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1.
Environ Pollut ; 349: 123903, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38599272

RESUMEN

To investigate watershed remediation within a Total Maximum Daily Load program, this study examined the field-scale filtration performance of two specialty absorbents. The goal was to simultaneously remove nutrients and biological pollutants along Canal 23 (C-23) in the St. Lucie River Basin, Florida. The filtration system installed in the C-23 river corridor was equipped with either clay-perlite with sand sorption media (CPS) or zero-valent iron and perlite green environmental media (ZIPGEM). Both media were formulated with varying combinations of sand, clay, perlite, and/or recycled iron based on distinct recipes. In comparison with CPS, ZIPGEM exhibited higher average removal percentages for nutrients. Findings indicated that ZIPGEM could remove total nitrogen up to 49.3%, total Kjeldahl nitrogen up to 67.1%, dissolved organic nitrogen (DON) up to 72.9%, total phosphorus up to 79.6%, and orthophosphate up to 73.2%. Both ZIPGEM and CPS demonstrated similar efficiency in eliminating biological pollutants, such as E. coli (both media exhibiting an 80% removal percentage) and chlorophyll a (both media achieving approximately 95% removal). Seasonality effects were also evident in nutrient removal efficiencies, particularly in the case of ammonia nitrogen; the negative removal efficiency of ammonia nitrogen from the fifth sampling event could be attributed to processes such as photochemical ammonification, microbial transformation, and mineralization of DON in wet seasons. Overall, ZIPGEM demonstrated a more stable nutrient removal efficiency than CPS in the phase of seasonal changes.


Asunto(s)
Restauración y Remediación Ambiental , Filtración , Nitrógeno , Fósforo , Dióxido de Silicio , Contaminantes Químicos del Agua , Filtración/métodos , Contaminantes Químicos del Agua/análisis , Restauración y Remediación Ambiental/métodos , Restauración y Remediación Ambiental/instrumentación , Florida , Purificación del Agua/métodos , Ríos/química , Óxido de Aluminio/química , Escherichia coli , Clorofila A , Arcilla/química , Hierro/química
2.
Environ Pollut ; 351: 124056, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38677464

RESUMEN

Reducing cadmium (Cd) content from contaminated farmland soils remains a major challenge due to the difficulty in separating commonly used adsorbents from soils. This study synthesized novel millimeter-sized magnetic Fe3O4/mercapto-functionalized attapulgite beads (MFBs) through a facile one-step gelation process incorporating alginate. The MFBs inherit the environmental stability of alginate and enhance its mechanical strength by hybridizing Fe3O4 and clay mineral components. MFBs can be easily separated from flooded soils by magnets. When applied to 12 Cd-polluted paddy soils and 14 Cd-polluted upland soils, MFBs achieved Cd(II) removal rates ranging from 16.9% to 62.2% and 9.8%-54.6%, respectively, within a 12-h period. The MFBs predominantly targeted the exchangeable and acid soluble, and reducible fractions of Cd, with significantly enhanced removal efficiencies in paddy soils compared to upland soils. Notably, MFBs exhibited superior adsorption performance in soils with lower pH and organic matter (OM) content, where the bioavailability and mobility of Cd are heightened. The reduction of Cd content by MFBs is a sustainable and safe method, as it permanently removes the bioavailable Cd from soil, rather than temporarily reducing its bioavailability. The functional groups such as -SH, -OH, present in attapulgite and alginate of MFBs, played a crucial role in Cd(II) adsorption. Additionally, attapulgite and zeolite provided a porous matrix structure that further enhanced Cd(II) adsorption. The results of X-ray photoelectron spectroscopy suggested that both chemical precipitation and surface complexation contributed to Cd(II) removal. The MFBs maintained 87.6% Cd removal efficiency after 5 regeneration cycles. The surface of the MFBs exposed new adsorption sites and increased the specific surface area during multiple cycles with Cd-contaminated soil. This suggests that MFBs treatment with magnetic retrieval is a potentially effective pathway for the rapid removal of Cd from contaminated farmland soils.


