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1.
Sci Total Environ ; 955: 177126, 2024 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-39461528

RESUMO

Reducing substances are a mixture of different forms and types and play extremely important roles in manipulating the redox status of sediments, benthic habitats, and substance exchanges at the sediment-water interface in aquatic ecosystems. However, little is known about their abundance, forms, and reducibility in sediments. In this study, the procedures were developed to sequentially fractionate sediment reducing capacity (RC) fractions with the pH dependence of KMnO4 oxidability. The procedures were then applied to 60 sediments from 2 lakes and 3 reservoirs, generating an RCpH7.0 fraction (oxidized at ~0.48 V [reference: SHE]) and an RCpH2.0 fraction (oxidized at ~0.95 V [reference: SHE]), and the component of each fraction was characterized. The RCpH7.0 fraction amounted to 45.4 ± 25.9 cmol e-·kg-1 DW, and the RCpH2.0 fraction amounted to 42.8 ± 22.9 cmol e-·kg-1 DW; fraction sizes depended greatly on sediment origin. Reducing organic substances (ROS) were the main contributors to the RC fractions, with mean value of 30.0 ± 24.1 and 38.5 ± 22.2 cmol e-·kg-1 DW in RCpH7.0 (% contribution: 68.0 ± 5.3 % of RCpH7.0) and RCpH2.0 (90.0 ± 1.5 % of RCpH2.0), respectively. The next contributor was Fe(II), with mean value of 13.5 ± 8.2 and 3.8 ± 3.7 cmol e-·kg-1 DW in RCpH7.0 (28.3 ± 5.2 %) and in RCpH2.0 (9.9 ± 8.6 %), respectively. The smallest component was sulfide (Sn), which had a mean of 2.0 ± 3.1 cmol e-·kg-1 DW in RCpH7.0 and was essentially negligible in RCpH2.0. The number of electrons lost per mole of reducing substances (Ni) differed between the two RC fractions and among sediments of different origins. NROS was lower in the RCpH7.0 fraction (0.22 ± 0.09) compared to the RCpH2.0 fraction (0.31 ± 0.12) and significantly related to levels of active Fe(III) and sulfides (Sn) (p < 0.05). The opposite pattern was seen for NFe(II) and NSn. Based on the compositive reducing capacity (CRC) for the RCpH7.0 fraction, sediment redox status could be classified as ROS-Fe(II) (3.8 ± 1.7 cmol e-·kg-1 DW) or ROS-Sn (10.1 ± 4.8 cmol e-·kg-1 DW) (weaker vs. stronger, respectively; p < 0.01). The RC-based index provides a more comprehensive perspective on characterizing sediment redox status compared to the Eh.

2.
Food Chem X ; 23: 101768, 2024 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-39280211

RESUMO

This study explored the impact of three packaging materials (wooden boxes, corrugated fiber boxes, shrink-wrapped boxes) combined with two ethylene scrubbers (1-MCP, KMnO4) on the shelf life of Golden Delicious apples. While previous research has extensively studied the effects of packaging and ethylene inhibitors independently, the novelty of this work lies in its combined evaluation of these factors under ambient storage conditions over an extended period of 160 days. The study specifically addresses a research gap by directly comparing the efficacy of 1-MCP and KMnO4 within different packaging environments, offering insights into their combined influence on key quality parameters such as firmness, juice yield, rot incidence, physiological loss in weight (PLW), acidity, and total soluble solids (TSS). Findings revealed that 1-MCP-treated apples, particularly when shrink-wrapped, experienced minimal reductions in firmness and juice yield, with significantly lower rot incidence and physiological loss in weight (PLW) compared to KMnO4-treated and control apples. Additionally, while acidity and juice content naturally declined over time, and TSS initially increased before decreasing, 1-MCP-treated apples exhibited more stable quality attributes. The study also noted a slower decline in organoleptic quality with 1-MCP and shrink-wrap packaging. The research concludes that the combination of 1-MCP treatment and shrink-wrap packaging most effectively extends the shelf life of Golden Delicious apples, highlighting the importance of integrated approaches to post-harvest management. This study provides a novel framework for improving storage techniques, particularly for ambient conditions where shelf life extension is most challenging.

