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1.
Anal Bioanal Chem ; 412(8): 1893-1899, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32016568

RESUMEN

Superoxide dismutase (SOD), also known as liver protein, is a substance widely distributed in various biological cells. It has the function of catalyzing the disproportionation reaction of superoxide free radicals. SOD can form an antioxidant chain together with peroxidase, catalase, and other substances in the body of organisms, and thus, is one of the indispensable important substances in the body of organisms. In this work, we provided a simple and fast visual electrochemiluminescence (ECL) sensor for SOD detection. CuInZnS quantum dots (QDs) worked as the ECL luminophore with hydrogen peroxide as co-reactant. In the sensing process, SOD and CuInZnS QDs on a glassy carbon electrode (GCE) competed with each other for hydrogen peroxide to produce superoxide during electrochemical luminescence, thus quenching the ECL signal of CuInZnS QDs. The proposed sensor can quantify SOD with a limit of detection (LOD) of 0.03 µg/mL. In addition, the change in the CuInZnS QDs ECL signal was easily observed with a smartphone camera. The results indicated that this sensor could effectively work in the detection of SOD in human blood. Graphical abstract.


Asunto(s)
Cobre/química , Técnicas Electroquímicas/métodos , Indio/química , Luminiscencia , Puntos Cuánticos/química , Sulfuros/química , Superóxido Dismutasa/análisis , Compuestos de Zinc/química , Técnicas Biosensibles , Límite de Detección , Reproducibilidad de los Resultados
2.
Chemosphere ; 243: 125439, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31995887

RESUMEN

This paper introduces a novel method for ethylenediaminetetraacetic acid (EDTA)-enhanced electrokinetic (EK) remediation by combining dual cation-exchange membranes and circulation methods for an aged electroplating soil contaminated by chrome (Cr), copper (Cu), and nickel (Ni). Three laboratory-scale EK experiments were carried out, including T1, the traditional EK process; T2, the traditional EDTA-enhanced EK process; and T3, the assisted EDTA-enhanced EK process. The results obtained show that removal of Cu and Ni in T3 was 3-10 times higher than after T1 and T2. However, the removal of Cr (total) was small in all experiments because of the high content of Cr(III). T3 eliminated the metal accumulation problem that existed for T1 and T2. Simultaneously, the highly acidified area (pH < 4) was reduced from 80% in T1 and T2 to only 20% in T3. The results obtained in T3 indicate that the chelating effect of EDTA has a greater ability to dissolve oxidizable Cu and Ni in the soil than the acidification effect. Toxicity evaluation confirmed that the soil treated by T3 presented a lower effect on a luminescent bacterium (Photobacterium phosphoreum T3) because soil pH tended to be more neutral after this treatment. This research provides a novel method for removing heavy metals from soil in a more environmentally friendly way and clarifies the cause of the existing problems of low removal efficiency and high accumulation in the traditional EK process.


Asunto(s)
Técnicas Electroquímicas/métodos , Restauración y Remediación Ambiental/métodos , Resinas de Intercambio de Catión , Compuestos de Cromo/aislamiento & purificación , Cobre/química , Cobre/aislamiento & purificación , Ácido Edético/química , Galvanoplastia , Metales Pesados/aislamiento & purificación , Níquel/aislamiento & purificación , Suelo/química , Contaminantes del Suelo/aislamiento & purificación
3.
Anal Bioanal Chem ; 412(4): 841-848, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31897553

RESUMEN

A sensitive photoelectrochemical (PEC) aptasensor was constructed for prostate-specific antigen (PSA) detection using an enhanced photocurrent response strategy. The p-n heterostructure CdS-Cu2O nanorod arrays were prepared on Ti mesh (CdS-Cu2O NAs/TM) by a simple hydrothermal method and successive ionic-layer adsorption reactions. Compared with the original CdS/TM, the synergistic effect of p-n type CdS-Cu2O NAs/TM and the internal electric field realizes the effective separation of photoinduced electron-hole pairs and improves the PEC performance. In order to construct the aptasensor, an amino-modified aptamer was immobilized on CdS-Cu2O NAs/TM to serve as a recognition unit for PSA. After the introduction of PSA, PSA was specifically captured by the aptamer on the PEC aptasensor, which can be oxidized by photogenerated holes to prevent electron-hole recombination and increase photocurrent. Under optimal conditions, the constructed PEC aptasensor has a linear range of 0.1-100 ng·mL-1 and a detection limit as low as 0.026 ng·mL-1. The results of aptasensor detection of human serum indicate that it has broad application prospects in biosensors and photoelectrochemical analysis.


