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1.
Artigo em Inglês | MEDLINE | ID: mdl-38135794

RESUMO

Photosensitization, a powerful oxidation reaction, offers significant potential for wastewater treatment in the context of industrial process water reuse. This environmentally friendly process can be crucial in reducing water consumption and industrial pollution. The ultimate goal is to complete process water reuse, creating a closed-loop system that preserves the inherent value of water resources. The photosensitized oxidation reaction hinges on three essential components: the photosensitizer, visible light, and oxygen. In this study, we assess the performance of three distinct materials-silica, chitosan, and spongin-as carrier materials for incorporating the phthalocyanine photosensitizer (ZnPcS4) in the heterogenous photosensitization process. Among the three materials under study, chitosan emerged as the standout performer in reactor hydrodynamic performance. In the photooxidation process, the photosensitizer ZnPcS4 exhibited notable efficacy, resulting in a significant reduction of approximately 20 to 30% in the remaining COD concentration of the cellar wastewater. Chitosan demonstrated exceptional hydrodynamic characteristics and displayed a favorable response to pH adjustments within the range of 8 to 10, outperforming the other two carrier materials. To further enhance the efficiency of continuous operation, exploring methods for mitigating photosensitizer bleaching within the reaction medium and investigating the impact of different pH values on the process optimization would be prudent.

2.
Brain Res ; 1807: 148322, 2023 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-36906226

RESUMO

Zinc is a transition metal that is particularly abundant in the mossy fibers of the hippocampal CA3 area. Despite the large number of studies about the zinc role in mossy fibers, the action of zinc in synaptic mechanisms is only partly known. The use of computational models can be a useful tool for this study. In a previous work, a model was developed to evaluate zinc dynamics at the mossy fiber synaptic cleft, following weak stimulation, insufficient to evoke zinc entry into postsynaptic neurons. For intense stimulation, cleft zinc effluxes must be considered. Therefore, the initial model was extended to include postsynaptic zinc effluxes based on the Goldman-Hodgkin-Katz current equation combined with Hodgkin and Huxley conductance changes. These effluxes occur through different postsynaptic escape routes, namely L- and N-types voltage-dependent calcium channels and NMDA receptors. For that purpose, various stimulations were assumed to induce high concentrations of cleft free zinc, named as intense (10 µM), very intense (100 µM) and extreme (500 µM). It was observed that the main postsynaptic escape routes of cleft zinc are the L-type calcium channels, followed by the NMDA receptor channels and by N-type calcium channels. However, their relative contribution for cleft zinc clearance was relatively small and decreased for higher amounts of zinc, most likely due to the blockade action of zinc in postsynaptic receptors and channels. Therefore, it can be concluded that the larger the zinc release, the more predominant the zinc uptake process will be in the cleft zinc clearance.


Assuntos
Fibras Musgosas Hipocampais , Zinco , Zinco/metabolismo , Sinapses/fisiologia , Hipocampo/metabolismo , Receptores de N-Metil-D-Aspartato/fisiologia , Transmissão Sináptica/fisiologia
3.
Environ Sci Pollut Res Int ; 28(19): 23958-23974, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33398734

RESUMO

Contaminants of emerging concern (CECs) are released daily into surface water, and their recalcitrant properties often require tertiary treatment. Electrochemical oxidation (EO) is often used as an alternative way to eliminate these compounds from water, although the literature barely addresses the neurotoxic effects of residual by-products. Therefore, this study investigated the performance of EO in the removal of five CECs (alprazolam, clonazepam, diazepam, lorazepam, and carbamazepine) and performed neurotoxicity evaluations of residual EO by-products in Wistar rat brain hippocampal slices. Platinum-coated titanium (Ti/Pt) and boron-doped diamond (BDD) electrodes were studied as anodes. Different current densities (13-75 A m-2), pH values (3-10), electrolyte dosages (NaCl), and matrix effects were assessed using municipal wastewater (MWW). The drugs were successfully degraded after 5 min of reaction for both the Ti/Pt and BDD electrodes when a current density of 75 A m-2 was applied. For Ti/Pt and BDD, neutral and acidic pH demonstrated better CEC removal performance, respectively. Compound degradation using MWW achieved 40% removal after 120 min for Ti/Pt and ranged between 33 and 52% for the BDD anode. For Ti/Pt, neurotoxicity studies using MWW indicated a decrease in reactive oxygen species (ROS) signals. However, when an artificial cerebrospinal fluid (ACSF) medium was reapplied, the signal recovered and increased to a value above the baseline, indicating that cells recovered part of their normal activity but remained in a different condition. For the BDD anode, the treated MWW did not cause significant ROS production variations, suggesting that he EO was effective in eliminating the toxicity of the treated solution.


