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1.
ACS Appl Mater Interfaces ; 13(6): 7801-7811, 2021 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-33534533

RESUMEN

Metal-organic frameworks (MOFs) stand as one of the most promising materials for the development of advanced technologies owing to their unique combination of properties. The conventional synthesis of MOFs involves a direct reaction of the organic linkers and metal salts; however, their postsynthetic modification is a sophisticated route to produce new materials or to confer novel properties that cannot be attained through the traditional methods. This work describes the postsynthetic MOF-to-MOF transformation of a nonluminescent MOF (Zn-based Oxford University-1 material [Zn-BDC, where BDC = 1,4-benzene dicarboxylate] (OX-1)) into a highly luminescent framework (Ag-based Oxford University-2 material [Ag-BDC] (OX-2)) by a simple immersion of the former in a silver salt solution. The conversion mechanism exploits the uncoordinated oxygen atoms of terephthalate linkers found in OX-1, instead of the unsaturated metal sites commonly employed, making the reaction much faster. The materials derived from the OX-1 to OX-2 transformation are highly luminescent and exhibit a selective response to acetone, turning them into a promising candidate for manufacturing fluorometric sensors for the diagnosis and monitoring of diabetes mellitus. Our methodology can be extended to other metals such as lead (Pb). The fabrication of a polymer mixed-matrix membrane containing OX-1 is used as a proof-of-concept for capturing Pb ions (as pollutants) from water. This research instigates the exploration of alternative methodologies to confer MOFs with special aptitudes for photochemical sensing or for environmental applications such as water purification.


Asunto(s)
Acetona/análisis , Diabetes Mellitus/diagnóstico , Plomo/aislamiento & purificación , Luminiscencia , Estructuras Metalorgánicas/química , Contaminantes Químicos del Agua/análisis , Plomo/química , Mediciones Luminiscentes , Estructuras Metalorgánicas/síntesis química , Tamaño de la Partícula , Propiedades de Superficie
2.
Ecotoxicol Environ Saf ; 208: 111704, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396035

RESUMEN

Clay minerals can adsorb both microorganisms and heavy metals. In this study, typical soil bacterium, Enterobacter sp. was applied to investigate the potential protection of the bacterial cells from Pb2+ stress by clay minerals. The sorption by two representative types of montmorillonite (Mt) were contrasted, i.e., Mts/Mtw with strong/weak CEC. There was no significant difference between the two clay minerals regarding their adsorption of Pb2+ cations in water (i.e., ~55 mg L-1). However, the sorption of bacterial cells on the two clay minerals showed evident contrasts, which resulted in the different capacity of Pb sorption. Mts with high CEC preferentially adsorbed abundant bacterial cells (rather than Pb2+) on its surface. The residual Pb2+ concentration in solution actually raised by 7.5% after the addition of Enterobacter sp. In addition, both the Pb-contaminated cells and "healthy" cells (with low Pb contamination) could be adsorbed onto Mt surface, whereas the latter dominated the adsorbents on Mts. This was due to that the Mts with high CEC could provide more exchangeable cations, building more cation bridging ligands between the microbial cells (whatever the types of cells) and clay surface. Furthermore, the adsorbed "healthy" bacterial cells might escape from clay surface via "self-liberating" mechanism, i.e., increasing electrostatic repulsion between the bacteria and clay during microbial decomposition of the medium. This study hence elucidated the protection of microorganisms from Pb2+ stress by Mt.


Asunto(s)
Arcilla/química , Enterobacter/efectos de los fármacos , Plomo/toxicidad , Contaminantes del Suelo/toxicidad , Adsorción , Bentonita/química , Cationes/química , Enterobacter/metabolismo , Plomo/química , Metales Pesados/química , Minerales/química , Contaminantes del Suelo/química
3.
ACS Appl Mater Interfaces ; 13(4): 5602-5613, 2021 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-33496182