3.
Sci Rep ; 14(1): 22510, 2024 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-39341927

RESUMO

The integration of natural fibers into Fiber Reinforced Polymers (FRPs) has emerged as a promising avenue for sustainable and high-performance composite materials. Natural fibers, derived from plants, offer notable advantages such as renewability, low cost, and environmental friendliness. Among these natural fibers, Hibiscus Rosa-Sinensis (HRS) plant fibers have gained significant attention owing to their widespread availability and unique mechanical properties. In this study, HRS fibers were chemically treated using Sodium Hydroxide (NaOH), Potassium Permanganate (KMnO4), and Acetic Acid (CH3COOH) at different weight percentages (3, 4, 5 Wt.%) and solutionizing times (1, 2, 3 h) based on Taguchi's L27 orthogonal array. The fibers, extracted from epidermis of the stems, underwent cleaning and chemical treatment after water retting. The crystallinity index, determined via X-ray Diffraction (XRD), indicated a maximum value of 65.77%. Thermo-gravimetric analysis (TGA) exhibited a degradation temperature of 365.24 °C and a material loss of 63.11%. Potassium Permanganate treatment at 4 Wt.% and 3 h of solutionizing time has yielded the best results. Multi-Layer Perceptron Artificial Neural Network (MLP-ANN) has been successfully applied to accurately predict the output physical characteristics of chemically treated HRS fibers using experimental data. The results are in close alignment with the literature. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) analyses have provided valuable insights into the microstructure and constituents of the chemically treated HRS fibers. This research emphasises on the effectiveness of the chemical treatment process in enhancing the properties of HRS plant fibers for potential composite applications.


Assuntos
Hibiscus , Redes Neurais de Computação , Hibiscus/química , Difração de Raios X , Permanganato de Potássio/química , Termogravimetria , Hidróxido de Sódio/química
4.
Environ Res ; 260: 119662, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39043355

RESUMO

Ultrafiltration (UF) is a highly efficient technique for algal-rich water purification, but it is heavily contaminated due to the complex water characteristics. To solve this problem, potassium permanganate (KMnO4) oxidation enhanced with sodium sulfite (Na2SO3) was proposed as a pretreatment means. The results showed that the end-normalized flux was elevated from 0.10 to 0.91, and the reversible fouling resistance was reduced by 99.95%. The membrane fouling mechanism also changed obviously, without the generation of cake filtration. Regarding the properties of algal-rich water, the zeta potential was decreased from -29.50 to -5.87 mV after KMnO4/Na2SO3 pretreatment, suggesting that the electrostatic repulsion was significantly reduced. Meanwhile, the fluorescent components in algal-rich water were significantly eliminated, and the removal of dissolved organic carbon was increased to 67.46%. In the KMnO4/Na2SO3 process, reactive manganese species (i.e., Mn(V), Mn(III) and MnO2) and reactive oxygen species (i.e., SO4•- and •OH) played major roles in purifying algal-rich water. Specifically, SO4•-, •OH, Mn(V) and Mn(III) could effectively oxidize algal pollutants. Simultaneously, the in-situ adsorption and coagulation of MnO2 could accelerate the formation of flocs by decreasing the electrostatic repulsion between cells, and protect the algal cells from being excessive oxidized. Overall, the KMnO4/Na2SO3 process showed significant potential for membrane fouling alleviation in purifying algal-rich water.


