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1.
Bioresour Technol ; 327: 124785, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33582520

RESUMO

Aiming at the accumulation of NO2--N and N2O during denitrification process, this work focused to improve the denitrification performance by Pd-Fe embedded multi-walled carbon nanotubes (MWCNTs). The main conclusions were as follows: 30 mg/L Pd-Fe/MWCNTs have shown an excellent promotion on denitrification (completely TN removal at 36 h). Meanwhile, enzyme activity results indicated that the generation of NO2--N, NH4+-N by Pd-Fe/MWCNTs led the occur of short-cut denitrification by increasing 203.9% the nitrite reductase activity. Furthermore, electrochemical results and index correlation analysis confirmed that the electron exchange capacity (1.401 mmol eg-1) of Pd-Fe/MWCNTs was positively related to nitrite reductase activity, indicating its crucial role in electron transport activity (0.46 µg O2/(protein·min) at 24 h) during denitrification process by Pd-Fe/MWCNTs played a role of chemical reductant and redox mediator.


Assuntos
Alcaligenes , Nanotubos de Carbono , Desnitrificação , Transporte de Elétrons , Oxirredução
2.
ACS Appl Mater Interfaces ; 13(3): 3701-3712, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33406818

RESUMO

Carbon nanohorns (CNHs), a type of nanocarbon, have been studied for the application of drug delivery systems (DDSs) because they are easily functionalized, support bone regeneration, can be used to perform photohyperthermia, have low toxicity, and are easily phagocytosed by macrophages. To take advantage of these features of CNHs, we developed a DDS for the local treatment of bone metastasis by loading the antibone resorption drug ibandronate (IBN) onto CNHs. The poor adsorption of IBN onto CNHs due to the weak hydrophilic-hydrophobic interaction was overcome by using calcium phosphates (CaPs) as mediators. In the fabrication process, we used oxidized CNH (OxCNH), which is less hydrophobic, onto which IBN was coprecipitated with CaP from a labile supersaturated CaP solution. OxCNH-CaP-IBN composite nanoparticles exerted stronger cell-suppressive effects than OxCNH and IBN in both murine macrophages (RAW264.7 cells) and osteoclasts (differentiated from RAW264.7 cells). OxCNH-CaP-IBN composite nanoparticles were efficiently phagocytosed by macrophage cells, where they specifically accumulated in lysosomes. The stronger cell-suppressive effects were likely due to intracellular delivery of IBN, i.e., the release of IBN from OxCNH-CaP-IBN composite nanoparticles via dissociation of CaP in the acidic environment of lysosomes. Our findings suggest that OxCNH-CaP-IBN composite nanoparticles are potentially useful for the local treatment of metastatic bone destruction.


Assuntos
Conservadores da Densidade Óssea/farmacologia , Portadores de Fármacos/química , Ácido Ibandrônico/farmacologia , Macrófagos/efeitos dos fármacos , Nanotubos de Carbono/química , Osteoclastos/efeitos dos fármacos , Animais , Conservadores da Densidade Óssea/administração & dosagem , Fosfatos de Cálcio/química , Ácido Ibandrônico/administração & dosagem , Camundongos , Nanotubos de Carbono/ultraestrutura , Células RAW 264.7
3.
ACS Appl Mater Interfaces ; 13(4): 5486-5497, 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33491443

