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The effect of introducing oxalic acid into the mother gel of TS-1 zeolite on the crystallization behavior and physiochemical properties was investigated. The addition of oxalic acid with a buffering action significantly accelerated the crystallization process of TS-1 while simultaneously inhibiting the formation of anatase. The resultant TS-1 zeolites displayed enhanced performance in catalyzing the epoxidation of 1-hexene with H2O2 as an oxidant. [ABSTRACT FROM AUTHOR]

Crystallization is one of the prominent unit operation processes in major chemical industries, such as pharmaceuticals, food, fine chemicals, etc. It is the last stage in the entire chemical process, and it is the purification step to separate one component from a multicomponent mixture using different crystallization methods. The objective of the crystallization process is to achieve good crystal attributes, such as good crystal purity, good crystal size distribution, mean crystal size, morphology, size, etc. The crystal quality can be achieved through various techniques that include the seeding technique and the non-seeding technique. The former is considered important when the objective of the product quality is not met with the usual crystallization process. It can direct towards process optimization. Although, it is a meaningful approach, it is a challenging task to achieve the desired quality of the crystal, process efficiency and optimization of the overall crystallization process. Seeding can also be done at a low level of supersaturation to trigger secondary nucleation, which is an important part of the crystallization process in crystal development. The solute concentration is increased in the existing solution with seeding of similar crystals. Reproducible crystal quality can be achieved by defining the reproducible crystal growth rate at the point of the process where seed crystals are added. The essential surface area of the seeds and the quality of the surface area are also important to define the size of the crystal. However, temperature and concentration play an important role in achieving the desired crystal attributes. The type of the temperature profile applied has a significant role in achieving the final crystalline product in the batch crystallization process. This experimental study aims to understand the particle size distribution of oxalic acid dihydrate (C2H2O42H2O) crystals by evaluating solubility of oxalic acid at three different temperatures using seed crystals of size 250 µm. [ABSTRACT FROM AUTHOR]

Rhubarb (Rheum rhaponticum L.) is a vegetable that, despite many health-promoting properties, contains large amounts of oxalic acid, which has a negative impact on human health. Treatment of rhubarb petioles with gaseous ozone is one way to improve their quality by changing their chemical properties. As part of the research, an analysis of the mechanical and chemical properties of rhubarb petioles was performed. The analyzes showed that the applied doses of ozone of 10 ppm during 1, 3 and 5 minutes lowered the concentration of oxalic acid during 5 days of tests performed after the ozonation treatment. The most favorable effect on the reduction of oxalic acid, amounting to 36%, was caused by gaseous ozone at a concentration of 10 ppm during 5 minutes compared to the control. In addition, it was noted that on the 1st and 3rd day after using ozone gas, the antioxidant activity of the tested raw material increased significantly. Also on the same days of testing, the total amount of polyphenols increased as a result of the use of ozone fumigation. The largest increase in the total amount of polyphenols, amounting to 12%, was observed for a dose of 10 ppm 5 minutes on the 1st day after the ozonation treatment compared to the control variant. In turn, no positive effect of the ozonation process on the content of vitamin C and the value of destructive force during three-point bending of rhubarb leaf petioles was noted. [ABSTRACT FROM AUTHOR]

Triethylamine is an effective indicator for evaluating seafood freshness. Therefore, a device capable of real-time monitoring of triethylamine is required. In this study, WO3 nanomaterials prepared using sodium tungstate as the tungsten source were used to assemble semiconductor sensors to detect low concentrations of triethylamine at low temperatures. To investigate the effects of different structural guides on the sensor performance, citric and oxalic acids were used as structural guiding agents to obtain WO3 nanoplates and nanoparticles, respectively. At an optimal operating temperature of 255 °C, the WO3 nanoplate sensor exhibited a response of 56.57 to 10 ppm triethylamine, with a sensitivity of 50 in the tested concentration range of 2.5-25 ppm triethylamine, and response/recovery times of 9 s/69 s. WO3 nanoplates performed better than that of WO3 nanoparticles. In addition, the effect of different structural guiding agents on the sensor properties was explored, and the response mechanism of the semiconductor sensor was investigated. WO3 nanoplate shows fast response time, high selectivity and low detection limit, that is an excellent TEA sensor, which makes it more promising used in food detection for practical applications. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China 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.)

To understand the degradation behaviour of rolled hanging scrolls for future conservation treatments, we evaluated the degradation–position profiles of naturally aged hanging scrolls and their model samples, which were subjected to different storage conditions. For the sample immersed in a CuSO4・5H2O solution and rolled around a glass rod, accelerated ageing using the open method (80°C, 65% RH) revealed a tendency of lower pH and higher discolouration towards the central positions, where rolling caused the most tightness. However, no clear tendencies were observed for the concentration variations of organic acids. The degradation effects of the organic acids emitted from the paulownia wooden box were also examined using the sealed tube method by enclosing the rolled painting paper and acidic paper containing organic acids together in a glass tube. Large amounts of oxalic and formic acids were detected at the periphery and scant migration of the organic acids was observed towards the centre, thus indicating that the central positions of the painting paper were less susceptible to the influence of the organic acids emitted from the external environment. By contrast, glycolic acid diffused towards the centre. The analysis of two naturally aged hanging scrolls showed different degradation behaviours. One sample, stored open in the rolled state, showed severe discolouration with the naked eye at the outermost back surface of the scroll. This was possibly associated with the large amount of sulfate ions originating from the external atmosphere, which kept the pH lower and increased discolouration towards the peripheral positions of the painting paper. For the sample stored in a paulownia wooden box, discolouration was not observed with the naked eye at the outermost back surface of the scroll, although lower pH and higher discolouration were observed towards the central positions. [ABSTRACT FROM AUTHOR]

Copyright of Tecnologia em Metalurgia, Materiais e Mineração is the property of Associacao Brasileira de Metalurgia e Materiais 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.)