Asunto(s)
Cadmio , Restauración y Remediación Ambiental , Compuestos de Silicona , Contaminantes del Suelo , Suelo , Contaminantes del Suelo/química , Cadmio/química , Adsorción , Restauración y Remediación Ambiental/métodos , Restauración y Remediación Ambiental/instrumentación , Suelo/química , Compuestos de Silicona/química , Compuestos de Magnesio/química , Compuestos Férricos/química
3.
Food Chem Toxicol ; 161: 112843, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35101578

RESUMEN

The extensive use of pesticides for better yield of crops have become major human concern over the decades. Pesticides are widely used in the fields to kill weeds and pests on the vegetable and crops to improve the quality and yield of the food knowing the fact that pesticides residue in food are very lethal for human being. Amongst, the hazardous pesticides, mancozeb is widely applied in the protection of crops. Thus the quantification of mancozeb residue is of great importance. This study reports the electrochemical monitoring of mancozeb through tungsten oxide reduced graphene oxide (WO3/rGO) nanocomposite. The engineered nanocomposite was characterized though different analytical tools such as FTIR, XRD and TEM to examine crystallinity, internal texture and the size. The FTIR result confirm the functionalities of GO and WO3/rGO nanocomposite in finger print and functional group region. Through XRD analysis, the size of the WO3/rGO nanocomposite was calculated as 31.6 nm. While the TEM analysis was also exploited to examine the 2D texture of GO and nanometric size of the WO3/rGO. To ensure the conductive nature of the WO3/rGO nanocomposite, the glassy carbon electrode was modified and exploited for cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions, the modified sensor showed exceptional response for mancozeb. The linear dynamic range was set from 0.05 to 70 µM in BRB buffer of pH 4. The LOD and LOQ for proposed method was calculated as 0.0038 and 0.0115 µM. The analytical applicability of chemically modified sensor was investigated in real matrix of different vegetable samples and the recovery values were observed in acceptable range. The electrochemical examination of present work reveals that WO3/rGO nanocomposite can be an exceptional aspirant for the determination of mancozeb at commercial level.


Asunto(s)
Técnicas Electroquímicas/instrumentación , Grafito/química , Maneb/química , Nanocompuestos/química , Óxidos/química , Tungsteno/química , Zineb/química , Técnicas Electroquímicas/métodos , Restauración y Remediación Ambiental/instrumentación , Restauración y Remediación Ambiental/métodos , Concentración de Iones de Hidrógeno
4.
World J Microbiol Biotechnol ; 37(9): 157, 2021 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-34417879

RESUMEN

Heavy metals and metalloids (HMMs) pose a serious threat to both environmental and human health. The unique characteristics and environmental toxicity of HMMs make their removal from the environment a major challenge. Constructed wetlands (CWs) are increasingly being used as an eco-friendly system for the removal of HMMs from aqueous environments. In this review, bibliometric analysis was performed using the Scopus database using VOSviewer software to assess the developing use of CWs in recent years. Heavy metal and metalloid (HMM) removal pathways were reviewed (such as precipitation, co-precipitation, adsorption and ion exchange, plant action and microbial action) along with the impact of key factors (pH, chemical oxygen demand, dissolved oxygen, HMM concentration, and temperature). This review aimed to establish the connections between published results, to help effectively optimize the use of CWs for the removal of HMMs and identify the most critical factors for their effective removal. Important aspects that require further research include assessing the synergistic toxicity between different pollutants and combining the use of CWs with other technologies to optimize pollutant remediation efficiency.


Asunto(s)
Contaminantes Ambientales/química , Restauración y Remediación Ambiental/métodos , Metaloides/química , Metales Pesados/química , Bibliometría , Restauración y Remediación Ambiental/instrumentación , Restauración y Remediación Ambiental/tendencias , Humedales
5.
Carbohydr Polym ; 267: 118151, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34119126

RESUMEN

Different cyclodextrin-calixarene nanosponges (CyCaNSs) have been characterized by means of FFC-NMR relaxometry, and used as sorbents to remove Pb2+ ions from aqueous solutions. Considering that the removal treatments may involve polluted waters with different characteristics, the adsorption experiments were performed on solutions without and with the addition of background salts, under different operational conditions. The adsorption abilities and affinities of the nanosponges towards Pb2+ ions were investigated by measuring the metal ion concentration by means of Inductively Coupled Plasma Emission Spectroscopy (ICP-OES) and Differential Pulse Anodic Stripping Voltammetry (DP-ASV). The acid-base properties of nanosponges and of metal ion as well as their interactions with the other interacting components of the systems have been considered in the evaluation of adsorption mechanism. Recycling and reuse experiments on the most efficient adsorbents were also performed. On the grounds of the results obtained, post-modified CyCaNSs appear promising materials for designing environmental remediation devices.


