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1.
Artigo em Inglês | MEDLINE | ID: mdl-38995339

RESUMO

The principle of Fenton reagent is to produce ·OH by mixing H2O2 and Fe2+ to realize the oxidation of organic pollutants, although Fenton reagent has the advantages of non-toxicity and short reaction time, but there are its related defects. The Fenton-like technology has been widely studied because of its various forms and better results than the traditional Fenton technology in terms of pollutant degradation efficiency. This paper reviews the electro-Fenton technology among the Fenton-like technologies and provides an overview of the homogeneous electro-Fenton. It also focuses on summarizing the effects of factors such as H2O2, reactant concentration, reactor volume and electrode quality, reaction time and voltage (potential) on the efficiency of electro-Fenton process. It is shown that appropriate enhancement of H2O2 concentration, voltage (potential) and reaction volume can help to improve the process efficiency; the process efficiency also can be improved by increasing the reaction time and electrode quality. Feeding modes of H2O2 have different effects on process efficiency. Finally, a considerable number of experimental studies have shown that the combination of electro-Fenton with ultrasound, anodic oxidation and electrocoagulation technologies is superior to the single electro-Fenton process in terms of pollutant degradation.

2.
Environ Technol ; : 1-7, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38875359

RESUMO

Using oil recovery wastewater as the target material, the degradation of organic matter in oilfield wastewater was studied in an anodic oxidation system using Ti/Ru-Ir oxide-coated anode and 0.7mMNa2SO4 as the electrolyte. The TOC of the wastewater was 210 mg/L at the beginning of the electrolysis in the electrolysis system, and it decreased from 210 to 93.6 mg/L after 50 min of electrolysis. Under the action of this system, sulfate was oxidized to persulfate, and the apparent concentration of persulfate was 15.02 mM, oxidation and degradation of organic matter in wastewater by the action of newly generated persulfate.. Afterwards, NaOH and Fe2(SO4)3 were added to the electrolyzed wastewater, and the TOC in the wastewater was further reduced to 25.1 mg/L due to the coagulation effect of the newly generated Fe(OH)3 precipitate. The TOC removal rate of the wastewater treated by this process reached 88.0%, which meets the discharge requirements. At the same time, the derived persulfate oxidized Fe(OH)3 to generate a green substance, which was identified as Na2FeO3 by IR, UV, and XRD analyses. Na2FeO3 served as a highly effective water-purifying agent, demonstrating superior performance when compared to FeO42-. The method reported in this study not only provides a strategy for waste resource recycling but also offers the potential for mass production of ferrate (IV).

3.
Environ Sci Pollut Res Int ; 31(27): 39663-39677, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38831146

RESUMO

The mixed wastewater generated by anodic oxidation coating facilities contains high levels of various contaminants, including iron, aluminum, conductivity, chemical oxygen demand (COD), and sulfate. In this study, the effectiveness of the membrane distillation (MD) process using polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) membranes was investigated to treat mixed wastewater from an anodized coating factory. The results indicate that both hydrophobic membranes effectively removed targeted contaminants. However, the PTFE membrane achieved higher removal efficiencies, with over 99% removal of sulfate, conductivity, iron, and aluminum, 85.7% of COD, and 86% of total organic carbon (TOC). In contrast, the PVDF membrane exhibited a significant decline in removal efficiency as the temperature increased and performed well only at lower feed temperatures. The PTFE membranes outperformed the PVDF membranes in treating chemically intensive anodic oxidation wastewaters. This superiority can be attributed to the PTFE membrane's morphology and structure, which are less influenced by feed water temperature and chemicals. Additionally, its slippery surface imparts anti-adhesion properties, effectively preventing membrane fouling, and maintaining the treated water quality and flux for longer operation time.


Assuntos
Destilação , Membranas Artificiais , Oxirredução , Politetrafluoretileno , Polivinil , Águas Residuárias , Águas Residuárias/química , Politetrafluoretileno/química , Polivinil/química , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Poluentes Químicos da Água , Polímeros de Fluorcarboneto
4.
ACS Appl Mater Interfaces ; 16(21): 27627-27639, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38766902