Assuntos
Preparações Farmacêuticas , Poluentes Químicos da Água , Animais , Diamante , Eletrodos , Oxirredução , Ratos , Ratos Wistar , Águas Residuárias , Poluentes Químicos da Água/análise
4.
Water Sci Technol ; 81(4): 732-743, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32460276

RESUMO

Wastewater treatment plants are not specially designed to remove pharmaceutically active compounds (PhACs), since these substances are toxic and bio-refractory. This paper aims to investigate and optimize the performance of the Trisep TS80 nanofiltration (NF) membrane for the removal of a mixture of two of the most detected PhACs in municipal wastewaters worldwide, sulfamethoxazole and diclofenac. Several NF tests were carried out to study the rejections of these contaminants both spiked in demineralized water, filtrated water taken from Mondego River and secondary effluent coming from a municipal wastewater treatment plant. Among the several studied operating variables, pH was the one that most affected the contaminant rejection and membrane permeability. In the case of synthetic effluent, an applied pressure of 10 bar and pH 7 were determined as the best operating conditions, which allowed almost total chemical oxygen demand retention and a global contaminant rejection of 96.3% to be achieved. The application of different water matrices (river water and secondary municipal effluent) had no relevant impact on process efficiency. Vibrio fischeri luminescence inhibition tests revealed that treatment by nanofiltration reduced acute toxicity of all studied effluents.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Diclofenaco , Nylons , Rios , Sulfametoxazol , Eliminação de Resíduos Líquidos , Águas Residuárias , Água
5.
Environ Sci Pollut Res Int ; 26(36): 37174-37192, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31749006

RESUMO

Parabens (esters of p-hydroxybenzoic acid) are xenobiosis belonging to endocrine disruptors and commonly used as a preservative in cosmetics, food, pharmaceutical, and personal care products. Their wide use is leading to their appearance in water and wastewater in the range from ng/L to mg/L. In fact, the toxicity of benzylparaben is comparable to bisphenol A. Therefore, it is important to find not only effective but also ecofriendly methods for their removal from aqueous environment since the traditional wastewater treatment approaches are ineffective. Herein, for the first time, such extended comparison of several radical-driven technologies for paraben mixture degradation is presented. The detailed evaluation included (1) comparison of ozone and hydroxyl peroxide processes; (2) comparison of catalytic and photocatalytic processes (including photocatalytic ozonation); (3) characterisation of catalysts using SEM, XRD, DRS, XPS techniques and BET isotherm; (4) mineralisation, biodegradability and toxicity assessment; and (5) cost assessment. O3, H2O2/Fe2+, H2O2/UVC, O3/H2O2, O3/UVA, O3/H2O2/UVA, UVA/catalyst, O3/catalyst and O3/UVA/catalyst were selected from advanced oxidation processes to degrade parabens as well as to decrease its toxicity towards Aliivibrio fischeri, Corbicula fluminea and Lepidium sativum. Research was focused on the photocatalytic process involving visible light (UVA and natural sunlight) and TiO2 catalysts modified by different metals (Ag, Pt, Pd, Au). Photocatalytic oxidation showed the lowest efficiency, while in combining ozone with catalysis and photocatalysis process, degradation efficiency and toxicity removal were improved. Photocatalytic ozonation slightly improved degradation efficiency but appreciably decreased transferred ozone dose (TOD). Results indicate that the degradation pathway is different, or different transformation products (TPs) could be formed, despite that the hydroxyl radicals are the main oxidant. Graphical abstract.