RESUMEN

Respiration monitoring and human sweat sensing have promising application prospects in personal healthcare data collection, disease diagnostics, and the effective prevention of human-to-human transmission of fatal viruses. Here, we have introduced a unique respiration monitoring and touchless sensing system based on a CsPb2Br5/BaTiO3 humidity-sensing layer operated by water-induced interfacial polarization and prepared using a facile aerosol deposition process. Based on the relationship between sensing ability and layer thickness, the sensing device with a 1.0 µm thick layer was found to exhibit optimal sensing performance, a result of its ideal microstructure. This sensor also exhibits the highest electrical signal variation at 0.5 kHz due to a substantial polarizability difference between high and low humidity. As a result, the CsPb2Br5/BaTiO3 sensing device shows the best signal variation of all types of breath-monitoring devices reported to date when used to monitor sudden changes in respiratory rates in diverse situations. Furthermore, the sensor can effectively detect sweat evaporation when placed 1 cm from the skin, including subtle changes in capacitance caused by finger area and motion, skin moisture, and contact time. This ultrasensitive sensor, with its fast response, provides a potential new sensing platform for the long-term daily monitoring of respiration and sweat evaporation.


Asunto(s)
Compuestos de Bario/química , Técnicas Biosensibles/instrumentación , Compuestos de Bromina/química , Respiración , Sudor/química , Titanio/química , Pruebas Respiratorias/instrumentación , Cesio/química , Diseño de Equipo , Humanos , Humedad , Plomo/química , Monitoreo Fisiológico/instrumentación , Nanocompuestos/química
4.
Ecotoxicol Environ Saf ; 208: 111626, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396146

RESUMEN

Soil application of biochars has been shown to effectively immobilize potentially toxic elements (PTEs). Soil water regime can also affect PTE availability. No previous studies have examined the interactive effect of biochars and soil water regime on Pb availability. Therefore, this study investigated the effect of high and low temperature (300 and 600°C) biochars derived from cow manure (CB), municipal compost (MB) and licorice root pulp (LB) applied at 3 wt%, under two soil moisture regimes (field capacity (FC) and saturation (ST)) on Pb release kinetics and chemical fractions in a Pb-contaminated calcareous soil. Results showed that CB and MB treatments significantly enhanced Pb stabilization compared to LB, attributed to their favorable chemical properties (high P, ash, carbonate, oxidizable C content and high pH) which could promote Pb conversion into stable chemical fractions. Immobilization of Pb was enhanced under saturated conditions compared to FC by the treatments, which is attributed to increased soil pH, reduction of metal oxides and possible formation of sulfides. The most significantly effective treatments were the CB300, CB600 and MB600 treatments under ST, as indicated by significant decrease in soil Pb mobility factor from 29.1% (CL+FC) to 21.2-22.9%, and 11.7-16.3% increase in non-EDTA-extractable Pb. Results of this study demonstrate that combined application of high ash biochars and soil water saturation significantly enhances Pb immobilization in calcareous soil.


Asunto(s)
Carbón Orgánico/química , Restauración y Remediación Ambiental/métodos , Plomo/química , Contaminantes del Suelo/química , Contaminación Ambiental , Estiércol , Óxidos , Suelo/química , Contaminantes del Suelo/análisis
5.
Food Chem ; 348: 129098, 2021 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-33515942

RESUMEN

We report the modular design and synthesis of an amine dangled Schiff base quinoline-morpholine conjugate (QMC) for highly selective detection of Pb2+ ions via fluorimetry. The sensing strategy of QMC towards Pb2+ ion exhibits a large blue shift with fluorescent enhancement via the intramolecular charge transfer (ICT) process. At the same time, QMC coordination with Pb2+, the CN single bond rotation between quinoline and morpholine rings and the CN isomerization process were blocked. Best of our knowledge, this is the first blue shifted turn-on fluorescent chemosensor for Pb2+ ion via the ICT process. Furthermore, QMC selectively detects Pb2+ ion without any interference with alkali, alkaline earth, and transition metal ions, and limit of detection (LOD) downs to 13 µM, which is a permissible level of Pb2+ ion in drinking water reported by WHO. The 1:2 binding stoichiometry between QMC and Pb2+ was confirmed by fluorimetric, 1H NMR titration, mass spectrometry, and theoretical studies. Finally, QMC was potentially applied for the sensing of Pb2+ ions in milk, red wine, live cells and an INHIBIT molecular logic function was constructed by using Pb2+ and EDTA as chemical inputs.


