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1.
J Ethnopharmacol ; 326: 117968, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38428655

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Urolithiasis is one of the oldest and most widespread urological diseases suffered globally. In the long history of Traditional Chinese Medicine, there're numerous herbs documented with strangury-relieving properties playing crucial roles in treating various urological disorders, including dysuria, hematuria, and renal colic, etc., which may be caused by urolithiasis. Exploring these herbs may reveal safer, more effective, and cost-efficient drugs and therapies for urolithiasis. AIM OF THE STUDY: This study aims to assess the anti-urolithiasis efficacy and safety of 46 Chinese traditional and folk herbal drugs using the fruit fly (Drosophila melanogaster) kidney stone model, in order to identify the most valuable ethnomedicinal materials. MATERIALS AND METHODS: Water extract and 50% ethanol extract of each herb were prepared respectively. 0.2% (w/w) sodium oxalate was chosen as appropriate lithogenic agent through fruit fly life span study. Male fruit-flies within three days of emergence were aged for an additional three days, then were randomly divided into experimental groups, model group and control groups (n = 20). The flies in blank control group, model group and positive control group were fed with standard food, standard food containing 0.2% sodium oxalate, standard food containing 0.2% sodium oxalate and 3% (w/w) Garcinia cambogia extract, respectively. Meanwhile, flies in the experimental groups were raised on standard food containing 0.2% sodium oxalate and 3% (w/w) herbal extract. The anti-urolithiasis capability of the extracts was evaluated using stone area ratio (the stone area divided by the area of the Malpighian tubule) and stone-clearing rate. Additionally, the 7-day mortality rate was employed as an indicator of safety. RESULTS: Out of the 46 herbs, 24 exhibited significant anti-urolithiasis effects in their water extracts. Among them, Herba Nephrolepidis, Herba Humuli, Herba Desmodii Styracifolii, Cortex Plumeriae Rubrae, and Herba Mimosae Pudicae showed us a low 7-day mortality rate of fruit-flies as well. However, only a limited number of herbal extracts (8 out of 46) showed obvious anti-urolithiasis activity in their 50% ethanol extracts. CONCLUSION: Highly potential anti-urolithiasis candidates were discovered from strangury-relieving herbs recorded in classical Traditional Chinese Medicine works, highlighting the significant value of traditional and folk ethnopharmacological knowledge.


Assuntos
Cálculos Renais , Urolitíase , Animais , Masculino , Drosophila melanogaster , Disuria/tratamento farmacológico , Extratos Vegetais/efeitos adversos , Urolitíase/tratamento farmacológico , Cálculos Renais/tratamento farmacológico , Ácido Oxálico/uso terapêutico , Água , Etanol/uso terapêutico
2.
J Environ Sci (China) ; 142: 204-214, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38527885

RESUMO

Naturally occurring hematite has been widely studied in the Fenton-like system for water pollutant remediation due to its abundance and non-toxicity. However, its inadequate catalytic activity results in difficulty in effectively degrading pollutants in the catalytic degradation system that it constitutes. Thus, we constructed a photochemical system composed of hematite with {001} facet of high activity facet and low-cost and non-toxic oxalic acid (OA) for the removal of various types of pollutants. The removal rate for the degradation of metronidazole, tetracycline hydrochloride, Rhodamine B, and hexavalent chromium by hematite nanoplate with the exposed {001} facet activating OA under visible light irradiation was 4.75, 2.25, 2.33, and 2.74 times than that by the exposed {110} facet, respectively. Density functional theory (DFT) calculation proved that the OA molecule was more easily adsorbed on the {001} facet of hematite than that on the {110} facet, which would favor the formation of the more Fe(III)-OA complex and reactive species. In addition, the reactive site of metronidazole for the attraction of radicals was identified on the basis of the DFT calculation on the molecular occupied orbitals, and the possible degradation pathway for metronidazole included carbon chain fracture, hydroxyethyl-cleavage, denitrogenation, and hydroxylation. Thus, this finding may offer a valuable direction in designing an efficient iron-based catalyst based on facet engineering for the improved activity of Fenton-like systems such as OA activation.


