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Solar-driven H2O-to-H2 conversion is a feasible artificial photoconversion technology for clean energy production. However, low photon utilization efficiency has become a major obstacle limiting the practical application of this technology. Herein, a metal atomic replacement (SbâNi) is conducted to disintegrate bulk Sb2S3 nanorods and synchronously grow the NiS nanolayers, and a flower-like Sb2S3-NiS nanocomposite with high BET specific surface area and synergistic exciton dynamics is constructed for simulated solar (SSL)-driven H2O-to-H2 conversion. The optimal Sb2S3-NiS nanocomposite is compounded with polyvinylidene fluoride (PVDF) to prepare a flexible PVDF/Sb2S3-NiS (PSN) hybrid membrane with stable structure and excellent recyclability via an electrospinning method. Due to the synergistically interacted organic-inorganic interface and high porosity, it is conducive to the exposure of effective active sites, exciton conduction and mass transfer and exchange, thereby an outstanding alkaline (Ph = 13.0) H2O-to-H2 conversion activity with a 0.06% of solar-to-hydrogen efficiency and over 280 h (70 cycles) of durable recycling is achieved under the collaborative drives of SSL and weak ultrasound (40 Hz). This study raises a state-of-the-art membrane material for solar-driven panel reaction technology.
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INTRODUCTION: Tobacco use is a major global health issue linked to psychiatric illnesses and high mortality rates. Nicotine, the primary compound absorbed during smoking, causes harm to various organs, particularly the brain. The current study examined the modulatory effect of Teucrium polium extract (TPE) on nicotine-induced biochemical and histological changes in the brains of mice. METHODS: Twenty-four mice were divided into four groups and were treated for three weeks. Group one was the control; Group two received 100 mg/kg TPE orally; Group three was subcutaneously injected with 2.5 mg/kg nicotine, and Group four received both nicotine and TPE. RESULTS: The brain tissue of the nicotine-induced group showed histopathological alterations and oxidative stress as indicated by increased lipid peroxidation and nitric oxide levels concomitant with decreased glutathione content and superoxide dismutase activity. DNA fragmentation was also detected by comet assay. Treatment with TPE significantly decreased oxidative stress and DNA fragmentation while increasing antioxidant biomarkers. Histopathological changes were also diminished. CONCLUSION: Through the antioxidant activity of TPE, it protected against nicotine-induced neurotoxicity in mice by impacting oxidative stress, DNA fragmentation, and brain histopathological changes.
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Solar-driven flat-panel H2O-to-H2 conversion is an important technology for value-added solar fuel production. However, most frequently used particulate photocatalysts are hard to achieve stable photocatalysis in flat-panel reaction module due to the influence of mechanical shear force. Herein, a highly active CdS@SiO2-Pt composite with rapid CdS-to-Pt electron transfer and restrained photoexciton recombination was prepared to process into an organic-inorganic membrane by compounding with polyvinylidene fluoride (PVDF). This PVDF networked organic-inorganic membrane displays high photostability and excellent operability, achieving improved simulated sunlight-driven alkaline H2O-to-H2 conversion activity (213.48 mmol m-2 h-1) following a 0.68% of solar-to-hydrogen efficiency. No obvious variation in its appearance and micromorphology was observed even being recycled for 50-times, which considerably outperforms the existing membrane photocatalysts. Subsequently, a homemade panel H2O-to-H2 conversion system was fabricated to obtain a 0.05% of solar-to-hydrogen efficiency. In this study, we opens up a prospect for practical application of photocatalysis technology.
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Developing carbon quantum dots (CQDs) from bio-waste lignin for effectively detecting Cu2+ is of great significance for promoting the value-added utilization of lignin resources. However, the limited amount of surface-active groups and low quantum yield of lignin-based CQDs hinder their application in this regard. Herein, bio-waste lignin was converted into value-added amine functionalized CQDs using a facile two-step hydrothermal approach. The as-synthesized CQDs modified with amino groups exhibit bright green fluorescence, abundant surface functional groups, high water solubility and uniform particle size (3.9 nm). Systematic analysis demonstrates that the rich NH2 groups (~12.3 %) on the CQDs backbone improve their fluorescence properties (quantum yield increased from 3.4 % to 21.1 %) and specific detection ability for Cu2+. The developed NH2-CQDs serve as an efficient fluorescent probe, displaying high sensitivity and selectivity towards Cu2+ in aqueous system, with a detection limit of 2.42 µmol/L, which is lower than the maximum permitted amount of Cu2+ in drinking water (20 µmol/L). The detection mechanism of NH2-CQDs for Cu2+ is attributed to the synergy of static quenching and photo-induced electron transfer. This study provides a valuable reference for the synthesis of high-quality fluorescent CQDs from lignin resources and the effective detection of trace Cu2+ in aquatic environments.
