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1.
J Environ Manage ; 289: 112506, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33831760

RESUMEN

Polyelectrolyte composite nanospheres are relatively new adsorbents which have attracted much attention for their efficient pollutant removal and reuse performance. A novel polyelectrolyte nanosphere with magnetic function (SA@AM) was synthesized via the electrostatic reaction between the polyanionic sodium alginate (SA) and the surface of a prepared terminal amino-based magnetic nanoparticles (AMs). SA@AM showed a size of 15-22 nm with 6.85 emu·g-1 of magnetization value, exhibiting a high adsorption capacity on Pb(II) ions representing a common heavy metal pollutant, with a maximum adsorption capacity of 105.8 mg g-1. The Langmuir isotherm adsorption fits the adsorption curve, indicating uniform adsorption of Pb(II) on the SA@AM surfaces. Repeated adsorption desorption experiments showed that the removal ratio of Pb(II) by SA@AM was more than 76%, illustrating improved regeneration performance. These results provide useful information for the production of bio-based green magnetic nano scale adsorption materials for environmental remediation applications.


Asunto(s)
Nanosferas , Contaminantes Químicos del Agua , Adsorción , Alginatos , Concentración de Iones de Hidrógeno , Iones , Cinética , Plomo , Fenómenos Magnéticos , Polielectrolitos , Aguas Residuales , Contaminantes Químicos del Agua/análisis
2.
Water Sci Technol ; 83(8): 1987-2000, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33905367

RESUMEN

In this experiment, three kinds of hydrous manganese dioxide (HMO) with different Zeta potentials were synthesized, and combined with KMnO4 for deep removal of Pb2+, Cd2+ and Ni2+. The competitive adsorption of three heavy metal ions was also investigated. The results indicated that the stronger the acidity, the higher the Zeta potential (-54.3) of the synthesized HMO. After regenerating HMO with acidic KMnO4 as eluent, the removal rates of Pb2+, Cd2+ and Ni2+ could still reach 79.25%, 80.13% and 60.43% after five cycles of adsorption. The promoting mechanism of KMnO4's effect on HMO was analyzed by SEM, TEM, EDS, FTIR, XRD, XPS, BET, and UV-vis. After absorbing heavy metal ions, HMO will release part of Mn (II), and the released Mn (II) reacts with KMnO4 to form a small amount of highly active in-situ HMO. The 'HMO + KMnO4' system can not only improve the removal rate of heavy metal ions by HMO, and reduce the amount of adsorbent, but also remove the released Mn (II). Because of its reproducibility, efficiency and simplicity, the research on water purification materials and technologies is of significance.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Adsorción , Sistemas Prepagos de Salud , Iones , Cinética , Reproducibilidad de los Resultados , Contaminantes Químicos del Agua/análisis
3.
Int J Mol Sci ; 22(6)2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33803919

RESUMEN

Ion channels are well recognized to select ions to pass through the cell membrane in a wide variety of cells [...].


Asunto(s)
Membrana Celular/genética , Fenómenos Electrofisiológicos/fisiología , Canales Iónicos/genética , Potenciales de la Membrana/genética , Humanos , Canales Iónicos/metabolismo , Iones/metabolismo
4.
Artículo en Inglés | MEDLINE | ID: mdl-33805146

RESUMEN

Massive production of carcinogenic fly ash waste poses severe threats to water bodies due to its disposal into drains and landfills. Fly ash can be a source of raw materials for the synthesis of adsorbents. Rag fly ash as a new class of raw materials could be a cheap source of Al and Si for the synthesis of Na-zeolites. In this work, NaOH activation, via a prefusion- and postfusion-based hydrothermal strategy, was practiced for the modification of rag fly ash into Na-zeolite. Morphology, surface porosity, chemical composition, functionality, mineral phases, and crystallinity, in conjunction with ion exchangeability of the tailored materials, were evaluated by SEM, ICP-OES, XRF, FTIR, XRD, and cation exchange capacity (CEC) techniques. Rag fly ash and the synthesized Na-zeolites were applied for the removal of Pb (II) from synthetic wastewater by varying the reaction conditions, such as initial metal ion concentration, mass of adsorbent, sorption time, and pH of the reaction medium. It was observed that Na-zeolite materials (1 g/100 mL) effectively removed up to 90-98% of Pb (II) ions from 100 mg/L synthetic solution within 30 min at pH ≈ 8. Freundlich adsorption isotherm favors the multilayer heterogeneous adsorption mechanism for the removal of Pb (II). It is reasonable to conclude that recycling of textile rag fly ash waste into value-added Na-zeolites for the treatment of industrial wastewater could be an emergent move toward achieving sustainable and green remediation.