Assuntos
Poluentes Ambientais , Nanopartículas , Compostos Férricos/química , Ácido Oxálico , Metronidazol , Luz , Peróxido de Hidrogênio/química , Catálise
3.
Microb Cell Fact ; 23(1): 64, 2024 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-38402158

RESUMO

Phosphate solubilizing fungi Penicillium oxalicum (POX) and Red yeast Rhodotorula mucilaginosa (Rho) have been applied in Pb remediation with the combination of fluorapatite (FAp), respectively. The secretion of oxalic acid by POX and the production of extracellular polymers (EPS) by Rho dominate the Pb remediation. In this study, the potential of Pb remediation by the fungal combined system (POX and Rho) with FAp was investigated. After six days of incubation, the combination of POX and Rho showed the highest Pb remove ratio (99.7%) and the lowest TCLP-Pb concentration (2.9 mg/L). The EPS combined with POX also enhanced Pb remediation, which has a 99.3% Pb removal ratio and 5.5 mg/L TCLP-Pb concentration. Meanwhile, Rho and EPS can also stimulate POX to secrete more oxalic acid, which reached 1510.1 and 1450.6 mg/L in six days, respectively. The secreted oxalic acid can promote FAp dissolution and the formation of lead oxalate and pyromorphite. Meanwhile, the EPS produced by Rho can combine with Pb to form EPS-Pb. In the combined system of POX + Rho and POX + EPS, all of the lead oxalate, pyromorphite, and EPS-Pb were observed. Our findings suggest that the combined application of POX and Rho with FAp is an effective approach for enhancing Pb remediation.


Assuntos
Apatitas , Produtos Biológicos , Minerais , Penicillium , Chumbo , Fosfatos , Ácido Oxálico
4.
Sci Total Environ ; 917: 170279, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38280577

RESUMO

The essential point of current study was to investigate the effect of a Fenton-like system established by oxalic acid and Fe(II) on gas emission, organic matter decomposition and humification during composting. Branches were pretreated with Fenton reagents (0.02 M FeCl2·4H2O + 1.5 M H2O2) and then adding 10 % oxalic acid (OA). The treatments were marked as B1 (control), B2 (Fenton reagent), B3 (10% OA) and B4 (Fenton-like reagent). The results collected from 80 d of composting showed that adding Fenton-like reagent benefited the degradation of organic substances, as reflected by the total organic carbon and dissolved organic carbon, and the maximum decomposition rate was observed in B4. In addition, the Fenton-like reagent could improve the synthesis of humus characterized by complex and stable compounds, which was consistent with the spectral parameters (SUVA254, SUVA280, E253/E203 and Fourier transform-infrared indicators) of DOC. Furthermore, the functional microbial succession performance and linear discriminant effect size analyses provided microbial evidence of humification improvement. Notably, compared with the control, the minimum value of CH4 cumulation was reported in B4, which decreased by 30.44 %. Concluded together, the addition of a Fenton-like reagent composed by OA and Fe(II) is a practical way to improve the humification. Furthermore, the mechanisms related to the promotion of humification should be investigated from free radicals, functional genes, and metabolic pathways.


Assuntos
Carbono , Compostagem , Ferro , Animais , Suínos , Esterco , Peróxido de Hidrogênio , Solo , Ácido Oxálico , Bactérias , Compostos Ferrosos , Substâncias Húmicas
5.
Waste Manag ; 174: 44-52, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38006757

RESUMO

With the increasing demand for lithium resources, the efficient recovery of lithium from spent lithium-ion batteries (LIBs) has become the focus of social attention. Herein, a combined process of reduction roasting of herb-medicine residue (HMR) and oxalic acid (OA) leaching is proposed to improve the recovery efficiency of lithium. Due to the large amount of reducing gas produced by the pyrolysis of herb-medicine residue, the layered structure of LiNixCoyMnzO2 cathode powder can be destroyed at 650℃ for 10 min, and the cathode powder is converted into Li2CO3, Ni, Co, MnO. Moreover, about 99.6 % of Li in the roasting residue can be selectively extracted by 0.5 mol L-1 oxalic acid for 20 min. Under the combined action of HMR and OA, the extraction efficiency and kinetics of lithium are improved simultaneously. This work achieves synergistic treatment of two types of waste from the perspective of waste management for waste. Meanwhile, it provides an alternative and innovative approach for the difficult problem of low efficiency of lithium recovery from spent LIBs.