Asunto(s)
Calixarenos/química , Ciclodextrinas/química , Plomo/aislamiento & purificación , Adsorción , Restauración y Remediación Ambiental/instrumentación , Equipo Reutilizado , Cinética , Plomo/química , Termodinámica , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación
6.
Braz J Microbiol ; 52(2): 651-661, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33443727

RESUMEN

The petrochemical industry is responsible for many accidental releases of pollutants in soil such as hydrocarbons and toxic metals. This co-contamination is responsible for a delay in the degradation of the organic pollution. Many successful technologies to remove these metals apply extracellular polymeric substances (EPS). In this study, we tested the application of an EPS from a Paenibacillus sp. to aid the bioremediation of soils contaminated with crude oil and nickel. We conducted a microcosm experiment to soils containing combinations of oil, nickel, and EPS. The final concentration of oil was evaluated with an infrared spectrometer. Also, we sequenced the metagenomes of the samples in an ion torrent sequencer. The application of EPS did not aid the removal of hydrocarbons with or without the presence of nickel. However, it led to a smaller decrease in the diversity indexes. EPS decreased the abundance of Actinobacteria and increased that of Proteobacteria. The EPS also decreased the connectivity among Actinobacteria in the network analysis. The results indicated that the addition of EPS had a higher effect on the community structure than nickel. Altogether, our results indicate that this approach did not aid the bioremediation of hydrocarbons likely due to its effect in the community structure that affected hydrocarbonoclastic microorganisms.


Asunto(s)
Bacterias/metabolismo , Biopolímeros/química , Restauración y Remediación Ambiental/métodos , Níquel/metabolismo , Paenibacillus/química , Microbiología del Suelo , Contaminantes del Suelo/metabolismo , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Biodegradación Ambiental , Restauración y Remediación Ambiental/instrumentación , Hidrocarburos/metabolismo , Paenibacillus/metabolismo , Petróleo/análisis , Petróleo/microbiología , Suelo/química
7.
Int J Environ Health Res ; 31(1): 85-101, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31210533

RESUMEN

Diclofenac is a commercial non-steroidal anti-inflammatory drug commonly present as a pollutant in naturally occurring water sources and wastewaters. In this work, the adsorption of diclofenac onto chitosan-coated magnetic nanosystems is proposed as a possible tool for remediation. Experimental and theoretical studies have been carried out to reveal the mechanisms associated with diclofenac interactions among all the components of the nanosystem. Mechanisms are presented, analyzed and discussed. A toxicological study in mice was carried out to evaluate the parameters associated with neurotoxicity of the nanodevice. The elucidation of the mechanisms implied in the adsorption process of diclofenac onto magnetic chitosan nanocomposites suggests that diclofenac remediation from water is possible by adsorption onto chitosan. The strategy innovates the commonly used methodologies for diclofenac remediation from pharmaceutical wastes. This magnetic nanotechnology would not induce damage on the nervous system in a murine model, in case of traces remaining in water sources.


Asunto(s)
Diclofenaco/análisis , Restauración y Remediación Ambiental/instrumentación , Nanotecnología/instrumentación , Contaminantes Químicos del Agua/química , Contaminación Química del Agua/prevención & control , Adsorción , Antiinflamatorios no Esteroideos/análisis , Fenómenos Magnéticos , Aguas Residuales/análisis
8.
Nat Commun ; 11(1): 3668, 2020 07 22.
Artículo en Inglés | MEDLINE | ID: mdl-32699271

RESUMEN

Restoration is becoming a vital tool to counteract coastal ecosystem degradation. Modifying transplant designs of habitat-forming organisms from dispersed to clumped can amplify coastal restoration yields as it generates self-facilitation from emergent traits, i.e. traits not expressed by individuals or small clones, but that emerge in clumped individuals or large clones. Here, we advance restoration science by mimicking key emergent traits that locally suppress physical stress using biodegradable establishment structures. Experiments across (sub)tropical and temperate seagrass and salt marsh systems demonstrate greatly enhanced yields when individuals are transplanted within structures mimicking emergent traits that suppress waves or sediment mobility. Specifically, belowground mimics of dense root mats most facilitate seagrasses via sediment stabilization, while mimics of aboveground plant structures most facilitate marsh grasses by reducing stem movement. Mimicking key emergent traits may allow upscaling of restoration in many ecosystems that depend on self-facilitation for persistence, by constraining biological material requirements and implementation costs.