Asunto(s)
Contaminantes Químicos del Agua , Zeolitas , Adsorción , Ceniza del Carbón , Iones , Plomo , Textiles , Aguas Residuales
5.
Int J Mol Sci ; 22(6)2021 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-33809183

RESUMEN

Packed red blood cells (pRBCs), the most commonly transfused blood product, are exposed to environmental disruptions during storage in blood banks. In this study, temporal sequence of changes in the ion exchange in pRBCs was analyzed. Standard techniques commonly used in electrolyte measurements were implemented. The relationship between ion exchange and red blood cells (RBCs) morphology was assessed with use of atomic force microscopy with reference to morphological parameters. Variations observed in the Na+, K+, Cl-, H+, HCO3-, and lactate ions concentration show a complete picture of singly-charged ion changes in pRBCs during storage. Correlation between the rate of ion changes and blood group type, regarding the limitations of our research, suggested, that group 0 is the most sensitive to the time-dependent ionic changes. Additionally, the impact of irreversible changes in ion exchange on the RBCs membrane was observed in nanoscale. Results demonstrate that the level of ion leakage that leads to destructive alterations in biochemical and morphological properties of pRBCs depend on the storage timepoint.


Asunto(s)
Conservación de la Sangre/métodos , Eritrocitos/metabolismo , Intercambio Iónico , Manejo de Especímenes/métodos , Carbonatos/metabolismo , Membrana Eritrocítica , Humanos , Iones/metabolismo , Ácido Láctico/metabolismo , Microscopía de Fuerza Atómica , Potasio/metabolismo , Sodio/metabolismo
6.
Artículo en Inglés | MEDLINE | ID: mdl-33807417

RESUMEN

In the present study we investigated the ability of the microalgal strain Parachlorella sp. AA1 to biologically uptake a radionuclide waste material. Batch experiments were conducted to investigate the biosorption of uranyl ions (U(VI)) in the 0.5-50.0 mg/L concentration range by strain AA1. The results showed that AA1 biomass could uptake U(VI). The highest removal efficiency and biosorption capacity (95.6%) occurred within 60 h at an initial U(VI) concentration of 20 mg/L. The optimum pH for biosorption was 9.0 at a temperature of 25 °C. X-ray absorption near edge structure analysis confirmed the presence of U(VI) in pellets of Parachlorella sp. AA1 cells. The biosorption methods investigated here may be useful in the treatment and disposal of nuclides and heavy metals in diverse wastewaters.


Asunto(s)
Chlorophyta , Contaminantes Químicos del Agua , Adsorción , Biomasa , Concentración de Iones de Hidrógeno , Iones , Cinética
7.
Sensors (Basel) ; 21(6)2021 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-33809491

RESUMEN

This article describes the design and the characterization of the ANTIGONE (ANalog To dIGital cONvErter) ASIC (Application Specific Integrated Circuit) built in AMS 0.35 m technology for low dc-current sensing. This energy-efficient ASIC was specifically designed to interface with multiple Ion-Sensitive Field-Effect Transistors (ISFETs) and detect biomarkers like pH, Na+, K+ and Ca2+ in human sweat. The ISFET-ASIC system can allow real-time noninvasive and continuous health monitoring. The ANTIGONE ASIC architecture is based on the current-to-frequency converter through the charge balancing principle. The same front-end can digitize multiple currents produced by four sweat ISFET sensors in time multiplexing. The front-end demonstrates good linearity over a dynamic range that spans from 1 pA up to 500 nA. The consumed energy per conversion is less than 1 J. The chip is programmable and works in eight different modes of operation. The system uses a standard Serial Peripheral Interface (SPI) to configure, control and read the digitally converted sensor data. The chip is controlled by a portable device over Bluetooth Low Energy (BLE) through a Microcontroller Unit (MCU). The sweat sensing system is part of a bigger wearable platform that exploits the convergence of multiparameter biosensors and environmental sensors for personalized and preventive healthcare.