Asunto(s)
Colorantes Fluorescentes/química , Lógica , Leche/química , Imagen Molecular/métodos , Quinolinas/química , Animales , Plomo/análisis , Plomo/química , Límite de Detección , Bases de Schiff/química , Espectrometría de Fluorescencia
6.
Ecotoxicol Environ Saf ; 208: 111677, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396009

RESUMEN

CH3NH3PbI3 is one of the most widely studied and most promising photoelectric conversion materials for large-scale application. However, once it is discharged into the aquatic environment, it will release a variety of lethal substances to the aquatic organisms. Herein, two typical aquatic pollution indicators, Scenedesmus obliquus (a typical phytoplankton) and Daphnia magna (a typical zooplankton), were used to assess the acute effects of CH3NH3PbI3 perovskite on aquatic organisms. The results showed that, when the initial CH3NH3PbI3 perovskite level (CPL) was 40 mg L-1 or higher, the growth of S. obliquus would be remarkably inhibited with significant decreases of chlorophyll content and protein content. And when the CPL was over 5 mg L-1, the survival of D. magna would be notably threatened. Specifically, the 72 h EC-50 of CH3NH3PbI3 perovskite to S. obliquus was calculated as 37.21 mg L-1, and the 24 h LC-50 of this perovskite to D. magna adults and neonates were calculated as 37.53 mg L-1 and 18.55 mg L-1, respectively. Moreover, remarkably solution pH declination and large amounts of lead bio-accumulation was observed in the both acute experiments, which could be the main reasons causing the above acute effects. Considering the strong acute effects of these CH3NH3PbI3 perovskite materials and their attractive application prospect, more attentions should be paid on their harmness to the environment.


Asunto(s)
Compuestos de Calcio/toxicidad , Daphnia/efectos de los fármacos , Plomo/toxicidad , Metilaminas/toxicidad , Óxidos/toxicidad , Scenedesmus/efectos de los fármacos , Titanio/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Organismos Acuáticos/efectos de los fármacos , Compuestos de Calcio/química , Humanos , Plomo/química , Metilaminas/química , Óxidos/química , Propiedades de Superficie , Titanio/química , Pruebas de Toxicidad Aguda , Contaminantes Químicos del Agua/química
7.
Anal Chem ; 93(3): 1818-1825, 2021 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-33372764

RESUMEN

All-inorganic lead halide perovskites have become promising alternatives to traditional semiconductor electrochemiluminescence (ECL) emitters because of their appealing optoelectronic attributes, but major challenges remain in improving their stability and enhancing charge injection/transfer capacities. Herein, a self-sustaining suprastructure was constructed by successively loading aminated carbon dots (NCDs) and CsPbBr3 perovskite quantum dots (PeQDs) in situ into hierarchical zeolite imidazole framework-8 (HZIF-8). The elaborated architecture guarantees not only improved stability via the peripheral HZIF-8 protective barrier but also accelerated charge transport and efficient self-enhanced ECL between PeQDs and the surrounding NCDs in a confined structure. As a result, the ternary nanocomposite is endowed with greatly improved stability and ECL efficiency. Based on this ternary nanocomposite as an electrode substrate, a novel ECL sensing strategy is further proposed for the first time to evaluate T4 polynucleotide kinase activity and screen its inhibitors. This work opens an avenue for the advancement of perovskite-based ECL emitters as well as the development of corresponding applications in the ECL domain.


Asunto(s)
Técnicas Biosensibles , Técnicas Electroquímicas , Mediciones Luminiscentes , Estructuras Metalorgánicas/química , Polinucleótido 5'-Hidroxil-Quinasa/análisis , Puntos Cuánticos/química , Bacteriófago T4/enzimología , Bromuros/química , Carbono , Cesio/química , Inhibidores Enzimáticos/farmacología , Plomo/química , Estructuras Metalorgánicas/síntesis química , Tamaño de la Partícula , Polinucleótido 5'-Hidroxil-Quinasa/antagonistas & inhibidores , Polinucleótido 5'-Hidroxil-Quinasa/metabolismo , Propiedades de Superficie
8.
Chemosphere ; 261: 128157, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33113652