RESUMO

Ultrawide-spectra-compatible camouflage materials are imperative for military science and national security due to the continuous advancement of various sophisticated multispectral detectors. However, ultrawide spectra camouflage still has challenges, as the spectral requirements for different bands are disparate and even conflicting. This work demonstrates an ultrawide spectra camouflage material compatible with visible (VIS, 400-800 nm), infrared (IR, 3-5 and 8-14 µm), and microwave (S-Ku bands, 2-12 GHz). The carbon nanotubes adsorbed on porous anodic alumina/aluminum flake powder (CNTs@PAA/AFP) material for ultrawide spectra camouflage is composed of bioinspired porous alumina surface layers for low visible reflection and aluminum flake powder substrate for low infrared emissivity, while the surface of the porous alumina layers is loaded with carbon nanotubes for microwave absorption. Compared with previous low-emissivity materials, CNTs@PAA/AFP has omnidirectional low reflectance (Ravg = 0.29) and high gray scale (72%) in the visible band. Further, it exhibits low emissivity (ε3-5µm = 0.15 and ε8-14µm = 0.18) in the dual infrared atmospheric window, which reduces the infrared lock-on range by 59.6%/49.8% in the mid/far-infrared band at high temperatures (573 K). The infrared camouflage performance calculated from the radiation temperature of CNTs@PAA/AFP coatings is enhanced to over 65%, which is at least 4 times greater than that of its substrate. In addition, the CNTs@PAA/AFP coating achieves high microwave absorption (RLmin = -42.46 dB) and an effective absorption bandwidth (EAB = 7.43 GHz) in the microwave band (S-Ku bands) due to the enhancement of interfacial polarization and conductive losses. This study may introduce new insight and feasible methods for multispectral manipulation, electromagnetic signal processing, and thermal management via bioinspired structural design and fabrication.

5.
ACS Appl Mater Interfaces ; 16(3): 3260-3269, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38221720

RESUMO

The anode stability is critical for efficient and reliable seawater electrolyzers. Herein, a NiFe-based film catalyst was prepared by anodic oxidation to serve as a model electrode, which exhibited a satisfactory oxygen evolution performance in simulated alkaline seawater (1 M KOH + 0.5 M NaCl) with an overpotential of 348 mV at 100 mA cm-2 and a long-term stability of over 100 h. After that, the effects of the current density and bulk pH of the electrolyte on its stability were evaluated. It was found that the electrode stability was sensitive to electrolysis conditions, failing at 20 mA cm-2 in 0.1 M KOH + 0.5 M NaCl but over 500 mA cm-2 in 0.5 M KOH + 0.5 M NaCl. The electrode dissolved, and some precipitates immediately formed at the region very close to the electrode surface during the electrolysis. This can be ascribed to the pH difference between the electrode/electrolyte interface and the bulk electrolyte under anodic polarization. In other words, the microzone acidification accelerates the corrosion of the electrode by Cl-, thus affecting the electrode stability. The operational performances of the electrode under different electrolysis conditions were classified to further analyze the degradation behavior, which resulted in three regions corresponding to the stable oxygen evolution, violent dissolution-precipitation, and complete passivation processes, respectively. Thereby increasing the bulk pH could alleviate the microzone acidification and improve the stability of the anode at high current densities. Overall, this study provides new insights into understanding the degradation mechanism of NiFe-based catalysts and offers electrolyte engineering strategies for the application of anodes.

6.
Environ Technol ; : 1-14, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38234107

RESUMO

Fluoxetine (FLX) is a selective serotonin reuptake inhibitor (SSRI) medication commonly used to treat mental health disorders, but it can be harmful to the environment if not properly disposed of due to incomplete metabolism. In this study, electrochemical anodic oxidation with mixed metal oxide anodes was studied as a method to remove FLX from water and wastewater. Iridium dioxide-coated titanium (Ti/IrO2) and ruthenium dioxide-coated Ti (Ti/RuO2) electrodes were found to be more effective than platinum-coated Ti (Ti/Pt) electrodes, with removal efficiencies of 91.5% and 93.9%, respectively. Optimal conditions for FLX removal were determined to be an applied current of 150 mA, initial pH of 5, and oxidation time of 120 min. The rate of FLX degradation (kFLX) for the Ti/Pt, Ti/IrO2, and Ti/RuO2 electrodes were determined to be 0.0081 min-1 (R2:0,8161), 0.0163 min-1 (R2:0,9823), and 0.0168 (R2:0,9901) min-1 for 25 mg/L initial FLX concentration, respectively. The kFLX values varied based on the initial FLX concentration and decreased as the initial FLX concentration increased. The specific energy consumption (SEC) after 120 min of operation was 51.0 kWh/m3 for the Ti/Pt electrode, 39.6 kWh/m3 for the Ti/IrO2 electrode, and 48.6 kWh/m3 for the Ti/RuO2 electrode under optimised conditions. Overall, electrochemical anodic oxidation is an effective method for removing FLX from water and wastewater, with Ti/IrO2 and Ti/RuO2 electrodes providing superior performance compared to Ti/Pt electrodes.