Assuntos
Biodegradação Ambiental , Parabenos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Aliivibrio fischeri , Catálise , Disruptores Endócrinos , Peróxido de Hidrogênio , Radical Hidroxila , Oxirredução , Ozônio , Luz Solar , Águas Residuárias , Poluentes Químicos da Água/análise , Purificação da Água/métodos
6.
Sci Total Environ ; 689: 79-89, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31271992

RESUMO

Self-organized TiO2 nanotubes as immobilized photocatalysts were evaluated in detail for the photocatalytic degradation of parabens mixtures from ultrapure water. This kind of approach can be a very suitable option for emerging contaminants degradation considering the possibility of the catalyst reuse and recovery which will be simpler than when catalytic powders are used. The anodization method was applied for the TiO2 nanotubes production under different preparation voltages (20, 30 and 40 V). These preparation conditions are important on the morphological characteristics of nanotubes such as length, as well as internal and external diameters. The photocatalytic efficiency was dependent on the materials preparation voltages. The photocatalytic oxidation was evaluated using two different irradiation sources, namely UVA and sunlight. These irradiation sources were evaluated for parabens mixture degradation using different number of catalytic plates. The increase of the number of plates improved the parabens degradation possibly due to the availability of more active sites which can be relevant for the hydroxyl radical's generation. The effect of the reactor design was also evaluated using sunlight irradiation. The configuration, position and solar concentrators can be important for the performance of degradation. The mechanism of degradation was analysed through by-products formation under sunlight irradiation. The main responsible for parabens degradation was hydroxyl radical. Decarboxylation, dealkylation and hydroxylation seem to be the most important reactional steps for the mixture decontamination.

7.
Sci Total Environ ; 646: 1468-1477, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30235632

RESUMO

Parabens are widely used as antimicrobial and preservative in pharmaceutical and personal products. Their presence has been detected in rivers and wastewater treatment plants. Photocatalytic ozonation process using a low amount of 0.1 wt% Ag-TiO2 proved to be efficient on the degradation of a mixture of five parabens using a low transferred ozone dose (TOD). The pH effect was analyzed under acidic and neutral conditions. Also, the effect of hydroxyl radical scavenger on parabens degradation and on by-products formation was discussed. Hydroxyl radical present a significant role over parabens degradation and also on by-products formation. The reaction mechanism was analyzed using municipal wastewater as a matrix to infer about the behavior of the process at actual conditions. Municipal wastewater as a matrix clearly enhanced the parabens degradation when compared with the case where ultrapure water was used. In fact, the TOD required for total parabens degradation is lowered 10-20 mg/L of TOD. Therefore, to understand the main responsible species for this improvement, the effects of several ions naturally present in wastewater (HCO3-, Cl- and SO42-) were tested. According to the results it seems that sulfate radical improves the process, while chloride and bicarbonate radicals decrease the process efficiency. In terms of toxicity the luminescence inhibition for Vibrio fischeri was analyzed. The inhibition significantly decreased for treated spiked municipal wastewater.