RESUMO

Flexible paper-based sensors may be applied in numerous fields, but this requires addressing their limitations related to poor thermal and water resistance, which results in low service life. Herein, we report a paper-based composite sensor composed of carboxylic carbon nanotubes (CCNTs) and poly-m-phenyleneisophthalamide (PMIA), fabricated by a facile papermaking process. The CCNT/PMIA composite sensor exhibits an ability to detect pressures generated by various human movements, attributed to the sensor's conductive network and the characteristic "mud-brick" microstructure. The sensor exhibits the capability to monitor human motions, such as bending of finger joints and elbow joints, speaking, blinking, and smiling, as well as temperature variations in the range of 30-90 °C. Such a capability to sensitively detect pressure can be realized at different applied frequencies, gradient sagittas, and multiple twists with a short response time (104 ms) even after being soaked in water, acid, and alkali solutions. Moreover, the sensor demonstrates excellent mechanical properties and hence can be folded up to 6000 times without failure, can bear 5 kg of load without breaking, and can be cycled 2000 times without energy loss, providing a great possibility for a long sensing life. Additionally, the composite sensor shows exceptional Joule heating performance, which can reach 242 °C in less than 15 s even when powered by a low input voltage (25 V). From the perspective of industrialization, low-cost and large-scale roll-to-roll production of the paper-based sensor can be achieved, with a formed length of thousands of meters, showing great potential for future industrial applications as a wearable smart sensor for detecting pressure and temperature, with the capability of electric heating.


Assuntos
Nanotubos de Carbono/química , Papel , Fenilenodiaminas/química , Ácidos Ftálicos/química , Polímeros/química , Dispositivos Eletrônicos Vestíveis , Técnicas Biossensoriais/instrumentação , Condutividade Elétrica , Humanos , Monitorização Fisiológica/instrumentação , Movimento (Física) , Nanotubos de Carbono/ultraestrutura
4.
J Chromatogr A ; 1638: 461888, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33482614

RESUMO

Lead contamination in drinking and natural water has reached alarming concentrations, thus necessitating the development of accurate and rapid determination systems for Pb(II) in aqueous systems. Two hyphenated flow injection-solid phase extraction- FAAS (FI-SPE-FAAS) systems using oxidized and m-phenylenediamine functionalized multiwalled carbon nanotubes for Pb(II) preconcentration from industrially contaminated real water samples have been proposed. The chemical and hydrodynamic parameters affecting Pb(II) sorption/desorption were optimized. The effect of common interfering ions in water was also studied. Different figures of merit such as preconcentration factor (> 70), detection limit (≤ 1.5 µg L-1), and relative standard deviation (≤ 1.3%) were achieved at the preconcentration time of 120 s for both the preconcentration systems. The method was applied to industrially contaminated real water samples and the spike recovery tests were carried out using standard Pb(II) solution traceable to NIST. The proposed method was validated using standard reference material 1640a supplied by NIST Gaithersburg, MD, USA.


Assuntos
Chumbo/análise , Nanotubos de Carbono/química , Espectrofotometria Atômica/métodos , Adsorção , Concentração de Íons de Hidrogênio , Nanotubos de Carbono/ultraestrutura , Padrões de Referência , Reprodutibilidade dos Testes , Reologia , Extração em Fase Sólida , Espectroscopia de Infravermelho com Transformada de Fourier , Água/análise , Poluentes Químicos da Água/análise
5.
J Chromatogr A ; 1638: 461889, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33485030

RESUMO

As a typical steroid hormone drug, estradiol (E2) is also one of the most frequently detected endocrine disrupting chemicals (EDCs) in the aquatic environment. Herein, in response to the potential risk of E2 in steroid hormone pharmaceutical industry wastewater to human and wildlife, a novel carbon nanotubes / amine-functionalized Fe3O4 (CNTs/MNPs@NH2) nanocomposites with magnetic responsive have been developed for the enrichment and extraction of E2 in pharmaceutical industry wastewater, where amino-functionalized Fe3O4 magnetic nanoparticles (MNPs@NH2) were used as a magnetic source. The resultant CNTs/MNPs@NH2 possessed both the features of CNTs and desired magnetic property, enabling to rapidly recognize and separate E2 from pharmaceutical industry wastewater. Meanwhile, the CNTs/MNPs@NH2 had good binding behavior toward E2 with fast binding kinetics and high adsorption capacity, as well as exhibited satisfactory selectivity to steroidal estrogen compounds. Furthermore, the change of pH value of aqueous phase in adsorption solvent hardly affected the adsorption of E2 by CNTs/MNPs@NH2, and the adsorption capacity of E2 ranged from 19.9 to 17.2 mg g-1 in the pH range of 3.0 to 11.0, which is a latent advantage of the follow-up development method to detect E2 in pharmaceutical industry wastewater. As a result, the CNTs/MNPs@NH2 serving as a solid phase extraction medium were successfully applied to efficiently extract E2 from pharmaceutical industry wastewater. Therefore, the CNTs/MNPs@NH2 nanocomposites could be used as a potential adsorbent for removing steroidal estrogens from water. More importantly, the developed method would provide a promising solution for the monitoring and analysis of EDCs in pharmaceutical industry wastewater.