7.
ChemSusChem ; 17(9): e202301691, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38192246

RESUMO

Methyl formate (MF) is one of the most important chemical commodities, which has a wide range of applications. Due to environmental friendliness, mild reaction conditions, and easy operations, electrosynthesis of MF has garnered increasing attention in recent years. In this work, we reported an electrosynthesis route toward MF in a halide-containing methanol solution. The thorough mechanistic investigations point out that electrosynthesis of MF is accomplished by instant reaction between aldehyde from anodic methanol oxidation, and methoxy bromide (CH3OBr) that is in-situ generated by reaction of Br2 from anodic oxidation of Br- with methoxide (CH3O-) from cathodic reduction of methanol. This method features high atomic economy only producing valuable MF and hydrogen gas, and shows distinct advantages compared to the reported MF electrosynthesis methods. Even at 200 mA/cm2, the faradaic efficiency (FE) of MF remains consistently around 60 % at the anode while a 100 % FE hydrogen gas is produced at the cathode.

8.
ACS Biomater Sci Eng ; 10(1): 377-390, 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38078685

RESUMO

Tantalum is receiving increasing attention in the biomedical field due to its biocompatible nature and superior mechanical properties. However, the bioinert nature of tantalum still poses a challenge and limits its integration into the bone tissue. To address these issues, we fabricated nanotubular (NT), nanocoral (NC), and nanodimple morphologies on tantalum surfaces via anodization. The size of these nanofeatures was engineered to be approximately 30 nm for all anodized samples. Thus, the influence of the anodized nanostructured morphology on the chemical and biological properties of tantalum was evaluated. The NT and NC samples exhibited higher surface roughness, surface energy, and hydrophilicity compared to the nonanodized samples. In addition, the NT samples exhibited the highest corrosion resistance among all of the investigated samples. Biological experiments indicated that NT and NC samples promoted human adipose tissue-derived mesenchymal stem cell (hADMSC) spreading and proliferation up to 5 days in vitro. ALP, COL1A1, and OSC gene expressions as well as calcium mineral synthesis were upregulated on the NT and NC samples in the second and third weeks in vitro. These findings highlight the significance of nanostructured feature morphology for anodized tantalum, where the NT morphology was shown to be a potential candidate for orthopedic applications.


Assuntos
Óxidos , Tantálio , Humanos , Tantálio/química , Corrosão , Óxidos/química , Diferenciação Celular
9.
Adv Mater ; 36(2): e2306741, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37880859

RESUMO

The membrane-electrode assembly (MEA) approach appears to be the most promising technique to realize the high-rate CO2 /CO electrolysis, however there are major challenges related to the crossover of ions and liquid products from cathode to anode via the membrane and the concomitant anodic oxidation reactions (AORs). In this perspective, by combining experimental and theoretical analyses, several impacts of anodic oxidation of liquid products in terms of performance evaluation are investigated. First, the crossover behavior of several typical liquid products through an anion-exchange membrane is analyzed. Subsequently, two instructive examples (introducing formate or ethanol oxidation during electrolysis) reveals that the dynamic change of the anolyte (i.e., pH and composition) not only brings a slight shift of anodic potentials (i.e., change of competing reactions), but also affects the chemical stability of the anode catalyst. Anodic oxidation of liquid products can also cause either over- or under-estimation of the Faradaic efficiency, leading to an inaccurate assessment of overall performance. To comprehensively understand fundamentals of AORs, a theoretical guideline with hierarchical indicators is further developed to predict and regulate the possible AORs in an electrolyzer. The perspective concludes by giving some suggestions on rigorous performance evaluations for high-rate CO2 /CO electrolysis in an MEA-based setup.