Assuntos
Permanganato de Potássio , Espécies Reativas de Oxigênio , Sulfitos , Purificação da Água , Permanganato de Potássio/química , Purificação da Água/métodos , Sulfitos/química , Espécies Reativas de Oxigênio/metabolismo , Membranas Artificiais , Manganês/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Ultrafiltração/métodos , Oxirredução
5.
Sci Rep ; 14(1): 12754, 2024 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-38830936

RESUMO

Humans are the only species who generate waste materials that cannot be broken down by natural processes. The ideal solution to this waste problem would be to employ only compostable materials. Biodegradable materials play a key role in creating a safer and greener world. Biodegradability is the gift that keeps on giving, in the sense of creating an Earth worth living. The future is thus best served by green energy, sustainability, and renewable resources. To realize such goals, waste should be considered as a valuable resource. In this context, Zea mays (Zm) root fibres, which are normally considered as agricultural waste, can be used as reinforcing substances in polymer matrices to produce structural composite materials. Before being used in composites, such fibres must be analysed for their physical properties. Chemical treatments can be employed to improve the structural quality of fibres, and the changes due to such modification can be analysed. Therefore, the current work examines the effect of permanganate treatment on the surface properties of Zm fibres. The raw and potassium permanganate-treated samples were assayed for various properties. Physical analysis of the fibre samples yielded details concerning the physical aspects of the fibres. The thermal conductivity and moisture absorption behaviour of the samples were analysed. Chemical analysis was employed to characterize the composition of both treated and untreated samples. p-XRD was employed to examine the crystalline nature of the Zm fibres. Numerous functional groups present in each sample were analysed by FTIR. Thermogravimetric analysis was used to determine the thermal stability of Zm fibres. Elemental analysis (CHNS and EDS) was used to determine the elemental concentrations of both raw and treated samples. The surface alterations of Zm fibres brought on by treatment were described using SEM analysis. The characteristics of Zm roots and the changes in quality due to treatment were reviewed, and there were noticeable effects due to the treatment. Both samples would have applications in various fields, and each could be used as a potential reinforcing material in the production of efficient bio-composites.


Assuntos
Raízes de Plantas , Permanganato de Potássio , Zea mays , Zea mays/química , Zea mays/metabolismo , Permanganato de Potássio/química , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Biodegradação Ambiental , Condutividade Térmica
6.
Chemosphere ; 363: 142716, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38945223

RESUMO

Due to its adverse health and environmental impacts, groundwater contamination by toxic organic compounds such as chlorinated solvents is a global concern. The slow-release permanganate gel (SRP-G) is a mixture of potassium permanganate (KMnO4) and colloidal silica solution. The SRP-G is designed to radially spread after injection via wells, gelate in situ to form gel barriers containing permanganate (MnO4-), and slowly release MnO4- to treat plumes of chlorinated solvents in groundwater. This study aimed to characterize the effects of temperature on the dynamics of SRP-G in saturated porous media. In gelation batch tests, the viscosity of ambient-temperature (24 °C) SRP-G with 30 g/L-KMnO4 was 21 cP at 70 min, 134 cP at 176 min, and peaked at 946 cP to solidification at 229 min. The viscosity of low-temperature (4 °C) SRP-G with 30 g/L-KMnO4 was 71 cP at 273 min, 402 cP at 392 min, and peaked at 818 cP to solidification at 485 min. A similar pattern, e.g., increased gelation lag time with low-temperature SRP-G, was observed for SRP-Gs with 40 g/L, 50 g/L, and 60 g/L KMnO4. In flow-through tests using a glass column filled with saturated sands, injection rates, spreading rates, and release durations were 0.6 mL/min, 46 mm/min, and 33 h for KMnO4(aq), 0.2 mL/min, 2 mm/min, and 38 h for ambient-temperature SRP-G, and 0.4 mL/min, 16 mm/min, and 115 h for low-temperature SRP-G, respectively. These results indicated that the injectability, injection rate, and gelation lag time of SRP-G and the size, release rate, and release duration of MnO4- gel barriers can be increased at low temperatures. The low-temperature SRP-G scheme can be useful for treating large or dilute dissolved plumes of chlorinated solvents or other pollutants in groundwater.


