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1.
Chemosphere ; 242: 125251, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896185

RESUMO

A novel nano-composite material (CMC-FeS@HA) combining the advantages of humic acid (HA) and FeS was synthesized to remediate hexavalent chromium (Cr(VI)) contaminated soil along with chromium (Cr) resistant microflora. The characteristic analysis confirmed the successful synthesis of the nano-composite, which provided further mechanism evidence of its detoxification effect on polluted soil. Energy Dispersive System analysis proved the adsorption of the microbe consortium (MC) for Cr. After remediation, Cr(VI) in all treatments was dramatically reduced and the leachable Cr in soil treated by CMC-FeS@HA and MC decreased 89.14% compared with control. The result of BCR sequential extraction showed that Cr was stabilized, whose form changed to oxidizable and residual from HOAC-extractable. Besides, CMC-FeS@HA, as a sustained-release acid with high biocompatibility, could continuously decrease the pH of strongly alkaline soil and created a suitable micro-ecological environment for soil microorganisms. Moreover, CMC-FeS@HA dramatically improved soil physicochemical property, soil microbial activity (dehydrogenase, hydrolase, urease, and invertase activities), and soil microecological diversity. In total, this study provided a useful technology for soil remediation, which innovatively combined chemical remediation and microbial-remediation with a positive effect on soil quality, providing a good approach for the multiple technology combination in the environmental cause.


Assuntos
Cromo/análise , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/análise , Adsorção , Poluição Ambiental/análise , Substâncias Húmicas/análise , Oxirredução , Solo/química
2.
J Hazard Mater ; 382: 121093, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31476721

RESUMO

In-situ passivation of soil chromium (Cr) contamination based on chemical and biological passivators has been widely concerned, however, the cooperative effect of two types of passivators on Cr passivation and soil properties was little investigated. In this study, nano zero valent iron (nZVI) and humic acid (HA) as the chemical passivators were selected and were combined with a novel Cr resistant strain QY-1 to study these two points. Results demonstrated that the combination was more effective in Cr immobilization, among which, HA + QY-1 had the highest passivation rate (82.83%), followed by nZVI + QY-1. HA + QY-1 alleviated soil Cr stress most efficiently as its soil relevant fertility indicators, microbial quantity, respiration and seed gemination rate significantly increased. On the contrary, nZVI decreased soil respiration and microbial abundance, but the addition of QY-1 could relieve this phenomenon. The results highlighted the ability of HA + QY-1 to remediate Cr contaminated soil and improve soil stability.

3.
Environ Pollut ; 255(Pt 2): 113252, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31542610

RESUMO

To develop a high efficient and eco-friendly approach to remediate cadmium (Cd) contaminated soil, we designed the activation and extraction systems, on the basis of combined effects between the ability of organic acids to activate Cd and the ability of mushroom accumulator (Lentinus edodes) to extract Cd. The results showed that the proportion of acetic acid-extractable Cd significant increased with the application of exogenous organic acids. Additionally, soil microecology analysis indicated that exogenous organic acids evidently enhanced the numbers of microbial cells and the activities of soil enzymes. Besides, high throughput sequencing analysis revealed exogenous organic acids improved the diversity and structure of soil bacterial community after remediation. Particularly, the combination application of mushroom and exogenous citric acid had highest accumulation efficiency of Cd, and its efficiency was 59.19% higher than single mushroom treatment. Hence, exogenous organic acids could alleviate soil microecology and increase mycoextraction efficiency, which suggested it was a feasible route to remediate Cd contaminated soil by the activation and extraction systems.


Assuntos
Cádmio/química , Poluentes do Solo/metabolismo , Agaricales , Bactérias , Biodegradação Ambiental , Cádmio/análise , Compostos Orgânicos , Cogumelos Shiitake , Solo/química , Poluentes do Solo/análise
4.
Environ Pollut ; 252(Pt A): 553-561, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31181500

RESUMO

Remediation of soil chromium (Cr) pollution is becoming more and more urgent. In this study, a multi-loaded nano-zero-valent iron (nZVI) material (CNH) was prepared by carboxymethyl cellulose (CMC) and humic acid (HA) as dispersant and support agent, respectively, and the remediation effect of CNH, HA and CN (CNH without HA) for Cr contaminated soil was investigated within 90 d cycle. After 7 d treatment of CNH, the HOAc-extractable Cr decreased significantly. After the 90 d remediation, the HOAc-extractable Cr decreased most in the treatment of 3% CNH, about 74.48% lower than control. All treatments eventually caused different decline of soil pH, with a range of 0.12-0.54, in which the CNH treatment group had the least depression. HA loading significantly weakened the toxicity of nZVI, resulting in the higher soil microbial quantity and enzyme activities compared with CN. Additionally, the improvement of soil microecology by CNH and HA was positively correlated with the ratio of application, while CN was negatively correlated (except FDA enzyme activity) with these indexes. These results emphasized the potential of the synthesized CNH as a promising material to remediate Cr contaminated soil. Furthermore, details of possible mechanistic insight into the Cr remediation were carefully discussed.