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Aminas , Carbono , Cobre , Lignina , Pontos Quânticos , Pontos Quânticos/química , Cobre/análise , Cobre/química , Lignina/química , Carbono/química , Aminas/química , Água/química , Poluentes Químicos da Água/análise , Corantes Fluorescentes/química , Espectrometria de Fluorescência/métodos , Limite de DetecçãoRESUMO
Excessive Cu2+ intake can cause neurological disorders (e.g. Wilson's disease) and adversely affect the gastrointestinal, liver, and kidney organs. The presence of Cu2+ is strongly linked to the emergence and progression of Wilson's disease (WD), and accurately measuring the amount of copper is a crucial step in diagnosing WD at an early stage in a clinical setting. In this work, CQDs were fabricated through a facile technique as a novel fluorescence-based sensing platform for detecting Cu(II) in aqueous solutions, and in the serum samples of healthy and affected individuals by WD. The CQDs interact with Cu(II) ions to produce Turn-on and Turn-off states at nano-molar and micro-molar levels, respectively, with LODs of 0.001 µM and 1 µM. In fact, the Cu2+ ions can act like a bridge between two CQDs by which the charge and electron transfer between the CQDs may increase, possibly can have significant effects on the spectroscopic features of the CQDs. To the best of our knowledge, this is the first reported research that can detect Cu(II) at low levels using two different complexation states, with promising results in testing serum. The potential of the sensor to detect Cu(II) was tested on serum samples from healthy and affected individuals by WD, and compared to results obtained by ICP-OES. Astonishingly, the results showed an excellent correlation between the measured Cu(II) levels using the proposed technique and ICP-OES, indicating the high potential of the fluorimetric CQD-based probe for Cu(II) detection. The accuracy, sensitivity, selectivity, high precision, accuracy, and applicability of the probe toward Cu(II) ions make it a potential diagnostic tool for Wilson's disease in a clinical setting.
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Cobre , Degeneração Hepatolenticular , Degeneração Hepatolenticular/diagnóstico , Degeneração Hepatolenticular/sangue , Cobre/sangue , Humanos , Espectrometria de Fluorescência/métodos , Limite de DetecçãoRESUMO
Over the past decades, CO2 greenhouse emission has been considerably increased, causing global warming and climate change. Indeed, converting CO2 into valuable chemicals and fuels is a desired option to resolve issues caused by its continuous emission into the atmosphere. Nevertheless, CO2 conversion has been hampered by the ultrahigh dissociation energy of C=O bonds, which makes it thermodynamically and kinetically challenging. From this prospect, photocatalytic approaches appear promising for CO2 reduction in terms of their efficiency compared to other traditional technologies. Thus, many efforts have been made in the designing of photocatalysts with asymmetric sites and oxygen vacancies, which can break the charge distribution balance of CO2 molecule, reduce hydrogenation energy barrier and accelerate CO2 conversion into chemicals and fuels. Here, we review the recent advances in CO2 hydrogenation to C1 and C2 products utilizing photocatalysis processes. We also pin down the key factors or parameters influencing the generation of C2 products during CO2 hydrogenation. In addition, the current status of CO2 reduction is summarized, projecting the future direction for CO2 conversion by photocatalysis processes.