Assuntos
Lítio , Gerenciamento de Resíduos , Ácido Oxálico , Pós , Reciclagem , Fontes de Energia Elétrica
6.
J Hazard Mater ; 465: 133026, 2024 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-38006858

RESUMO

A novel approach of ball milling and oxalic acid was employed to modify sludge-based biochar (BOSBC) to boost its activation performance for peroxymonosulfate (PMS) towards efficient degradation of sulfamethoxazole (SMX). 98.6% of SMX was eliminated by PMS/BOSBC system within 60 min. Furthermore, PMS/BOSBC system was capable of maintaining high removal rates for SMX (>88.8%) in a wide pH range from 3 to 9, and displayed a high tolerance to background electrolytes including inorganic ions and humic acid (HA). Quenching experiments, electron paramagnetic resonance (EPR) analysis, in-situ Raman characterization and PMS decomposition experiments confirmed that the non-radicals of 1O2 and surface-bound radicals were the main contributors to SMX degradation by PMS/BOSBC system. The results of ecotoxicity assessment illustrated that all transformed products (TPs) generated in PMS/BOSBC system were less toxic than that of SMX. After five reuse cycles, PMS/BOSBC system still maintained a high removal rate for SMX (77.8%). Additionally, PMS/BOSBC system exhibited excellent degradation performance for SMX in various real waters (Yangtze River water (76.5%), lake water (74.1%), tap water (86.5%), and drinking water (98.1%)). Overall, this study provided novel insights on non-metal modification for sludge-based biochar and non-radical mechanism, and offered a feasible approach for municipal sludge disposal.


Assuntos
Carvão Vegetal , Sulfametoxazol , Poluentes Químicos da Água , Sulfametoxazol/química , Esgotos , Ácido Oxálico , Poluentes Químicos da Água/química , Peróxidos/química , Água
7.
Int J Phytoremediation ; 26(4): 472-480, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37599450

RESUMO

In order to study the effects of oxalic acids on plant growth and Pb accumulation in different parts of the plants of intercropping Arabis alpina and Zea mays, pot experiment was conducted to investigate the changes of oxalic acid contents of the plants and Pb accumulation through exogenous oxalic acid addition (0, 5, 25 and 50 mmol kg-1). The results showed the root biomass of intercropped A. alpina and total biomass of Z. mays increased by 3.22 folds and 2.97 folds with 5 mmol kg-1 oxalic acid treatment. The oxalic acid contents of shoots and root secretions decreased by 86.5% and 44.3%, respectively. The BCF (bio-accumulation factor) and TF (translocation factor) of intercropping A. alpina reduced under 25 - 50 mmol kg-1 oxalic acid treatments. There were relationships between exogenous oxalic acid treatment concentrations and oxalic acid contents of A. alpina shoots, Z. mays root secretions. The Pb contents of shoots of A. alpina and Z. mays were related to exogenous oxalic acid additions and oxalic acid contents of shoots. In general, 5 mmol kg-1 oxalic acid treatment, that can improve plant growth of intercropped A. alpina and Z. mays, which Pb translocation and accumulation of A. alpina were promoted, whereas Pb accumulation of A. alpina was inhibited with 25 - 50 mmol kg-1 concentrations addition. This study will provide a basis for promoting the application of phytoremediation techniques and efficient crop production in heavy metal contaminated areas.


Hyperaccumulators intercropped with crops will remediate heavy metal soils or mitigate the damage caused by heavy metals to plants through oxalic acid secretion by the root system. However, the effect of oxalic acid changes on plant growth and Pb accumulation is lacking. Our study investigated the changes in oxalic acid content at different concentrations and sites affected the ability of intercropped plants to grow and accumulate Pb. This work shown that under intercropping conditions, exogenous oxalic acid promotes intercropped plant growth as well as soil pH reduction, Pb content in shoots both Arabis alpina and Zea mays is influenced by exogenous oxalic acid content, while lower Z. mays roots Pb content is determined by a combination of exogenous addition and aboveground oxalic acid content. Low concentrations of oxalic acid promoted Pb enrichment in roots of A. alpina, while reducing the uptake of Pb content in Z. mays. This article gives us a better understanding for the response of intercropping plants to the use of organic acids under heavy metal stress and how to modify their environment so as to favor growth.