The possible fabrication of porous anodic oxide films on aluminium in ionic liquids based on choline dihydrogen citrate eutectic mixtures both with oxalic acid and isopropyl alcohol and ethylene glycol, has been investigated. The anodisation has been carried out in either potentiostatic or galvanostatic regime, at temperatures of 45–80°C, for different process durations. Quite compact, uniform anodic alumina layers have been obtained. Based on AFM and SEM investigations, pore diameters between 50 and 80 nm and interpore distances in the range of 160–200 nm have been estimated, with values influenced by the electrolyte type and anodisation conditions. The highest anodisation rate of about 0.4 µm min−1 has been determined by applying operation temperatures of 60°C. The recorded EIS spectra showed a pure capacitive behaviour and high anodic oxide resistances of 106–107 Ω cm2 order. [ABSTRACT FROM AUTHOR]

• The effects of three pre-activators (colloidal Ti, oxalic acid, phosphoric acid) on the performance of a PCC was compared. • The pre-activators promote nucleation by peeling off the original oxide film and increasing the specific surface area. • Different pre-activators did not alter the formation mechanism, but significantly changed the growth rate and morphology. • Phosphoric acid was the overall best choice for pre-activating the Mg alloy considering on the PCC performance and cost. In this study, Mg–6.0Zn–3.0Sn–0.5Mn (ZTM630) magnesium alloy was pre-activated by colloidal Ti, oxalic acid, and phosphoric acid, and a phosphate conversion coating (PCC) was prepared on the alloy surface. The morphology and corrosion resistance of the prepared PCCs were investigated. Surface morphology studies showed that the phosphate crystals that formed the coating were the smallest for the sample pre-activated by phosphoric acid. The coating on the colloidal Ti and the phosphoric acid samples had the largest and the smallest thickness and surface roughness, respectively. The reason for the discrepancy was analyzed by comparing the surface morphologies of alloy samples immediately after the pre-activation treatment and various phosphating treatments. X-ray diffraction analysis revealed that all three PCCs contained the same compounds. The corrosion resistance time from the copper sulfate drop test and the electrochemical data from the potentiodynamic polarization curves showed that the coating pre-activated by phosphoric acid had the best corrosion resistance. Finally, the 1500 h neutral salt spray corrosion test confirmed that the phosphating treated magnesium alloy, which was pre-activated by phosphoric acid, exhibited excellent corrosion resistance and behavior. [ABSTRACT FROM AUTHOR]

Tellurium is a technology-critical element (TCE), with relatively limited data on its behavior in the environment, especially the pedosphere. As with other TCEs, its more widespread use, especially in new energy sources, might lead to Te spillage during production or in the eventual waste. Investigation of tellurium's interaction with soil is a necessary step in the research into the physiochemical transformation and determining the mobility of different tellurium species. To broaden the hitherto scarce knowledge of tellurium behavior in the soil environment, selected soluble tellurium compounds were introduced into different types of well-characterized soil (content of fertilizers, organic matrix, clay minerals, Mn, Fe, pH). The study of Te(IV) and Te(VI) sorption indicated that after 7 days the sorption is quantitative and close to 100%. Addition of Fe 2 O 3 to a soil deficient in Mn and Fe increases its sorption potential by about 10 percentage points. Based on fractionation study (0.11 mol L−1 CH 3 COOH, 0.1 mol L−1 ascorbic acid in oxalate buffer (pH 3), 30% H 2 O 2 at 85 °C followed by 0.5 mol L−1 CH 3 COONH 4), it was shown that the presence of Mn/Fe (oxyhydr)oxides plays an essential role in the mobility of Te, especially Te(VI), regardless of the soil type. In the soil poor in reducible fraction and rich in organic matrix (peat), the organic fraction was responsible for the immobilization of Te, especially Te(IV). Extraction of the mobile fraction after incubation in the presence of DI water (Te extraction: 7–8%), oxalic acid (5–7%) or citric acid (6%) (mimicking rhizosphere activity) indicated that these did not play a significant role in Te retention. Nevertheless, soil modification with biocarbon limited the effect of citrates on Te mobilization. This knowledge is fundamental, i.e. in the context of soil remediation processes and counteracting the migration of Te in the environment from anthropogenic sources (e.g. solar farms). [Display omitted] • Soils differing in Mn/Fe (oxyhydr)oxides content differ in Te(IV/VI) sorption. • Te(IV) and Te(VI) sorption after 7 days is close to 100%. • Te(IV) binds stronger, mostly to Mn/Fe (oxyhydr)oxides and organic matter (long-term). • Up to 60% of Te(VI) is bound to reducible phases in soil. • Addition of Bio-C and LMWOA has no significant impact on Te retention. [ABSTRACT FROM AUTHOR]

Red mud (RM) and spent oyster mushroom substrate (SOMS), by-products of industrial and agricultural production, can be recycled for polluted freshwater purification, bringing about a win-win situation. In this study, unacidified RM and RM acidified with oxalic acid (O-RM) and hydrochloric acid (H-RM), respectively, were mixed with SOMS to produce a porous ceramsite as a potential constructed wetlands (CWs) substrate. The results showed that the O-RM, H-RM, and RM ceramsites displayed fine compressive strengths of 7.75 ± 1.14, 8.40 ± 1.30, and 8.84 ± 0.69 MPa after calcining at 950 °C for 30 min, respectively. The phosphorus adsorption capacities of H-RM, O-RM, and RM ceramsite at a solid-liquid ratio of 25 g/L were 1.18 mg/g, 0.88 mg/g, and 1.06 mg/g, respectively. Toxicity release experiments showed that the ceramsites did not cause secondary environmental pollution, except for arsenic (ranging from 0.210 to 0.238 mg/L). The H-RM ceramsite was tested in a tidal flow-vertical flow CW (TF-VFCW) with Iris pseudacorus L. and Canna indica L plants. In the TF-VFCW, the average chemical oxygen demand (COD), ammonia nitrogen (NH 4 +-N), total nitrogen (TN), and total phosphorus (TP) removal rates were 81.01, 90.25, 66.90, and 77.32 %, respectively. Plant growth had less impact on COD and NH 4 -N removal but had greater limited TN and TP removal. Scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction analysis confirmed that acid pretreatment and the incorporation of SOMS significantly increased the surface and interior porous structures of the ceramsite and enhanced phosphate adsorption by the polyhydroxyl aluminum-iron complex ions. Bacteroides and Campylobacter used the energy produced during polyhydroxyalkanoic acid (PHA) catabolism to absorb phosphorus. Therefore, the synergistic effect of the substrate, plants, and microorganisms achieved the removal of phosphorus from CWs and offered effective and environmentally friendly recycling of RM and SOMS. [Display omitted] • Phosphorus is an essential nutrient causing eutrophication in the freshwater ecosystems. • Spent oyster mushroom substrate (SOMS) is a good pore-forming material and can be used to prepare porous red mud ceramsite. • The ceramsite does not leach toxic pollutants and has good compressive strength. • In CWs, the ceramsite plays an effective role in removing pollutants. [ABSTRACT FROM AUTHOR]