Asunto(s)
Aptámeros de Nucleótidos/química , Compuestos de Cadmio/química , Cobre/química , Nanotubos/química , Antígeno Prostático Específico/sangre , Sulfuros/química , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Humanos , Límite de Detección , Nanotubos/ultraestructura
4.
Anal Bioanal Chem ; 412(4): 1011-1024, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31897563

RESUMEN

Cabbage flower-like Ho3+/NiO nanostructure (CFL-Ho3+/NiO NSs) with significant electrocatalytic oxidation has been published for the first time. First, structure and morphology of CFL-Ho3+/NiO-NSs have been described by XRD, SEM, and EDX methods. Then, CFL-Ho3+/NiO-NSs have been applied as a modifier for simultaneous electrochemical detection of methotrexate (MTX) and carbamazepine (CBZ). Functions of the modified electrode have been dealt with through electrochemical impedance spectroscopy (EIS). It has been demonstrated that the electrode response has been linear from 0.001-310.0 µM with a limit of detection of 5.2 nM and 4.5 nM (3 s/m) through DPV for MTX and CBZ. Diffusion coefficient (D) and heterogeneous rate constant (kh) have been detected for MTX and CBZ oxidation at the surface of the modified electrode. Moreover, CFL-Ho3+/NiO-NS/GCE has been employed for determining MTX and CBZ in urine and drug specimens. Outputs showed the analyte acceptable recovery. Therefore, the electrode could be applied to analyze both analytes in drug prescription and clinical laboratories. Graphical abstract Electrochemical sensor based on bifunctional cabbage flower-like Ho3+/NiO nanostructures modified glassy carbon electrode for simultaneous detecting methotrexate and carbamazepine was fabricated.


Asunto(s)
Analgésicos no Narcóticos/farmacocinética , Carbamazepina/farmacocinética , Monitoreo de Drogas/métodos , Inmunosupresores/farmacocinética , Metotrexato/farmacocinética , Analgésicos no Narcóticos/análisis , Analgésicos no Narcóticos/sangre , Analgésicos no Narcóticos/orina , Carbamazepina/análisis , Carbamazepina/sangre , Carbamazepina/orina , Técnicas Electroquímicas/métodos , Holmio/química , Humanos , Inmunosupresores/análisis , Inmunosupresores/sangre , Inmunosupresores/orina , Límite de Detección , Metotrexato/análisis , Metotrexato/sangre , Metotrexato/orina , Nanoestructuras/química , Níquel/química , Oxidación-Reducción , Comprimidos
5.
Chem Commun (Camb) ; 56(10): 1513-1516, 2020 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-31919482

RESUMEN

A potentiometric resolved photoelectrochemical (PEC) system based on CdS nanowires and SnNb2O6 nanosheets was developed. To prove the applicability of this system in PEC multi-biomarker analysis, a label free PEC immunosensor for two cardiac biomarkers, myoglobin and cardiac troponin I, was constructed.


Asunto(s)
Biomarcadores/análisis , Técnicas Electroquímicas/métodos , Nanoestructuras/química , Nanocables/química , Compuestos de Estaño/química , Técnicas Biosensibles , Compuestos de Cadmio/química , Humanos , Mioglobina/análisis , Sulfuros/química , Troponina I/análisis
6.
Chem Commun (Camb) ; 56(11): 1705-1708, 2020 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-31942910

RESUMEN

We report ultrathin organic photovoltaic elements optimized to run photofaradaic reactions in biological conditions. We demonstrate concurrent oxygen reduction to hydrogen peroxide and glucose oxidation. The devices are powered by deep-red irradiation in the tissue transparency window. We utilize bilayers of phthalocyanine, acting as the light absorber, and perylene diimide, functioning as both electron-acceptor and the hydrogen peroxide evolution electrocatalyst. These heterojunction bilayers are stable when irradiated in simulated physiological conditions, producing photovoltages sufficient to simultaneously drive cathodic oxygen reduction to H2O2 and anodic oxidation of glucose. We find that optimization of the anode metal is critical for sustained photofaradaic reactivity. Our results demonstrate a robust "wet" thin film photovoltaic with potential for physiological applications where localized electrochemical manipulation is desired, in particular the delivery of reactive oxygen species.