Assuntos
Recuperação e Remediação Ambiental , Géis , Água Subterrânea , Compostos de Manganês , Óxidos , Permanganato de Potássio , Poluentes Químicos da Água , Água Subterrânea/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Porosidade , Recuperação e Remediação Ambiental/métodos , Óxidos/química , Géis/química , Permanganato de Potássio/química , Compostos de Manganês/química , Temperatura , Viscosidade , Temperatura Baixa , Dióxido de Silício/química
7.
Drug Chem Toxicol ; : 1-13, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38508688

RESUMO

The present study aimed to elucidate the suitability of formalin and KMnO4 as therapeutics for fish diseases in Indian major carp, Labeo rohita, while considering their impact on fish stress levels. Acute toxicity tests revealed that the 96-hour LC50 values for formalin and KMnO4 were 66.58 ppm and 2.89 ppm, respectively. Sub-lethal concentrations of formalin (6.65 ppm, 3.32 ppm, and 2.21 ppm) and KMnO4 (0.289 ppm, 0.145 ppm, and 0.096 ppm), along with control groups, were administered to the fish for different exposure periods (24, 48, 72, and 96 hours) and different hematological, biochemical, and immunological parameters were analyzed. The findings demonstrated that formalin exposure resulted in a significant decrease (p < 0.05) in hematological parameters, immunological parameters, and serum protein levels. Conversely, formalin exposure led to significant increases (p < 0.05) in serum glucose, SGOT, SGPT, and ALP levels. In contrast, KMnO4 exposure significantly decreased (p < 0.05) hematological parameters and serum protein levels, while significantly increasing (p < 0.05) immunological parameters. To evaluate curative efficacy, challenge studies were conducted using three sub-lethal concentrations of formalin and KMnO4 against Aeromonas hydrophila (ATCC 7966) infection. Based on the aforementioned results, the recommended doses of formalin and KMnO4 were found to be 6.65 ppm and 0.289 ppm, respectively.

8.
J Fish Dis ; 47(2): e13891, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37990596

RESUMO

Micropterus salmoides rhabdovirus (MSRV) is a significant pathogen that causes high morbidity and mortality in largemouth bass, leading to enormous economic losses for largemouth bass aquaculture in China. The aim of this study was to investigate the efficacy of four disinfectants (potassium permanganate, glutaraldehyde, trichloroisocyanuric acid and povidone iodine) on MSRV, to control the infection and transmission of MSRV in largemouth bass aquaculture. The disinfectants were tested at different concentrations (5, 25, 50, 100 and 500 mg/L) prepared with distilled water for 30 min contact time, and the viral nucleic acid was quantified using qPCR and the infectivity was tested by challenge experiment. Potassium permanganate at 5-500 mg/L, glutaraldehyde at 500 mg/L, trichloroisocyanuric acid at 50-500 mg/L and povidone iodine at 500 mg/L concentration could effectively decrease the virus nucleic acid, and the survival rate of largemouth bass juveniles after challenge experiment increased significantly from 3.7% ± 6.41% to 33.33 ± 11.11% - 100%. Moreover, the minimum effective time of 5 mg/L potassium permanganate was further studied at 2, 5, 10 and 20 min contact time. The viral nucleic acid decreased significantly at 5-20 min exposure time, and the survival rate increased significantly from 7.41% ± 6.41% to 77.78 ± 11.11% - 100%. The median lethal concentration (LC50 ) values of potassium permanganate were 10.64, 6.92 and 3.7 mg/L at 24, 48 and 96 h, respectively. Potassium permanganate could be used for the control of MSRV in the cultivation process; the recommended concentration is 5 mg/L and application time should be less than 24 h. The results could be applied to provide a method to control the infection and transmission of MSRV in water, and improve the health status of largemouth bass.