Assuntos
Cromo/química , Poluição Ambiental/análise , Recuperação e Remediação Ambiental/métodos , Ferro/química , Poluentes do Solo/análise , Solo/química , Carboximetilcelulose Sódica , Substâncias Húmicas , Microbiologia do Solo
5.
Chemosphere ; 228: 44-53, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31022619

RESUMO

Although iron nanoparticles (NPs) have been used for environmental remediation of heavy metal, their potential to remediate lead (Pb) contaminated soil and effect on soil micro-ecology is unclear. The purpose of this study was to investigate the potential of nanoscale zerovalent iron (nZVI), nanoscale zerovalent iron supported by biochar (nZVI@BC), ferrous sulfide (FeS-NPs), ferrous sulfide supported by biochar (FeS-NPs@BC), ferriferrous oxide (Fe3O4-NPs) and ferriferrous oxide supported by biochar (Fe3O4-NPs@BC) to remediate Pb contaminated soil and the influences for soil micro-ecology. The results showed that biochar (BC) could improve the crystal shape and superficial area of iron-based nanoparticles. Soil pH values was significantly decreased by FeS-NPs and FeS-NPs@BC, but increased by other iron-nanoparticles. The ability to reduce available Pb concentration showed significant difference among these iron-nanoparticles, that is, the immobilized rate were nZVI by 45.80%, nZVI@BC by 54.68%, FeS-NPs by 2.70%, FeS-NPs@BC by 5.13%, Fe3O4-NPs by 47.47%, Fe3O4-NPs@BC by 30.51% at day 90. Almost all soil enzyme activities in Fe3O4-NPs and Fe3O4-NPs@BC groups were increased, but the majority of the enzyme activities were inhibited in other iron-based nanoparticles groups, while the maximum bacterial number was determined in FeS-NPs group. Furthermore, microbial diversity analysis showed that FeS-NPs has significantly changed microbial community richness and diversity, followed by nZVI and Fe3O4-NPs. Accordingly, our results suggested that nZVI@BC had the best immobilization effect on Pb in high-concentration Pb-contaminated alkaline soil, but the toxic effect of Fe3O4-NPs on soil micro-ecology was relatively minimal.


Assuntos
Recuperação e Remediação Ambiental/métodos , Ferro/química , Chumbo/análise , Nanopartículas , Poluentes do Solo/química , Bactérias/citologia , Bactérias/enzimologia , Carvão Vegetal , Compostos Ferrosos , Ferro/análise , Nanopartículas/química , Solo/química , Poluentes do Solo/análise
6.
Ecotoxicol Environ Saf ; 166: 116-122, 2018 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-30253286

RESUMO

Although the effect of heavy metal on soil microbial diversity was widely studied, the interaction among micro-ecological environment in heavy metal contaminated soil was less known. In this study, we systematically investigated the influence of cadmium (Cd) on soil micro-ecological environment (pH, nutrient content, soil enzyme activities, microbial biomass, bacterial and fungal diversities). Results showed that pH values slightly decreased with the Cd level increase, whereas the nutrient content including of Olsen-P (OSP), Alkeline-N (ALN), Olsen-K (OSK) and organic matter (OM) did not show significant difference in different treatments. In contrast to physicochemical properties, the biochemical qualities were easily influenced by Cd pollutant, resulting in soil microbial numbers and enzyme activities significantly decreased. High-throughput sequencing showed that microbial community composition was significantly affected by heavy metal. For bacteria, Actinobacteria abundance significantly decreased in Cd treated soil, corresponding to Proteobacteria and Firmicutes increased. For fungi, the most dominant phyla member (Ascomycota) was significantly decreased whereas Zygomycota significantly increased with Cd addition. These results further revealed the integral interrelation of micro-ecology environmental players under the stress of different Cd levels.