Asunto(s)
Técnicas Electroquímicas/métodos , Peróxido de Hidrógeno/síntesis química , Imidas/química , Indoles/química , Perileno/análogos & derivados , Técnicas Electroquímicas/instrumentación , Diseño de Equipo , Glucosa/química , Oro/química , Imidas/efectos de la radiación , Indoles/efectos de la radiación , Luz , Membranas Artificiales , Oxidación-Reducción , Oxígeno/química , Perileno/química , Perileno/efectos de la radiación , Fotoquímica/métodos
7.
Food Microbiol ; 87: 103381, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31948622

RESUMEN

Indirect impedance has been used for the detection and enumeration of bacteria, however there is limited data regarding the ability of the method to measure growth and inhibition of microorganisms in food in response to preservatives. The aim of this study was to evaluate the suitability of the technique to determine maximum growth rates of Listeria innocua (used as a surrogate for Listeria monocytogenes) in complex food matrices to which multiple preservative factors had been applied and assess the suitability of the data for use in predictive microbiology. Growth of L. innocua in laboratory medium (BHI broth) and two food matrices (zucchini purée and béarnaise sauce) under varying conditions of pH (5 & 5.3), water activity (0.93, 0.96 & 0.98) and acetic and propionic acid concentration (0, 1 & 2 mM) was monitored by the conductimetric Rapid Automated Bacterial Impedance Technology (R.A.B.I.T) system by means of CO2 emission for up to 120 h. Growth rates of L. innocua were determined for several conditions across the three test matrices and a good correlation between detection times and initial inoculum level was observed in most cases (R2 ≥ 0.82). However, growth of L. innocua was not detected in a large number of conditions and comparison of growth rates determined by indirect impedance to those determined by plate counts indicated that in general, the R.A.B.I.T. system under-estimated growth. This study demonstrates that there are limitations associated with the technology, and as a result the system may be unsuitable for measuring microbial growth rates in complex food matrices under the environmental conditions tested and within the time duration of the study.


Asunto(s)
Recuento de Colonia Microbiana/métodos , Técnicas Electroquímicas/métodos , Microbiología de Alimentos/métodos , Listeria/química , Listeria/crecimiento & desarrollo , Dióxido de Carbono/análisis , Dióxido de Carbono/metabolismo , Impedancia Eléctrica , Contaminación de Alimentos/análisis , Concentración de Iones de Hidrógeno , Listeria/metabolismo , Listeria monocytogenes/química , Listeria monocytogenes/crecimiento & desarrollo , Listeria monocytogenes/metabolismo , Agua/análisis , Agua/metabolismo
8.
Anal Bioanal Chem ; 412(4): 915-922, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31900531

RESUMEN

A tetrahedral DNA probe can effectively overcome the steric effects of a single-stranded probe to obtain well-controlled density and minimize nonspecific adsorption. Herein, a highly sensitive electrochemical biosensor is fabricated for determination of protein using a tetrahedral DNA probe and rolling circle amplification (RCA). N- and P-co-doped graphene (NP-rGO) is prepared, and AuNPs are then electrodeposited on it for DNA probe immobilization. Benefitting from the synergistic effects of the excellent electrical conductivity of NP-rGO, the stability of the tetrahedral DNA probe and the signal amplification of RCA, the biosensor achieves a low limit of 3.53 × 10-14 M for thrombin and a wide linear range from 1 × 10-13 to 1 × 10-7 M. This study provides a sensitive and effective method for the detection of protein in peripheral biofluids, and paves the way for future clinical diagnostics and treatment of disease. Graphical abstract.


Asunto(s)
Aptámeros de Nucleótidos/química , Técnicas Biosensibles/métodos , Grafito/química , Trombina/análisis , Sondas de ADN/química , Técnicas Electroquímicas/métodos , Oro/química , Humanos , Ácidos Nucleicos Inmovilizados/química , Límite de Detección , Nanopartículas del Metal/química , Técnicas de Amplificación de Ácido Nucleico/métodos
10.
Ecotoxicol Environ Saf ; 190: 110123, 2020 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-31891837