Assuntos
Aminas/química , Indústria Farmacêutica , Estradiol/isolamento & purificação , Compostos Férricos/química , Nanocompostos/química , Nanotubos de Carbono/química , Águas Residuárias/química , Adsorção , Aerobiose , Anaerobiose , Estradiol/análise , Humanos , Cinética , Magnetismo , Nanocompostos/ultraestrutura , Reprodutibilidade dos Testes , Extração em Fase Sólida , Solventes/química , Temperatura , Águas Residuárias/análise
6.
Int J Pharm ; 595: 120269, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33486033

RESUMO

Graphene nanoribbons are thin strips of single sheet graphene used in diagnoses and treatments of cancer, inflammation and Alzheimer's disease and considered as a good nanocarrier in gene, photo-thermal, anti-microbial therapies, etc. This review article focuses on the overview of bio-conjugation and molecular interaction of graphene nanoribbons with different biomolecules present in body like enzymes and peptides. The use of graphene nanoribbons as biosensor, artificial receptor and cellular device extends their applications in theranostic and drug delivery. The relationship between graphene and biological molecules like RNA, DNA, etc. using molecular dynamics related to the electronic properties are discussed for site-specific action. The biodegradation and use of graphene nanoribbons in safe concentration are important aspects for the prevention of toxicity in living cells and body environment. Graphene nanoribbons display various applications in bio-imaging, green chemistry and material sciences due to electro-mechanical properties such as higher surface area, greater loading capacity, elevated thermal capacity, etc. The functionalized graphene nanoribbons demonstrated better adsorption and adhesive binding properties to mammalian cells which make them ideal bio-carrier for gene transfection and nucleic acid delivery. Further, research and development of graphene nanoribbons for novel drug delivery is currently necessary to overcome barriers like environmental toxicity and extensive cost.


Assuntos
Grafite/química , Nanotubos de Carbono/química , Animais , Técnicas Biossensoriais , Sistemas de Liberação de Medicamentos , Terapia Genética , Humanos , Simulação de Dinâmica Molecular , Neoplasias/tratamento farmacológico
7.
Chemosphere ; 269: 129325, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33385665

RESUMO

Electro-Fenton (EF) technique has gained significant attention in recent years owing to its high efficiency and environmental compatibility for the degradation of organic pollutants and contaminants of emerging concern (CECs). The efficiency of an EF reaction relies primarily on the formation of hydrogen peroxide (H2O2) via 2e─ oxygen reduction reaction (ORR) and the generation of hydroxyl radicals (●OH). This could be achieved through an efficient cathode material which operates over a wide pH range (pH 3-9). Herein, the current progresses on the advancements of carbonaceous cathode materials for EF reactions are comprehensively reviewed. The insights of various materials such as, activated carbon fibres (ACFs), carbon/graphite felt (CF/GF), carbon nanotubes (CNTs), graphene, carbon aerogels (CAs), ordered mesoporous carbon (OMCs), etc. are discussed inclusively. Transition metals and hetero atoms were used as dopants to enhance the efficiency of homogeneous and heterogeneous EF reactions. Iron-functionalized cathodes widened the working pH window (pH 1-9) and limited the energy consumption. The mechanism, reactor configuration, and kinetic models, are explained. Techno economic analysis of the EF reaction revealed that the anode and the raw materials contributed significantly to the overall cost. It is concluded that most reactions follow pseudo-first order kinetics and rotating cathodes provide the best H2O2 production efficiency in lab scale. The challenges, future prospects and commercialization of EF reaction for wastewater treatment are also discussed.