Assuntos
Bass , Desinfetantes , Doenças dos Peixes , Ácidos Nucleicos , Rhabdoviridae , Animais , Desinfetantes/farmacologia , Glutaral , Permanganato de Potássio , Povidona-Iodo , Doenças dos Peixes/prevenção & controle , Água
9.
Chemosphere ; 346: 140641, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37939932

RESUMO

In this study, we systematically explore coagulation behavior, ultrafiltration membrane fouling behavior and the mechanism involved in during the process of pre-oxidation of potassium permanganate and coagulation of aluminum chloride at different condition to treat model pollutants (humic acid, HA) and natural water. The KMnO4 pre-oxidation significantly enhances flocs formation, and for HA artificial water the flocs size increases from 82 to 122 µm at pH 5.5, from 63 to 185 µm at pH 7.0 and from 0 to 75 µm at pH 8.5, respectively, as for natural water it increases from 72 to 139 µm. The enhanced coagulation at pH 5.5 is attributed to the increased polymeric Al speciation after pre-oxidation along with the generated Mn2+ damaging the electric double layer structure. And for pH 8.5 it is mainly caused by the in-situ MnO2 as combination nuclei during pre-oxidation. Besides, for pH 7.0, the combined effect of in-situ MnO2 and the increased polymeric Al speciation both contribute to improvement of the coagulation. What's more, the enhanced Al coagulation by pre-oxidation of KMnO4 also helps alleviate the membrane fouling for both HA artificial water and natural water, and a much rougher surface with larger flocs forms after KMnO4-aided Al coagulation filtration. This study provides an alternative perspective on the mechanism of pre-oxidation coagulation process.


Assuntos
Permanganato de Potássio , Purificação da Água , Permanganato de Potássio/química , Compostos de Manganês , Óxidos , Membranas Artificiais , Ultrafiltração , Água
10.
Heliyon ; 9(11): e21957, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38028001

RESUMO

Recovering resources from wastewater treatment is vital for the transition from a linear to a circular economy model in the water sector. Volatile Fatty Acids (VFAs) are valuable products among the possible recovered resources. This study investigates the influence of potassium permanganate (KMnO4) addition during acidogenic fermentation of waste activated sludge for enhancing VFAs production. Specifically, different fermentation batch tests with and without KMnO4 addition were carried out using two distinctive sewage sludges as feedstocks. Results showed that KMnO4 addition increased the VFAs yield up to 144 and 196 mgCOD/g VSS for the two sludges. When KMnO4 was used as pre-treatment, 55 % of sCOD were VFAs. This latter result was mainly debited to the recalcitrant organics' disruption promoted by the oxidative permanganate ability.

11.
Heliyon ; 9(10): e20858, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37867834

RESUMO

In-situ chemical oxidation (ISCO) is a commonly used method for the remediation of environmental contaminants in groundwater systems. However, traditional ISCO methods are associated with several limitations, including safety and handling concerns, rebound of groundwater contaminants, and difficulty in reaching all areas of contamination. To overcome these limitations, novel Controlled-Release Biodegradable Polymer (CRBP) pellets containing the oxidant KMnO4 were designed and tested. The CRBP pellets were encapsulated in Polyvinyl Acetate (CRBP-PVAc) and Polyethylene Oxide (CRBP-PEO) at different weight percentages, baking temperatures, and time. Their release efficiency was tested in water, soil, and water and soil mixture media. Results showed that CRBP-PVAc pellets with 60 % KMnO4 and baked at 120 °C for 2 min had the highest release percentage and rate across different conditions tested. Natural organic matter was also found to be an important factor to consider for in-field applications due to its potential reducing effect with MnO4-. Overall, the use of CRBP pellets offers an innovative and sustainable solution to remediate contaminated groundwater systems, with the potential to overcome traditional ISCO limitations. These findings suggest that CRBP pellets could provide sustained and controlled release of the oxidant, reducing the need for multiple injections and minimizing safety and handling concerns. This study represents an important step towards developing a new and effective approach for ISCO remediation.

