE elements and HAc mainly existed in the form of REAc2+, with a relative proportion of approximately 15 %. The presence of the HAc-Ac- conjugate acid-base pair provided a buffer capacity. In the MgSO 4 -HAc compound system, column leaching was controlled by internal diffusion, and the supplementation of HAc decreased the activation energy of the RE leaching reaction to 7.11 kJ/mol while increasing the leaching rate. Besides, the HAc-Ac- buffer system increased the pH of the leaching process and promoted the hydrolysis of ion-exchangeable phase Al, thereby inhibiting its leaching. Single-factor experiments indicated that under the optimal conditions, the leaching efficiency of RE elements reached 98.40 %, while the leaching efficiency of Al was 66.61 %. Compared with the ammonium and magnesium salts leaching systems, the leaching efficiency of RE elements increased by more than 6 %, while the leaching efficiency of Al was reduced by 23.33 %. This paper plays an important role in promoting the efficient and green extraction of IATREO. [ABSTRACT FROM AUTHOR]

Exposure of concrete to various acids can hardly be overstated due to the widespread use of concrete in the construction industry. The effect of selected factors on the degradation of ordinary Portland cement (OPC 53 grade) paste and mortar exposed to acetic acid is investigated in this paper. Various test parameters such as mass loss, loss in cross-sectional area, relative dynamic elastic modulus (RDEM), loss in flexural and compressive strength are used to assess the selected factors and the results obtained are analysed to determine the most favourable test conditions for degradation, that can be adopted for developing an accelerated test method. The factors used for the investigation are replenishment of acid solution, concentration of acid solution, ratio of surface area of specimen to volume of liquid acid solution (S/L), shape of the specimen and nature of the specimen. This paper also investigates the interrelationships among test parameters and adopts interpretation of acid consumption to assess the aggressiveness of the acid solution. It was found that renewing conditions and high concentrations of acid solution (0.5 M) indicate rapid degradation. The aggressiveness of 0.125 M acetic acid solutions in renewing conditions is about 5 times that of non-renewing conditions respectively. The rate of degradation is inversely related to S/L ratio. Cylindrical specimens have a marginal increase in degradation than prismatic specimens. It is preferable to evaluate acid attack on mortar specimens rather than paste specimens due to higher loss in cross-sectional area and relative dynamic elastic modulus (RDEM).

The ionic-type rare earth ore, abundant in medium and heavy rare earth elements, is a strategic mineral resource. The removal of aluminum from ionic rare earth leaching solution results in over 8% loss of rare earths. Preliminary research has found that adding acetic acid (HAc) during aluminum removal process can effectively reduce the loss of rare earth elements. In this paper, through the calculation of the species distribution in the La 2 (SO 4) 3 -Al 2 (SO 4) 3 -HAc-H 2 O system, it is found that HAc forms an AlOH-Ac+ complex with aluminum ions, with a proportion of up to 70%, which will increase the initial precipitation pH of aluminum hydroxide. Furthermore, HAc and lanthanum form a LaAc2+ complex, and the proportion can reach more than 20%. Moreover, the zeta potential, FT-IR, and XPS tests of aluminum hydroxide, obtained by neutralization precipitation, revealed that the complexation of HAc and aluminum can reduce the precipitation rate of aluminum hydroxide, so that its particle size increases, the specific surface area decreases, and the van der Waals force adsorption sites are reduced. HAc can be chemically adsorbed on aluminum hydroxide, thereby increasing the zeta potential of aluminum hydroxide and ultimately reducing its electrostatic adsorption effect on rare earths. Additionally, the complexation of HAc and rare earth elements can reduce the local supersaturation of rare earth hydroxides and decline the coprecipitation of rare earth elements. Finally, under a precipitation endpoint pH of 5.2, HAc concentration of 0.006 mol/L, aluminum concentration of 0.2 g/L, rare earth concentration of 0.8 g/L, magnesium ion concentration of 0.5 g/L and magnesium oxide slurry concentration of 0.45 mol/L, the aluminum removal efficiency obtained with rare earth leaching solution reached 98.47%, and the rare earth loss efficiency was 2.62%. Compared with the control, the rare earth loss efficiency was reduced by 5.59%. This paper provides guidance for the efficient and green development of ionic-type rare earth ore. • Adding a small amount of acetic acid can effectively reduce rare earth loss during the aluminum removal process. • The fomation of AlOH-Ac+ can reduce the nucleation rate of aluminum hydroxide and increase its zeta potential. • The fomation of LaAc2+ can reduce the local supersaturation and coprecipitation of rare earth hydroxides. • The rare earth loss efficiency was only 2.62% under the optimal aluminum removal conditions. [ABSTRACT FROM AUTHOR]