Assuntos
Nanotubos de Carbono , Poluentes Químicos da Água , Eletrodos , Peróxido de Hidrogênio , Cinética , Oxirredução
8.
Water Sci Technol ; 83(2): 257-270, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33504692

RESUMO

This paper presents a study of V and N co-doping TiO2 embedding multi-walled carbon nanotubes (MWCNTs) supported on γ-Al2O3 pellet (V/N-TiO2-MWCNTs/γ-Al2O3) composite photocatalyst induced by pulsed discharge plasma to enhance the removal of acid orange II (AO7) from aqueous solution. The photocatalytic activity of the V/N-TiO2-MWCNTs/γ-Al2O3 composite to AO7 removal induced by the pulsed discharge plasma was evaluated. The results indicate that the V/N-TiO2-MWCNTs/γ-Al2O3 composite possesses enhanced photocatalytic activity that facilitates the removal of AO7 compared with the TiO2-MWCNTs/γ-Al2O3 and TiO2/γ-Al2O3 composites. Almost 100% of AO7 is removed after 10 min under optimal conditions. The V0.10/N0.05-TiO2-MWCNTs/γ-Al2O3 photocatalyst exhibits the best removal effect for AO7. Analysis of the removal mechanism indicates that the enhancement of the removal of AO7 resulting from V and N co-doping causes TiO2 lattice distortion and introduces a new impurity energy level, which not only reduces the band gap of TiO2 but also inhibits the recombination of the ecb-/hvb+ pairs.


Assuntos
Nanotubos de Carbono , Compostos Azo , Catálise , Naftalenos , Plasma , Titânio
9.
J Environ Manage ; 277: 111434, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33045646

RESUMO

This study assessed the environmental impacts of the formulation of graphene oxide (GO)/multi-walled carbon nanotubes (MWCNTs) conductive membranes and of the process operating parameters of electrically-enhanced palm oil mill effluent (POME) filtration. Two different analyses approaches were employed, cradle-to-gate approach for conductive membrane production and gate-to-gate approach for the POME filtration process. The parameters in conductive-membrane formulation (e.g. the weight ratio of carbon nanomaterials, and concentration of GO/MWCNT nanohybrids) and process operating parameters (e.g. electric field strength and electricity operating mode) were investigated. The findings herein are twofold. Firstly, for the fabrication of GO/MWCNT conductive membranes, the best weight ratio of GO:MWCNTs was found to be 1:9, given its superior membrane electrical conductivity with lower environmental impacts by 8.51% compared to pristine MWCNTs. The most suitable concentration of carbon nanomaterials was found to be 5 wt%, given its lowest impacts on resource depletion, human health, and ecosystems. Secondly, for the electrically-enhanced POME filtration, the optimum process operating parameters were found to be the application of an electric field of 300 V/cm in the continuous mode, given its lower environmental impacts (22.99%-89.30%) secondary to its requirement of the least electricity to produce permeate. The present study has established not only the optimized conditions in membrane formulation but also the operating parameters of electrically-enhanced filtration; such findings enable the use of cleaner production and sustainable approach to minimize fouling for industrial applications, whilst maintaining excellent efficiency.