12.
MethodsX ; 11: 102395, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37791011

RESUMO

Traditional methods for determining superoxide dismutase (SOD) content and catalase (CAT) activity rely on measuring the absorbance of individual tissue (biological) samples using a cuvette and spectrophotometer, rather than cell cultures. Although there are kits available for SOD and CAT assays, these allow for high-throughput analysis of samples and might be too expensive for research laboratories in countries from the Global South, such as South Africa. This paper describes a simple and cost-effective method to determine SOD content and CAT activity in mammalian cell cultures following exposure to environmental chemical mixtures by measuring absorbance in 96-well microplates. Moreover, the equipment used for this method is considered standard for cell culture laboratories, while the reagents and consumables are easily obtainable.•Antioxidant enzyme levels can be measured in vitro in cell cultures.•The supernatant obtained can be used to determine protein concentration, SOD content, and CAT activity.•This method is simple and affordable, allowing for the analysis of multiple samples (up to 32 samples per microplate).

13.
Int J Surg Case Rep ; 111: 108802, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37725858

RESUMO

INTRODUCTION AND IMPORTANCE: Potassium permanganate has been historically used as an abortifacient, but it is now considered an outdated practice. Despite the lack of scientific evidence supporting its effectiveness as an abortifacient, some communities still hold misguided beliefs about its abortifacient properties. CASE PRESENTATION: We report a case of a 38-year-old multiparous North African woman. Who experienced excessive vaginal bleeding after using potassium permanganate as an abortifacient. The examination revealed carbonized ulcerated lesions on the vaginal walls and cervix. Once the patient was stabilized, the medical team performed sutures on the vaginal lesions and inserted an intravaginal tampon to arrest the bleeding. The patient was discharged after 72 h. CLINICAL DISCUSSION: In the last century, potassium permanganate was utilized as a method of abortion, but this practice has gradually fallen out of use. Regrettably, due to misinformation and a lack of comprehensive documentation, certain underdeveloped regions persist in employing this unsafe approach. The aim of this report is to inform obstetricians about the harmful effects of potassium permanganate, and the injuries it can cause. Given the scarcity and age of published reports on the subject, this document highlights the crucial importance of proper management to prevent these practices and ensure the safety of the women concerned. CONCLUSIONS: The use of potassium permanganate in abortion presents serious risks, and despite its outdated nature, false beliefs about its abortifacient properties persist. Raising awareness among healthcare professionals and the general public is crucial in preventing the harmful effects of these erroneous beliefs.

14.
Bioresour Technol ; 386: 129482, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37451511

RESUMO

Hydrochars formed by hydrothermal carbonization of hickory wood, bamboo, and wheat straw at 200 °C were modified by potassium permanganate (KMnO4) for the sorption of Pb(II), Cd(II), and Cu(II). The wheat straw hydrochar (WSHyC) modified with 0.2 M KMnO4 resulted in the most promising adsorbent (WSHyC-0.2KMnO4). Characterization of WSHyC and WSHyC-0.2KMnO4 revealed that the modified hydrochar features large specific surface area, rich of surface oxygenic functional groups (OCFG), and a significant amount of MnOx micro-particles. Batch adsorption experiments indicated that the adsorption rate by WSHyC-0.2KMnO4 was faster than for WSHyC, attaining equilibrium after around 5 h. The optimum adsorption capacity (Langmuir) of Pb(II), Cd(II), and Cu(II) by WSHyC-0.2KMnO4 was 189.24, 29.06 and 32.68 mg/g, respectively, 12 âˆ¼ 17 times greater than by WSHyC. The significantly enhanced heavy metal adsorption can be attributable to the increased OCFG and MnOx microparticles on the surface, thereby promoting ion exchange, electrostatic interactions, and complexation mechanisms.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Cádmio , Permanganato de Potássio , Carvão Vegetal , Chumbo , Adsorção , Triticum , Cinética
15.
Chemosphere ; 336: 139153, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37290516

RESUMO

Radical-based advanced oxidation process (AOPs) has attracted great interests in wastewater treatment field. However, by the traditional radical-based method, the degradation of organic pollution is greatly suppressed when radicals react with the co-existing anions in the solution. Herein, an efficient method for degrading of contaminant under high salinity conditions is discussed through a non-radical pathway. Carbon nanotubes (CNTs) was employed as an electron transfer medium to facilitate the electron conversion from contaminants to potassium permanganate (PM). Based the results of quenching experiments, probe experiments, and galvanic oxidation process experiments, the degradation mechanism of CNTs/PM process was demonstrated to be electron transfer, rather than reactive intermediate Mn species. As a result, typical influencing factors including salt concentration, cations, and humic acid have less of an impact on degradation during CNTs/PM processes. In addition, the CNTs/PM system exhibits superior reusability and universality of pollutants, which has the potential to be applied as a non-radical pathway for the purification of contaminant in the large-scale high salinity wastewater treatment.