Assuntos
Arabis , Poluentes do Solo , Zea mays , Chumbo , Ácido Oxálico , Biodegradação Ambiental , Poluentes do Solo/análise , Plantas
8.
Small ; 20(9): e2304941, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37822184

RESUMO

Urolithiasis stands as a prevalent ailment within the urinary system, with hyperoxaluria and hypocitraturia being the most frequent manifestations characterized by excessive oxalic acid (OA) and deficient citric acid (CA) levels in urine. Detecting these compounds in urine quantitatively holds paramount importance for early urolithiasis screening. Existing methodologies fall short in achieving simultaneous and on-site identification of OA and CA, posing challenges for accurate urolithiasis screening. Addressing this concern, the study successfully accomplishes the concurrent identification of OA and CA in urine through a combination of dual-spectral analysis and biomimetic peroxidase utilization. Bovine serum albumin and dithiothreitol-modified copper nanoclusters (BSA-DTT-CuNCs) are employed as biomimetic peroxidases, effectively mitigating interference and enabling the simultaneous determination of OA and CA. The quantification range spans from 0 to 12 mm for OA and 0.5 to 2.5 mm for CA, with detection limits of 0.18 and 0.11 mm, respectively. To facilitate swift and on-location urine analysis, a fully automated urine analyzer (FAUA) is introduced that streamlines the process of biomarker pretreatment and identification within urine samples. Validation with real urine samples from urolithiasis patients demonstrates the method's diagnostic precision, highlighting the dual-spectral technique and analyzer's promising role in urolithiasis screening.


Assuntos
Peroxidase , Urolitíase , Humanos , Ácido Oxálico , Biomimética , Peroxidases , Urolitíase/diagnóstico , Ácido Cítrico , Corantes
9.
J Sci Food Agric ; 104(2): 788-796, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-37669105

RESUMO

BACKGROUND: Calcium is important in the formation of bones and teeth, cell metabolism, and other physiological activities. In this work, casein phosphopeptide-calcium chelate (CPP-Ca) was synthesized and the optimal process parameters for the chelation reaction were obtained. The bioavailability of calcium in CPP-Ca was investigated by in vitro gastrointestinal simulated digestion. The existence of phytic acid and oxalic acid in the digestion system was evaluated to clarify the calcium holding ability of casein phosphopeptide (CPP). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify oligopeptides from CPP-Ca. RESULTS: The optimal process parameters for the chelation reaction were: peptide concentration 7.76 mgmL-1 , pH 8.54, and reaction temperature 43.3 °C. The digestion in vitro results indicated that the calcium release rate of CPP-Ca in the stomach for 2 h reached 85%, and about 50% of the ionized calcium was re-chelated with CPP in the intestine. Phytic acid and oxalic acid could lead to a sharp decrease in soluble calcium but around 50% of the calcium was still retained in the form of chelates in the presence of CPP. The LC-MS/MS identified 19 casein-derived oligopeptides after digestion, and calcium modifications were found on eight peptides derived from ß-casein and αs2 -casein. CONCLUSIONS: This study clarified the excellent calcium holding capacity of CPP in the presence of phytic acid and oxalic acid. Liquid chromatography-tandem mass spectrometry also revealed peptide changes, and identified peptides that chelate with calcium. These findings provided significant insights that could be relevant to the further utilization and product development of peptide-calcium chelate in the food industry. © 2023 Society of Chemical Industry.


Assuntos
Cálcio , Fragmentos de Peptídeos , Cálcio/metabolismo , Fosfopeptídeos/química , Fosfopeptídeos/metabolismo , Caseínas/química , Cromatografia Líquida , Ácido Fítico , Espectrometria de Massas em Tandem , Cálcio da Dieta , Digestão , Oligopeptídeos , Ácido Oxálico
10.
J Insect Sci ; 23(6)2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-38055939

RESUMO

A significant amount of researcher and practitioner effort has focused on developing new chemical controls for the parasitic Varroa destructor mite in beekeeping. One outcome of that has been the development and testing of "glycerol-oxalic acid" mixtures to place in colonies for extended periods of time, an off-label use of the otherwise legal miticide oxalic acid. The majority of circulated work on this approach was led by practitioners and published in nonacademic journals, highlighting a lack of effective partnership between practitioners and scientists and a possible failure of the extension mandate in beekeeping in the United States. Here, we summarize the practitioner-led studies we could locate and partner with a commercial beekeeper in the Southeast of the United States to test the "shop towel-oxalic acid-glycerol" delivery system developed by those practitioners. Our study, using 129 commercial colonies between honey flows in 2017 split into 4 treatment groups, showed no effectiveness in reducing Varroa parasitism in colonies exposed to oxalic acid-glycerol shop towels. We highlight the discrepancy between our results and those circulated by practitioners, at least for the Southeast, and the failure of extension to support practitioners engaged in research.