RESUMEN

Porous titanium-based PbO2 electrodes were successfully fabricated by pulse electrodeposition method. The primary pulse electrodeposition parameters, including pulse frequency (f), duty ratio (γ), average current density (Ja) and electrodeposition time (t) were considered in this study. An orthogonal experiment was designed based on those four factors and in three levels. SEM images and XRD results suggest that the surface morphology and structure of PbO2 electrodes could be easily changed by varying pulse electrodeposition parameters. Orthogonal analysis reveals that the increase of f and Ja could decrease the average grain size of PbO2 electrodes, which is conducive to create more active sites and promote the generation of hydroxide radicals. The electrochemical degradation of Azophloxine was carried out to evaluate the electrochemical oxidation performance of pulse electrodeposited electrodes. The results indicate that the influences of four factors can be ranked as follow: Ja >γ≈ t > f. The higher f, larger Ja and longer t could facilitate the optimization of the integrated electrochemical degradation performance of prepared PbO2 electrode. The accelerated life time is dominated by Ja and t, coincident with the average weight increase of ß-PbO2 layer. The optimal parameters of pulse electrodeposition turn out to be: f = 50 Hz, γ = 30%, Ja = 25 mA cm-2, t = 60 min. Together, the consequences of the experiments give assistance to uncover and roughly conclude the mechanism of pulse electrodeposition.


Asunto(s)
Galvanoplastia/métodos , Plomo/química , Modelos Teóricos , Óxidos/química , Titanio/química , Compuestos Azo/análisis , Electrodos , Naftalenosulfonatos/análisis , Oxidación-Reducción , Porosidad , Propiedades de Superficie , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos
9.
Chemosphere ; 261: 128220, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33113653

RESUMEN

The knowledge about lead (Pb) sorption on soil-derived black carbons (SBCs) under different cultivation intensities of soils is limited. In this study, chemical and spectroscopic methods were applied to investigate the Pb sorption mechanisms on SBCs in soils from a forest land, a rubber plantation area, and a vegetable farm with none, less and highly intensive cultivation, respectively, that are located in the Hainan Island of China. Results showed that the specific surface area and cation exchange capacity of the SBCs from the less and highly intensive cultivation soils were 4.5- and 2.7-fold, and 1.3- and 1.8-fold higher compared to that of SBC from the no-cultivation soil, which subsequently enhanced the Pb sorption capacities of SBCs in iron exchange fraction. Ion exchange and hydrogen bonded Pb fractions together accounted for about 80% of total Pb sorbed on all SBCs at an externally added 1000 mg L-1 Pb solution concentration. The OC-O groups also played key roles in Pb sorption by forming complexes of OC-O-Pb-O and/or OC-O-Pb. Overall, SBCs in soils under all studied cultivation intensities showed high potential to sorb Pb (with the maximum absorbed Pb amount of 46.0-91.3 mg g-1), and increased Pb sorption capacities of the studied soils by 18.7-21.1 mg kg-1 in the stable fraction (complexation). Therefore, SBC might be a potential environment-friendly material to enhance the Pb immobilization capacity of soil.


Asunto(s)
Contaminantes Ambientales/química , Plomo/química , Suelo/química , Hollín/química , Adsorción , China , Contaminantes Ambientales/aislamiento & purificación , Hierro , Plomo/aislamiento & purificación
10.
Chemosphere ; 261: 128144, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33113655

RESUMEN

The improper disposal of waste containing toxic metals promotes serious environmental problems. Biosorption stands out as a powerful technique in removing toxic metals from aqueous solutions, making it an efficient and low-cost technique, since it makes use of abundant materials and of natural origins. This work aimed to study the application of the bark of Caryocar coriaceum Wittm, as a possible bioabsorbent for the removal of Lead (II) present in aqueous solutions, for this, residues of this material were collected in a public market, where they were washed and dried, then crushed, sieved (32mesh) and washed again, to then be used in the kinetic, isotherm and thermodynamic tests of lead (II) ions adsorption. After the experiments, it was found that the increase of the temperature disfavored the rate of lead (II) adsorption, ranging from 15.6 to 13.5 mg.L-1, for temperatures of 5 °C and 35 °C, respectively. The pseudo-second order kinetic model best characterizes the adsorption velocity obtaining a linear regression coefficient of 0.9997, while the pseudo-first order obtained a value of 0.7117. Adsorption occurred by chemisorption, with intra-film diffusion. The isothermal model that best represented the adsorption was Langmuir's (R2 0.99). It was concluded that the bark of Caryocar coriaceum Wittm is a good alternative to be used as a bioabsorbent for solutions containing dissolved lead (II).