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Serum 25(OH)D deficiency consistently demonstrated molecular mechanisms through which chronic inflammation is associated with the risk of nasopharyngeal carcinoma (NPC). This study aimed to determine the association between serum 25(OH)D and NPC. A matched case-control study was conducted at two local hospitals. A total of 300 histologically confirmed NPC cases were matched with controls for age, gender, and ethnicity, and assessed for vitamin D status and other nutritional factors. Mean Vitamin D concentration was significantly lower among cases compared to controls (63.17 ± 19.15 nmol/L and 67.34 ± 23.06 nmol/L) (t = -2.41, p = 0.016). Multiple conditional logistic regression analysis indicated that higher levels of serum 25(OH)D were associated with reduced odds of NPC (AOR = 0.73, 95% CI = 0.57-0.94, p = 0.016) controlling for confounders including BMI, physical activity, smoking status, alcohol consumption, consumption of food high in vitamin D, salted fish consumption, and family history of NPC. There was a significant association between inadequate serum 25(OH)D status with accumulation of four risk factors and increased odds of getting NPC using polynomial regression analysis. Increased NPC odds ratios were observed after sequential accumulation of additional risk factors with the presence of inadequate serum 25(OH)D status (OR = 0.54, 95% CI = 0.27, 4.77, p = 0.322, OR = 1.04, 95% CI = 0.64, 1.72, p = 0.267, OR = 1.15, 95% CI = 0.73, 1.80, p = 0.067, OR = 1.93, 95% CI = 1.13, 3.31, p = 0.022, and OR = 5.55, 95% CI = 1.67, 10.3, p < 0.001 respectively). Future research in Malaysia should involve both prospective cohort studies and randomized controlled trials to confirm and further clarify the role of vitamin D in NPC outcomes.
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Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas , Deficiência de Vitamina D , Humanos , Calcifediol , Estudos de Casos e Controles , Malásia/epidemiologia , Carcinoma Nasofaríngeo/epidemiologia , Neoplasias Nasofaríngeas/epidemiologia , Estudos Prospectivos , Fatores de Risco , Vitamina D/sangue , Deficiência de Vitamina D/complicações , Masculino , FemininoRESUMO
Electrochemically converting nitrate, a widely distributed nitrogen contaminant, into harmless N2 is a feasible and environmentally friendly route to close the anthropogenic nitrogen-based cycle. However, it is currently hindered by sluggish kinetics and low N2 selectivity, as well as scarce attention to reactor configuration. Here, we report a flow-through zero-gap electrochemical reactor that shows a high performance of nitrate reduction with 100% conversion and 80.36% selectivity of desired N2 in the chlorine-free system at 100 mg-N·L-1 NO3- while maintaining a rapid reduction kinetics of 0.07676 min-1. More importantly, the mass transport and current utilization efficiency are significantly improved by shortening the inter-electrode distance, especially in the zero-gap electrocatalytic system where the current efficiency reached 50.15% at 5 mA·cm-2. Detailed characterizations demonstrated that during the electroreduction process, partial Cu(OH)2 on the cathode surface was reconstructed into stable Cu/Cu2O as the active phase for efficient nitrate reduction. In situ characterizations revealed that the highly selective *NO to *N conversion and the N-N coupling step played crucial roles during the selective reduction of NO3- to N2 in the zero-gap electrochemical system. In addition, theoretical calculations demonstrated that improving the key intermediate *N coverage could effectively facilitate the N-N coupling step, thereby promoting N2 selectivity. Moreover, the environmental and economic benefits and long-term stability shown by the treatment of real nitrate-containing wastewater make our proposed electrocatalytic system more attractive for practical applications.
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Nitratos , Águas Residuárias , Nitratos/química , Eletrodos , Nitrogênio/análise , Nitrogênio/química , CinéticaRESUMO
In this study, we found that alumina (Al2O3) may improve the degradation of phenolic pollutants by KMnO4 oxidation. In KMnO4/Al2O3 system, the removal efficiency of 2,4-Dibromophenol (2,4-DBP) was increased by 26.5%, and the apparent activation energy was decreased from 44.5 kJ/mol to 30.9 kJ/mol. The mechanism of Al2O3-catalytic was elucidated by electrochemical processes, X-ray photoelectron spectroscopy (XPS) characterization and theoretical analysis that the oxidation potential of MnO4- was improved from 0.46 V to 0.49 V. The improvement was attributed to the formation of coordination bonds between the O atoms in MnO4- and the empty P orbitals of the Al atoms in Al2O3 crystal leading to the even-more electron deficient state of MnO4-. The excellent reusability of Al2O3, the good performance on degradation of 2,4-DBP in real water, the satisfactory degradation of fixed-bed reactor, and the enhanced removal of 6 other phenolic pollutants demonstrated that the KMnO4/Al2O3 system has satisfactory potential industrial application value. This study offers evidence for the improvement of highly-efficient MnO4- oxidation systems.