Assuntos
Resíduos Industriais , Nanotubos de Carbono , Ecossistema , Condutividade Elétrica , Eletricidade , Resíduos Industriais/análise , Óleo de Palmeira , Óleos Vegetais
10.
Chemosphere ; 263: 128005, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297038

RESUMO

The supply of safe drinking and clean water is becoming increasingly challenging proposition throughout the world. The deployment of environmentally sustainable nanomaterials with unique advantages namely high efficiency and selectivity, earth-abundance, recyclability, low-cost of production processes, and stability, has been a priority although several important challenges and constraints still remained unresolved. Carbon nanomaterials namely activated carbon, multi-walled- and single-walled carbon nanotubes, have been developed and applied as adsorbents for wastewater treatment and purification; graphene and graphene oxide-based nanomaterials as well as carbon and graphene quantum dots-derived nanomaterials have shown significant promise for water and wastewater treatment and purification, especially, for industrial- and pharmaceutical-laden wastes. This review encompasses advanced carbonaceous nanomaterials and methodologies that are deployed for the elimination of contaminants and ionic metals in aqueous media, and as novel nanosorbents for wastewater, drinking and ground water treatment. Additionally, recent trends and challenges pertaining to the sustainable carbon and graphene quantum dots-derived nanomaterials and their appliances for treating and purifying wastewater are highlighted.


Assuntos
Nanoestruturas , Nanotubos de Carbono , Purificação da Água , Águas Residuárias , Água
11.
Phys Chem Chem Phys ; 23(1): 219-228, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33325925

RESUMO

The strategic approaches to the design of self-assembled hybrids of biomolecular systems at the nanoscale such as deoxyribonucleic acid (DNA) with single-wall carbon nanotubes (CNTs) and their structural analog, boron nitride nanotubes (BNNTs), rely on understanding how biomolecules recognize and mediate intermolecular interactions with the nanomaterial's surface. In this paper, we consider peptide nucleic acid (PNA), which is a synthetic analog of DNA, and investigate its interaction with a zigzag CNT and BNNT of similar diameter. The results based on the molecular dynamics method find that PNA provides definitive contrasts in the adsorption on the tubular surface in aqueous solution: it prefers to wrap along the circumferential direction on a (11,0) CNT, whereas it binds along the axial direction adopting an extended configuration on a (11,0) BNNT. Moreover, gas-phase Monte Carlo simulations show a dependence of the nanotube diameter on the calculated adsorption energy, with BNNTs exhibiting higher adsorption energy compared to CNTs, and the largest-diameter (25,0) tubular configuration facilitates encapsulation of PNA rather than PNA being adsorbed on its sidewall. The results are expected to be of relevance in the design of novel PNA-based archetypal hybrid materials for nanoscale applications in health-related areas including biosensing.


Assuntos
Compostos de Boro/química , Nanotubos de Carbono/química , Ácidos Nucleicos Peptídicos/química , Adsorção , Simulação de Dinâmica Molecular , Método de Monte Carlo
12.
Environ Pollut ; 270: 116192, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33338957

RESUMO

Polyethylene terephthalate (PET) is a possible key component of nanoplastics in water environments, which can migrate pollutants through co-transport. In this regard, the co-transport of endocrine disruptors (such as bisphenol A, BPA) by nanoplastics is of emergent concern because of its cytotoxicity/bioaccumulation effects in aquatic organisms. In this work, a computational study is performed to reveal the BPA adsorption mechanism onto PET nanoplastics (nanoPET). It is found that the outer surface of nanoPET has a nucleophilic nature, allowing to increase the mass transfer and intraparticle diffusion into the nanoplastic to form stable complexes by inner and outer surface adsorption. The maximum adsorption energy is similar (even higher) in magnitude with respect to nanostructured adsorbents such as graphene, carbon nanotubes, activated carbon, and inorganic surfaces, indicating the worrying adsorption properties of nanoPET. The adsorption mechanism is driven by the interplay of dispersion (38-49%) and electrostatics effects (43-50%); specifically, dispersion effects dominate the inner surface adsorption, while electrostatics energies dominate the outer surface adsorption. It is also determined that π-π stacking is not a reliable interaction mechanism for aromatics on nanoPET. The formed complexes are also highly soluble, and water molecules behave as non-competitive factors, establishing the high risk of nanoPET to adsorb and migrate pollutants in water ecosystems. Furthermore, the adsorption performance is decreased (but not inhibited) at high ionic strength in salt-containing waters. Finally, these results give relevant information for environmental risk assessment, such as quantitative data and interaction mechanisms for non-biodegradable nanoplastics that establish strong interactions with pollutants in water.