• Yttrium is lost via adsorption and coprecipitation during the aluminum removal process. • HAc complexed with Y3+, which increased the precipitation pH and inhibited supersaturation of Y(OH) 3. • HAc formed inner sphere complexes with Al(OH) 3 , which inhibited electrostatic adsorption of the Y3+. • When HAc was increased from 0 to 0.012 mol/L, the yttrium loss efficiency decreased from 18.91 wt% to 12.66 wt%. The leaching liquor extracted from ion-adsorption type rare earth (RE) ores contains large amounts of aluminum (Al) ions. The neutralization-precipitation method for Al removal results in the loss of large amounts of RE, leading to the waste of RE resources. Preliminary research has shown that the introduction of acetic acid (HAc) during the Al removal process could effectively reduce RE loss. However, there has been no in-depth study on the forms of RE loss during the Al removal process with the neutralization-precipitation method and the function mechanism of HAc. In this paper, the yttrium element was used as a representation of RE for relevant research. It was found that the forms of RE loss mainly include adsorption loss and coprecipitation loss, and the addition of HAc can simultaneously reduce both types of loss. The addition of HAc can generate Y(Ac)2+ and Y(Ac) 2 + complexes with Y3+, leading to an increase in the initial precipitation pH of yttrium hydroxide from 6.62 to 6.87, thereby reducing the coprecipitation loss of RE. Additionally, HAc was adsorbed on the aluminum hydroxide (Al(OH) 3), which increased the surface potential and decreased the specific surface area of Al(OH) 3 , thus reducing the adsorption loss of RE. Finally, through precipitation experiments on a mixed solution of aluminum sulfate and yttrium sulfate, it was found that when the neutralization pH was 5.2, the percentage of yttrium lost decreased from 18.91 % to 12.66 % as the concentration of HAc was increased from 0 to 0.012 mol/L. The above function mechanism of HAc was further verified through XPS, SEM-EDS, and other tests on the precipitate. [ABSTRACT FROM AUTHOR]

With economic and social development, there is a growing focus on menstrual hygiene, and traditional sanitary napkins are no longer sufficient to meet women's needs. In this study, quercetin (QC) was efficiently and uniformly ultrasonic sprayed on thermally bonded chitosan nonwovens (CS) to prepare a multifunctional surface layer of sanitary napkins (QC X @CS). CS sprayed with 3 layers of QC (QC 3 @CS) exhibits excellent mechanical properties and high antibacterial rates against Escherichia coli (99.51 %) and Staphylococcus aureus (99.87 %), respectively. Besides, QC 3 @CS demonstrates strong free radical scavenging abilities, which have great potential to reduce the effects of reactive oxygen species on immune and metabolic functions during menstruation. QC 3 @CS demonstrates strong deodorizing abilities, with rates of 87.22 % for acetic acid and 90.88 % for ammonia, which could effectively eliminate the unpleasant odor associated with menstruation. Moreover, QC 3 @CS ensures excellent water absorption, anti-return properties, and cytocompatibility. This study may provide valuable insights into developing functional sanitary napkin materials based on natural extracts. [Display omitted] [ABSTRACT FROM AUTHOR]