Asunto(s)
Ericales/química , Plomo/química , Modelos Teóricos , Corteza de la Planta/química , Contaminantes Químicos del Agua/análisis , Adsorción , Difusión , Concentración de Iones de Hidrógeno , Iones , Cinética , Soluciones , Termodinámica
11.
Chemosphere ; 260: 127683, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32758774

RESUMEN

This study represents the first ever work on a novel oxone treated hydrochar as an adsorbent for the efficient removal of different contaminants from aqueous solutions. Pine wood hydrochar (HC) was prepared by hydrothermal treatment at 300 °C and oxidized with oxone to produce oxidized pine wood hydrochar (OHC). Different analytical tools such as elemental analysis, FTIR, TGA, FE-SEM, and BET were used for the characterization of the OHC. Conductometric titration of OHC showed a substantial increase from 22 µmol/g to 600 µmol/g in the hydrochar carboxylic content. The OHC sorption performance was assessed by using Pb(II) ions and methylene blue (MB) dye as two models of contaminants. Sorption benchmarks were performed by varying the contaminant initial concentration, time, and temperatures. Sorption kinetic data was fitted well to the pseudo-second order kinetic model with high correlation coefficients (R2 > 0.99) and isothermal data was fitted to the Langmuir model. The highest adsorption capacities for MB and Pb(II) were 86.7 mg/g and 46.7 mg/g, respectively. This study proves that oxone treatment could be a potential sustainable oxidation method to tune the hydrochar surface to increase selectivity towards heavy metal ions and dye sorption.


Asunto(s)
Plomo/química , Azul de Metileno/química , Contaminantes Químicos del Agua/química , Adsorción , Concentración de Iones de Hidrógeno , Cinética , Metales Pesados , Azul de Metileno/análisis , Soluciones , Ácidos Sulfúricos , Temperatura , Agua , Contaminantes Químicos del Agua/análisis
12.
Bull Environ Contam Toxicol ; 105(2): 283-290, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32734360

RESUMEN

The current study investigated the efficiency of sepiolite (SE), sodium humate (HS), microbial fertilizer (JF) and SE combined with JF/HS in a ratio of 2:1 (w/w) (JF-2SE and HS-2SE) on Cd, Pb and As bioavailability in field trials with rice (Oryza sativa L.). The results showed that all the amendments remarkably decreased (p < 0.05) the contents of available Cd and available Pb in soil. Only JF-2SE treatment reduced available As concentration in soil. All the amendments were found to effectively reduce (p < 0.05) the contents of As in brown rice. Both JF-2SE and HS-2SE co-applications reduced the concentrations of Cd in brown rice to 0.108 and 0.135 mg kg-1, and that of Pb reduced to 0.2 and 0.175 mg kg-1, which met the national standard limit of China. Thus, the co-application of JF/HS-2SE can be a promising remediation strategy in Cd, Pb and As co-contaminated paddy soil.


Asunto(s)
Cadmio/química , Restauración y Remediación Ambiental/métodos , Plomo/química , Contaminantes del Suelo/química , Disponibilidad Biológica , Cadmio/análisis , China , Contaminación Ambiental , Fertilizantes , Plomo/análisis , Silicatos de Magnesio , Oryza , Suelo/química , Contaminantes del Suelo/análisis
13.
Ecotoxicol Environ Saf ; 205: 111132, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32836155

RESUMEN

Due to high sorption capacity for heavy metals, magnetic biochar (MBC) has the potential to adsorb heavy metals in soils, which are then removed together with MBC from soils by a magnetic field. In this study, two magnetic biochars (MBC300 and MBC700) were derived from the magnetization of wheat straw biochars pyrolyzed at 300 and 700 °C. Strong binding of Pb with iron oxide particles deposited on biochar was observed. After the MBCs (7.5%, w/w) were applied to two naturally Pb-polluted soils (named as He-soil and Hu-soil) for 720 h, the removal efficiency of Pb from the soil by MBC300 (26.8-40.1%) was similar (p > 0.05) to that by MBC700 (25.1-42.1%). This is because MBC300 has lower sorption capacity for Pb but higher recovery percentage from soils as a result of lower saturation magnetization. The removal efficiencies of Pb by the two MBCs were 13-17% higher for He-soil than for Hu-soil, which was due to higher proportion of mobile forms of Pb in He-soil (82.3%) than in Hu-soil (51.5%). Spectroscopic analysis indicated that Pb in soils tended to bind onto the surface of MBC in more stable forms. Moreover, removing Pb from soils by MBC could decrease Pb concentration in ryegrass by about 30%. Therefore, it might be a potential method to remedy Pb-polluted soils.