Assuntos
Descontaminação , Nanotubos de Carbono , Poluentes Químicos da Água , Oxirredução , Óxidos , Salinidade
16.
Huan Jing Ke Xue ; 44(6): 3278-3287, 2023 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-37309946

RESUMO

In this study, coconut shell biochar modified by KMnO4 (MCBC) was used as the adsorbent, and its removal performance and mechanism for Cd(Ⅱ) and Ni(Ⅱ) were discussed. When the initial pH and MCBC dosage were separately 5 and 3.0 g·L-1, respectively, the removal efficiencies of Cd(Ⅱ) and Ni(Ⅱ) were both higher than 99%. The removal of Cd(Ⅱ) and Ni(Ⅱ) was more in line with the pseudo-second-order kinetic model, indicating that their removal was dominated by chemisorption. The rate-controlling step for Cd(Ⅱ) and Ni(Ⅱ) removal was the fast removal stage, for which the rate depended on the liquid film diffusion and intraparticle diffusion (surface diffusion). Cd(Ⅱ) and Ni(Ⅱ) were mainly attached to the MCBC via surface adsorption and pore filling, in which the contribution of surface adsorption was greater. The maximum adsorption amounts of Cd(Ⅱ) and Ni(Ⅱ) by MCBC were individually 57.18 mg·g-1 and 23.29 mg·g-1, which were approximately 5.74 and 6.97 times that of the precursor (coconut shell biochar), respectively. The removal of Cd(Ⅱ) and Zn(Ⅱ) was spontaneous and endothermic and had obvious thermodynamic characteristics of chemisorption. Cd(Ⅱ) was attached to MCBC through ion exchange, co-precipitation, complexation reaction, and cation-π interaction, whereas Ni(Ⅱ) was removed by MCBC via ion exchange, co-precipitation, complexation reaction, and redox. Among them, co-precipitation and complexation were the main modes of surface adsorption of Cd(Ⅱ) and Ni(Ⅱ). Additionally, the proportion of amorphous Mn-O-Cd or Mn-O-Ni in the complex may have been higher. These research results will provide important technical support and theoretical basis for the practical application of commercial biochar in the treatment of heavy metal wastewater.


Assuntos
Cocos , Permanganato de Potássio , Cádmio , Adsorção
17.
Ultrason Sonochem ; 98: 106502, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37379744

RESUMO

1000 kHz high-frequency ultrasound at 0.12 and 0.39 W/mL intensity was used to enhance the inactivation of suspensions of Microcystis aeruginosa cells using KMnO4. With 10 mg/L of KMnO4, ultrasound at 0.12 W/mL intensity was found to be effective in inactivating the cyanobacteria within 10 min. A Weibull model was found to describes the inactivation well. Its concave shape shows that some cells have a certain resistance to this treatment. Cytometry and microscopic analysis confirm that the treatment damages cell integrity. Despite that the extracellular organic matter in the water was not significantly increased. The concentration of extracellular cyanobacterial toxins even decreased. The filtered suspension of inactivated cyanobacteria was used to cultivate mung beans, and the suspension did not hinder their germination. This provides a new idea for using cyanobacteria-laden wastewater. These findings suggest a technique for speeding up the oxidation of Microcystis cells using KMnO4 with ultrasound at moderate intensity, which provide new insights into the biological effects of ultrasound.