RESUMEN

In this work, a novel manganese dioxide-graphene nanosheets (MnO2-GNSs) composite was synthesized by a facile one-step hydrothermal method, in which manganese dioxide (MnO2) was fabricated by hydrothermal reduction of KMnO4 with GNSs. The structure and morphology of MnO2-GNSs composite were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis and X-ray photoelectron spectroscopy (XPS). A sensitive non-enzymatic electrochemical sensor based on MnO2-GNSs composite for the detection of low concentration hydrogen peroxide (H2O2) was fabricated. The electrochemical properties of MnO2-GNSs composite modified glassy carbon electrode (MnO2-GNSs/GCE) were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometry. The observations confirmed that the fabricated sensor exhibited high electrocatalytic activity for oxidation of H2O2 owing to the catalytic ability of MnO2 particles and the conductivity of GNSs. Under the optimum conditions, the calibration curve was linear for the amperometric response versus H2O2 concentration over the range 0.5-350 µM with a low detection limit of 0.19 µM (S/N = 3) and high sensitivity of 422.10 µA mM-1 cm-2. The determination and quantitative analysis of H2O2 in antiseptic solution on MnO2-GNSs/GCE exhibited percent recovery of 96.50%-101.22% with relative standard deviation (RSD) of 1.48%-4.47%. The developed MnO2-GNSs/GCE might be a promising platform for the practical detection of H2O2 due to its prominent properties including excellent reproducibility, good anti-interference and repeatability.


Asunto(s)
Técnicas Electroquímicas/métodos , Grafito/química , Peróxido de Hidrógeno/análisis , Compuestos de Manganeso/química , Modelos Químicos , Óxidos/química , Carbono/química , Catálisis , Espectroscopía Dieléctrica , Electrodos , Límite de Detección , Reproducibilidad de los Resultados
11.
Ecotoxicol Environ Saf ; 190: 110098, 2020 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-31901811

RESUMEN

Prostate cancer is one of the primary causes of death around the world. As an important drug, flutamide has been used in the clinical diagnosis of prostate cancer. However, the over dosage and improper discharge of flutamide could affect the living organism. Thus, it necessary to develop the sensor for detection of flutamide with highly sensitivity. In this paper, we report the synthesis of lanthanum cobaltite decorated halloysite nanotube (LCO/HNT) nanocomposite prepared by a facile method and evaluated for selective reduction of flutamide. The as-prepared LCO/HNT nanocomposite shows the best catalytic performance towards detection of flutamide, when compared to other bare and modified electrodes. The good electrochemical performance of the LCO/HNT nanocomposite modified electrode is ascribed to abundant active sites, large specific surface area and their synergetic effects. Furthermore, the LCO/HNT modified electrode exhibits low detection limit (0.002 µM), wide working range (0.009-145 µM) and excellent selectivity with remarkable stability. Meaningfully, the developed electrochemical sensor was applied in real environmental samples with an acceptable recovery range.


Asunto(s)
Contaminantes Ambientales/análisis , Flutamida/análisis , Lantano/química , Nanocompuestos/química , Catálisis , Arcilla , Técnicas Electroquímicas/métodos , Electrodos , Grafito/química , Humanos , Límite de Detección , Minerales , Nanotubos/química
12.
Bioelectrochemistry ; 132: 107412, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31889632

RESUMEN

The synthesis of a series of methyl 2-alkyl-5-aryl-4-ferrocenoylpyrrolidine-2-carboxylates has been achieved by [3 + 2] dipolar cycloaddition of azomethine ylides to acryloylferrocene. The electrochemical properties of novel products were examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). These techniques revealed the quasi-reversible one-electron oxidation process. The DNA-binding capacity of all the products was also studied using CV and DPV, and significant interactions between synthesized compounds and nucleic acid, mostly of the electrostatic type, were disclosed. DFT calculations and molecular docking tests were carried out to gain a more exhaustive insight into the interactions of the obtained products with nucleic acid. A detailed characterization of the new compounds was performed by IR, NMR and elemental analyses, followed by single-crystal X-ray diffraction experiments for two representatives.