8.
Chemosphere ; 208: 674-681, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29894968

RESUMO

Corbicula fluminea, an Asian clam, is one of the worst invasive species in Europe that can survive in very adverse environmental conditions. Despite its negative impacts, the species also has the capacity to bioaccumulate heavy metals, contaminants and can be exploited for wastewater treatment purposes. The capacity of the Asian clam to remove Escherichia coli, used as fecal contamination indicator, was analyzed. Conventional wastewater treatment plants are not suitable to remove bacteria, thus resulting in treated municipal wastewater with high bacterial loads. E. coli clearance rate was analyzed as function of the number of clams. The bivalves can remove bacteria until concentrations below the detection limit in about 6 h. The adsorption on the clam shells' and bioaccumulation on the soft tissues were also analyzed. The depuration of clams along 48 h were analyzed revealing that no bacteria was detected in the water. Thus, these results suggest that Asian clam can bioprocess E. coli. On the other hand, results obtained by this methodology were compared with ozonation and photocatalytic oxidation using TiO2, Ag, Au, Pd-TiO2. In all treatments it was possible to achieve concentrations of E. coli below the detection limit. However, photocatalytic oxidation demands about 4700 folds more energy than ozonation, besides the costs associated with catalysts. Comparing complexity of ozonation with biofiltration, this study suggests that application of biofiltration using C. fluminea can be a suitable solution to minimize the presence of bacteria in wastewater, reducing environmental and economic impacts.


Assuntos
Corbicula/microbiologia , Escherichia coli/isolamento & purificação , Ozônio/química , Adsorção , Animais , Bactérias/isolamento & purificação , Europa (Continente) , Filtração , Oxirredução , Águas Residuárias/microbiologia , Poluentes da Água/isolamento & purificação
9.
Environ Sci Pollut Res Int ; 25(22): 21968-21981, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29797198

RESUMO

The main goal of this work was to assess the performance of an integrated membrane system for the treatment and valorization of wastewater generated from an olive mill (OMW) coming from a traditional extraction press. Two different lots of this effluent were firstly processed in an ultrafiltration (UF) pilot unit after a pretreatment by screening. The effect of transmembrane pressure (TMP) and temperature on the chemical oxygen demand (COD) reduction and removal of total phenolic (TPh) content was investigated. Under optimal conditions (TMP = 1.5 bar and T = 20 °C), 20.6 and 26.8% for COD and TPh removal were achieved, respectively. The permeate from UF was then treated by nanofiltration (NF) in order to obtain a retentate enriched in phenolic compounds. The influence of pressure drop (ΔP), temperature, and pH on the removal of COD, TPh, and permeate flow was examined using a 23 full-factorial experimental design. The effect of the independent variables and their interactions on the process performance was analyzed with Pareto charts. Multivariable regression models allowed to built 3D surface plots. The best conditions that maximize the COD abatement (83.3%) and TPh removal (93.1%) were ΔP = 18 bar, T = 20 °C, and a pH 2.7. It can be concluded that the integration of UF and NF processes investigated in this work is a promising strategy for the treatment and valorization of OMW.


Assuntos
Resíduos Industriais , Olea , Fenóis/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Análise da Demanda Biológica de Oxigênio , Indústria de Processamento de Alimentos , Concentração de Íons de Hidrogênio , Membranas Artificiais , Análise Multivariada , Fenóis/análise , Projetos Piloto , Temperatura , Ultrafiltração , Eliminação de Resíduos Líquidos/instrumentação , Águas Residuárias/química
10.
Gen Physiol Biophys ; 37(2): 213-221, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29593127

RESUMO

The accumulation of intracellular ionic zinc and pharmaceutical compounds, like the antibiotic sulfamethoxazole, may contribute to various neuropathologies. Sulfamethoxazole and the drug trimethoprim, are inhibitors of enzymes involved in the synthesis of tetrahydrofolate and also of carbonic anhydrases. The inhibition of the latter enzymes, which are localized both intra- and extracellularly and have a key role in pH regulation, causes alkalinization that is associated with higher spontaneous transmitter release. Intense synaptic stimulation causes the entry of released zinc into postsynaptic neurons, through glutamate receptor channels or voltage dependent calcium channels. The aim of this study was to evaluate the effect of sulfamethoxazole (180 µM) on basal postsynaptic zinc and to compare it with that caused by two depolarizing media, containing high potassium or tetraethylammonium, which may induce long term synaptic plasticity. The studies were performed in brain slices from gestating rats, at the mossy fiber synapses from hippocampal CA3 area, using the zinc indicator Newport Green. In the presence of KCl (20 mM) and sulfamethoxazole (180 µM) the zinc signals were enhanced, unlike in tetraethylammonium (25 mM). After sulfamethoxazole the tetraethylammonium evoked zinc signal had reduced amplitude. Thus, the data suggests that sulfamethoxazole enhances transmitter release affecting synaptic zinc physiology.