Assuntos
Cianobactérias , Microcystis , Purificação da Água , Permanganato de Potássio/farmacologia , Oxirredução , Purificação da Água/métodos
18.
Ecotoxicol Environ Saf ; 262: 115171, 2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37348221

RESUMO

The remediation of cadmium (Cd) contaminated soil is challenging for agricultural practices. In this study, a novel vinasse biochar modified by potassium ferrate (K2FeO4) was synthesized to immobilize Cd in agricultural soil. Three biochars [i.e., vinasse biochar (BC), KMnO4 modified vinasse biochar (MnBC), and K2FeO4 modified vinasse biochar (FeBC)] were applied to compare their efficiencies of Cd immobilization. The results showed that the orders of pH, ash content, and functional groups in different biochar were the same following BC < MnBC < FeBC. Scanning electron microscope images showed that the FeBC has more micropores than MnBC and BC. X-ray diffraction identified manganese oxides and iron oxides within MnBC and FeBC, indicating that Mn and Fe were well loaded on the biochar. In the soil-based pot experiment, both MnBC and FeBC significantly reduced soil available Cd by 23-38% and 36-45% compared with the control, respectively (p < 0.05). In addition, the application of BC, MnBC, and FeBC significantly increased the yield, chlorophyll, and vitamin C of Chinese cabbage (p < 0.05), and decreased its Cd uptake compared with the control. Notably, shoot Cd significantly reduced when 2% FeBC was applied (p < 0.05). Overall, using K2FeO4 to modify vinasse biochar enriched the surface functional groups and minerals as well as reduced Cd availability in soil and its uptake by the plant. Our study showed that K2FeO4 modified vinasse biochar could be used as an ideal amendment for the remediation of Cd-contaminated soil.

19.
Carbohydr Polym ; 316: 121058, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37321741

RESUMO

Hydrophilic hemostatic sponge plays an important role in trauma bleeding control because of its robust coagulant functions. However, its strong tissue adhesion can easily result in wound tear and rebleeding during removing the sponge. Herein, the design of a hydrophilic anti-adhesive chitosan/graphene oxide composite sponge (CSAG) that possesses stable mechanical strength, rapid liquid absorption and strong intrinsic/extrinsic coagulation stimulations, is reported. For one thing, CSAG exhibits outstanding hemostatic performance, which significantly outperforms two commercial hemostats in two in vivo serious bleeding models. For another, CSAG shows low tissue adhesion; its peeling force is approximately 79.3 % lower than the commercial gauze. Moreover, in the peeling process, CSAG triggers partial detachment of the blood scab, because of the exist of bubbles or cavities at the interface, allowing the CSAG to be easily and safely peeled off from the wound without rebleeding. This study opens new avenues in constructing anti-adhesive trauma hemostatic materials.


Assuntos
Quitosana , Hemostáticos , Humanos , Aderências Teciduais , Hemostasia , Hemostáticos/farmacologia , Hemorragia
20.
Acta Chim Slov ; 70(1): 44-58, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-37005616

RESUMO

Permanganate  ions were adsorbed on carbonate intercalated Co-Al-layered double hydroxide (Co-Al-LDH) and MoS2 and after a while the adsorbed  ions were reduced to MnO2. Reduction of adsorbed  ion was catalyzed on the surface of carbonate intercalated Co-Al-LDH but  ions reacted with MoS2 surface. Adsorption kinetic tests were carried out at different temperatures, ionic strengths, pH, initial adsorbate concentrations and shaking rates. The adsorption kinetics was studied by the kinetics of adsorption study in the regions with constant adsorption acceleration (KASRA) model and KASRA, ideal-second-order (ISO), intraparticle diffusion, Elovich and (non-ideal process of adsorption kinetics (NIPPON) equations.In this work, a new equation called NIPPON equation was introduced. In this equation, it was assumed that during a non-ideal process, adsorbate species molecules were adsorbed simultaneously on the same type adsorption sites with different activities. Indeed, the average values of adsorption kinetic parameters were calculated by the NIPPON equation. Also, the character of boundaries of regions obtained from the KASRA model can be determined by this equation.

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