Asunto(s)
Restauración y Remediación Ambiental/métodos , Plomo/química , Contaminantes del Suelo/química , Adsorción , Carbón Orgánico , Contaminación Ambiental/análisis , Plomo/análisis , Lolium , Fenómenos Magnéticos , Metales Pesados/análisis , Pirólisis , Suelo/química , Contaminantes del Suelo/análisis , Triticum
14.
PLoS One ; 15(8): e0238105, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32853282

RESUMEN

Biochar derived from straw is a potential low-cost adsorbent for metal ions and organic pollutants, but its practical application is still limited by the adsorption capacity. In this study, the correlation between the biochar's properties and pyrolysis temperature was explored. The adsorption mechanism was studied by monitoring the changes of biochar properties before and after adsorption using BET, SEM, XPS and FT-IR spectroscopy. The adsorption mechanism was revealed following the adsorption kinetics and the changes in biochar's properties before and after adsorption. The methylene blue (MB) and Pb2+ adsorption removal efficiency reached 95% at the initial concentration of 125 and 500 mg/L, respectively. Physisorption, chemisorption, and pore filling mechanisms determined the adsorption process of MB and Pb2+ on biochar. The Pb2+ adsorption process was highly affected by chemical co-precipitation at higher pyrolysis temperatures. The appearance of tar particles increased the adsorption rate of Pb2+. The biochar obtained at the pyrolysis temperature at 500, 800 and 900°C proved to be applicable for Pb2+ removal. Chemisorption and porosity dominated the MB adsorption, and biochars produced at pyrolysis temperatures of 200, 800 and 900°C are potential materials for MB removal. This study provides optimal pyrolysis conditions for transforming maize straw into valuable, low-cost materials for the removal of different pollutants.


Asunto(s)
Carbón Orgánico/química , Plomo/química , Azul de Metileno/química , Zea mays/química , Adsorción , Cinética , Plomo/aislamiento & purificación , Azul de Metileno/aislamiento & purificación , Pirólisis , Propiedades de Superficie , Residuos
15.
Chemosphere ; 259: 127488, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32640376

RESUMEN

A Ce-doped Ti/PbO2 electrode was prepared in a deposition solution containing Ce3+ and Pb2+ ions by electrodeposition, and the surface morphology, crystal structure and elemental states were characterized by SEM, XRD and XPS. The electrode was used to investigate the simultaneous degradation of three phthalate esters (PAEs), i.e., dimethyl phthalate (DMP), diethyl phthalate (DEP) and dibutyl phthalate (DBP) in synthetic wastewaters. The results showed that the electrode exhibited excellent electrocatalytic activity and good reusability and stability, and the removal efficiencies of 5 mg L-1 DBP, DMP and DEP in 0.05 M Na2SO4 (pH 7) reached 98.2%, 95.8% and 81.1% at current density of 25 mA cm-2 after 10 h degradation, respectively. The degradation processes followed pseudo first-order kinetic model very well, and the observed rate constants of DBP, DEP and DMP were 0.42, 0.40 and 0.29 h-1, respectively. The energy consumption in three PAEs degradation was also assessed. The main degradation products of the three PAEs were identified by using liquid chromatography-tandem mass spectrometry, and the possible degradation pathways mainly included dealkylation, hydroxyl addition, decarboxylation and benzene ring cleavage. This work is a promising candidate for efficient treatment of multiple PAEs in wastewater and protection of the aquatic ecological environment.


Asunto(s)
Cerio/química , Galvanoplastia/métodos , Restauración y Remediación Ambiental/métodos , Ácidos Ftálicos/química , Aguas Residuales/química , Contaminantes Químicos del Agua/química , Dibutil Ftalato/química , Electrodos , Ésteres/química , Plomo/química , Óxidos/química , Titanio/química
16.
Chemosphere ; 260: 127587, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32663673

RESUMEN

In this work, a three-dimension grapnene-PbO2 (3DG-PbO2) composite anode was prepared using coelectrodeposition technology for electrocatalytic oxidation of perfluorooctane sulfonate (PFOS). The effect of 3DG on the surface morphology, structure and electrocatalytic activity of PbO2 electrode was investigated. The results indicated that the 3DG-PbO2-0.08 anode (3DG concentration in electrodeposition solution was 0.08 g L-1) possessed the best electrocatalytic activity due to its stronger ·OH radicals generation capacity, more active sites and smaller charge-transfer resistance. The degradation rate constant of PFOS on 3DG-PbO2-0.08 anode was 2.33 times than that of pure PbO2 anode. Additionally, the by-products formed in electrocatalytic degradation of PFOS were identified and a PFOS degradation pathway was proposed accordingly, which was dominated by the dissociation of -CF2- groups via the attack of ·OH radicals. Finally, the toxicity evolution of degradation solution was examined to evaluate the ecological risk of electrocatalytic oxidation of PFOS by acute toxicity assays to zebrafish embryos.