Six kinds of CuFe 2 O 4 , including capsule-shaped CuFe 2 O 4 -C, plate-shaped CuFe 2 O 4 -P, polyhedral-shaped CuFe 2 O 4 -O, and irregular shaped catalysts prepared by co-precipitation (CuFe 2 O 4 -CO), by microwave heating (CuFe 2 O 4 -MW), and by hydrothermal synthesis (CuFe 2 O 4 -S), were used in the microwave-assisted catalytic wet peroxide oxidation (MW-CWPO) process to remove phenol from wastewater. The physicochemical properties of the catalysts were dependent on preparation methods. The catalytic activities were in the order of CuFe 2 O 4 -CO (95.3 %) >> CuFe 2 O 4 -P (78.8 %) > CuFe 2 O 4 -C (72.7 %) > CuFe 2 O 4 -MW (67.1 %) > CuFe 2 O 4 -S (63.3 %) > CuFe 2 O 4 -O (60.0 %). Effects of CuFe 2 O 4 -CO dosage, H 2 O 2 , pH, phenol initial concentration, anions, and MW in the MW-CWPO process were then systematically studied. Under optimal conditions of pH = 3, H 2 O 2 = 1 mL/L, and CuFe 2 O 4 -CO = 0.5 g/L, MW energy of 99 kJ (550 W, 3 min) and 132 kJ (550 W, 4 min) were found essential to achieve 99.6 % removal rate of phenol and 95.3 % removal rate of chemical oxygen demand (COD). Possible degradation pathways were suggested: phenol was firstly oxidized into hydroquinone and catechol, which further degraded into p -benzoquinone, 1,2 -benzoquinone, respectively. Finally, these compounds transformed into oxalic acid, CO 2 , and H 2 O within 4 min. The proposed mechanism suggested that the catalyst CuFe 2 O 4 -CO generates more "hot spots" due to its irregular shape, which enhances MW scattering and absorbing abilities. Consequently, the chemical composition and crystal structure of the catalyst significantly promote the decomposition of H 2 O 2 to generate free radicals. The CuFe 2 O 4 -CO has an opportunity of potential engineering application due to its high efficiency and stability. [Display omitted] • Six kinds of CuFe 2 O 4 are prepared and CuFe 2 O 4 -CO exhibits the highest catalytic activity for phenol degradation. • Catalyst with an irregular or surface fluff capsule shape exhibit excellent abilities of scattering and absorbing MW. • A synergistic effect of catalyst, MW, and H 2 O 2 contributes to the high degradation efficiency of phenol. • MW combined with catalyst enhance the H 2 O 2 utilization efficiency to generate more free radicals. [ABSTRACT FROM AUTHOR]

In the present study, organic acids - oxalic acid, citric acid, tartaric acid and siderophore Desferrioxamine B were evaluated for their efficiencies to selectively recover Cu from its mold production waste. XRD analysis showed that copper mold production waste mainly consisted of Fe and Cu. The complete dissolution of this waste in aqua regia and subsequent analysis via ICP-MS revealed metal contents of 355.3 mg/g Fe and 293.9 mg/g Cu. Among all the organic acids, citric acid had the highest leaching efficiency (58.5 %) for Fe while leaching <1 % of Cu. Whereas, the leaching of Cu and Fe was poor in oxalic acid medium and Cu leaching was also negligible in tartaric acid medium. Only Fe showed 11.2 % leaching efficiency at 2 mol/L tartaric acid. The step-by-step leaching of production waste with citric acid lead to 100 % leaching of Fe while leaving 93.1 % of Cu with a yield of >99 % in the solid residue in the 4th step. Further, the siderophore Desferrioxamine B could effectively leach Fe (91.2 %) while 21.4 % leaching of Cu in 30 days. The presence of Fe impedes the leaching of Cu from the waste as demonstrated by leaching and DFT calculations due to higher stability of Fe-citrate and Fe-desferrioxamine B complex compared to Cu-organic complexes. This recycling technique described herein is simple, reliable and environmentally friendly for recovery of Cu from copper mold production waste. [Display omitted] • DFOB could leach 91.2 % Fe while leaching of Cu was 21.4 %. • Citric acid could leach 100 % Fe while Cu leaching was 6.8 % in multi-step leaching. • ITC determined Cu-oxalate affinity constant to 1.21 × 10−4 ± 9.19 × 10−6 • Fe-DFOB complex was more stable than Cu-DFOB complex by 63.74 kcal/mol. [ABSTRACT FROM AUTHOR]

The complexity of industrial wastewater, heavy metals and organic pollutants often co-exist, making it difficult for conventional water processing to effectively purify water. Herein, natural siderite and bagasse were facilely developed as an iron-based mineral/biochar composite (Fe@BC=1:2) via one-step co-pyrolysis. This process achieved the simultaneous removal of hexavalent chromium (Cr(VI)) and methylene blue (MB) in the presence of oxalic acid (OA). Biochar perfectly implemented the reduction and effective dispersion of iron ore. The formation of iron species optimized the Zeta potential and electrochemical performance of biochar, which facilitated the adsorption and electron transfer process for oxalate and Cr(VI). The Fe@BC=1:2/OA system demonstrated excellent performance under various conditions, and the pseudo-second-order kinetic model indicated that chemisorption was the dominant mechanism for the Cr(VI) and MB removal. The Cr(VI) reduction was synergistically driven by the electron transfer of OA over the conjugated structure of biochar and the iron species redox processes. This was accompanied by the generation and intensification of biochar-induced persistent free radicals (PFRs), which consequently triggered the oxidative degradation of the adsorbed MB. This work provides a broader perspective on preparing cost-effective iron-based biochar from natural minerals and biomass for the simultaneous removal of heavy metals and organic pollutants. [Display omitted] • Iron-based mineral/biochar composite was facilely prepared by one-step co-pyrolysis. • Fe@BC=1:2 achieved simultaneous removal of Cr(VI) and MB in the presence of OA. • Iron species raised the Zeta potential of biochar and favored the anion adsorption. • The electron transfer of OA and the redox of iron species led to Cr(VI) reduction. • MB removal was attributed to adsorption and oxidative degradation. [ABSTRACT FROM AUTHOR]

One of the factors affecting the life expectancy of hanging scrolls is the storage environment. Our study focused on clarifying the degradation behaviour of painting paper, concentrating on the specific storage conditions that provide an airtight environment in a storage box and the stacked structure of the rolled paper rather than considering the materials of the wooden storage box or the gases generated from it. The degradation behaviour and rates for the sealed tube and moist heat ageing methods, excluding the additional effects of light and air pollutants, were compared. When the painting paper was immersed in a CuSO4・5H2O solution instead of a copper green pigment, the oxidation of the painting paper, attributed to Cu2+, proceeded faster with the sealed tube method than with the moist heat method. The co-occurring organic acids generated, namely glycolic and formic acids, which were secondary components, were detected in a higher amount in the first lining paper than the painting paper. This implies that the acids migrated from the painting paper into the lining paper. However, oxalic acid, which was the main component, did not significantly migrate and remained in the reaction system in the sealed tube without volatilising. This increased the hydrogen ion concentration in the painting paper and accelerated acid hydrolysis. Consequently, discolouration and a decrease in the degree of polymerisation and physical strength proceeded faster with the sealed tube method than with the moist heat method. Thus, although this result does not necessarily invalidate the storage system of a rolled hanging scroll in a box, the storage of a deteriorated hanging scroll in a closed system is expected to degrade the painting paper faster than it would in an open system. [ABSTRACT FROM AUTHOR]