10.
Sci Total Environ ; 912: 168841, 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38036133

RESUMO

The use of electrocoagulation (EC) and anodic oxidation (AO) processes was studied for improving a treatment system for landfill leachates based on a membrane bioreactor (MBR) and a nanofiltration step. The main limitation of the current full-scale system is related to the partial removal of organic compounds that leads to operation of the nanofiltration unit with a highly concentrated feed solution. Application of the EC before the MBR participated in partial removal of the organic load (40 %) with limited energy consumption (2.8 kWh m-3) but with additional production of iron hydroxide sludge. Only AO allowed for non-selective removal of organic compounds. As a standalone process, AO would require a sharp increase of the energy consumption (116 kWh for 81 % removal of total organic carbon). But using lower electric charge and combining AO with EC and MBR processes would allow for achieving high overall removal yields with limited energy consumption. For example, the overall removal yield of total organic carbon was 65 % by application of AO after EC, with an energy consumption of 21 kWh m-3. Results also showed that such treatment strategy might allow for a significant increase of the biodegradability of the effluent before treatment by the MBR. The MBR might then be dedicated to the removal of the residual organic load as well as to the removal of the nitrogen load. The data obtained in this study also showed that the lower electric charge required for integrating AO in a coupled process would allow for strongly decreasing the formation of undesired by-products such as ClO3- and ClO4-.


Assuntos
Poluentes Químicos da Água , Poluentes Químicos da Água/química , Ferro , Esgotos , Oxirredução , Reatores Biológicos , Carbono
11.
Adv Mater ; 36(5): e2305375, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37930270

RESUMO

Maximizing atom-utilization efficiency and high current stability are crucial for the platinum (Pt)-based electrocatalysts for hydrogen evolution reaction (HER). Herein, the Pt single-atom anchored molybdenum (Mo) foil (Pt-SA/Mo-L) as a single-atom alloy electrode is synthesized by the laser ablation strategy. The local thermal effect with fast rising-cooling rate of laser can achieve the single-atom distribution of the precious metals (e.g., Pt, Rh, Ir, and Ru) onto the Mo foil. The synthesized self-standing Pt-SA/Mo-L electrode exhibits splendid catalytic activity (31 mV at 10 mA cm-2 ) and high-current-density stability (≈850 mA cm-2 for 50 h) for HER in acidic media. The strong coordination of Pt-Mo bonding in Pt-SA/Mo-L is critical for the efficient and stable HER. In addition, the ultralow electrolytic voltage of 0.598 V to afford the current density of 50 mA cm-2 is realized by utilization of the anodic molybdenum oxidation instead of the oxygen evolution reaction (OER). Here a universal synthetic strategy of single-atom alloys (PtMo, RhMo, IrMo, and RuMo) as self-standing electrodes is provided for ultralow voltage and membrane-free hydrogen production.

12.
Adv Mater ; 36(13): e2308647, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38143285

RESUMO

Seawater electrolysis (SWE) is a promising and potentially cost-effective approach to hydrogen production, considering that seawater is vastly abundant and SWE is able to combine with offshore renewables producing green hydrogen. However, SWE has long been suffering from technical challenges including the high energy demand and interference of chlorine chemistry, leading electrolyzers to a low efficiency and short lifespan. In this context, hybrid SWE, operated by replacing the energy-demanding oxygen evolution reaction and interfering chlorine evolution reaction (CER) with a thermodynamically more favorable anodic oxidation reaction (AOR) or by designing innovative electrolyzer cells, has recently emerged as a better alternative, which not only allows SWE to occur in a safe and energy-saving manner without the notorious CER, but also enables co-production of value-added chemicals or elimination of environmental pollutants. This review provides a first account of recent advances in hybrid SWE for hydrogen production. The substitutional AOR of various small molecules or redox mediators, in couple with hydrogen evolution from seawater, is comprehensively summarized. Moreover, how the electrolyzer cell design helps in hybrid SWE is briefly discussed. Last, the current challenges and future outlook about the development of the hybrid SWE technology are outlined.

13.
Chemosphere ; 346: 140635, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37939930

RESUMO

The development of non-expensive and efficient technologies for the elimination of Glyphosate (GLP) in water is of great interest for society today. Here we explore novel electrocatalytic effects to boost the anodic oxidation of GLP on Pt-doped (3-13met%) SnO2-Sb electrodes. The study reveals the formation of well disperse Pt nanophases in SnO2-Sb that electrocatalyze GLP elimination. Cyclic voltammetry and in-situ spectroelectrochemical FTIR analysis evidence carboxylate-mediated Pt-GLP electrocatalytic interactions to promote oxidation and mineralization of this herbicide. Interestingly, under electrolytic conditions Pt effects are proposed to synergistically cooperate with hydroxyl radicals in GLP oxidation. Furthermore, the formation of by-products has been followed by different techniques, and the studied electrodes are compared to commercial Si/BDD and Ti/Pt anodes and tested for a real GLP commercial product. Results show that, although BDD is the most effective anode, the SnO2-Sb electrode with a 13 met% Pt can mineralize GLP with lower energy consumption.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Titânio , Oxirredução , Eletrodos , Compostos de Estanho , Glifosato
14.
Molecules ; 28(21)2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37959806