Asunto(s)
Ácidos Alcanesulfónicos/análisis , Técnicas Electroquímicas/métodos , Fluorocarburos/análisis , Grafito/química , Plomo/química , Nanocompuestos/química , Óxidos/química , Titanio/química , Contaminantes Químicos del Agua/análisis , Ácidos Alcanesulfónicos/toxicidad , Animales , Electrodos , Galvanoplastia , Embrión no Mamífero/efectos de los fármacos , Fluorocarburos/toxicidad , Oxidación-Reducción , Contaminantes Químicos del Agua/toxicidad , Pez Cebra
17.
Int J Occup Environ Med ; 11(3): 140-147, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32683426

RESUMEN

BACKGROUND: The major portion of lead in the body resides in skeletal system. The bone turnover affects the release of lead into the circulation from bones. The bone turnover biomarkers (BTM) in lead-battery workers with long-term exposure to lead have not been explored yet. OBJECTIVE: To evaluate the BTM (formation and resorption) in lead-battery workers with long-term exposure to lead in lead-battery manufacturing plant. METHODS: 176 male lead-exposed workers and 80 matched comparison group were studied. All participants were examined for blood lead levels (BLLs), bone formation biomarkers- serum osteocalcin (OC), alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BALP)-and bone resorption biomarkers-serum pyridinoline (PYD), deoxypyridinoline (DPYD), tartarate-resistant acid phosphatase-5b (TRACP-5b), and urinary hydroxyproline (UHYP). RESULTS: We found a significantly higher bone formation biomarkers such as BALP (p=0.007) and bone resorption biomarkers, eg, PYD (p=0.048), TRCAP-5b (p=0.001), and UHYP (p=0.001) in lead-exposed workers. A significant (p=0.041) negative correlation (ρ ­0.128) was noted between BLLs and OC. A significant positive correlation was noted between BLLs and TRACP-5b (ρ 0.176, p=0.005) and UHYP (ρ 0.258, p=0.004). Serum OC (p=0.040) and UHYP (p=0.015) levels changed significantly with BLL level. Bone resorption biomarkers levels- PYD, TRACP-5b, and BALP-were higher among those with higher BLLs levels. The duration of exposure was significantly associated with BALP (p=0.037), DPYD (p=0.016), TRACP-5b (p=0.001), and UHYP (p=0.002) levels. CONCLUSION: Long-term lead exposure affects the bone turnover.


Asunto(s)
Biomarcadores/sangre , Remodelación Ósea/fisiología , Suministros de Energía Eléctrica , Plomo/toxicidad , Exposición Profesional/análisis , Fosfatasa Ácida/sangre , Fosfatasa Ácida/metabolismo , Adulto , Fosfatasa Alcalina/sangre , Biomarcadores/análisis , Resorción Ósea/sangre , Estudios de Casos y Controles , Estudios Transversales , Suministros de Energía Eléctrica/efectos adversos , Humanos , Isoenzimas/sangre , Isoenzimas/metabolismo , Plomo/química , Intoxicación por Plomo/sangre , Intoxicación por Plomo/diagnóstico , Masculino , Instalaciones Industriales y de Fabricación , Persona de Mediana Edad , Exposición Profesional/efectos adversos , Exposición Profesional/estadística & datos numéricos , Osteocalcina/sangre , Lugar de Trabajo
18.
Chemosphere ; 260: 127574, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32688316