The aim of this study was to synthesise magnetic CuFe2O4-Fe2O3 composite materials with enhanced photo-Fenton catalytic activity for the degradation of organic dyes in the presence of oxalic acid as radical-producing source. The composite catalysts were prepared by a simple hydroxide precipitation process followed by an annealing at 300°C with different annealing times. Their phase composition, morphology, surface atomic composition, surface functional groups and magnetic properties were characterised by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The catalytic tests were carried out using methylene blue as a cationic dye and methyl orange as an anionic dye. According to the results, all CuFe2O4-Fe2O3 composite catalysts exhibited significantly higher photo-Fenton activities than CuFe2O4 sample under UVA light and visible light, which can be attributed to the enhanced content of Fe species and the high roughness observed on composite surface. These composite catalysts were found effective in degrading both cationic and anionic dyes although the decomposition of methyl orange was more difficult than that of methylene blue. Moreover, oxalic acid was also experimentally proved to be an excellent radical-producing source, which is superior to H2O2, in our photo-Fenton catalytic system. When the annealing time used in the synthetic procedure was extended, the catalytic performance of composite samples tended to increase but their magnetic properties were reduced, revealing that the annealing time is an important factor to be considered for the preparation of magnetic photo-Fenton composite catalysts. [ABSTRACT FROM AUTHOR]

This article explores the electro-chemical Carbon dioxide Reduction Cell (eCO2RC), delving into fundamental principles, methods, applications, and the latest approaches for converting CO 2 emissions into valuable products. Product outcomes depend on electron exchange and electrode surface attributes used in the CO 2 reduction. The study focuses on C 1 and C 2 products, emphasizing the necessity for selective materials and catalysts to enhance product recovery while minimizing energy consumption. Converting eCO 2 into valuable products is seen as a crucial method for transforming waste into value, addressing the challenge of mitigating global warming through gas emission reduction. [Display omitted] • CO 2 utilization was critically reviewed. • Fundamental, methods, and applications of eCO 2 RC were discussed. • CO 2 conversion to C1 and C2 products were discussed. [ABSTRACT FROM AUTHOR]

• Various reductants were examined in the leaching of pyrolusite, focusing on the detailed investigation of DL-malic acid as a green reductant. • Investigation and optimization of parameters such as particle size, DL-malic acid and sulfuric acid concentration, leaching time and temperature. • Kinetic modeling was performed for reductive leaching of manganese in the presence of DL-malic acid. • Mn 3 O 4 nanoparticles were produced. Securing critical metals is crucial for the transition from fossil fuels to renewable energies. In this regard, extracting metals from various sources and low-grade ores can lead to the sustainable production of metals. Manganese, as a strategic metal, can play a significant role in achieving this goal. In this study, various reductants such as oxalic acid, citric acid, ascorbic acid, acetic acid, tannic acid, hydrogen peroxide, iron (II) sulfate, sodium thiosulfate, and DL-malic acid were used to evaluate the feasibility and comparison on the manganiferous iron ore leaching. DL-malic acid was chosen as the main reductant to investigate other factors because it is novel (as a reductant), eco-friendly, cost-effective, accessible, and easily storable. Therefore, more detailed studies on the dissolution of manganiferous iron ore in the presence of DL-malic acid as the reductant were carried out considering different levels of temperature, particle size, acid concentrations, and leaching time. Increasing the temperature from 298 K to 348 K notably boosted the leaching recovery from 27.00 % to 70.11 %. It was observed that decreasing the ore particle size from -212 μm to -38 μm resulted in an enhancement of leaching recovery from 57.74 % to 70.11 %. Also, adding only 250 % stoichiometry of DL-malic acid notably increased the leaching recovery to 70.11 %, compared to just 5.32 % in a reductant-free medium. It should be noted that the concentration of sulfuric acid had a direct impact on leaching recovery, increasing by 28.28 % with a concentration of 0.5 M and by 93.08 % with a concentration of 4 M. In this research work, the kinetic of the leaching process was modeled using the modified shrinking core model (MSCM). The calculated activation energy was about 33 kJ/mole, which confirmed that the mixed mechanism controlled the reaction. Mn 3 O 4 nanoparticles were synthesized using a pregnant leach solution (PLS) and through a multi-stage co-precipitation method. In this method, hydrogen peroxide was used to modify the manganese hydroxide phase as a more eco-friendly method than other heat treatment methods. The SEM and EDX analyses revealed an average particle size of 80 nm with spherical shapes and no impurities. The XRD pattern of the synthesized nanoparticles confirmed the Mn 3 O 4 phase composition. [Display omitted] [ABSTRACT FROM AUTHOR]

Nitrogen-rich graphitic carbon nitride (g-C 3 N 5) has emerged as a promising and fascinating photocatalyst for tackling problems related to antibiotic pollution. Herein, porous O-doped g-C 3 N 5 with N vacancy (g-C 3 N 5 -x-O) was fabricated via a facile two-step pyrolysis technique using 3-amino-1,2,4-triazole and oxalic acid as precursors. The sample modified with 2.0 mol.% oxalic acid (CN-2.0) exhibits a porous structure with a specific surface area of 249.78 m2. g−1, 2.77 times greater than that of pristine g-C 3 N 5 (CN-0). In addition, the existence of O-doping and N vacancies in g-C 3 N 5 framework not only promotes charge transfer properties but also suppresses photogenerated electron-hole recombination according to the results of transient photocurrent responses, photoluminescence and electrochemical impedance spectra. The CN-2.0 sample displays the highest photocatalytic activity, which eliminates 77.3% sulfamethoxazole (SMX, 20 mg. L−1) after 60 min irradiation under UV 365 nm light source. The addition of peroxymonosulfate (PMS, HSO 5 -) significantly accelerates SMX photodegradation rate as well as reduces the influence of pH solution during treatment process. The reactive oxygen species including •O 2 −, 1O 2 , SO 4 •−, •OH, h+ contribute to SMX removal. The efficient degradation of numerous antibiotic classes highlights the possible applicability of g-C 3 N 5-x -O. Interestingly, the catalyst retains its high activity and stability even after four consecutive reuse cycles. The intermediates of SMX degradation were determined and plausible SMX degradation pathways were proposed. Toxicity assessments demonstrated that the overall toxicity of the solution decreased after treatment. This work provides a feasible strategy to design and modulate g-C 3 N 5 photocatalyst activated by PMS for antibiotic removal in wastewater. [Display omitted] • Porous g-C 3 N 5-x -O catalyst was first utilized for PMS photoactivation. • The g-C 3 N 5-x -O has excellent charge mobility and slow e−/ h+ recombination rate. • SMX can be removed efficiently by the CN-2.0/PMS/UV system in various conditions. • Possible reaction mechanism and SMX degradation pathways were proposed. • The combined system shows the ability to reduce the overall toxicity. [ABSTRACT FROM AUTHOR]