Asunto(s)
Adaptación Fisiológica , Restauración y Remediación Ambiental/métodos , Hydrocharitaceae/fisiología , Humedales , Zosteraceae/fisiología , Plásticos Biodegradables , Biomimética/métodos , Ecología/métodos , Restauración y Remediación Ambiental/instrumentación , Florida , Países Bajos , Agua de Mar , Suecia , Clima Tropical , Indias Occidentales
9.
Rev Environ Health ; 35(4): 311-321, 2020 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-32598323

RESUMEN

Indoor air pollutant is a serious problem due to its wide diversity and variability. The harmful substances from construction materials and decorative materials may make the indoor air pollution become more and more serious and cause serious health problems. In this paper, the review summarizes the advanced technologies for the removal of indoor air pollutants and the development in the treatment of indoor air pollution by catalytic oxidation technologies. Meanwhile, some catalytic oxidation mechanisms of indoor air pollutants are proposed in detail, and suggestions for the indoor air pollution treatment are also presented, in order to provide some reference for subsequent research.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/prevención & control , Monitoreo del Ambiente , Restauración y Remediación Ambiental/métodos , Catálisis , Restauración y Remediación Ambiental/instrumentación , Oxidación-Reducción
10.
Sci Rep ; 10(1): 5488, 2020 03 26.
Artículo en Inglés | MEDLINE | ID: mdl-32218470

RESUMEN

Successful recruitment of new individuals is essential for recovery of degraded coral reefs. Enhancing supply of coral larvae increases initial settlement, however post-settlement survival can be influenced by density-dependent processes. We investigated the influence of larval density on settlement, colony abundance and growth to 24 months for Acropora tenuis in the north-western Philippines, to determine whether larval supply can be optimised to maximise successful recruitment. Thirty different densities of coral larvae were enclosed for five days around settlement tiles and highest total settlement occurred on tiles with highest larval densities. After 12 months, however, colony abundance and coral cover was lower on high density tiles (supplied with ~2,500-5,000 larvae) than tiles supplied with ~1,000-2,000 larvae. Coral cover at 24 months remained highest on tiles supplied with ~1,000-2,500 larvae. Larval density influenced larval substratum selection, with proportionally fewer larvae settling in typically preferred locations as density increased. We conclude that larval density can influence post-settlement colony abundance and coral cover to 12 months, with coral cover trends persisting to 24 months. We show that optimising larval densities can maximise coral recruitment and growth, however oversupply of larvae at very high densities can have negative outcomes for larval restoration.


Asunto(s)
Antozoos/crecimiento & desarrollo , Arrecifes de Coral , Restauración y Remediación Ambiental/métodos , Animales , Restauración y Remediación Ambiental/instrumentación , Larva/crecimiento & desarrollo , Filipinas , Densidad de Población , Factores de Tiempo
11.
Sci Rep ; 10(1): 3634, 2020 02 27.
Artículo en Inglés | MEDLINE | ID: mdl-32107469

RESUMEN

This study presents the removal of phosphate from aqueous solution using a new silver nanoparticles-loaded tea activated carbon (AgNPs-TAC) material. In order to reduce costs, the tea activated carbon was produced from tea residue. Batch adsorption experiments were conducted to evaluate the effects of impregnation ratio of AgNPs and TAC, pH solution, contact time, initial phosphate concentration and dose of AgNPs-AC on removing phosphate from aqueous solution. Results show that the best conditions for phosphate adsorption occurred at the impregnation ratio AgNPs/TAC of 3% w/w, pH 3, and contact time lasting 150 min. The maximum adsorption capacity of phosphate on AgNPs-TAC determined by the Langmuir model was 13.62 mg/g at an initial phosphate concentration of 30 mg/L. The adsorption isotherm of phosphate on AgNPs-TAC fits well with both the Langmuir and Sips models. The adsorption kinetics data were also described well by the pseudo-first-order and pseudo-second-order models with high correlation coefficients of 0.978 and 0.966, respectively. The adsorption process was controlled by chemisorption through complexes and ligand exchange mechanisms. This study suggests that AgNPs-TAC is a promising, low cost adsorbent for phosphate removal from aqueous solution.