RESUMO

Tungsten oxide has received considerable attention as photo-anode in photo-assisted water splitting due to its considerable advantages such as significant light absorption in the visible region, good catalytic properties, and stability in acidic and oxidative conditions. The present paper is a first step in a detailed study of the mechanism of porous WO3 growth via anodic oxidation. In-situ electrochemical impedance spectroscopy (EIS) and intensity modulated photocurrent spectroscopy (IMPS) during oxidation of W illuminated with UV and visible light are employed to study the ionic and electronic processes in slightly acidic sulfate-fluoride electrolytes and a range of potentials 4-10 V. The respective responses are discussed in terms of the influence of fluoride addition on ionic and electronic process rates. A kinetic model is proposed and parameterized via regression of experimental data to the EIS and IMPS transfer functions.

15.
Chemosphere ; 345: 140396, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37820875

RESUMO

Tetrahydrofurfuryl alcohol (THFA), a widely applied raw materials, intermediate and solvent in the fields of agricultural, industry (especially in nuclear industry), is a potentially hazardous and non-biodegradable pollutant in wastewater. In this study, the electrochemical degradation pathways of THFA by a boron-doped diamond (BDD) anode with different current density (jappl = 20, 40 and 60 mA cm-2) and electrolyte solution (KNO3, KCl and K2SO4) was carefully investigated. The results exhibit that high chemical oxygen demand (COD) removal and mineralization rates were achieved by rapid non-selective oxidation in electrolyte solutions mediated by hydroxyl radicals (∙OH) and active chlorine (sulfate) under constant current electrolysis. In-depth data analysis using the high performance liquid chromatography and liquid chromatography/mass spectroscopy, the underlying removal pathways of THFA in KNO3, KCl and K2SO4 electrolyte solutions are proposed according to the effect of different mineralization mechanisms.


Assuntos
Boro , Poluentes Químicos da Água , Boro/química , Diamante/química , Poluentes Químicos da Água/análise , Sulfatos/química , Eletrodos
16.
Water Res ; 246: 120674, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37857008

RESUMO

Electrified membrane technologies have recently demonstrated high potential in tackling water pollution, yet their practical applications are challenged by relying on large precursor doses. Here, we developed a Janus porous membrane (JPEM) with synergic direct oxidation by Magnéli phase Ti4O7 anode and electro-Fenton reactions by CuFe2O4 cathode. Organic pollutants were first directly oxidized on the Ti4O7 anode, where the extracted electrons from pollutants were transported to the cathode for electro-Fenton production of hydroxyl radical (·OH). The cathodic ·OH further enhanced the mineralization of organic pollutant degradation intermediates. With the sequential anodic and cathodic oxidation processes, the reagent-free JPEM showed competitive performance in rapid degradation (removal rate of 0.417 mg L-1 s-1) and mineralization (68.7 % decrease in TOC) of sulfamethoxazole. The JPEM system displayed general performance to remove phenol, carbamazepine, and perfluorooctanoic acid. The JPEM runs solely on electricity and oxygen that is comparable to that of PEM relies on large precursor doses and, therefore, operation friendly and environmental sustainability. The high pollutant removal and mineralization achieved by rational design of the reaction processes sheds light on a new approach for constructing an efficient electrified membrane.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Fenol , Fenóis , Eletrodos , Oxirredução , Peróxido de Hidrogênio
17.
J Microsc ; 292(1): 37-46, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37681465