Asunto(s)
ADN/metabolismo , Técnicas Electroquímicas/métodos , Compuestos Ferrosos/metabolismo , Metalocenos/metabolismo , Cristalografía por Rayos X , Teoría Funcional de la Densidad , Compuestos Ferrosos/química , Espectroscopía de Resonancia Magnética , Metalocenos/química , Estructura Molecular , Oxidación-Reducción , Espectrofotometría Infrarroja
13.
Bioelectrochemistry ; 132: 107446, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31927190

RESUMEN

In the present study, minimization of hazardous bio-sludge production was investigated using a bioelectrochemical system supplied by an alternating current electric field and supplemented with phenol as a cabon source. The experiments were conducted in an air-conditioned bioreactor and at neutral pH value. Moreover, steel wool and carbon cloth were utilized as electrodes in the bioelectrochemical system. The experiments were operated in an air-conditioned bioreactor at 25 ℃ and a neutral pH value with carbon to nitrogen (C/N) ratio of 0.5-6. The results obtainedshowed that complete phenol electro-biodegradation occurred at a C/N ratio ofa frequency of 5 Hz, and 0.4 peak-to-peak voltage (Vpp) over 2 h.Besides, sludge production and sludge yield were obtained at the C/N ratio of 0.5-6 by 200-382 mg VSS/g COD and 82-89.4 mg TSS/g COD, respectively. Ultimately, the C/N ratio of 1 seemed to be optimum for microbial growth with the phenol biodegradation efficiency of 99.9% as well as the lowest sludge production. These results demonstrated that the proposed bioelectrochemical system supplied by low-frequency and low-voltage electric current could reduce hazardous sludge production.


Asunto(s)
Técnicas Electroquímicas/métodos , Sustancias Peligrosas , Aguas del Alcantarillado , Análisis de la Demanda Biológica de Oxígeno , Biomasa , Reactores Biológicos , Electricidad , Aguas Residuales/química
14.
Chemosphere ; 241: 125125, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31683418

RESUMEN

Acid Orange 7 (AO7), as a most common and widely used synthetic dyes in the printing and dyeing industry, was hardly degradable by traditional wastewater treatment methods. Here, activated carbon fiber (ACF) as an in-situ regenerated cathodic adsorbent in the electrochemical/Fe3+/peroxymonosulfate process (EC/ACF/Fe3+/PMS) was firstly investigated for AO7 removal and compared with several different processes. The results indicated that the effective adsorption of AO7 on ACF can be enhanced under electrolytic conditions, while the adsorbed AO7 on ACF can be completely degraded and mineralized in EC/ACF/Fe3+/PMS process resulting in the in-situ regeneration of ACF. Besides, the electrical energy per order values were investigated, which showed an apparent reduction of electrical energy consumption from 0.42831 to 0.09779 kWh m-3 when ACF-cathode replaced Pt-cathode. Further study revealed that higher conversion rate of Fe2+ from Fe3+ was observed with ACF-cathode. It deserved to be mentioned that the removal efficiency of AO7 was satisfactory and stable even after reusing ACF cathode for 10 times. Furthermore, structure and elements of ACF surface were investigated, which indicated the structure of ACF was intact in EC/ACF/Fe3+/PMS due to inhibition of ACF corrosion by electron migration at cathode. In addition, the total iron content of the effluent in EC/ACF/Fe3+/PMS was lower than that of EC/Fe3+/PMS due to the deposition of iron on ACF-cathode surface. Therefore, advantages of EC/ACF/Fe3+/PMS for AO7 degradation were not only a much higher oxidation efficiency and in-situ regenerated cathodic adsorbent, but also a lower electrical energy consumption and lesser iron ions contents in the effluent.


Asunto(s)
Compuestos Azo/química , Bencenosulfonatos/química , Fibra de Carbono/química , Técnicas Electroquímicas/métodos , Hierro/química , Peróxidos/química , Purificación del Agua/métodos , Adsorción , Carbón Orgánico/química , Colorantes/química , Electrodos , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química
15.
Chemosphere ; 241: 125124, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31683421

RESUMEN

Efficient electrochemical generation of ferrate (Fe(VI)) is still challenged by the passivation of iron materials. Herein, we employed Fe(0)-plated carbon sheet as an anode to enable an efficient production of Fe(VI) with its concentration reached up to 55 mM, which was 8 times higher than that with iron sheet of the same size as an anode. The SEM results showed that the close and uniform dispersion of tapered Fe(0) particles on the surface of carbon sheet helped prevent the formation of passivated layer. The preparative process of electro-deposited Fe(0) affected the generation of Fe(VI). The increase of electroplating time to 40 min and electroplating temperature to 30 °C promoted the production of Fe(VI), and the change in the concentration of Fe2+ in electroplated solution showed little impact on Fe(VI) generation. However, the addition of additives inhibited Fe(VI) generation. As well, an effective removal of cyanide was achieved using on-line production of Fe(VI), comparable to that by NaClO and higher than that by other traditional oxidants containing H2O2, O3, and KMnO4. This study would provide an simple and promising iron anode for efficient production of Fe(VI) by electrochemical method.