Lactiplantibacillus plantarum , the biomarker that occupied an important position in fermented radish paocai with high quality, was selected and applied as a starter culture to manufacture fermented radishes. Herein, this work developed a method of enhanced fermentation by using L. plantarum WWPC to shorten the fermentation period and improve the flavor and safety of fermented radish products. Particularly, the effect of L. plantarum WWPC on physicochemical characteristics and flavor profiles of liquid-state-based radish paocai and solid-state-based dried-fermented radish was systematically investigated. The results indicated that the enhanced fermentation inoculated with L. plantarum WWPC could accelerate the fermentation process (2 times in radish paocai) and postpone the yellowing of white radish paocai (ΔE >5). Meanwhile, the content of nitrite in radish products diminished with the participation of L. plantarum WWPC. Furthermore, enhanced fermentation with L. plantarum WWPC improved the flavor profiles of white radish paocai, especially lactic acid, oxalic acid, Glu, ocimenol, and trans -4-thujanol. Meanwhile, the predominant flavor substances mainly consisting of Glu, octanal, and 4-methylthio-3-butenyl isothiocyanate were affluent in red dried-fermented radish inoculated with L. plantarum WWPC. The pleasant and abundant taste and aroma of the enhanced fermented radish products possessed further verified the practicality and appropriateness of L. plantarum WWPC for radish fermentation. These findings could contribute to synthetically exploiting and developing radish products with high quality. • Enhanced fermentation is conserved to enrich flavor profiles of fermented radishes. • Enhanced fermentation improves product safety during solid or liquid fermentation. • L. plantarum WWPC contributes to shortening the fermentation cycle of paocai. • L. plantarum WWPC is conducive to postponing the yellowing of radish paocai. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru 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.)

Two field experiments were conducted to study the effect of irrigation intervals (I) at (20, 35,50 days between irrigation) and antioxidant materials (control, Ascorbic acid, Oxalic acid, Tanic acid) on growth, productivity and quality attributes of sugar beet, split plot design in 3 replications was used in this study. The results showed that, irrigation intervals at 20 days gave the highest significant values in total dry weight, leaf area, root diameter, biological yield, root yield, sugar yield, Potassium and Sodium % while, irrigation intervals at 50 days recorded the highest values of root length, sucrose % and Quality %, in both seasons. On the other hand the irrigation intervals at 35 days showed the greatest significant values of a amino N in both seasons. Both of ascorbic acid and oxalic acid recorded the highest significant values of root length, biological yield, root yield, leaf weight, sucrose % and potassium content in both seasons, while the same effect on sodium content was in the first seasons and on quality % was in the second seasons. The effect of interactions between irrigation intervals (I) and antioxidant materials recorded significant differences in total dry weight (gm), leaf area (cm2), sugar yield (ton/fed), Sucrose%, Quality%, Potassium and Sodium%, a amino N in both seasons and root length (cm) in the second seasons. Both of Ascorbic acid and Oxalic acid treatments with irrigation intervals 20 and 35 days recorded the highest sugar yield in both seasons. It could be concluded that the combination between irrigation intervals at 20 or 35 days with both ascorbic acid and oxalic acid treatments recorded the highest productivity of sugar beet and sugar yield in both seasons. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia 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.)

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of 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.)

• Easy-to-prepare and effective fluorescent probe for the detection of oxalic acid. • Rhodamine-6G amide based dinuclear zinc complex is designed for the probe. • Highly linear fluorescent response over the range of 0-10 μM oxalic acid. • Detection limit of the probe for oxalic acid can reach to 1.20 μM. • Recycling of the probe can be achieved by the treatment with sodium sulfide. Oxalic acid (OA) existing widely in animal, plants, and factory processes may affect human health and result in environmental pollution. It is highly desired to develop a rapid fluorescent sensing for accurate determination of OA content in food and wastewater. We are the first to design an easy-to-prepare rhodamine-6G based zinc complex as a fluorescent probe for the selective detection of OA and explore the sensing mechanism between zinc complex and OA. The zinc complex presents the coordination with two Zn2+ and both of rapid color and linear fluorescent response toward OA in the range of 0-10 μM. The detection limit of the probe for OA can reach to 1.20 μM, which is superior to those reported in the literature. Compared with other dicarboxylic acids, the binuclear zinc complex probe displays rapid detection and high selectivity for OA over a wide pH range due to the steric hindrance and ring strains. The recycling of the probe can be achieved by the treatment with sodium sulfide to form zinc sulfide and regenerate the intermediate. [Display omitted] [ABSTRACT FROM AUTHOR]

Iron pyrite (FeS2) has attracted intense research interest for low-cost supercapacitor applications due to its improved electrical conductivity in comparison with its oxide counterpart. Herein, we demonstrate a novel strategy for the facile synthesis of N-doped FeS2 nanosphere films on iron substrate, which includes anodization of Fe and subsequent thermal annealing treatment. The rodlike ferrous oxalate films are obtained by anodization of Fe in an oxalic acid electrolyte. Then, nanosphere-like N-doped FeS2 films can be readily achieved through thermal annealing of ferrous oxalate films under ammonia (NH3) atmosphere in the presence of sulfur powder. The N-doped FeS2 electrode fabricated without the need for any binder shows superior rate capability and enhanced specific capacitance compared to the pristine FeS2. The prepared N-doped FeS2 nanosphere electrode displays a high specific capacitance of 238.2 mF cm-2 at 3 mA cm-2 over a potential range of -1.2 to 0 V and good cycling stability with a capacitance retention of 84.3% after 5000 cycles. [ABSTRACT FROM AUTHOR]

Ni-rich layered cathode is known as the main limit for the fast charge of Li-ion batteries. With a focus on Ni-rich LiNi0.80 Co0.10Mn0.10O2 (NCM811) cathode, two strategies have been attempted to improve the rate capability of Li-ion cells, one by breaking down the spherical secondary structure to increase the material's surface area and the other by reconstructing the native surface layer to reduce interfacial resistance between the active material and the electrolyte. In the milling process, it was found that conducting carbon buffers NCM811 particles from breaking down, and that a decrease in the content of carbon makes it possible to break down the spherical secondary structure. Because NCM811 particles are natively covered by a dense and resistive surface layer consisting mainly of alkaline residual lithium compounds (RLCs), adding an appropriate amount of H2C2O4 into the slurry is shown to dramatically reduce interfacial resistance between the cathode and electrolyte. This is because H2C2O4 reacts with RLCs to reconstruct the texture of the dense native surface layer, which allows the liquid electrolyte to permeate and wet the active material and hence reduces the electrolyte-electrode interfacial resistance. This simple process provides an operation-viable and cost-effective strategy for improving the rate capability of Li-ion batteries. [ABSTRACT FROM AUTHOR]