RESUMO

The development of raster STM electric lithography has enabled the etching of nano/microscale patterns on both few-layer graphene (FLG) and high-depth graphite structures on the bulk HOPG substrates under ambient conditions. This approach utilises a nanoscale probe tip as a machining tool to directly fabricate conductive sample surfaces without the need for resists or masks. Compared to conventional nano/micro machining methods, the capability of ultraaccurate fabrication of nanoscale patterns using this technique is unmatched. The resulting FLG structures exhibit ultrasmooth flat bottoms and uniformly controlled depths ranging from 0.34 to 3.0 nm (less than 10 layers). This work represents a significant advancement as it demonstrates the perfect etching of FLG structures in designated nano/microscale regions using raster STM electric lithography in the constant current mode, which reaches the limitation of top-down manufacturing techniques. Additionally, raster STM electric lithography in the constant height mode can directly etch high-depth structures (up to ∼100 nm). The geometric shape and number of layers of the etched graphene structures determined by either local anodic oxidation (LAO) or the electric discharge (ED) mechanism. The LAO mechanism results in less debris and smoother edges compared to the ED mechanism, which is caused by the random electrical discharge between the tip and the sample. The well-controlled raster STM electric lithography technique is believed to be a promising and facile approach for constructing nano/microscale graphene-based devices.

18.
Nanomaterials (Basel) ; 13(18)2023 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-37764542

RESUMO

The synergistic combination of hybrid perovskites with graphene-related materials is leading to optoelectronic devices with enhanced performance and stability. Still, taking advantage of the solution processing of perovskite onto graphene is especially challenging. Here, MAPbBr3 perovskite is grown on single-layer graphene/graphene oxide (Gr/GO) patterns with 120 µm periodicity using a solution-processed method. MAPbBr3 rounded crystals are formed with sizes ranging from nanometers to microns, either forming continuous films or dispersed particles. A detailed morphological and structural study reveals a fully oriented perovskite and very different growth habits on the Gr/GO micro-patterns, which we relate to the substrate characteristics and the nucleation rate. A simple method for controlling the nucleation rate is proposed based on the concentration of the precursor solution and the number of deposited perovskite layers. The photoluminescence is analyzed in terms of the crystal size, strain, and structural changes observed. Notably, the growth on top of Gr/GO leads to a huge photostability of the MAPbBr3 compared with that on glass. Especially outstanding is that of the microcrystals, which endure light densities as high as 130 kW/cm2. These results allow for anticipating the design of integrated nanostructures and nanoengineered devices by growing high-stability perovskite directly on Gr/GO substrates.

19.
Chemosphere ; 341: 140016, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37652250

RESUMO

Nitrate (NO3-) is one of the most common pollutants in natural bodies of water and as such threatens both human health and the safety of aquatic environment. There are efficient electrochemical techniques to directly remove NO3-, but inexpensive, selective and electrocatalytic strategies to eliminate NO3- by converting it into benign nitrogen (N2) remain challenging. This work studied Cu particles that were formed directly on a Ni foam (Cu-NF) and evaluated their electrocatalytic NO3- reduction performance. The use of carbon nanotubes (CNT) functionalized with titanium suboxides (TiSO) as the anode facilitated the generation of active chlorine species that had a key role in the removal of NH4+. An electrochemical system that integrated a Cu-NF cathode with a TiSO-CNT anode could remove 88.5% of NO3- with a >99% N2 selectivity when operated over 6 h (4.1 × 10-4 h-1) at a potential of -1.2 V vs Ag/AgCl. Because the chloride ions are very common in natural sources of water, this technique offers a sustainable and environmentally friendly approach for the removal of NO3- from contaminated water sources.


Assuntos
Nanotubos de Carbono , Nitratos , Humanos , Nitrogênio , Técnicas Eletroquímicas , Água , Eletrodos , Titânio
20.
Materials (Basel) ; 16(15)2023 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-37569910

RESUMO

Titanium alloy Ti6Al4V is a commonly used bone implant material, primarily prepared as a porous material to better match the elastic modulus of human bone. However, titanium alloy is biologically inert and does not have antibacterial properties. At the same time, the porous structure with a large specific surface area also increases the risk of infection, leading to surgical failure. In this paper, we prepared three porous samples with different porosities of 60%, 75%, and 85%, respectively (for short, 3D-60, 3D-75, and 3D-85) using 3D printing technology and clarified the mechanical properties. Through tensile experiments, when the porosity was 60%, the compressive modulus was within the elastic modulus of human bone. Anodic oxidation technology carried out the surface modification of a 3D-printed porous titanium alloy with 60% porosity. Through change, the different voltages and times on the TiO2 oxide layer on the 3D-printed porous titanium alloy are different, and it reveals the growth mechanism of the TiO2 oxide layer on a 3D-printed unique titanium alloy. The surface hydrophilic and antibacterial properties of 3D-printed porous titanium alloy were significantly improved after modification by anodic oxidation.

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