Asunto(s)
Camellia sinensis/química , Carbón Orgánico/química , Restauración y Remediación Ambiental/métodos , Nanopartículas del Metal/química , Fosfatos/química , Plata/química , Adsorción , Restauración y Remediación Ambiental/instrumentación , Cinética , Hojas de la Planta/química , Preparaciones de Plantas/química , Contaminantes del Agua/química
12.
Chemosphere ; 248: 126029, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32035385

RESUMEN

The use of electrokinetic Fenton (EK Fenton) process, as promising soil remediation approach, was investigated by using an iron electrode with different supporting electrolytes (tap water, H2O2, and citric acid) to depollute soil spiked with petroleum where kaolin was selected as low hydraulic conductivity. The results clearly confirm that, the combination of electrokinetic remediation (EK) and Fenton technologies, is an efficient oxidizing approach for removing hydrocarbons from this kind of soil. In fact, the electrokinetic Fenton reactions and the control of the soil pH conditions by adding citric acid enhanced the oxidation process because the addition of the H2O2 with iron electrode resulted in higher removal efficiencies (89%) for total petroleum hydrocarbons (TPHs). These figures allowed to confirm that EK Fenton process with pH control contributed for the transport of H2O2 and Fe2+ ions in the soil by electromigration and eletro-osmotic phenomena. Conversely, no control of pH conditions when only EK was applied, achieved lower hydrocarbons removal (27%) after 15 d of treatment due to the precipitation of iron ions. Finally, the efficiency of the EK Fenton remediation prevented the generation of secondary effluent with higher organic content, avoiding its treatment by other advanced oxidation process.


Asunto(s)
Restauración y Remediación Ambiental/métodos , Contaminación por Petróleo , Contaminantes del Suelo/química , Ácido Cítrico/química , Técnicas Electroquímicas/instrumentación , Electrodos , Restauración y Remediación Ambiental/instrumentación , Hidrocarburos/química , Peróxido de Hidrógeno/química , Concentración de Iones de Hidrógeno , Hierro/química , Caolín/química , Ósmosis , Oxidación-Reducción , Suelo/química
13.
Environ Pollut ; 260: 113944, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32014741

RESUMEN

Polycyclic aromatic hydrocarbons (PAHs) in soil are not only detrimental to environment but also to human health. Double dielectric barrier discharge (DDBD) plasma reactor used for the remediation of pyrene contaminated soil was studied. The performance of DDBD reactor was optimized with influential parameters including applied voltage, type of carrier gas, air feeding rate as well as pyrene initial concentration. The analysis of variance (ANOVA) results showed that input energy had a great effect on pyrene remediation efficiency followed by pyrene initial concentration, while, the effect of air feeding rate was insignificant. More specifically, the remediation efficiency of pyrene under air, nitrogen and argon as carrier gas were approximately 79.7, 40.7 and 38.2% respectively. Pyrene remediation efficiency is favored at high level of applied voltages and low level of pyrene initial concentration (10 mgkg-1) and air feeding rate (0.85 L/min). Moreover, computation of the energy efficiency of the DDBD system disclosed that an optimal applied voltage (35.8 kV) and higher initial pyrene concentration (200 mgkg-1) favored the high energy efficiency. A regression model predicting pyrene remediation under DDBD plasma condition was developed using the data from a face-centered central composite design (FCCD) experiment. Finally, the residual toxicity analysis depicted that the respiratory activity increased more than 21 times (from 0.04 to 0.849 mg O2 g-1) with a pyrene remediation efficiency of 81.1%. The study demonstrated the DDBD plasma technology is a promising method not only for high efficiency of pyrene remediation, but also recovering biological function without changing the physical-chemical properties of soil.