Assuntos
Mel , Varroidae , Estados Unidos , Animais , Abelhas , Ácido Oxálico/farmacologia , Glicerol/farmacologia , Sudeste dos Estados Unidos , Criação de Abelhas/métodos
11.
J Insect Sci ; 23(6)2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-38055944

RESUMO

Oxalic acid (OA) is a popular miticide used to control Varroa destructor (Mesostigmata: Varroidae) in western honey bee (Apis mellifera L.) (Hymenoptera: Apidae) colonies. Our aim was to investigate which method of OA application (dribbling, fogging, or vaporizing) was the most effective at reducing V. destructor infestations (Experiment 1) and to improve upon this method by determining the treatment interval that resulted in the greatest V. destructor control (Experiment 2). We used the product Api-Bioxal (97% OA) and maintained 40 honey bee colonies (10/treatment) in both experiments. In Experiment 1, the treatments included (i) dribbling 50 ml of 3% OA solution, (ii) vaporizing 4 g of solid OA, (iii) using an insect fogger supplied with 2.5% OA dissolved in ethyl alcohol, and (iv) an untreated control. After 3 weeks, only the vaporization method reduced V. destructor infestations (from 9.24 mites/100 bees pretreatment to 3.25 mites/100 bees posttreatment) and resulted in significantly increased brood amounts and numbers of adult bees over those of the controls. In Experiment 2, all colonies were treated with 4 applications of OA via vaporization at a constant concentration of 4 g OA/colony. In this experiment, the groups were separated by treatment intervals at either 3-, 5-, or 7-day intervals. We observed that 5- and 7-day treatment intervals significantly reduced V. destructor populations from pretreatment levels over that of the controls and 3-day intervals. Our data demonstrate the efficacy of OA in reducing V. destructor infestation, particularly vaporizing 4 g every 5-7 days as the most effective method of application.


Assuntos
Acaricidas , Himenópteros , Varroidae , Abelhas , Animais , Ácido Oxálico , Acaricidas/farmacologia , Volatilização
12.
J Insect Sci ; 23(6)2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-38055946

RESUMO

The ectoparasitic mite, Varroa destructor (Anderson and Trueman), is the leading cause of western honey bee colony, Apis mellifera (L.), mortality in the United States. Due to mounting evidence of resistance to certain approved miticides, beekeepers are struggling to keep their colonies alive. To date, there are varied but limited approved options for V. destructor control. Vaporized oxalic acid (OA) has proven to be an effective treatment against the dispersal phase of V. destructor but has its limitations since the vapor cannot penetrate the protective wax cap of honey bee pupal cells where V. destructor reproduces. In the Southeastern United States, honey bee colonies often maintain brood throughout the year, limiting the usefulness of OA. Prior studies have shown that even repeated applications of OA while brood is present are ineffective at decreasing mite populations. In the summer of 2021, we studied whether incorporating a forced brood break while vaporizing with OA would be an effective treatment against V. destructor. Ninety experimental colonies were divided into 2 blocks, one with a brood break and the other with no brood break. Within the blocks, each colony was randomly assigned 1 of 3 treatments: no OA, 2 g OA, or 3 g OA. The combination of vaporizing with OA and a forced brood break increased mite mortality by 5× and reduced mite populations significantly. These results give beekeepers in mild climates an additional integrated pest management method for controlling V. destructor during the summer season.


Assuntos
Acaricidas , Criação de Abelhas , Abelhas , Ácido Oxálico , Varroidae , Animais , Abelhas/efeitos dos fármacos , Abelhas/parasitologia , Himenópteros/efeitos dos fármacos , Himenópteros/parasitologia , Ácido Oxálico/farmacologia , Estações do Ano , Varroidae/efeitos dos fármacos , Volatilização , Acaricidas/farmacologia , Criação de Abelhas/métodos , Cruzamento/métodos
13.
Environ Geochem Health ; 46(1): 19, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38147168