The oxidation mechanism of methylglyoxal (CH 3 COCHO) in the aqueous phase plays a crucial role in the formation of secondary organic aerosols (SOA). To date, the investigations of reaction mechanisms of MG in the aqueous phase still needs to be refined, and the oxidation mechanisms of MG in the existence of various oxidants (e.g., H 2 O 2 , O 3, ∙NO 3 , etc.) are in controversy. In this paper, we investigated the hypothesis that small-molecule organic acids are the primary products in cloud water and fog droplets, while large-molecule organic acids and oligomers play crucial roles in wet aerosols. Specifically, the hydration reaction, oxidation mechanism and oligomerization reaction of MG in aqueous phase were investigated on a theoretical basis. It has been indicated that the hydration reaction is a significant initiating reaction of MG in the atmospheric aqueous phase, whose generated hydrated compounds played a critical part in the process of forming oligomers. The aqueous oxidation reaction of MG could form a variety of organic acids, including pyruvic acid, formic acid, acetic acid, and oxalic acid. In the presence of OH radicals, pyruvic acid was the main first-generation production, which undergoes further reactions to form acetic acid, oxalic acid, and mesoxalic acid. Acetic acid was mainly derived from the reaction of OH radicals with pyruvic acid, whereas oxalic and mesoxalic acids were mainly generated by the OH radical reaction for MG and pyruvic acid. Of these, the formation of acetic acid was thermodynamically most favorable. Additionally, the reactions of MG with other oxidants also provided the possible pathways for pyruvic acid production. At 298 K, we calculated the rate constants for the reaction of MGHY with NO 3 , OH, HO 2 radicals, and O 3 to be 4.48 × 108, 2.54 × 107, 1.26 × 10−2, and 4.38 × 10−4 M−1 s−1, with atmospheric aqueous phase lifetimes (τ) of 4.43, 3.12 × 103, 2.21 × 1011, and 3.17 × 108 h, respectively. The theoretical results from this work will facilitate the explanation for the MG reaction process in the aqueous phase so as to further correctly estimate the relationship between the aqueous phase chemistry of MG and the formation of SOA. [Display omitted] • The aqueous oxidation reaction of methylglyoxal was studied theoretically. • The main oxidation products are organic acids. • OH radicals are the main oxidant for removal of methylglyoxal. • The hydration of methylglyoxal is favored at higher RH. [ABSTRACT FROM AUTHOR]

The International Maritime Organization (IMO) has implemented new sulfur content regulations for marine fuels in response to growing environmental concerns, including global warming. These regulations severely and costly restrict refinery operations. Oxidative desulfurization (ODS) is an attractive desulfurization method that has advantages such as mild operating conditions and a hydrogen-free process over traditional processes such as hydrodesulfurization (HDS). One can employ oxidative desulfurization in addition to or instead of hydrodesulfurization. Organic sulfur molecules undergo oxidative desulfurization, which results in the formation of polar sulfones. The refined fuel oil is then separated from the oxidized sulfones using methods such liquid-liquid extraction, distillation, and absorption. This work examines and simulates the process of separating sulfur-containing oxidized chemicals from fuel oil utilizing oxidative desulfurization technology. Acetic acid served as the catalyst and hydrogen peroxide as the chosen oxidant. This effort involved simulating the oxidative desulfurization of fuel oil and then using absorption methods to separate the oxidized sulfones. Subsequent procedures including absorption and distillation were used to separate and recover the resultant effluent, solvent, and oxidant from the remaining components. According to the simulation results, the procedure was run at 80 °C and a modest pressure of less than 5 bar. Sulfur content in the original hydrocarbon fuel was 3.5% by weight; at the output, it was less than 0.5% by weight. The findings of the sensitivity analysis of a few key factors demonstrated that the conversion percentage increased from 84 to 98% when the reactor's diameter was changed from 0.5 to 1.2 m and its length was extended to the desired amount. The reaction conversion percentage has increased significantly when the mass flow rate of hydrogen peroxide is increased from 0.5 to 1.5 kg/h, the pressure is increased from 1.5 to 5 bar, and the temperature is raised to 30 °C. According to the process optimization data, the ideal state had an exergy efficiency of 55.57%, a solvent waste rate of 1.75%, and a sulfur content of 0.22% in the fuel. [ABSTRACT FROM AUTHOR]