RESUMEN

Artisanal and small-scale gold mining (ASGM) operations are major contributors to the Philippines' annual gold (Au) output (at least 60%). Unfortunately, these ASGM activities lacked adequate tailings management strategies, so contamination of the environment is prevalent. In this study, soil contamination with copper (Cu), lead (Pb), zinc (Zn) and arsenic (As) due to ASGM activities in Nabunturan, Davao de Oro, Philippines was investigated. The results showed that ASGM-impacted soils had Cu, Pb, Zn and As up to 3.6, 83, 73 and 68 times higher than background levels, respectively and were classified as 'extremely' polluted (CD = 30-228; PLI = 5.5-34.8). Minerals typically found in porphyry copper-gold ores like pyrite, chalcopyrite, malachite, galena, sphalerite and goethite were identified by XRD and SEM-EDS analyses. Furthermore, sequential extraction results indicate substantial Cu (up to 90%), Pb (up to 50%), Zn (up to 65%) and As (up to 48%) partitioned with strongly adsorbed, weak acid soluble, reducible and oxidisable fractions, which are considered as 'geochemically mobile' phases in the environment. Although very high Pb and Zn were found in ASGM-impacted soils, they were relatively immobile under oxidising conditions around pH 8.5 because of their retention via adsorption to hydrous ferric oxides (HFOs), montmorillonite and kaolinite. In contrast, Cu and As release from the historic ASGM site samples exceeded the environmental limits for Class A and Class C effluents, which could be attributed to the removal of calcite and dolomite by weathering. The enhanced desorption of As at around pH 8.5 also likely contributed to its release from these soils.


Asunto(s)
Minería , Contaminantes del Suelo/análisis , Contaminantes del Suelo/química , Suelo/química , Arsénico/análisis , Arsénico/química , Cobre/análisis , Cobre/química , Oro/análisis , Hierro/química , Compuestos de Hierro/química , Plomo/análisis , Plomo/química , Minerales/química , Filipinas , Sulfuros/química , Difracción de Rayos X , Zinc/análisis , Zinc/química
19.
Bull Environ Contam Toxicol ; 105(1): 146-154, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32488396

RESUMEN

Biochar was for the first time produced from Suaeda glauca. The immobilization of Pb and Cd by this biochar and pig manure biochar was examined in two types of soils by diethylene triamine pentaacetic acid (DTPA) extraction. Addition of biochars decreased DTPA extractable Pb and Cd in Fluvo-aquic soil with reduction rates being 11.3%-48.4% and 0.74%-64.9% compared with the control treatment. The pig manure biochar favored the immobilization of Pb and S. glauca biochar favored the immobilization of Cd. Biochars can effectively immobilize heavy metals in Fluvo-aquic soil. However, the addition of biochars increased extractable Pb and Cd in red soil, with pig manure biochars showing greater rates. This is ascribed to that the competition effects of ions released from biochar enhanced the moving of heavy metals from iron and manganese oxides bound form to organic matter bound form, and hence enhanced the mobility and bioavailability of heavy metals.


Asunto(s)
Cadmio/química , Plomo/química , Contaminantes del Suelo/química , Animales , Disponibilidad Biológica , Carbón Orgánico/química , Chenopodiaceae , Compuestos de Manganeso , Estiércol , Metales Pesados/análisis , Óxidos , Suelo , Contaminantes del Suelo/análisis , Porcinos
20.
Bull Environ Contam Toxicol ; 105(1): 166-172, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32564099

RESUMEN

The growth response, tolerance, and enrichment characteristics of six ornamental species, Chlorophytum comosum, Calendula officinalis, Iris lacteal, Belamcanda chinensis, Saponaria officinalis, and Polygonum lapathifolium were studied under hydroponic culture with lead (Pb) concentrations ranging from 0 to 1000 mg/L. The results showed that the growth of the tested ornamental species under Pb stress was inhibited. Belamcanda chinensis presented the largest tolerance index (0.75), and Calendula officinalis had the highest toxicity threshold (500 mg/L) under Pb stress. The highest Pb contents in the shoots were detected in Iris lacteal and Belamcanda chinensis. The enrichment coefficients in the shoots of Iris lacteal and Belamcanda chinensis were significantly higher than those in the other ornamental species. In conclusion, Iris lacteal and Belamcanda chinensis are the most tolerant and have the greatest Pb enrichment and translocation abilities under Pb stress, and thus, they have a strong potential to restore Pb-contaminated water bodies and soils.


Asunto(s)
Biodegradación Ambiental , Hidroponia , Plomo/química , Iris (Planta) , Raíces de Plantas/crecimiento & desarrollo , Suelo , Contaminantes del Suelo
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