RESUMO

Antimony (Sb) and arsenic (As) contamination in agricultural soil poses human health risks through agricultural products. Soil washing with degradable low molecular weight organic acids (LMWOAs) is an eco-friendly strategy to remediate agricultural soils. In this study, three eco-friendly LMWOAs, oxalic acid (OA), tartaric acid (TA), and citric acid (CA), were used to treat Sb and As co-contaminated agricultural soil from Xikuangshan mine area. The OA, TA, and CA washed out 18.4, 16.8, and 26.6% of Sb and 15.3, 19.9, and 23.8% of As from the agricultural soil, with CA being the most efficient reagent for the soil washing. These organic acids also led to pH decline and macronutrients losses. Fraction analysis using a sequential extraction procedure showed that the three organic acids targeted and decreased the specifically sorbed (F2) (by 19.3-37.6% and 2.41-23.5%), amorphous iron oxide associated (F3) (by 49.1-61.2% and 51.2-70.2%), and crystallized iron oxide associated (F4) (by 12.3-26.0% and 26.1-29.1%) Sb and As. The leachability of Sb and As, as well as their concentrations and bioconcentration factor (BCF) in vegetables reduced due to the soil washing. It demonstrated that the bioavailability of both the elements was decreased by the organic acids washing. The concentrations of Sb and As in typical vegetable species cultivated in CA washed soil were less than the threshold value for consumption safety, while those in OA and TA washed soils were still higher than the value, suggesting that only CA is a potential washing reagent in soil washing for Sb- and As-contaminated agricultural soil.


Assuntos
Arsênio , Solo , Humanos , Antimônio , Disponibilidade Biológica , Compostos Orgânicos , Ácido Oxálico , Ácido Cítrico
14.
J Agric Food Chem ; 71(46): 17810-17818, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37945529

RESUMO

Zea mays L. is an annual grass of the Gramineae family and is known as one of the cereal crops. Its by-products exhibited significant medicinal properties. In some regions of China, water extracts of Z. mays roots (RM) are utilized to treat kidney stones, but no research has been reported. In our present study, a bioassay-guided isolation method was used to yield five new lignans (1-5) as well as 15 known components, among which 8-15 and 17-20 were first identified from the genus. The fractions and all components were evaluated for their abilities to inhibit sodium oxalate-induced injury to human proximal tubular HK-2 cells. Fraction 50W and compounds 3, 4, and 11 exhibited the most potent activities. Further investigation indicated that these potential agents inhibited the LDH release, decreased the MDA and H2O2 concentrations, and increased the level of SOD2 in HK-2 cells. These results indicated that RM is a promising and valuable crop waste for further development and utilization in nephrolithiasis pharmaceutical research.


Assuntos
Ácido Oxálico , Zea mays , Humanos , Peróxido de Hidrogênio , Rim , China
15.
Environ Sci Pollut Res Int ; 30(56): 119343-119355, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37924400

RESUMO

The heterogeneous catalytic reduction of Cr(VI) to Cr(III) is an effective strategy for aqueous Cr(VI) contamination abatement, which requires the development of highly efficient, low-cost, and recyclable catalysts. Herein, Ni2P/N-doped biocarbon composites (Ni2P/N-BC) were fabricated through an anoxic pyrolysis process using NaCl and KCl as activators. A precursor of yeast biomass provided the essential C, N, and P elements for Ni2P/N-BC formation. When adopted for Cr(VI) reduction in the presence of oxalic acid as a reductant, the fabricated Ni2P/N-BC performed superior catalytic activity with a 100% Cr(VI) reduction efficiency within 10 min (Ni2P/N-BC-5 = 0.2 g L-1, oxalic acid = 0.4 g L-1, Cr(VI) = 20 mg L-1). Typical affecting parameters, e.g., catalyst dosage, oxalic acid loading, reaction temperature, initial solution pH, and water matrix, were investigated. Ni2P/N-BC exhibited good applicability in a broad pH range from 3.0 to 9.0 and in actual aquatic systems. Cr(VI) reduction efficiency remained 92.7% after five recycle runs. Such promising catalytic activity may originate from the well-crystallized Ni2P, N-doped biocarbon framework and high specific surface area of the materials. Preliminary reaction mechanism analysis indicated that the favorable charge state of Ni2P, fast hydrogen transfer, affinity of oxalic acid to Cr(VI), and inherent electron transfer in the biocarbon matrix contributed to effective Cr(VI) reduction. This work not only provides a facile and low-cost strategy to construct Ni2P/N-doped biocarbon nanosheet composite using environmentally benign biomass but also brings new insights for the remediation of Cr(VI) contamination.