High-salt petrochemical wastewater requires advanced treatment for water reuse due to its high salinity and the presence of refractory organic compounds. Heterogeneous catalytic ozonation is an effective advanced treatment method, with the key to its success lying in the preparation of catalysts. A novel carbon-coated copper-based core-shell catalyst (C/Cu-Al 2 O 3) was successfully prepared. In this work, Al 2 O 3 was used as a carrier and copper as an active component to construct a catalyst with levodopa (L-DOPA) shell and embedded copper sites through the self-polymerization of L-DOPA. The active groups in L-DOPA molecules such as amine and carboxyl groups can be introduced into catalyst and L-DOPA also served as carbon source to reduce Cu(II) to more reactive Cu(I) and Cu(0). Under optimal conditions, its chemical oxygen demand (COD) removal rate for high-salt petrochemical wastewater reached 62.5%. After 20 cycles, its COD removal rate was maintained at above 53%. Electron paramagnetic resonance (EPR) investigations, quenching tests, and degradation experiments of oxalic acid revealed that the generation of embedded copper sites (Cu-O, Cu-N) and the construction of the carbon shell provided the catalyst with rich surface hydroxyl groups and Lewis acid sites, which promoted the decomposition of ozone into hydroxyl radicals (•OH), superoxide radicals (•O 2 -), and singlet oxygen (1O 2) and achieved efficient degradation of organic compounds. [Display omitted] • Core-shell ozonation catalyst (C/Cu-Al 2 O 3) with a good stability for treatment of high-salt petrochemical wastewater. • Prepared C/Cu-Al 2 O 3 catalyst is equipped with rich surface hydroxyl groups and Lewis acid sites. • L-DOPA is benefit the introduction of Cu and adjustment the proportion of Cu(II)/Cu(I). • Both free-radical and non-free-radical were responsible for COD removal during the catalytic ozonation process. [ABSTRACT FROM AUTHOR]

In this study, an efficient process for waste ITO target recycling has been proposed on the purpose of individual recovery of indium and tin. In 2 O 3 in waste ITO target was selectively dissolved through H 2 SO 4 leaching in the presence of H 2 O 2 under the conditions of H 2 SO 4 concentration of 2.0 mol/L, liquid to solid ratio (L/S) of 4.0 mL/g, reaction temperature of 80 ºC and time of 5.0 h. In the meantime, most of tin was remained in the leach residue in the form of H 2 SO 4 -stable SnO 2 , achieving the efficient separation of indium and tin. The indium-rich leach solution was further processed with oxalic acid under the conditions of C 2 O 4 2-/In3+ mole ratio of 1.8, reaction temperature of 30 °C and time of 1.0 h to selectively precipitate indium in the form of indium oxalate. The obtained Sn-free indium oxalate precipitates were further subjected to a calcination process for its complete thermal decomposition. Indium was finally recovered in the form of In 2 O 3 powder, which is an ideal raw material for indium metal recovery or fabrication of new ITO targets. XRD, SEM, TG-DSC and XPS analysis were utilized to clarified the reaction mechanisms of the recycling process. [Display omitted] • A closed-loop process was proposed for waste ITO target recycling. • Selective indium dissolution was achieved through an oxidative acid leaching process. • Oxalic acid was used to selectively precipitate indium for complete In-Sn separation. • The target product of In 2 O 3 was obtained through the calcination of indium oxalate. • The reaction mechanisms of the whole recycling process were clarified. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of 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.)

In this study, we investigated the effect of reducing agents to decrease the chemical decomposition of SPS. We added reducing agents (hypophosphite, formaldehyde, glyoxylic acid, hydrazine, and oxalic acid) into the Cu plating bath and examined their effects on the voltammetric response, bath performance, and stability of SPS. Among these, hydrazine and oxalic acid resulted in the formation of precipitates, and thus could not be used for accurate analysis. Hypophosphite was electrochemically active in the cathodic region due to the reduction of metallic phosphite, which led to errors in the CVS analysis. Therefore, it was determined that only formaldehyde and glyoxylic acid could be used as reducing agents in Cu electrolytes. Formaldehyde reduced the rate of SPS decomposition more effectively. The bath performance with and without formaldehyde was evaluated by performing a via-fill test. Consequently, when formaldehyde was not present, SPS was rapidly decomposed by Cu+, and the filling performance became poor after aging for 3 h. However, when formaldehyde was present, the filling performance was maintained for up to 9 h and SPS decomposition in the open-circuit condition rarely occurred. These results indicate that formaldehyde reduces the number of active radicals, thereby reducing the chemical oxidation of SPS. [ABSTRACT FROM AUTHOR]

• It is possible the selective leaching with increased temperature depend on the dissolvability differences of copper and iron oxalate in presence of oxalic acid. • Dissolution behavior of copper and iron in autoclave have changed based on temperature. • Under leaching conditions of 5 M H 2 O 2 , 318 K, 100 g/L H 2 C 2 O 4 and 180 min, iron and copper were extracted as 90.6%, 1.73%, respectively. • Under conditions of 443 K, 100 g/L H 2 C 2 O 4 , 3 M H 2 O 2 and 180 min, metal extractions were obtained as 88.5% Cu and 2.11% Fe. This study investigated the dissolution behavior of metals from chalcopyrite concentrate in a pressure reactor system in the presence of hydrogen peroxide by oxalic acid leaching. The fact that the compounds formed by copper and iron with oxalic acid had different dissolution coefficients showed that metals could be selectively extracted based on the leaching temperature. The effects of various leaching parameters on metal extraction in the autoclave system were investigated at different H 2 O 2 concentrations (1–5 M), H 2 C 2 O 4 concentrations (25–125 g/L), leaching temperatures (318–443 K) and leaching times (15–180 min). While iron and copper extraction as a result of 180 min of leaching with 5 M H 2 O 2 , 318 K and 100 g/L H 2 C 2 O 4 was respectively 90.6% and 1.73%, 88.5% of copper and 2.11% of iron could be extracted as a result of 180 min of leaching with 3 M H 2 O 2 , 443 K and 100 g/L H 2 C 2 O 4. The reversal of the copper and iron extraction dissolution behavior started after the leaching temperature of 378 K. In the XRD analysis of leach residues obtained at low leaching temperatures, CuC 2 O 4 peaks were dominant, while at high temperature conditions, Fe 2 O 3 peaks were dominant. [ABSTRACT FROM AUTHOR]

This study compared the effect of experimental polymer-based desensitizers with NaF and oxalic acid (OA) for preventing root demineralization via observation using micro-CT. Bovine root dentin surfaces were treated with coating materials: no treatment; MS0(+) (MS Coat One®); MS3000(+) (MS Coat®); MS0(-); MS3000(-); MS7000(+/-); fluoride gel (NaF9000). MS; MS polymer, 0-7000; NaF concentrations, (+/-); OA. The specimens were scanned using micro-CT before and after demineralization (pH4.5, 10 h). Following this, the mean mineral loss (ML) after demineralization was calculated, and the specimens were observed under a scanning electron microscope (SEM). The ML values of MS3000(+), MS7000(-), MS7000(+) and NaF9000 were significantly lower than the other groups (p<0.05). Under an SEM, a membrane structure was observed to have formed on the dentin surface in the presence of the MS, fluoride, and OA. The experimental polymer-based desensitizer with oxalic acid and a high concentration of fluoride is effective for preventing root demineralization. [ABSTRACT FROM AUTHOR]