Asunto(s)
Técnicas Biosensibles , Dispositivos Electrónicos Vestibles , Humanos , Iones , Sodio , Sudor
8.
J Environ Manage ; 288: 112441, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33823454

RESUMEN

The pollution in soils and groundwater caused by the tannery have attracted public attention. However, few studies have been done on the migration and species distribution of Cr and coexisting ions produced by tanning in the vadose zone. In this paper, an in-production tannery and a suspended tannery were selected to compare the migration of Cr and other inorganic ions from tanneries in the vadose zone. Results showed that the sewage treatment station and the temporary waste storage site had the highest concentration of pollutants. Cr exhibited a cumulative effect in the middle soil layer (100-300 cm) in the suspended tannery. However, in the in-production tannery, the cumulative effect occurred only at the temporary waste storage site. The distribution of pollutants in the soils at different depths was fixed in the suspended tannery field. But in the in-production tannery field, it was closely related to daily production. Visual MINTEQ showed that the saturation index of a species of Cr was positive or negative simultaneously in the two sites, indicating that (1) the change of saturation index of Cr had no relationship with operation of tannery. (2) the influence of Cr precipitation or dissolution was related to the source strength, the coexisting ions, and pH. This study contributed to understanding the migration of characteristic pollutants caused by tanneries in the vadose zone under different external environments, and provided a reference for the quantification calculation of the source load of pollutants caused by industrial infiltration into the groundwater.


Asunto(s)
Contaminantes del Suelo , Contaminantes Químicos del Agua , Cromo/análisis , Residuos Industriales/análisis , Iones , Contaminantes del Suelo/análisis , Curtiembre , Contaminantes Químicos del Agua/análisis
9.
Int J Mol Sci ; 22(6)2021 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-33802882

RESUMEN

The curcumin degradation represents a significant limitation for its applications. The stability of free curcumin (FC) and immobilized curcumin in complex particles (ComPs) based on different polysaccharides was studied under the action of several factors. Ultraviolet-visible (UV-VIS) and Fourier-transform infrared (FTIR) spectroscopy proved the FC photodegradation and its role as a metal chelator: 82% of FC and between 26% and 39.79% of curcumin within the ComPs degraded after exposure for 28 days to natural light. The degradation half-life (t1/2) decreases for FC when the pH increases, from 6.8 h at pH = 3 to 2.1 h at pH = 9. For curcumin extracted from ComPs, t1/2 was constant (between 10 and 13 h) and depended on the sample's composition. The total phenol (TPC) and total flavonoids (TFC) content values increased by 16% and 13%, respectively, for FC exposed to ultraviolet light at λ = 365 nm (UVA), whereas no significant change was observed for immobilized curcumin. Antioxidant activity expressed by IC50 (µmoles/mL) for FC exposed to UVA decreased by 29%, but curcumin within ComPs was not affected by the UVA. The bovine serum albumin (BSA) adsorption efficiency on the ComPs surface depends on the pH value and the cross-linking degree. ComPs have a protective role for the immobilized curcumin.


Asunto(s)
Curcumina/farmacología , Polisacáridos/química , Sustancias Protectoras/farmacología , Adsorción , Animales , Antioxidantes/análisis , Compuestos de Bifenilo/química , Tampones (Química) , Bovinos , Curcumina/química , Curcumina/efectos de la radiación , Flavonoides/análisis , Depuradores de Radicales Libres/química , Concentración de Iones de Hidrógeno , Concentración 50 Inhibidora , Iones , Metales/química , Fenoles/análisis , Picratos/química , Albúmina Sérica Bovina/química , Soluciones , Espectroscopía Infrarroja por Transformada de Fourier , Rayos Ultravioleta
10.
Int J Mol Sci ; 22(6)2021 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-33809742

RESUMEN

The voltage-dependent anion channel (VDAC) is the major pathway for metabolites and ions transport through the mitochondrial outer membrane. It can regulate the flow of solutes by switching to a low conductance state correlated with a selectivity reversal, or by a selectivity inversion of its open state. The later one was observed in non-plant VDACs and is poorly characterized. We aim at investigating the selectivity inversion of the open state using plant VDAC purified from Phaseolus coccineus (PcVDAC) to evaluate its physiological role. Our main findings are: (1) The VDAC selectivity inversion of the open state occurs in PcVDAC, (2) Ion concentration and stigmasterol affect the occurrence of the open state selectivity inversion and stigmasterol appears to interact directly with PcVDAC. Interestingly, electrophysiological data concerning the selectivity inversion of the PcVDAC open state suggests that the phenomenon probably does not have a significant physiological effect in vivo.