Asunto(s)
Restauración y Remediación Ambiental , Hidrocarburos Policíclicos Aromáticos , Pirenos , Contaminantes del Suelo , Biodegradación Ambiental , Restauración y Remediación Ambiental/instrumentación , Restauración y Remediación Ambiental/normas , Pirenos/metabolismo , Contaminantes del Suelo/metabolismo
14.
Artículo en Inglés | MEDLINE | ID: mdl-31868088

RESUMEN

The reduction of ammonia emissions from air was experimentally investigated by advanced oxidation processes (AOPs) utilizing the combination of ultraviolet irradiation with ozone. The influence of operating conditions such as initial ammonia concentration and flow rate of gas on the reduction of ammonia concentration was investigated in homemade photochemical unit. The conversion of ammonia decreased with increasing initial concentration of ammonia and with increasing flow rate of air (decreasing retention time). The highest conversion of ammonia (97%) was achieved under lower initial concentration of ammonia (30 ppm) and lower flow rate of air (28 m3/h). The energy per order was evaluated for the advanced oxidation process too. The energy consumption was about 0.037 kWh/m3/order for the 97% ammonia conversion at 30 ppm of initial ammonia concentration and 28 m3/h flow rate of air. Based on the results, the advanced oxidation process combining the UV irradiation and ozone was effective for mitigation of ammonia concentration and presents a promising technology for the reduction of odor emissions from livestock buildings. Moreover, the AOPs are suitable for application for high flow rate of air, especially for ammonia abatement from livestock buildings, where very high efficiency is expected.


Asunto(s)
Contaminantes Atmosféricos/análisis , Amoníaco/análisis , Restauración y Remediación Ambiental/métodos , Ozono/química , Rayos Ultravioleta , Contaminantes Atmosféricos/química , Contaminantes Atmosféricos/efectos de la radiación , Amoníaco/química , Amoníaco/efectos de la radiación , Restauración y Remediación Ambiental/instrumentación , Peróxido de Hidrógeno/química , Oxidación-Reducción
15.
Artículo en Inglés | MEDLINE | ID: mdl-31847211

RESUMEN

Heavy metals contaminated sediment has become a worldwide environmental issue due to its great harm to human and aquatic organisms. Thus, economical, effective, and environmentally-friendly remediation technologies are urgently needed. Among which, combined remediation technologies have attracted widespread attention for their unique advantages. This paper introduces combined remediation technologies based on physical-, chemical-, and bio-remediation of heavy metal polluted sediments. Firstly, the research progress in physical-chemical, bio-chemical, and inter-organismal (including plants, animals, microorganisms) remediation of heavy metal polluted sediments are summarized. Additionally, the paper analyzes the problems of the process of combined remediation of heavy metals in river sediments and outlooks the future development trends of remediation technologies. Overall, this review provides useful technology references for the control and treatment of heavy metal pollution in river sediments.


Asunto(s)
Restauración y Remediación Ambiental/métodos , Sedimentos Geológicos/análisis , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisis , Contaminación Química del Agua/prevención & control , Restauración y Remediación Ambiental/instrumentación , Ríos
16.
J Agric Food Chem ; 67(49): 13550-13557, 2019 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-31721576

RESUMEN

Enantioselectivity is usually ignored when assessing potential biochar-based methods of redressing pesticide contamination of soils. In this study, the effect of woodchip biochar (WBC) on the enantioselective dissipation of metalaxyl in soil and its uptake and translocation by lettuce were investigated. S-metalaxyl (T1/2 = 29.8 days) dissipated more quickly than R-metalaxyl (T1/2 = 36.4 days) in unamended soil. The addition of WBC to the soil decreased the dissipation rate and the enantioselectivity of metalaxyl. Metalaxyl distribution showed opposing enantioselectivity in lettuce, with roots and shoots showing preferences for R-metalaxyl and S-metalaxyl, respectively. Enrichment with WBC decreased the concentrations of metalaxyl and metalaxyl acid enantiomers in lettuce and reduced the ability of the shoots to transport the highly toxic R-metalaxyl from roots. This is the first study to provide evidence that amending soil with biochar affects the enantioselective uptake and translocation of a chiral pesticide.