Assuntos
Saccharomyces cerevisiae , Poluentes Químicos da Água , Biomassa , Cromo , Ácido Oxálico
16.
Chemosphere ; 344: 140371, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37820874

RESUMO

Unsaturated polyester resins (UPR) are composed of prepolymers and styrene diluents, while the former are produced by co-polycondensation between diol, unsaturated diacid and saturated diacid. In this work, bio-based UPR prepolymers were synthesized from bio-based oxalic acid, itaconic acid, and ethylene glycol, which were then diluted with bio-based isosorbide methacrylate (MI). Meanwhile, the phenylphosphonate were introduced into the molecular chains of prepolymers to achieve intrinsic flame retardancy of bio-based UPR. The potential of the reactive MI diluents as substitutes of volatile styrene, was also assessed through the volatility test, curing kinetics and gel contents analysis. For UPR materials with styrene diluents, the UPR materials can achieve UL-94 V0 level and the 28% of limiting oxygen index (LOI) with 2.63 wt% of phosphorus contents. By contrast, the UPR materials with MI diluents can reach UL-94 V0 level with only 2.14 wt% of phosphorus contents. As the phosphorus contents were further increased to 2.63 wt%, UPR materials can achieve highest 29%, while the peak of heat release rate (PHRR) and total heat release (THR) were decreased by 68.01% and 48.62%, respectively. The Flame Retardancy Index (FRI) was also used to comprehensively evaluate the flame retardant performance of UPR composites. Compared with neat UPR, the composites with MI diluents and phosphorus containing structures increased from 1.00 to 6.46. The mechanism for improved flame retardancy was analyzed from gaseous and condensed phase. Additionally, the tensile strengths of bio-based UPR materials with styrene and MI diluents were studied. This work provides an effective method to prepared high-performance and fully bio-based UPR materials with improved flame retardant properties and safety application of reactive diluents.


Assuntos
Retardadores de Chama , Poliésteres , Excipientes , Isossorbida , Ácido Oxálico , Fósforo , Estirenos
17.
Chemosphere ; 345: 140500, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37866501

RESUMO

Chemically mediated recovery of phosphorous (P) as vivianite from the sludges generated by chemical phosphorus removal (CPR) is a potential means of enhancing sustainability of wastewater treatment. This study marks an initial attempt to explore direct P release and recovery from lab synthetic Fe-P sludge via reductive dissolution using ascorbic acid (AA) under acidic conditions. The effects of AA/Fe molar ratio, age of Fe-P sludge and pH were examined to find the optimum conditions for Fe-P reductive solubilization and vivianite precipitation. The performance of the reductive, chelating, and acidic effects of AA toward Fe-P sludge were evaluated by comparison with hydroxylamine (reducing agent), oxalic acid (chelating agent), and inorganic acids (pH effect) including HNO3, HCl, and H2SO4. Full solubilization of Fe-P sludge and reduction of Fe3+ were observed at pH values 3 and 4 for two Fe/AA molar ratios of 1:2 and 1:4. Sludge age (up to 11 days) did not affect the reductive solubilization of Fe-P with AA addition. The reductive dissolution of Fe-P sludge with hydroxylamine was negligible, while both P (95 ± 2%) and Fe3+ (90 ± 1%) were solubilized through non-reductive dissolution by oxalic acid treatment at an Fe/oxalic acid molar ratio 1:2 and a pH 3. With sludge treatment with inorganic acids at pH 3, P and Fe release was very low (<10%) compared to AA and oxalic acid treatment. After full solubilization of Fe-P sludge by AA treatment at pH 3 it was possible to recover the phosphorus and iron as vivianite by simple pH adjustment to pH 7; P and Fe recoveries of 88 ± 2% and 90 ± 1% respectively were achieved in this manner. XRD analysis, Fe/P molar ratio measurements, and magnetic attraction confirmed vivianite formation. PHREEQC modeling showed a reasonable agreement with the measured release of P and Fe from Fe-P sludge and vivianite formation.


Assuntos
Fósforo , Águas Residuárias , Esgotos , Eliminação de Resíduos Líquidos , Fosfatos , Ácido Ascórbico , Ácido Oxálico , Hidroxilaminas
18.
Ecotoxicol Environ Saf ; 266: 115593, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37856985