Assuntos
Nanotubos de Carbono , Poluentes Químicos da Água , Adsorção , Compostos Benzidrílicos , Ecossistema , Microplásticos , Modelos Teóricos , Fenóis , Polietilenotereftalatos , Poluentes Químicos da Água/análise
13.
Food Chem ; 340: 128128, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33010646

RESUMO

In this research, a novel signal-on aptasensor for highly sensitive detection of zearalenone (ZEN) was reported based on target-induced amplification strategy. Specifically, chitosan functionalized acetylene black and multi-walled carbon nanotubes (CS@AB-MWCNTs) nanocomposite with large specific surface area and excellent conductivity was synthesized and served as the sensing platform. In addition, carboxylated graphene oxide-labeled ZEN binding aptamer (CGO-ZBA) would specifically recognized with ZEN to detach from the electrode, allowing the electrochemical signal of [Fe(CN)6]3-/4- increased more obviously. Under the optimal conditions, the proposed aptasensor exhibited exceptional detection performances for ZEN with a linear range from 10 fg mL-1 to 1 ng mL-1 and a low limit of detection of 3.64 fg mL-1. Given its great sensitivity, excellent selectivity, satisfactory stability and reproducibility, this method would provide a promising application for ZEN and other biomolecules by replacing the corresponding nucleicacidsequences.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Eletroquímicas/métodos , Nanocompostos/química , Zearalenona/análise , Acetileno/química , Quitosana/química , Eletrodos , Grafite/química , Limite de Detecção , Nanotubos de Carbono/química , Reprodutibilidade dos Testes , Zearalenona/química
14.
Chemosphere ; 263: 128043, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297058

RESUMO

The presence of pharmaceutical micropollutants in water and wastewater is considered a serious environmental issue. To eliminate these pollutants, biodegradation of pharmaceuticals using enzymes such as laccase, is proposed as a green method. In this study, immobilized laccase was used for the removal of two model pharmaceutical compounds, carbamazepine and diclofenac. Polyvinylidene fluoride (PVDF) membrane modified with multi-walled carbon nanotubes (MWCNTs) were synthesized as a tailor-made support for enzyme immobilization. Covalently immobilized laccase from Trametes hirsuta exhibited remarkable activity and activity recovery of 4.47 U/cm2 and 38.31%, respectively. The results also indicated improvement in the operational and thermal stability of the immobilized laccase compared to free laccase. Finally, by using immobilized laccase in a mini-membrane reactor, removal efficiencies of 27% in 48 h and 95% in 4 h were obtained for carbamazepine and diclofenac, respectively. The findings suggest that immobilized laccase on PVDF/MWCNT membranes is a promising catalyst for large-scale water and wastewater treatment which is also compatible with existing treatment facilities.


Assuntos
Nanocompostos , Nanotubos de Carbono , Preparações Farmacêuticas , Enzimas Imobilizadas , Concentração de Íons de Hidrogênio , Lacase , Polyporaceae , Polivinil , Trametes
15.
Chemosphere ; 263: 128124, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297113

RESUMO

In this study, oxidants and nanomaterials were used to improve titanium dioxide based photocatalytic degradation of sulfolane. Hydrogen peroxide (H2O2), sodium persulfate (SPS) and ozone (O3) were the oxidants studied and carbon nanotubes (CNT) and nanosized zero valent iron (nZVI) were used as the nanomaterials. The impact of these oxidants and nanomaterials was evaluated at various dosages in both Milli-Q water and groundwater. The results indicate that with a suitable dose of oxidants or nanomaterials, photocatalytic degradation of sulfolane in Milli-Q water can be enhanced. The addition of ozone contributed to a significant increase in sulfolane degradation rate in Milli-Q water. The experiments conducted in groundwater showed that oxidants (H2O2, SPS and O3) increased the degradation of sulfolane while the nanomaterials (CNT and nZVI) impeded sulfolane degradation in groundwater.