Asunto(s)
Alanina/análogos & derivados , Carbón Orgánico/química , Restauración y Remediación Ambiental/métodos , Lactuca/metabolismo , Plaguicidas/química , Contaminantes del Suelo/química , Adsorción , Alanina/química , Alanina/metabolismo , Biodegradación Ambiental , Restauración y Remediación Ambiental/instrumentación , Plaguicidas/metabolismo , Raíces de Plantas/química , Raíces de Plantas/metabolismo , Contaminantes del Suelo/metabolismo
17.
Sci Total Environ ; 677: 175-183, 2019 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-31055098

RESUMEN

Several industrial activities produce wastewater with high sulfate content that can cause significant environmental issues. Although bioelectrochemical systems (BESs) have recently been studied for the treatment of sulfate contained in this wastewater, the recovery of elemental sulfur with BESs is still in its beginnings. This work proposes a new reactor configuration named BES-EC, consisting of the coupling of a BES with an electrochemical cell (EC), to treat this type of wastewater and recover elemental sulfur. The reactor consisted of four electrodes: i) an abiotic anode, ii) a biocathode for the autotrophic sulfate reduction, iii) an anode of an electrochemical cell (EC) for the partial oxidation of sulfide to elemental sulfur (the biocathode and the EC anode were placed in the same chamber) and iv) an abiotic EC cathode. Several cathode potentials and sulfate loads were tested, obtaining high sulfate removal rates (up to 888 mg SO42--S L-1 d-1 at -0.9 V vs. SHE with a specific energy consumption of 9.18 ±â€¯0.80 kWh kg-1 SO42--S). Exceptionally high theoretical elemental sulfur production rates (up to 498 mg S0-S L-1 d-1) were achieved with the EC controlled at a current density of 2.5 A m-2. Electron recovery around 80% was observed throughout most of the operation of the integrated system. In addition, short experiments were performed at different current densities, observing that sulfate removal did not increase proportionally to the higher applied current density. However, when the BES was controlled at 30 A m-2 and the EC at 7.5 A m-2, the proportion of elemental sulfur produced corresponded to 92.9 ±â€¯1.9% of all sulfate removed.


Asunto(s)
Reactores Biológicos , Técnicas Electroquímicas/métodos , Restauración y Remediación Ambiental/métodos , Sulfatos/química , Azufre/química , Aguas Residuales/análisis , Contaminantes Químicos del Agua/análisis , Electrodos , Restauración y Remediación Ambiental/instrumentación , Oxidación-Reducción , Azufre/análisis
18.
Environ Sci Pollut Res Int ; 26(19): 19598-19605, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31077053

RESUMEN

The ability of standard soils to capture heavy metals or polycyclic aromatic hydrocarbons (PAHs) from ammoniacal copper zinc arsenate (ACZA)- or creosote-treated wood, respectively, was assessed using pressure-treated posts immersed in a freshwater pond. The soil, in heat-sealed, permeable plastic mesh sachets, was able to intercept copper, zinc, arsenic, and PAHs migrating from the posts. Chemical levels were much higher immediately adjacent to the posts and declined with distance from the posts. Metals were consistently detected around ACZA-treated posts, while 10 of the 16 EPA priority pollutants were detected in at least one sachet embedded around creosote-treated posts at each sampling point. These results were consistent with traditional sediment sampling methods. The primary advantages of the sachets were their consistency in terms of soil characteristics and the ease with which they could be retrieved from the pond. Further studies are planned to better understand the role of soil characteristics in the sachets on the ability to capture migrating preservatives.


Asunto(s)
Monitoreo del Ambiente/métodos , Restauración y Remediación Ambiental/métodos , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes del Suelo/análisis , Suelo/química , Madera/química , Arseniatos/análisis , Cobre/análisis , Creosota/análisis , Restauración y Remediación Ambiental/instrumentación , Diseño de Equipo , Polímeros/química , Zinc/análisis
19.
Sci Total Environ ; 659: 963-972, 2019 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-31096426