RESUMO

Vermicompost is a promising amendment for immobilization of cadmium (Cd) in soils; however, its effectiveness can be influenced by rhizosphere environment conditions, such as pH and the presence of low-molecular-weight organic acids (LMWOAs). In this study, a batch experiment was conducted to examine the characteristics of Cd adsorption by vermicompost at different pH (pH = 3, 5, and 7) and after the addition of different LMWOAs (oxalic acid; citric acid; malic acid). Furthermore, a series of morphology and structural analyses were conducted to elucidate the mechanisms of observed effects. The results showed that the adsorption capacity of vermicompost for Cd increased as pH increased, and chemisorption dominated the adsorption process. Changes in pH altered adsorption performance by affecting the -OH groups of alcohol/phenol and the -CH2 groups of aliphatics. Further, the addition of oxalic acid promoted Cd adsorption, and the effect was concentration dependent. Modifying the verimicompost surface with more adsorption sites might be the main reason. Conversely, citric acid and malic acid showed the ability to inhibit Cd adsorption by vermicompost. Citric acid caused a blocking effect by covering flocculent substances on the vermicompost surface while reducing surface adsorption sites by dissolving mineral components such as iron oxides. However, the action of malic acid did not appear to be related to changes in morphology or the structure of vermicompost. Overall, the results of this study partially explain the limited effectiveness of Cd immobilization within the rhizosphere by vermicompost, and provide theoretical support for regulating rhizosphere environments to improve the effectiveness of vermicompost immobilization of Cd.


Assuntos
Cádmio , Poluentes do Solo , Cádmio/análise , Adsorção , Rizosfera , Solo/química , Compostos Orgânicos , Ácido Oxálico/química , Ácido Cítrico/química , Concentração de Íons de Hidrogênio , Poluentes do Solo/análise
19.
Int J Pharm ; 647: 123516, 2023 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-37863447

RESUMO

Thiabendazole is an anthelmintic drug used to treat strongyloidiasis (threadworm), cutaneous and visceral larva migrans, trichinosis, and other parasites. The active pharmaceutical ingredient is typically administered orally as tablets that should be chewed before swallowing. Current formulations combine the active ingredient with excipients, including sodium saccharinate as a sweetener. Thiabendazole's low aqueous solubility hinders fast dissolution and absorption through the mucous membranes. We sought to reformulate this medicine to improve both solubility and palatability. We utilized the possibility of protonation of the azole nitrogen atom and selected four different hydrogen donors: saccharin, fumaric, maleic, and oxalic acids. Solvothermal synthesis resulted in salts with each co-former, whereas neat and liquid-assisted grinding enabled the synthesis of additional formulations. Product formation was observed by powder X-ray diffraction. To better understand the structural basis of the proton transfer, we solved the crystal structures of the salts with saccharin, maleic acid, and oxalic acid using single-crystal X-ray diffraction. The structure of the salt with fumaric acid was solved by powder X-ray diffraction. We further characterized the salts with vibrational spectroscopic and thermoanalytical methods. We report a broad tunability of the aqueous solubility of thiabendazole by salt formation. Reformulation with maleic acid provided a 60-fold increase in solubility, while saccharin and oxalic acid gave a modest improvement. Fumaric acid resulted in a solid with only slightly higher solubility. Furthermore, saccharin is a sweetener, while the acids taste sour. Therefore, the salts formed also result in an intrinsic improvement of palatability. These results can inform new strategies for oral and chewable tablet formulations for treating helminthic infections.


Assuntos
Anti-Helmínticos , Anti-Infecciosos , Sais/química , Sacarina/química , Pós , Tiabendazol , Difração de Raios X , Solubilidade , Edulcorantes , Comprimidos , Ácido Oxálico
20.
Food Res Int ; 173(Pt 2): 113416, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37803754

RESUMO

A novel stable PVA/HPMC/roselle anthocyanin (RAE) indicator film co-pigmented with oxalic acid (OA) was prepared, its properties, application effects and stability enhancement mechanism were investigated correspondingly. The structural characterization revealed that more stable network was formed due to the co-pigmentation facilitated generation of molecular interactions. Meanwhile, the co-pigmentation improved film mechanical and hydrophobic properties compared to both PVA/HPMC/RAE newly prepared (PHRN) or stored (PHRS) film, expressing as higher tensile strength values (12.25% and 14.44% higher than PHRN and PHRS), lower water solubility (7.22% and 10.09% lower than PHRN and PHRS) and water vapor permeability values (33.20% and 21.05% lower than PHRN and PHRS) of PVA/HPMC/RAE/OA newly prepared (PHON) or stored (PHOS) film. Compared with the PHRS film, the PHOS film still presented more distinguishable color variations when being applied to monitor shrimp freshness, owing to the stabilization behaviors of co-pigmentation in anthocyanin conformation. Hence, the co-pigmentation was an effective strategy to enhance film stability, physical and pH-responsive properties after long term storage, leading to better film monitoring effects when applied in real-time freshness monitoring.


Assuntos
Antocianinas , Hibiscus , Antocianinas/química , Ácido Oxálico , Resistência à Tração , Permeabilidade
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