Asunto(s)
Phaseolus/metabolismo , Semillas/metabolismo , Estigmasterol/metabolismo , Canales Aniónicos Dependientes del Voltaje/metabolismo , Medición de Intercambio de Deuterio , Activación del Canal Iónico/efectos de los fármacos , Iones , Cinética , Liposomas , Concentración Osmolar , Phaseolus/efectos de los fármacos , Semillas/efectos de los fármacos , Estigmasterol/farmacología
11.
Water Sci Technol ; 83(7): 1677-1690, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33843751

RESUMEN

Electrochemical water softening has been widely used in industrial circulating cooling water systems; however, their low deposition efficiency is the main drawback that limits usage in medium to large enterprises. In this work, the effect of different parameters on the hardness removal efficiency and energy consumption of the electrochemical water softening system is experimentally studied, and the performance of water softening applied by high frequency electric fields and direct current electric fields are comparative analyzed. The impact factors of the electrochemical water softening system are as follows: initial feed concentration of solute, magnitude of voltage, inter-electrode distance, area of cathode and frequency of power supply. To improve the analysis efficiency, the L25 (55) orthogonal table is used to investigate the five different factors at five levels. The experimental results are shown that the initial feed concentration of solute is the most significant factor affecting the hardness removal efficiency. The optimal combination for water softening in the group applied by high frequency electric field and direct current electric field are A3B2C1D4E3 and A2B5C3D1 respectively. The energy utilization of the device applied by high frequency electric field is 3.2 times that applied by direct current electric field. The practice shows that direct current electric fields have a better softening effect, and are is more suitable for scaling ion removal. Particle image velocimetry (PIV) was used to observe the flow field induced by the electrolysis and found that the vertical and horizontal velocities of the flow field at low voltage are conducive to the migration of scaled ions to the cathode, and then the electrolytic reaction and deposition reaction synergy effect is the optimal.


Asunto(s)
Electricidad , Ablandamiento del Agua , Electrodos , Iones
12.
Int J Mol Sci ; 22(5)2021 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-33806395

RESUMEN

Alveolar type II (ATII) cells are a key structure of the distal lung epithelium, where they exert their innate immune response and serve as progenitors of alveolar type I (ATI) cells, contributing to alveolar epithelial repair and regeneration. In the healthy lung, ATII cells coordinate the host defense mechanisms, not only generating a restrictive alveolar epithelial barrier, but also orchestrating host defense mechanisms and secreting surfactant proteins, which are important in lung protection against pathogen exposure. Moreover, surfactant proteins help to maintain homeostasis in the distal lung and reduce surface tension at the pulmonary air-liquid interface, thereby preventing atelectasis and reducing the work of breathing. ATII cells may also contribute to the fibroproliferative reaction by secreting growth factors and proinflammatory molecules after damage. Indeed, various acute and chronic diseases are associated with intensive inflammation. These include oedema, acute respiratory distress syndrome, fibrosis and numerous interstitial lung diseases, and are characterized by hyperplastic ATII cells which are considered an essential part of the epithelialization process and, consequently, wound healing. The aim of this review is that of revising the physiologic and pathologic role ATII cells play in pulmonary diseases, as, despite what has been learnt in the last few decades of research, the origin, phenotypic regulation and crosstalk of these cells still remain, in part, a mystery.