Asunto(s)
Cianuros/aislamiento & purificación , Técnicas Electroquímicas/métodos , Hierro/química , Purificación del Agua/métodos , Carbono/química , Electrodos , Oxidantes , Oxidación-Reducción , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/aislamiento & purificación
16.
Chemosphere ; 241: 125103, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31683438

RESUMEN

In this paper, a novel electrode named 2.5D Ti/Sb-SnO2/PANI was developed by magnetically in-situ integration of adsorbent and electrocatalyst, where the green synthetic Fe3O4/polyaniline (PANI) nanoparticles with fair adsorption capability were used as auxiliary electrodes and coated on the surface of Ti/Sb-SnO2 main electrode, to enrich the pollutants in the vicinity of anode and therefore boost the electrochemical oxidation (EO) efficiency. Since the interchangeable auxiliary electrodes can endow the anode with adjustability and versatility, the effect of auxiliary electrodes on the surface structure and electrochemical properties of 2.5D Ti/Sb-SnO2/PANI were extensively investigated. Results showed that a tiny amount of Fe3O4/PANI auxiliary electrodes changed the solid-liquid interface, brought massive less acessible active sites and kept the similar electrode impedance and same EO capability of 2D Ti/Sb-SnO2. In terms of organic elimination and solution biodegradability enhancement, 2.5D Ti/Sb-SnO2/PANI showed a boosted 30%-60% EO efficiency on two typical biorefractory targets, i.e., Acid Red G and lignosulphonate. The specific effectiveness was dependent on the loading amount of magenetic PANI nanoparticles. The operating mechanism of the assembled 2.5D Ti/Sb-SnO2/PANI electrode was further proposed based on many details, as well as a design rule for developing novel electrodes with high efficient EO performance for wastewater treatment. Moreover, the assembled 2.5D electrode was proved to have good sustainability and recyclability, which shows a great potential in the practical applications.


Asunto(s)
Técnicas Electroquímicas/métodos , Electrodos/normas , Nanopartículas/química , Aguas Residuales/química , Purificación del Agua/métodos , Compuestos de Anilina , Catálisis , Magnetismo/métodos , Oxidación-Reducción , Compuestos de Estaño/química , Titanio/química
17.
Chemosphere ; 241: 125038, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31610455

RESUMEN

The use of humic acid (HA) and fulvic acid (FA) as reinforcing agents to improve the efficiency of electrokinetic remediation (EKR) were investigated for the first time using an artificially contaminated soil. A series of soil leaching tests and bench-scale EKR experiments were performed to elucidate the mechanisms of As removed from artificially contaminated soil. The characterization of total reducing capacity (TRC) and functional group were carried out to reveal the difference of HA and FA. The observations demonstrated that with 0.1 M NaOH and KCl as the anolyte, using both HA and FA enhanced the efficiency of EKR. After 25 days of EKR, the removal efficiency of TAs in HA/FA-enhanced EKR was about 2.0-3.0 times greater than when unenhanced. Compared to HA, more As was removed in EKR with FA, which has more TRC and oxygen-containing groups. These EKR experimental results, with the support of data obtained from soil leaching test, indicate that competitive adsorption, reductive dissolution and complexation were the reasons why HA and FA promoted the release of As in the soil and further enhanced the remediation efficiency.


Asunto(s)
Arsénico/aislamiento & purificación , Benzopiranos/farmacología , Técnicas Electroquímicas/métodos , Restauración y Remediación Ambiental/métodos , Sustancias Húmicas/análisis , Contaminantes del Suelo/aislamiento & purificación , Adsorción , Contaminantes del Suelo/análisis , Temperatura Ambiental
18.
Chemosphere ; 241: 125058, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31610461