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Óxido de Alumínio , Poluentes Químicos da Água , Óxido de Alumínio/química , Óxidos/química , Oxirredução , Compostos de Manganês/química , Fenóis , Catálise , Poluentes Químicos da Água/químicaRESUMO
Constructing high-efficiency composite photocatalysts with enhanced charge transfer and a rapid surface catalytic reaction has recently received significant attention. Herein, a hydrochar-mediated NiFe2O4 nanosheet (C/NFO) composite was rationally constructed by a simple hydrothermal method. Intimate interface contacts and chemical interactions between hydrochar and NFO were formed. The prepared C/NFO samples exhibited remarkable visible-light-driven catalytic CO2 reduction properties under mild reaction conditions with Ru(bpy)32+ sensitization. As the optimized sample, 16%-C/NFO achieved a 4-fold enhancement of CO production (17.49 µmol/h) compared with that of pure NFO. The C/NFO samples demonstrated good activity and structural stability in the CO2 photoreduction system. The carbon source of CO derived from CO2 was verified through isotopic labeling experiments using 13CO2. In situ photoluminescence and electrochemical characterizations confirmed the role of electron transfer intermediates of C/NFO. The synergistic effect of the nanosheet-like structure of NFO, combined with the surface functional groups of hydrochar, facilitated an exceptionally high rate of charge transfer and exposed abundant active adsorption sites for CO2, thereby promoting the efficient separation of photogenerated charge carriers and enhancing photocatalytic activity for CO2 reduction. This study presents a promising strategy for the rational design of hydrochar coupled with transition metal compound catalysts for efficient CO2 photoreduction.
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Combustion of fossil fuels, industry and agriculture sectors are considered as the largest emitters of carbon dioxide. In fact, the emission of CO2 greenhouse gas has been considerably intensified during the last two decades, resulting in global warming and inducing variety of adverse health effects on human and environment. Calling for effective and green feedstocks to remove CO2, low-cost materials such as coal ashes "wastes-to-materials", have been considered among the interesting candidates of CO2 capture technologies. On the other hand, several techniques employing coal ashes as inorganic supports (e.g., catalytic reduction, photocatalysis, gas conversion, ceramic filter, gas scrubbing, adsorption, etc.) have been widely applied to reduce CO2. These processes are among the most efficient solutions utilized by industrialists and scientists to produce clean energy from CO2 and limit its continuous emission into the atmosphere. Herein, we review the recent trends and advancements in the applications of coal ashes including coal fly ash and bottom ash as low-cost wastes to reduce CO2 concentration through adsorption and catalysis processes. The chemical routes of structural modification and characterization of coal ash-based feedstocks are discussed in details. The adsorption and catalytic performance of the coal ashes derivatives towards CO2 selective reduction to CH4 are also described. The main objective of this review is to highlight the excellent capacity of coal fly ash and bottom ash to capture and selective conversion of CO2 to methane, with the aim of minimizing coal ashes disposal and their storage costs. From a practical view of point, the needs of developing new advanced technologies and recycling strategies might be urgent in the near future to efficient make use of coal ashes as new cleaner materials for CO2 remediation purposes, which favourably affects the rate of global warming.
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Single atomic metal (SAM) cocatalysis is a potential strategy to improve the performance of photocatalytic materials. However, the cocatalytic mechanism of SAM sites in different valence states is rarely reported. Herein, single atomic Pt2+/Pt0 active sites were anchored on Sb2S3 nanorods to synergistically improve the photoactivity for hydrogen production under simulated sunlight. Experimental results and density functional theory calculations indicated that the coexistence of single atomic Pt2+/Pt0 sites synergistically improves the broadband light harvesting and promotes the Sb2S3-to-Pt electron transfer following inhibited photoexciton recombination kinetics and enhanced H proton adsorption capacity, resulting higher and more durable photoactivity for hydrogen production. Therefore, the optimal Sb2S3-Pt0.9 composite catalyst achieved remarkably enhanced hydrogen evolution rate of 1.37 mmolâg-1âh-1 (about 105-fold greater of that of Sb2S3 NRs) under faintly alkaline condition, and about 5.41 % of apparent quantum yield (AQY700 nm) was achieved, which shows obvious superiority in hydrogen production by contrasting with the reported Sb2S3-based photocatalysts and conventional semiconductor photocatalytic materials modified with noble metals. This study elucidate a well-defined mechanism of multisite cocatalysis for photoactivity improvement.