Assuntos
Água Subterrânea , Nanotubos de Carbono , Poluentes Químicos da Água , Purificação da Água , Peróxido de Hidrogênio , Oxidantes , Tiofenos , Poluentes Químicos da Água/análise
16.
J Environ Sci (China) ; 101: 413-427, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33334535

RESUMO

Passive techniques are a constantly evolving approach to the long-term monitoring of micropollutants, including pharmaceuticals, in the aquatic environment. This paper presents, for the first time, the calibration results of a new CNTs-PSDs (carbon nanotubes used as a sorbent in passive sampling devices) with an examination of the effect of donor phase salinity, water pH and the concentration of dissolved humic acids (DHAs), using both ultrapure and environmental waters. Sampling rates (Rs) were determined for the developed kinetic samplers. It has been observed that the impact of the examined environmental factors on the Rs values strictly depends on the type of the analytes. In the case of ß-blockers, the only environmental parameter affecting their uptake rate was the salinity of water. A certain relationship was noted, namely the higher the salt concentration in water, the lower the Rs values of ß-blockers. In the case of sulfonamides, water salinity, water pH 7-9 and DHAs concentration decreased the uptake rate of these compounds by CNTs-PSDs. The determined Rs values differed in particular when the values obtained from the experiments carried out using ultrapure water and environmental waters were compared. The general conclusion is that the calibration of novel CNTs-PSDs should be carried out under physicochemical conditions of the aquatic phase that are similar to the environmental matrix.


Assuntos
Nanotubos de Carbono , Poluentes Químicos da Água , Calibragem , Monitoramento Ambiental , Sulfonamidas , Água , Poluentes Químicos da Água/análise
17.
Chemosphere ; 262: 128215, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182126

RESUMO

The effluent from conventional treatment process (including anaerobic digestion and anoxic-oxic treatment) for pig farm wastewater was difficult to treat due to its low ratio of biochemical oxygen demand to chemical oxygen demand (BOD5/CODCr) (<0.1). In the present study, electro-Fenton (EF) was used to improve the biodegradability of the mentioned effluent and the properties of self-prepared CeO2-doped multi-wall carbon nanotubes (MWCNTs) electrodes were also studied. An excellent H2O2 production (165 mg L-1) was recorded, after an 80-min electrolysis, when the mass ratio of MWCNTs, CeO2 and pore-forming agent (NH4HCO3) was 6:1:1. Results of scanning electron microscopy (SEM), transmission electron microscope (TEM) and x-ray photoelectron spectroscopy (XPS) showed that addition of NH4HCO3 and the doping of CeO2 could increase the superficial area of the electrode as well as the oxygen reduction reaction (ORR) electro-catalytic performance. The BOD5/CODCr of the wastewater from the first stage AO process increased from 0.08 to 0.45 and CODCr reduced 71.5% after an 80-min electrolysis, with 0.3 mM Fe2+ solution. The non-biodegradable chemical pollutants from the first stage AO process were degraded by EF. The non-biodegradable pollutants identified by LC-MS/MS in the effluent from AO process including aminopyrine, oxadixyl and 3-methyl-2-quinoxalinecarboxylic acid could be degraded by EF process, with the removal rates of 81.86%, 34.39% and 7.13% in 80 min, and oxytetracycline with the removal rate of 100% in 20 min. Therefore, electro-Fenton with the new CeO2-doped MWCNTs cathode electrode will be a promising supplement for advanced treatment of pig farm wastewater.