RESUMEN

Electrocatalytic oxidation and detoxication of capecitabine (CAP) in aqueous solution were investigated with Ti/SnO2-Sb/Ce-PbO2 anode. The relative contributions of generated free radicals showed an increase in the pseudo zero order tare constants in the following order: OH (9.4%) < SO4- (24.2%) < O2- (53.3%). The operating parameters and solution matrixes, i.e. applied current densities, initial CAP concentrations, initial Cl- and NO3- concentrations, influencing the CAP degradation efficiency were evaluated. The kinetic rate constant of 0.1404 min-1 was found within 7 min at current density of 10 mA cm-2 and initial CAP concentration of 20 mg L-1, while the mineralization efficiency of 59.5%, mineralization current efficiency of 2.06%, detoxication rate to Escherichia coli of 55.5% were achieved at reaction time 90 min. The major degradation pathways of CAP were oxidation, defluorination and bond cleavage, following with the formation of carboxylic acids, NO3-, NO2-, NH4+ and F-. Electrochemical oxidation process based on Ti/SnO2-Sb/Ce-PbO2 anode is proved to be effective for elimination, mineralization and detoxication of aqueous CAP.


Asunto(s)
Capecitabina/química , Técnicas Electroquímicas/métodos , Contaminantes Químicos del Agua/química , Electrodos , Restauración y Remediación Ambiental/métodos , Cinética , Oxidación-Reducción , Titanio/química
19.
Chemosphere ; 241: 125010, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31605993

RESUMEN

In this study, electrochemical oxidation of Acid Orange 7 (AO 7) azo dye has been investigated using a Fe-doped PbO2 electrode. The degradation of AO 7 followed pseudo-first-order reaction kinetics. The removals of AO 7, chemical oxygen demand (COD) and total organic carbon (TOC) were 87.15%, 49.88% and 44.94% after 60 min of electrolysis at the optimal conditions (Na2SO4 concentration 0.1 M, initial pH 5, initial AO 7 concentration 100 mg L-1 and applied current density 20 mA cm-2), respectively. And the corresponding degradation rate constant was 0.035 min-1. The intermediates formed during electrochemical process were identified, and a possible degradation pathway was proposed, which was initiated by the oxidation of azo bond (-NN-), hydroxylation and substitution reaction of -NH2 and -SO3H under the attack of OH, and ended with the formation of mineralization products such as NH4+, NO3-, SO42-, CO2 and H2O. The toxicity of treated AO 7 solution towards Vibrio fischeri increased slightly at first and then rapidly reduced to non-toxicity with prolonging time. The results indicate that electrochemical oxidation of AO 7 using Fe-doped PbO2 electrode is a promising way.


Asunto(s)
Compuestos Azo/química , Bencenosulfonatos/química , Técnicas Electroquímicas/métodos , Electrólisis/métodos , Plomo/química , Óxidos/química , Contaminantes Químicos del Agua/química , Análisis de la Demanda Biológica de Oxígeno , Electrodos , Electrólisis/normas , Cinética , Oxidación-Reducción , Contaminantes Químicos del Agua/análisis
20.
Chemosphere ; 241: 125020, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31614314

RESUMEN

A nanocomposite of graphene and titanium dioxide (G/TiO2) was prepared using the sol-gel method for use in an electrochemical adsorption/regeneration process. The effect of annealing temperature on electrochemical characteristics of the nanocomposites was investigated by cyclic voltammetry and constant current electrochemical regeneration, using methylene blue (MB) as the adsorbate. The G/TiO2 could be regenerated more rapidly and with less corrosion than the bare graphene. The G/TiO2 annealed at 400 °C had a higher proportion of anatase phase TiO2 (ca. 7% rutile TiO2) compared to that annealed at 500 °C (ca. 40% rutile TiO2). Cyclic voltammetry indicated that the G/TiO2 annealed at 400 °C had a higher activity for MB oxidation than the nanocomposite annealed at 500 °C. Similarly, the regeneration of MB loaded G/TiO2 annealed at 400 °C was much faster than for the nanocomposite annealed at 500 °C. Complete regeneration of the G/TiO2 annealed at 400 °C was obtained after an electrochemical charge of 21 C per mg of adsorbate. The G/TiO2 annealed at 400 °C was regenerated in half the time required for the bare graphene. TEM studies showed that the bare graphene was rapidly corroded, while corrosion was not observed for the G/TiO2 nanocomposites.


Asunto(s)
Colorantes/química , Técnicas Electroquímicas/métodos , Grafito , Nanocompuestos/química , Reciclaje/métodos , Titanio , Adsorción , Corrosión , Electrodos , Azul de Metileno/química
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