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The increasing consumption of antibiotics and their subsequent release to wastewater or groundwater and ultimately to the water supply (or drinking water) has great concerns. This paper presents a visible light (VL) activated ferrate(VI) (FeVIO42-, Fe(VI)) system to degrade the selected antibiotic, trimethoprim (TMP), efficiently. An oxygen doped ZnIn2S4 nanosheet (O-ZIS) coupled with a black phosphorus (BP) heterostructure (O-ZIS/BP), is fabricated by a simple electrostatic self-assembly method. The O-ZIS/BP photocatalyst is comprehensively characterized by surface and analytical techniques, which show superior separation efficiency of the photoinduced charge carriers in the heterostructure. A VL-O-ZIS/BP-Fe(VI) system achieves more than 80% removal in 1.0 min and complete removal of TMP in 3.0 min. Comparatively, only â7% and â24% of TMP are degraded by O-ZIS/BP and Fe(VI) in 1.0 min, respectively. The degradation experiments using probe molecules of reactive species and electron paramagnetic resonance (EPR) measurements reveal involvement of superoxide (O2-â¢), hydroxyl radical (â¢OH), and iron(V)/iron (IV) (FeV/FeIV) species in the mechanism of TMP degradation. Oxidized products of TMP are identified and reaction pathways are given. Theoretical calculations predict the initial attack on the TMP molecule by the reactive species in the VL-O-ZIS/BP-Fe(VI) system. The activation of Fe(VI) by VL-heterostructure photocatalysts accelerates the degradation of antibiotics, demonstrating its potential for water depollution.
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Annona muricata is a common plant used in Africa and South America to manage various types of disease. However, there is insufficient toxicological information or published standard available regarding repeated dose animal toxicity data. As part of the safety assessment, we exposed Sprague Dawley rats to an acute oral toxicity of A. muricata. The intent of the current study was to use advanced proton nuclear magnetic resonance (1H NMR) in serum and urinary metabolomics evaluation techniques to provide the in vivo acute toxicological profile of A. muricata leaf ethanol extract in accordance with the Organization for Economic Co-operation and Development's (OECD) 423 guidelines. A single 2000 mg/kg dose of A. muricata leaf ethanol extract was administered to Sprague Dawley rats over an observational period of 14 days. The toxicity evaluation (physical and behavior observation, body weight, renal function test, liver function test and 1H NMR analysis) showed no abnormal toxicity. Histopathological analysis manifested mild changes, i.e., the treated kidney manifested mild hypercellularity of mesangial cells and mild red blood cell congestion. In addition, there was mild hemorrhage into tissue with scattered inflammatory cells and mild dilated central vein with fibrosis in the liver. However, the changes were very mild and not significant which correlate with other analyses conducted in this study (biochemical test and 1H NMR metabolomic analysis). On the other hand, urinary 1H NMR analysis collected on day 15 revealed high similarity on the metabolite variations for both untreated and treated groups. Importantly, the outcomes suggest that A. muricata leaf ethanol extract can be safely consumed at a dose of 2000 mg/kg and the LD50 must be more than 2000 mg/kg.