RESUMEN

Concerning the contamination of phthalate esters (PAEs) in river sediments, this mini-review introduces four recently reported novel "integrated electrokinetic (EK) processes" for the remediation purpose, namely two combined technologies of the EK process and advanced oxidation process (EK-AOP Processes) and two combined technologies of the EK process and biological process (EK-BIO Processes). The following is a comprehensive summary for these remediation processes: (1) the EK process coupled with nano-Fe3O4/S2O82- oxidation process - Test results have shown that nanoscale Fe3O4 played a significant role in activating persulfate oxidation. Even a recalcitrant compound like di(2­ethylhexyl)phthalate (DEHP), its concentration in test sediment was reduced to 1.97 mg kg-1, far below the regulatory levels set by Taiwan EPA; (2) the EK process integrated with a novel Fenton-like process catalyzed by nanoscale schwertmannite (nano-SHM) - Test results have revealed that simultaneous injection of nano-SHM slurry and H2O2 into the anode reservoir and sediment compartment is a good practice. 70-99% in removal efficiency was obtained for various target PAEs; (3) enhanced in situ bioremediation coupled with the EK process for promoting the growth of intrinsic microorganisms by adding H2O2 as an oxygen release compound (ORC) - Test results have demonstrated that an intermittent mode of injecting lab-prepared ORC directly into the contaminant zone would be beneficial to the growth of intrinsic microorganisms in test sediment for in situ bioremediation of target PAEs; and (4) coupling of a second-generation ORC (designated 2G-ORC) with the EK-biological process - Test results have proved that 2G-ORC is long-lasting and can be directly utilized as the carbon source and oxygen source for microbial growth resulting in an enhanced biodegradation of PAEs. Except DEHP having a residual concentration of 4 µg kg-1, all other target PAEs in test sediment were totally removed by this novel combined remediation process.


Asunto(s)
Restauración y Remediación Ambiental/métodos , Ésteres/química , Sedimentos Geológicos/química , Ácidos Ftálicos/química , Contaminación Química del Agua/prevención & control , Biodegradación Ambiental , Restauración y Remediación Ambiental/instrumentación
20.
J Air Waste Manag Assoc ; 69(9): 1059-1069, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31050600

RESUMEN

Xylene is the main component of many volatile industrial pollution sources, and the use of biotechnology to remove volatile organic compounds (VOCs) has become a growing trend. In this study, a biotrickling filter for gaseous xylene treatment was developed using activated sludge as raw material to study the biodegradation process of xylene. Reaction conditions were optimized, and long-term operation was performed. The optimal pH was 7.0, gas-liquid ratio was 15:1 (v/v), and temperature was 25 °C. High-throughput sequencing technique was carried out to analyze microbial communities in the top, middle, and bottom layers of the reactor. Characteristics of microbial diversity were elucidated, and microbial functions were predicted. The result showed that the removal efficiency (RE) was stable at 86%-91%, the maximum elimination capacity (EC) was 303.61 g·m-3·hr-1, residence time was 33.75 sec, and the initial inlet xylene concentration was 3000 mg·m-3, which was the highest known degradation concentration reported. Kinetic analysis of the xylene degradation indicated that it was a very high-efficiency-activity bioprocess. The rmax was 1059.8 g·m-3·hr-1, and Ks value was 4.78 g·m-3 in stationary phase. In addition, microbial community structures in the bottom and top layers were significantly different: Pseudomonas was the dominant genus in the bottom layer, whereas Sphingobium was dominant in the top layer. The results showed that intermediate metabolites of xylene could affect the distribution of community structure. Pseudomonas sp. can adapt to high concentration xylene-contaminated environments. Implications: We combined domesticated active sludge and reinforced microbial agent on biotrickling filter. This system performed continuously under a reduced residence time at 33.75 sec and high elimination capacity at 303.61 g·m-3·hr-1 in the biotrickling reactor for about 260 days. In this case, predomestication combined with reinforcing of microorganisms was very important to obtaining high-efficiency results. Analysis of microbial diversity and functional prediction indicated a gradient distribution along with the concentration of xylene. This implied a rational design of microbial reagent and optimizing the inoculation of different sites of reactor could reduce the preparation period of the technology.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire/prevención & control , Restauración y Remediación Ambiental/métodos , Microbiota , Xilenos/análisis , Biodegradación Ambiental , Restauración y Remediación Ambiental/instrumentación , Filtración/métodos , Gases/análisis
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