The influences of preharvest calcium spray (PCS) and postharvest chitosan coating (PCC) treatments on the levels of sugar, organic acid, and phenolics were evaluated for Chinese dwarf cherry fruit during cold storage. An orthogonal method was applied using the decay rate as index. The optimised treatment was spraying 2.0% Ca(NO3)2 solution before 21 d of harvest and postharvest application of 0.1% chitosan coating. Compared to the control group, the PCS+PCC treatment group showed a significantly reduced fruit decay rate at the end of storage. Total sugars (91.3–143.1 mg/g), organic acids (11.3–29.4 mg/g), and phenolic (912.4–2337.5 mg/g) contents in optimised group are averagely higher than those in control group. Glucose (24.7–64.8 mg/g) was the predominant sugar, followed by sucrose and fructose. Malic acid (5.2–22 mg/g) was the predominant acid, followed by succinic, citric, tartaric, and oxalic acid. The total phenolic content was relatively stable from 0 to 30 d, and then decreased. The levels of procyanidin and flavonol exhibited similar trends. The antioxidant activities were positively associated with phenolic contents. These findings suggest that treatment with PCS+PCC could be used commercially for extending the storage time and improve Chinese dwarf cherry quality for up to 30 days. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of 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.)

The chemical-assisted electrochemical hydrogen evolution reaction (CAHER) emerges as a prospective energy-saving method to obtain high-purity hydrogen. Selecting suitable auxiliary reactive chemicals (ARC) for the CAHER system is vital. In this study, we propose that oxalic acid can be used as ARC of the CAHER system. Compared with water electrolysis, lower energy consumption is required for hydrogen production in the presence of oxalic acid. The anode potential needed by oxalic acid assisted water electrolysis (OAWE) is half of that of water electrolysis. For OAWE, more hydrogen is produced with the increase of oxalic acid concentration and temperature. [ABSTRACT FROM AUTHOR]

In the present study, we investigated the effect of an anode temperature on current transient process during porous anodic alumina growth and morphology of the anodic layers. Alumina films were formed in a 0.4 M oxalic acid at a constant voltage mode and electrolyte temperature. The temperature of the Al anode was controlled by thermoelectric Peltier element and varied in the range of 5 °C-60 °C. Surface morphology of both sides of anodic films and their cross-sections were analyzed by scanning electron microscopy (SEM) with subsequent statistical analysis of the SEM images by ImageJ software. It was found that when anode temperature was increased from 5 °? to 50 °? the pores diameter and interpore distance has not changed, but the porous structure became more ordered. According to these results, the rate of chemical dissolution of the barrier layer and pore walls did not depend on the anode temperature. At the anode temperature of 60 °?, pores diameter has increased 1.7 times and there was a distortion of the ordering of porous cells. It was concluded that the temperature difference between the aluminum substrate and electrolyte is an important parameter affecting the formation of ordered structure of nanoporous anodic alumina. [ABSTRACT FROM AUTHOR]

Microbial phosphorus (P) as an active component of P pool plays an important role in regulating the availability of P to plants. Direct or indirect changes in soil pH, available P and organic Carbon (C) induced by low molecular weight organic acids (LMWOA) affect soil microorganisms, but have not been well considered in the contents of microbial P. This study aims to investigate the changes in microbial P, available P, pH and organic C induced by LMWOA in a calcareous, neutral and acidic soil. The relationship between microbial P and soil properties (soil pH, available P and organic C) was also explored. The soils were added with citric acid, malic acid, oxalic acid or their mixture (ratio, 1:1:1) at 0, 10, 20 or 40 mmol kg-1 soil. Soil microbial P, available P and organic C levels were increased and pH values were decreased to variable extents in the soils 15 days after the addition of LMWOA. No evident interactive effects among the organic acids were observed on the soil changes above mentioned. The change in microbial P induced by LMWOA was mainly ascribed to the direct effects from the changes in organic C, soil pH, available P, among which, the change in soil organic C had the most important positive impact. [ABSTRACT FROM AUTHOR]

• Zinc oxalate synthesized in a batch reactor at 2 bar pressure with an average Faradaic efficiency of 73.9%. • Pure oxalic acid extracted from zinc oxalate with 58.2 % efficiency using ester hydrolysis process. • Low water content in the electrolyte solution ∼37 ppm and optimised current density of 15 mA/cm2 enhances oxalate formation. Electrochemical conversion of CO 2 to value added chemicals is a promising route for its utilization and mitigation from atmosphere. Nevertheless, an industrial process involving CO 2 electroreduction is yet to be a reality and requires further studies on improving the existing processes. In the present work, we report new insights into the electrochemical conversion of CO 2 to zinc oxalate at SS 304 L cathode in acetonitrile in the presence of a sacrificial Zn anode. The influence of current density, water content in the electrolyte solution and pressure on product selectivity were evaluated. In addition, oxalic acid synthesis from zinc oxalate was studied using ester hydrolysis process. Our results showed that the product yield is affected due to CO 2 reduction to carbonate, decomposition of acetonitrile to cyanide and glycolate formed due to partial reduction of oxalate. Experiments performed in a batch reactor at 2 bar pressure showed that an average Faradaic efficiency of 73.9% can be obtained for zinc oxalate. A yield of 58.1% was obtained for the extraction of oxalic acid. Both zinc oxalate and oxalic acid obtained from this process were compared with commercially available products to confirm its purity. [ABSTRACT FROM AUTHOR]

Aim: Evaluate the effect of adhesives systems combined with desensitizer agents on the microtensile bond strength (µTBS) of a composite resin to dentin. Methods: Cervical dentin of thirty-two human molars were used to simulate hypersensitivity areas. The teeth were divided into four groups (n=8), according to the type of adhesive system and desensitizer agents. No desensitizer was used in the control (Clearfil SE Bond - CS). Two experimental groups were pretreated with either MS Coat Bond (MS) or Biofluorid 12 (BF) immediately prior to bonding with CS. The last group corresponded to Gluma Comfort Bond + Desensitizer (GC) application. After dentin treatments, a composite block was built-up on dentin surface and after 24 hours teeth were serially sectioned to obtain bonded bean specimens. Beams were stored in water for 24 hours or one year. Subsequently, the specimens were submitted to the µTBS test. Data were analyzed by two-way mixed ANOVA and Bonferroni's test (a = 0.05). Results: At 24 hours, there was no significant difference in µTBS among groups. However, at one year, dentin treated with MS or BF demonstrated significantly lower µTBS of CS to dentin compared to control and GC, which kept their µTBS stable. Conclusion: The effect of MS and BF desensitizer agents on the µTBS of CS to dentin did not reduce the µTBS at 24 hours, but it decreases significantly after one year. [ABSTRACT FROM AUTHOR]