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Carmine radish (Raphanus sativus L.) is famousforcontaininganaturalredpigment(redradishpigment) that grown in Fuling, Chongqing City, China. MATE (multidrug and toxic compound extrusion), as an integral member of the multidrug efflux transporter family, has various functions in plants. However, noinformationhasbeenavailableaboutcharacteristicsoftheMATEgenefamily in carmine radish. In this study, total of 85 candidate MATE gene family members classifiedinto 4 groups were identified and foundtobewidelyandrandomlydistributedindifferent genome. Synteny analysis revealed that twenty-one segmental and ten tandem duplications acted as important regulators for the expansion of RsMATE genes. The Ka/Ks ratios of RsMATE indicated that RsMATE may have undergone intense purification in the radish genome. Cis-acting element analysis of RsMATE in the promoter region indicated that RsMATE were mainly related to the abiotic stress response and phytohormone. Quantitative real-time polymerase chain reaction (qRT-PCR) showed that RsMATE40-b, RsMATE16-b and RsMATE13-a genes were significantly expressed under ABA (abscisic acid) and NaCl stress treatments respectively. In addition, the expression patterns of fifteen key RsMATE genes were investigated in 'XCB' (Xichangbai) and 'HX' (Hongxin) roots under Cadmium (Cd) stress for different treatment times using qRT-PCR, of those, RsMATE49-b, RsMATE33 and RsMATE26 transcripts were strongly altered at different time points in XCB responsive to Cd stress,compared to HX. This study will provide valuable insights for studying the functional characterization of the MATE gene in carmine radish and other plants.
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Raphanus , Raphanus/metabolismo , Cádmio/metabolismo , Carmim/metabolismo , Genes de Plantas , Família Multigênica , Regulação da Expressão Gênica de PlantasRESUMO
COVID-19, a pandemic of acute respiratory syndrome diseases, led to significant social, economic, psychological, and public health impacts. It was not only uncontrolled but caused serious problems at the outbreak time. Physical contact and airborne transmission are the main routes of transmission for bioaerosols such as SARS-CoV-2. According to the Centers for Disease Control (CDC) and World Health Organization (WHO), surfaces should be disinfected with chlorine dioxide, sodium hypochlorite, and quaternary compounds, while wearing masks, maintaining social distance, and ventilating are strongly recommended to protect against viral aerosols. Ozone generators have gained much attention for purifying public places and workplaces' atmosphere, from airborne bioaerosols, with specific reference to the COVID-19 pandemic outbreak. Despite the scientific concern, some bioaerosols, such as SARS-CoV-2, are not inactivated by ozone under its standard tolerable concentrations for human. Previous reports did not consider the ratio of surface area to volume, relative humidity, temperature, product of time in concentration, and half-life time simultaneously. Furthermore, the use of high doses of exposure can seriously threaten human health and safety since ozone is shown to have a high half-life at ambient conditions (several hours at 55% of relative humidity). Herein, making use of the reports on ozone physicochemical behavior in multiphase environments alongside the collision theory principles, we demonstrate that ozone is ineffective against a typical bioaerosol, SARS-CoV-2, at nonharmful concentrations for human beings in air. Ozone half-life and its durability in indoor air, as major concerns, are also highlighted in particular.
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Poluição do Ar em Ambientes Fechados , COVID-19 , Ozônio , Humanos , SARS-CoV-2 , Poluição do Ar em Ambientes Fechados/análise , Pandemias/prevenção & controle , Aerossóis e Gotículas RespiratóriosRESUMO
How to collaboratively reduce Cr(VI) and break Cr(III) complexes is a technical challenge to solve chromium-containing wastewater (CCW) pollution. Solar photovoltaic (SPV) technology based on semiconductor materials is a potential strategy to solve this issue. Sb2 S3 is a typical semiconductor material with total visible-light harvesting capacity, but its large-sized structure highly aggravates disordered photoexciton migration, accelerating the recombination kinetics and resulting low-efficient photon utilization. Herein, the uniform mesoporous CdS shell is in situ formed on the surface of Sb2 S3 nanorods (NRs) to construct the core-shell Sb2 S3 @CdS heterojunction with high BET surface area and excellent near-infrared light harvesting capacity via a surface cationic displacement strategy, and density functional theory thermodynamically explains the breaking of SbS bonds and formation of CdS bonds according to the bond energy calculation. The SbSCd bonding interaction and van der Waals force significantly enhance the stability and synergy of Sb2 S3 /CdS heterointerface throughout the entire surface of Sb2 S3 NRs, promoting the Sb2 S3 -to-CdS electron transfer due to the formation of built-in electric field. Therefore, the optimized Sb2 S3 @CdS catalyst achieves highly enhanced simulated sunlight-driven Cr(VI) reduction (0.154 min-1 ) and decomplexation of complexed Cr(III) in weakly acidic condition, resulting effective CCW treatment under co-action of photoexcited electrons and active radicals. This study provides a high-performance heterostructured catalyst for effective CCW treatment by SPV technology.