Asunto(s)
Células Epiteliales Alveolares/patología , Células Epiteliales Alveolares/fisiología , Enfermedades Pulmonares/fisiopatología , Pulmón/fisiología , Células Epiteliales Alveolares/citología , Animales , Humanos , Inmunidad Innata , Iones/metabolismo , Pulmón/anatomía & histología , Enfermedades Pulmonares/etiología , Enfermedades Pulmonares/patología , Proteínas Asociadas a Surfactante Pulmonar/metabolismo , Regeneración
13.
Int J Mol Sci ; 22(6)2021 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-33803618

RESUMEN

A series of thiosemicarbazone derivatives was prepared and their anti-tumor activity in vitro was tested. The X-ray investigation performed for compounds T2, T3 and T5 confirmed the synthesis pathway and assumed molecular structures of analyzed thiosemicarbazones. The conformational preferences of the thiosemicarbazone system were characterized using theoretical calculations by AM1 method. Selected compounds were converted into complexes of Cu (II) ions. The effect of complexing on anti-tumor activity has been investigated. The copper(II) complexes, with Schiff bases T1, T10, T12, T13, and T16 have been synthesized and characterized by chemical and elemental analysis, FTIR spectroscopy and TGA method. Thermal properties of coordination compounds were studied using TG-DTG techniques under dry air atmosphere. G361, A375, and SK-MEL-28 human melanoma cells and BJ human normal fibroblast cells were treated with tested compounds and their cytotoxicity was evaluated with MTT test. The compounds with the most promising anti-tumour activity were then selected and their cytotoxicity was verified with cell cycle analysis and apoptosis/necrosis detection. Additionally, DNA damages in the form of a basic sites presence and the expression of oxidative stress and DNA damage response genes were evaluated. The obtained results indicate that complexation of thiosemicarbazone derivatives with Cu (II) ions improves their antitumor activity against melanoma cells. The observed cytotoxic effect is associated with DNA damage and G2/M phase of cell cycle arrest as well as disorders of the antioxidant enzymes expression.


Asunto(s)
Antineoplásicos/farmacología , Complejos de Coordinación/farmacología , Cobre/farmacología , Melanoma/patología , Tiosemicarbazonas/farmacología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Forma de la Célula/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Complejos de Coordinación/química , Cobre/química , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Enlace de Hidrógeno , Concentración 50 Inhibidora , Iones , Melanoma/genética , Conformación Molecular , Necrosis , ARN Mensajero/genética , ARN Mensajero/metabolismo , Temperatura , Tiosemicarbazonas/química
14.
Adv Exp Med Biol ; 1280: 149-159, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33791980

RESUMEN

Ion chromatography (IC) represents an important technique for separation of charged and polar compounds. Traditionally, IC is often used for the analysis of small inorganic ions. Due to the development of eluent suppression technology that allows continuous online desalting and conversion of high-salt eluents into pure water, IC has been coupled with mass spectrometry (MS) for the analysis of more diverse range of anionic and cationic analytes. Recent studies have demonstrated that IC-MS is a powerful technique with exquisite detection sensitivity, high reproducibility, and quantitative capability for metabolomic analysis. In this chapter, we provide a brief overview of IC principles and IC-MS for metabolomic analysis.


Asunto(s)
Cromatografía , Metabolómica , Iones , Espectrometría de Masas , Reproducibilidad de los Resultados
15.
Chimia (Aarau) ; 75(4): 252-256, 2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33902790

RESUMEN

Laser-induced fluorescence studies on mass-selected biomolecules are a promising route to understand their properties in the gas phase and probe their intrinsic properties in a solvent-free environment. Fluorescence has been used to investigate the conformation and dynamics of gaseous biomolecular ions. With Förster Resonance Energy Transfer (FRET), it is now possible to obtain sensitive intramolecular distance information from large biomolecules, like proteins, with high chemical specificity. With growing interest and applications, gas-phase fluorescence measurements can shed greater light on the characteristics of proteins in the gas phase. Compared to the solution phase measurements, gas-phase fluorescence can also help understand the influence of solvent interactions on the protein structure and function.


Asunto(s)
Transferencia Resonante de Energía de Fluorescencia , Proteínas , Gases , Iones
16.
Sensors (Basel) ; 21(5)2021 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-33652955