Background: Plants with high biomass can be manipulated for their reducing sugar content which ultimately upon fermentation produces ethanol. This concept was used to enhance the production of reducing sugar from cattail (Typha latifolia) by oxalic acid (OAA) pre-treatment followed by enzymatic saccharification. Result: The optimum condition of total reducing sugar released from OAA pre-treatment was found to be 22.32 mg/ml (OAA—1.2%; substrate concentration (SC)—6%; reaction time (RT)—20 min) using one variable at a time (OVAT). Enzymatic saccharification yielded 45.21 mg/ml of reducing sugar (substrate concentration (SC)—2.4%; enzymatic dosage—50 IU/g; pH 7.0; temp—50 °C) using response surface methodology (RSM). Conclusion: We conclude that Typha can be used as a potential substrate for large-scale biofuel production, employing economical bioprocessing strategies. [ABSTRACT FROM AUTHOR]

• Li and Fe in LiFePO 4 are selectively separated via dimethyl oxalate leaching. • 99.19 % Li is recovered as Li 3 PO 4 with a purity of 99.62 %. • Fe is retained in leached residue as FeC 2 O 4 ·2H 2 O with a purity of 95.34 %. • Detailed leaching mechanism is explored. Recycling of spent lithium-ion batteries (LIBs) has great significance in sustainable global development and environmental protection. In this study, a novel strategy is proposed to selectively separate and integrate valuable elements from spent LiFePO 4 (SLFP) cathode materials via an eco-friendly leaching process using dimethyl oxalate. By properly regulating and controlling the leaching parameters, 99.19 % Li and 96.28 % P were leached into solution, whereas only 0.2 % Fe was dissolved. Leaching mechanism revealed that the high-efficiency dissolution of the SLFP cathode materials is due to the joint action of methanol and oxalic acid derived from dimethyl oxalate hydrolysis. Furthermore, the lithium-containing leaching solution was used to prepare Li 3 PO 4 products with a purity of 99.62 % through crystallization, and the Fe was retained in leach residue in the form of FeC 2 O 4 ·2H 2 O with a purity of 99.54 %. These findings provide a reliable reference for environmental protection, selective recovery, and process design of SLFP LIBs. [Display omitted] [ABSTRACT FROM AUTHOR]

Metal vanadium smelting produces roasting-acid leaching tailings containing approximately 1% vanadium residue, making it challenging to store and recycle these waste tailings in an environmentally friendly manner. To address this issue, a clean method called ultrasonic-enhanced oxalic acid complexation was proposed in this study for efficient removal of residual vanadium. Under the optimal conditions, the removal rate of vanadium and the decomposition rate of oxalic acid reached 86.88% and 23.6%. An in-depth analysis on the experimental results in combination with thermodynamics found a virtuous cycle chain induced by ultrasonic cavitation. Ultrasonic waves facilitated the decomposition of oxalic acid, producing more CO 2 to supplement the limited cavitation bubble nucleuses. Consequently, the cavitation effect was strengthened, leading to an increased yield of OH radicals. This resulted in a continuous improvement in the oxidation environment. Furthermore, the enhanced virtuous cycle generated by ultrasonic cavitation produced powerful microjets that facilitated the stripping and dispersion of mineral particles. Overall, the oxalic acid-ultrasonic leaching technique offers a clean and efficient technology for separating vanadium. [ABSTRACT FROM AUTHOR]

This study was designed to investigate the effects of natural deep eutectic solvents (NADESs) on extraction efficiency and antioxidant activities of phenolic compounds from Toona sinensis seeds (TSSs) compared with ethanol and water extraction methods. The single factor experiment was employed to optimize the extraction conditions of TSSs phenolic compounds on NADESs. Results indicate that the NADES of choline chloride-oxalic acid (CC-OA) with a molar ratio of 2:1 (solid/liquid ratio: 1:90 (m/v), extraction time: 30 min) showed the highest total phenolic content (32.58 mg GAE/g DW) and antioxidant activities (DPPH radical scavenging activity: 95.94%) compared with ethanol or water extraction. In addition, 15 main phenolic compounds were identified in the extracts of CC-OA solvent, while only 9 and 6 main compounds were identified in the extracts of ethanol and water solvents, respectively. The molecular dynamic simulation result illustrates that the high extraction efficiency of the NADES mainly attributing to their high compatibility as well as hydrogen interaction between ellagic acid (the main polyphenol in TSSs) and CC-OA solvent. In summary, the NADES (CC-OA at the ratio of 2:1) showed superior extraction efficiency on TSSs phenolic compound compared with ethanol or water extraction which could be an environmentally friendly method for the high-value utilization of TSSs. [ABSTRACT FROM AUTHOR]

The approval of oxalic acid as a treatment for Varroa destructor infestation of honey bee hives gives beekeepers an additional option for controlling this devastating parasite and disease vector, but the effects of oxalic acid on developing bees are not completely understood. In this study, we find that doses of oxalic acid not reported to be toxic to adult bees are toxic to larval bees. While it has been recommended that oxalic acid only be used during broodless periods because it does not penetrate cappings and is only effective in killing phoretic mites, it is tempting to use it at other times of the year because of the dearth of effective treatment options. Knowing whether oxalic acid is toxic to larvae and at what doses is important for beekeepers as they manage their colony population throughout the year. [ABSTRACT FROM AUTHOR]

Recovery of gallium from light emitting diodes (LEDs) is receiving great attention due to both high content of gallium and potential risk of environmental pollution. In this study, a novel environment-friendly route was proposed for efficient recovery of gallium from surface mounted device (SMD) of LEDs by using organic acid. Reduction of non-metallic components, selection of lixiviants, optimization of leaching parameters, and possible mechanism of gallium were investigated. Results showed that pyrolysis could reduce non-metallic components effectively, and 22% weight loss was achieved at 733 K. Selection of lixiviant experiments indicated that 83.42% gallium could be extracted from SMD LEDs by oxalic acid, which was much higher than that of 79.89% by hydrochloric acid, 70.62% by citric acid, and 71.69% by DL-malic acid. Further investigation revealed that 90 °C of leaching temperature, 10 g L−1 of pulp density, 0.7 M of oxalic acid and 48–75 μm of particle size were the optimum conditions for effective gallium leaching by oxalic acid. After optimization, the gallium recovery efficiency reached as high as 90.36% in 60 min. Such efficient gallium leaching came from the higher dissociation constant of oxalic acid and the formation of ferrous oxalate which would promote the generation and maintenance of H+. Hence, oxalic acid could be a promising lixiviant for efficient recovery of gallium from SMD LEDs. [ABSTRACT FROM AUTHOR]