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The photocatalysis-Fenton synergistic reaction has great potential for water purification but generally suffers from unsatisfactory electron transfer due to an undesirable interface structure. Herein, we developed a novel heterojunction of oxygen vacancy-rich TiO2-x confined in the layer space of a synthetic montmorillonite-like iron silicate (denoted as TiO2-x/FeMMT) that addresses the issue mentioned above. Two-dimensional layered montmorillonite-like silicates in heterojunctions as a support not only provided more active sites for the reaction but also induced oxygen vacancies in TiO2-x through interfacial effects to enhance the visible-light harvesting ability. Notably, such loading TiO2-x as an electron donor accelerated the Fe(III)/Fe(II) redox cycling and facilitated the effective activation of H2O2, while Fe(III) in the montmorillonite-like silicate as electron trap sites greatly improved the separation of photogenerated electron-hole pairs. More interestingly, the internal electric field and oxygen vacancies (Vo) existing at the interface realized the directional migration of photogenerated electrons and improved the energy band structure of the heterojunction, respectively. Eventually, the TiO2-x/FeMMT composites exhibited superior photocatalysis-Fenton performance toward degradation removal of phenol, dinotefuran (DIN), and sulfamethoxazole (SMX) under visible-light irradiation. This paves the way for the rational design of high-efficiency heterojunction catalysts based on layered silicates for environment-related applications.
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A sub-bituminous natural coal sample (R.C) was treated with sulfuric acid (S.C) and nitric acid (N.C) as modified products and enhanced adsorbents for obtaining ciprofloxacin (CFX) antibiotic residuals from water. The characterization studied demonstrates enhancement in the surface area and the incorporation of new active oxygenated, sulfur-bearing, and nitrogen-bearing chemical groups into the structure of coal samples. This was reflected in the adsorption capacities that were enhanced from 164.08 mg/g (R.C) to 489.2 mg/g and 518.5 mg/g for N.C and S.C, respectively. The impact of the acid modification processes was evaluated based on the energetic and steric properties of their adsorption systems considering the parameters of the advanced monolayer equilibrium model with one energy site. The determined occupied active sites' density of R.C (46.32-61.44 mg/g), N.C (168.7-364.9 mg/g), and S.C (159.2-249.9 mg/g) reflects an increase in the quantities of active centers after the acid treatment processes, especially with HNO3. The higher efficiencies of the active sites of S.C to adsorb more CFX molecules (n = 2.08-2.31) than N.C (n = 1.41-2.16) illustrate its higher adsorption capacity. The energetic investigation [adsorption (Ë40 kJ/mol) and Gaussian (Ë8 kJ/mol) energies] suggested adsorption of CFX by N.C and S.C mainly by physical processes such as van der Waals forces, hydrogen bonding, dipole bonding, and π-π interactions. Moreover, the determined thermodynamic functions including entropy, internal energy, and free enthalpy reflect the spontaneous and endothermic uptake of CFX on the surfaces of N.C and S.C.
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The electrochemical nitrate reduction reaction (NitRR) affords a sustainable way for nitrate mitigation and ammonia synthesis, but there are still some problems such as poor nitrate conversion, low ammonia selectivity, and slow reaction kinetics. A clear structure-performance relationship is essential for designing efficient catalysts and understanding the reaction mechanisms. Herein, ultrathin nickel metal-organic framework (Ni-MOF) nanosheets supported on Ni foam featuring a well-defined stable structure, large electrochemically active surface area, and low electron transport resistance were prepared by a one-step solvothermal process. At -1.4 V, the nitrate reduction, rate constant, ammonia selectivity, and yield reached 96.4%, 0.448 h-1, 80%, and 110.13 ug·h-1·cm-2, respectively. Experimental and theoretical studies demonstrated that the hydroxyl-ligated Ni atoms exhibited higher nitrate adsorption properties and lower activation energy towards NitRR compared to carboxylic acid-ligated Ni atoms. Mechanism investigations revealed a nitrate-to-ammonia reaction pathway involving multiple intermediate species on Ni-MOF nanosheet catalysts. This work offers a new avenue to construct highly efficient electrocatalysts for the selective transformation of nitrate to valuable ammonia.