RESUMEN

Saliva can be used for health monitoring with non-invasive wearable systems. Such devices, including electrochemical sensors, may provide a safe, fast, and cost-efficient way of detecting target ions. Although salivary ions are known to reflect those in blood, no available clinical device can detect essential ions directly from saliva. Here, we introduce an all-solid-state, flexible film sensor that allows highly accurate detection of sodium levels in saliva, comparable to those in blood. The wireless film sensor system can successfully measure sodium ions from a small volume of infants' saliva (<400 µL), demonstrating its potential as a continuous health monitor. This study includes the structural characterization and error analysis of a carbon/elastomer-based ion-selective electrode and a reference electrode to confirm the signal reliability. The sensor, composed of a pair of the electrodes, shows good sensitivity (58.9 mV/decade) and selectivity (log K = -2.68 for potassium), along with a broad detection range of 5 × 10-5 ≈ 1 M with a low detection limit of 4.27 × 10-5 M. The simultaneous comparison between the film sensor and a commercial electrochemical sensor demonstrates the accuracy of the flexible sensor and a positive correlation in saliva-to-blood sodium levels. Collectively, the presented study shows the potential of the wireless ion-selective sensor system for a non-invasive, early disease diagnosis with saliva.


Asunto(s)
Técnicas Biosensibles , Sodio , Electrodos , Humanos , Lactante , Electrodos de Ion-Selectivo , Iones , Reproducibilidad de los Resultados , Saliva
17.
J Chromatogr A ; 1642: 462002, 2021 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-33735642

RESUMEN

The formation of halide adducts ion is an important pathway to improve the sensitivity of analytes in liquid chromatography (LC) combined with negative electrospray ionization (ESI) mass spectrometry (MS). Although adding modifier in mobile phase is generally the simplest way to form anions adducts, the formation of halide adducts ion requires a complex post-column addition strategy since traditional halide ionization enhancement reagents are incompatible with LC systems. To solve this problem, the volatile organochlorine salt tetramethyl ammonium chloride (TMAC) was therefore investigated as a potentially non-corrosive mobile phase modifier that was confirmed to be compatible with both LC and MS systems in this study. When short-chain, medium-chain, and long-chain chlorinated paraffins (CPs) were determinated simultaneously by ultra-high performance LC combined with ESI high resolution MS (UPLC-ESI-HRMS), all of them tended to ionize by forming [M+Cl]- ions and exhibited excellent sensitivity with the instrumental detection limits of 1-4 pg/µL. Meanwhile, their sensitivities towards CPs were less dependent on their Cl content with the total relative response factors of 0.8-3.5. The method's utility was demonstrated through determination of CPs in surface soil and chicken muscle samples. This was an effective and practical method to enhance the selectivity for [M + Cl]- ions and improve sensitivity towards CPs with various carbon lengths. Importantly, post-column addition was not required, and thus the analytical procedure was simplified. The method has also improved sensitivity towards some other organohalides and may be generally useful in the determination of challenging organic analytes.


Asunto(s)
Halogenación , Parafina/análisis , Compuestos de Amonio Cuaternario/química , Animales , Pollos , Cromatografía Líquida de Alta Presión , Medios de Cultivo , Iones , Cloruro de Metileno/química , Estándares de Referencia , Suelo/química , Espectrometría de Masa por Ionización de Electrospray
18.
Environ Int ; 152: 106512, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33756431

RESUMEN

Wastewater treatment for heavy metals is currently transitioning from pollution remediation towards resource recovery. As a controllable and environment-friendly method, electrochemical technologies have recently gained significant attention. However, there is a lack of systematic and goal oriented summarize of electrochemical metal recovery techniques, which has inhibited the optimized application of these methods. This review aims at recent advances in electrochemical metal recovery techniques, by comparing different electrochemical recovery methods, attempts to target recycling heavy metal resources with minimize energy consumption, boost recovery efficiency and realize the commercial application. In this review, different electrochemical recovery methods (including E-adsorption recovery, E-oxidation recovery, E-reduction recovery, and E-precipitation recovery) for recovering heavy metals are introduced, followed an analysis of their corresponding mechanisms, influencing factors, and recovery efficiencies. In addition, the mass transfer efficiency can be promoted further through optimizing electrodes and reactors, and multiple technologies (photo-electrochemical and sono-electrochemical) could to be used synergistically improve recovery efficiencies. Finally, the most promising directions for electrochemical recovery of heavy metals are discussed along with the challenges and future opportunities of electrochemical technology in recycling heavy metals from wastewater.