Assuntos
Cádmio/análise , Metais Pesados/análise , Microbiota/efeitos dos fármacos , Microbiologia do Solo , Poluentes do Solo/análise , Bactérias/efeitos dos fármacos , Biomassa , Ecologia , Fungos/efeitos dos fármacos , Solo/química
7.
Environ Pollut ; 240: 717-724, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29778057

RESUMO

In this study, the dynamic Cr(VI) removal process from water by the synthesized multilayer material coated nanoscale zerovalent iron (SBC-nZVI) was systematically discussed at different treatment conditions. The results showed that initial pH, contact time, Cr(VI) concentration and the dosage of SBC-nZVI were important parameters that influenced the Cr(VI) removal efficiency. The major Cr(VI) removal occurred within 60 min and gradually tend to equilibrium with consistent treatment. The removal efficiency was highly depended on pH values and the adsorption kinetics agreed well with the pseduo-second-order model (PSO). When the initial Cr(VI) concentration was below 15 mg/L, the removal rate could reach to about 100%. Moreover, the removal efficiency increased with the increase of SBC-nZVI dosage, which related to the increase of reactive sites. To understand the removal mechanism, SBC-nZVI before and after reaction with Cr(VI) were characterized by fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). These analysis showed that the interaction of SBC-nZVI with Cr(VI) was mainly controlled by reduction and electrostatic attraction. Therefore, these results explained the interaction between Cr(VI) and SBC-nZVI material in detail, and further proved that SBC-nZVI could be an effective material to remove Cr(VI) from water.


Assuntos
Cromo/análise , Recuperação e Remediação Ambiental/métodos , Ferro/química , Poluentes Químicos da Água/análise , Água/química , Adsorção , Cinética , Microscopia Eletrônica de Varredura/métodos , Espectroscopia Fotoeletrônica/métodos , Difração de Raios X/métodos
8.
Biosens Bioelectron ; 73: 256-263, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26092130

RESUMO

A rapid and ultrasensitive signal-off photoelectrochemical sensor has been developed under visible-light irradiation, for the detection of perfluorooctanoic acid (PFOA), especially low level PFOA present in environment, whereby a novel nanostructured probe made of molecularly imprinted polymer (MIP) modified AgI nanoparticles-BiOI nanoflake arrays (AgI-BiOINFs) is designed as the photoactive electrode (denoted as MIP@AgI-BiOINFs). Here, the unique nanoarchitectured hybrid of AgI-BiOINFs was first in situ synthesized via a facile successive ionic layer adsorption and reaction (SILAR) approach and then employed as a matrix to graft the recognition element of MIP. Such a newly designed PEC sensor exhibits high sensitivity and selectivity for the determination of PFOA. The PEC analysis is highly linear over the PFOA concentration ranging from 0.02 to 1000.0 ppb with a detection limit of 0.01 ppb (S/N=3). This value obtained by using the facile PEC sensor is comparable to the results obtained by using well-established liquid chromatography-tandem mass spectrometry (LC-MS/MS). Toward practical applications, this low-cost and sensitive assay was successfully applied to measure PFOA in real water samples.


Assuntos
Técnicas Biossensoriais/métodos , Caprilatos/análise , Fluorcarbonetos/análise , Técnicas Biossensoriais/estatística & dados numéricos , Bismuto , Técnicas Eletroquímicas/métodos , Iodetos , Nanopartículas Metálicas/química , Impressão Molecular/métodos , Nanocompostos/química , Compostos de Prata , Poluentes Químicos da Água/análise
9.
Anal Chim Acta ; 785: 34-42, 2013 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-23764441

RESUMO

A new, highly sensitive bifunctional electrochemical sensor for the simultaneous determination of pentachlorophenol (PCP) and copper ions (Cu(2+)) has been developed, where organic-inorganic hybrid ultrathin films were fabricated by alternate assembly of humic acid (HA) and exfoliated Mg-Al-layered double hydroxide (LDH) nanosheets onto ITO substrates via a layer-by-layer (LBL) approach. The multilayer films were then characterized by means of UV-vis spectrometry, scanning electron microscopy (SEM), and atomic force microscope (AFM). These films were found to have a relatively smooth surface with almost equal amounts of HA incorporated in each cycle. Its electrochemical performance was systematically investigated. Our results demonstrate that such a newly designed (LDH/HA)n multilayer films, combining the individual properties of HA (dual recognition ability for organic herbicides and metal ions) together with LDH nanosheets (a rigid inorganic matrix), can be applied to the simultaneous analysis of PCP and Cu(II) without interference from each other. The LBL assembled nanoarchitectures were further investigated by X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR), which provides insight for bifunctional sensing behavior. Under the optimized conditions, the detection limit was found to be as low as 0.4 nM PCP, well below the guideline value of PCP in drinking water (3.7 nM) set by the United States Environmental Protection Agency (U.S. EPA), and 2.0 nM Cu(2+), much below the guideline value (2.0 mg L(-1), ~31.2 nM) from the World Health Organization (WHO), respectively. Toward the goal for practical applications, this simple and cost-effective probe was further evaluated by monitoring PCP and Cu(II) in water samples.


Assuntos
Cobre/análise , Técnicas Eletroquímicas , Substâncias Húmicas/análise , Hidróxidos/química , Nanoestruturas/química , Pentaclorofenol/análise , Água Potável/análise , Eletrodos , Íons/química , Metais/química , Compostos de Estanho/química
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