Assuntos
Cério/química , Eletrólise/métodos , Nanotubos de Carbono/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Animais , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Catálise , Eletrodos , Fazendas , Peróxido de Hidrogênio/análise , Oxirredução , Suínos
18.
Chemosphere ; 262: 128053, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182130

RESUMO

Nowadays, more and more attention is focused on the environmental harm brought by the wide production and use of carbon nanotubes. In this study, the metabolic function of sediment microbial community was investigated after unfunctionalized or functionalized multi-walled carbon nanotubes (MWCNTs) were incorporated. The surface functional groups on the studied functionalized MWCNTs in this work were hydroxyl, carboxyl, and amino, respectively. The metabolic functional diversity was determined by Biolog EcoPlates after one-month exposure to MWCNTs. Incorporating 0.5 wt% amino functionalized MWCNTs significantly decreased the microbial activity and diversity, and all types of MWCNTs caused great inhibition on the microbial metabolism at the dosage of 2.0 wt%. The sediment microbes preferred polymers and amino acids. Principal component and similarity analysis indicated that the microbial carbon metabolism was more affected by the MWCNT dosage compared with the functionalization, and 2.0 wt% amino functionalized MWCNTs made the greatest difference in metabolic function of sediment microbial community. These consequences may help to assess the environmental risks of MWCNTs from the aspect of ecological relevance of sediment microbial community.


Assuntos
Sedimentos Geológicos/microbiologia , Microbiota/efeitos dos fármacos , Nanotubos de Carbono/toxicidade , Rios/microbiologia , Poluentes Químicos da Água/toxicidade , Sedimentos Geológicos/química , Modelos Teóricos , Nanotubos de Carbono/química , Rios/química , Propriedades de Superfície , Poluentes Químicos da Água/química
19.
J Environ Sci (China) ; 99: 260-266, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33183703

RESUMO

Metal phthalocyanine has been extensively studied as a catalyst for degradation of carbamazepine (CBZ). However, metal phthalocyanine tends to undergo their own dimerization or polymerization, thereby reducing their activity points and affecting their catalytic properties. In this study, a catalytic system consisting of O-bridged iron perfluorophthalocyanine dimers (FePcF16-O-FePcF16), multi-walled carbon nanotubes (MWCNTs) and H2O2 was proposed. The results showed MWCNTs loaded with FePcF16-O-FePcF16 can achieve excellent degradation of CBZ with smaller dosages of FePcF16-O-FePcF16 and H2O2, and milder reaction temperatures. In addition, the results of experiments revealed the reaction mechanism of non-hydroxyl radicals. The highly oxidized high-valent iron-oxo (Fe(IV)=O) species was the main reactive species in the FePcF16-O-FePcF16/MWCNTs/H2O2 system. It is noteworthy that MWCNTs can improve the dispersion of FePcF16-O-FePcF16, contributing to the production of highly oxidized Fe(IV)=O. Then, the pathway of CBZ oxidative degradation was speculated, and the study results also provide new ideas for metal phthalocyanine-loaded carbon materials to degrade emerging pollutants.


Assuntos
Ferro , Nanotubos de Carbono , Carbamazepina , Peróxido de Hidrogênio , Oxirredução
20.
Food Chem ; 338: 127805, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32798814

RESUMO

In order to meet the requirements of pesticide residues' detection in complex matrix samples, the magnetic fluorinated multi-wall carbon nanotubes (M-F-MWCNTs) were prepared and applied as new QuEChERS clean-up materials. Combined with GC-MS, an improved QuEChERS method was successfully developed for the detection of organophosphorus pesticide residues. The results showed that the M-F-MWCNTs could effectively remove the interfering substances in Lycium ruthenicum Murr. (L. ruthenicum) samples. The recoveries of 10 tested targets were 74.9% to 113.5% with the relative standard deviations (RSDs) of 3.9-14.7%. The experiment results pointed out that the M-F-MWCNTs were qualified as QuEChERS clean-up materials and expected to be applied to other complex matrix samples and pesticide targets.


Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Lycium/química , Nanotubos de Carbono/química , Resíduos de Praguicidas/análise , Flúor/química , Análise de Alimentos/instrumentação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Limite de Detecção , Fenômenos Magnéticos , Organofosfatos/análise
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