Asunto(s)
Metales Pesados , Purificación del Agua , Adsorción , Iones , Metales Pesados/análisis , Aguas Residuales
19.
Ecotoxicol Environ Saf ; 215: 112137, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33740490

RESUMEN

In the past few decades, industrialization has caused a large number of pollutants to be released into the atmosphere. Forest ecosystems play an important function in regulating the biogeochemistry and the circulation of metal ions pollutants. Forest ecosystems affect the absorption of pollutants and dissolution of nutrients from the atmosphere and vegetation canopy, thereby influencing the content and composition of forest floor leachate and soil solution. This study examined changes in acid anions (NO3-, SO42-, Cl-) and metal cations (K+, Ca2+, Na2+, Mg2+, Fe3+, Pb2+, Cu2+, Cd2+) in rainfall, throughfall, stemflow, and forest floor leachate for five different forests (Larix principis-rupprechtii, Picea wilsonii, Picea crassifolia, Betula platyphylla and Rhododendron communities). The results showed that the enrichment capacity of acid anions and metal cations in the vegetation canopy of the coniferous forests (L. principis-rupprechtii, P. wilsonii, P. crassifolia) was stronger than that of the broad-leaved forests (B. platyphylla and Rhododendron communities). The content of acid anions and metal cations in stemflow of coniferous forests were 3.7-5.6 times and 0-9.3 times higher than those of broad-leaved forests, respectively. Corresponding values in throughfall were 1-1.4 times and 0.3-2.4 times, respectively. The contents of NO3-, Cl-, K+, Mg2+, Fe3+, Pb2+, Cu2+, and Cd2+ in leachate filtered from the soil layers that are deepening gradually showed consistent decreasing trend for all the forest stands. In addition, NO3-, Cl-, K+, Mg2+, Fe3+, and Pb2+ were also concentrated in the topsoil, except for Cu2+ and Cd2+. Nevertheless, SO42- and Na+ were concentrated in the subsoil, whereas Ca2+ was concentrated in the upper soil layers. Soil organic carbon (SOC) and total nitrogen (TN) contents in coniferous forest stands were 20-37% and 34-63% higher than those in broad-leaved forest stands, respectively. This results also shown that the contents of OC and TN has a strong correlation with the content of partial metal cations in soil and litter, indicating that coniferous forest stands had stronger ion scavenging and adsorption capacity in soil layer and litter layer than broad-leaved forest stands. Therefore, L. principis-rupprechtii, P. wilsonii, P. crassifolia had higher air pollutant adsorption and soil pollution remediation capacities than the other two forests. Thus, we recommend planting coniferous tree species (L. principis-rupprechtii, P. wilsonii and P. crassifolia) for eco-rehabilitation and water purification to improve the ecological service function of forest ecosystems.


Asunto(s)
Restauración y Remediación Ambiental , Bosques , Tracheophyta/fisiología , Adsorción , Betula , Carbono/química , China , Ecosistema , Iones , Nitrógeno/análisis , Picea , Suelo/química , Árboles
20.
Environ Sci Technol ; 55(8): 5569-5578, 2021 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-33683864

RESUMEN

The natural formation of silver nanoparticles (AgNPs) via biotic and abiotic pathways in water and soil media contributes to the biogeochemical cycle of silver metal in the environment. However, the formation of AgNPs in the atmosphere has not been reported. Here, we describe a previously unreported source of AgNPs via the reduction of Ag(I) by SO2 in the atmosphere, especially in moist environments, using multipronged advanced analytical and surface techniques. The rapid reduction of Ag(I) in the atmospheric aqueous phase was mainly caused by the sulfite ions formed from the dissolution of SO2 in water, which contributed to the formation of AgNPs and was consistent with the Finke-Watzky model with a major contribution of the reduction-nucleation process. Sunlight irradiation excited SO2 to form triplet SO2, which reacted with water to form H2SO3 and greatly enhanced Ag(I) reduction and AgNP formation. Different pH values affected the speciation of Ag(I) and S(IV), which were jointly involved in the reduction of Ag(I). The formation of AgNPs was also observed in the atmospheric gas phase via direct reduction of Ag(I) by SO2(gas), which occurred even in 50 ppbv SO2(gas). The natural occurrence of AgNPs in the atmosphere may also be involved in silver corrosion, AgNP transformation and regeneration, detoxification of gaseous pollutants, and the sulfur cycle in the environment.


Asunto(s)
Nanopartículas del Metal , Plata , Iones , Dióxido de Azufre , Luz Solar
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