Assuntos
Anti-Infecciosos/toxicidade , Fibras Musgosas Hipocampais/efeitos dos fármacos , Sulfametoxazol/toxicidade , Sinapses/efeitos dos fármacos , Zinco/metabolismo , Animais , Feminino , Fibras Musgosas Hipocampais/metabolismo , Técnicas de Cultura de Órgãos , Gravidez , Ratos , Ratos Wistar
11.
Sci Total Environ ; 630: 1016-1027, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29554723

RESUMO

The environmental and economic impact of invasive bivalve species implies the development of suitable pest management strategies. Chemical control is the most usual approach. However, the production of toxic intermediates as well as the unavoidable impact over non target biota is of special concern. Another approach consists on the physical removal of the animals from the invaded sites. The high biofiltration and bioaccumulation capacity of such animals make them interesting for the removal of contaminants from water and wastewater. In this context, environmental applications can be given for these pests encompassing nutrients removal for the recovery of eutrophic sites, water disinfection, organic and metal contaminants abatement. These approaches may be integrated with pest management where the physical removed animals from the invaded spots could be used for assembling biofilter for water and wastewater decontamination. However, some drawbacks must be addressed before proposing such alternative. In fact, the further spreading of the bivalves into non-invaded sites must be avoided. Moreover, some operational questions must be addressed such as the fate of contaminated animals after biofiltration. Bearing in mind the interesting results already available in this subject, this paper aims to critically overview literature regarding the environmental applications of invasive bivalves.

12.
Environ Sci Pollut Res Int ; 25(8): 7346-7357, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29275482

RESUMO

Parabens are widely used as antimicrobial and preservatives in pharmaceutical and personal care products and are continuously reaching the water streams. Conventional wastewater treatments are proven inefficient on the removal of this kind of contaminants from wastewater. Therefore, catalytic ozonation appears as a suitable option, due to the oxidant power of ozone and its high capacity of hydroxyl radical generation in the presence of a suitable catalyst. The main drawback of catalytic ozonation is related with the choice of stable and active catalysts at low cost. On this way, two volcanic rocks were tested to enhance the removal of a mixture of parabens by ozonation, improving their degradation. Indeed, catalytic ozonation with volcanic rock allowed total paraben degradation using a transferred ozone dose (TOD) of 55 mg/L which corresponds to a reduction of about threefold the amount of TOD comparatively with single ozonation (170 mg/L of TOD). Due to the presence of semiconductors on volcanic rock composition, the effect of UVA irradiation on paraben degradation was analyzed. The neutral and basic conditions enhanced catalytic ozonation comparatively to acid conditions. Higher pH values allowed a total methylparaben degradation with 35 mg O3/L, whereas for low pH values, 55 mg O3/L was required. The use of a radical scavenger proven that hydroxyl radicals are the main responsible for paraben degradation with catalytic ozonation. This was confirmed through the analysis of the by-products, where 4-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid (3,4-diHBA), 2,4-dihydroxybenzoic acid, and hydroquinone were quantified.


Assuntos
Radical Hidroxila/química , Ozônio/química , Parabenos/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Catálise , Conservantes Farmacêuticos , Poluentes Químicos da Água/química
13.
Environ Technol ; 39(3): 308-316, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28278089

RESUMO

A novel integrated methodology involving Fenton's process followed by ion exchange (IE) was proposed for the treatment of olive mill wastewater. Fenton's process was optimized and it was able to remove up to 81% of chemical oxygen demand when pH 3.5, reaction time 1 h, [Fe2+] = 50 mg L-1 and [Fe2+]/[H2O2] = 0.002 were applied. In spite of the potential of this treatment approach, final iron removal from the liquid typically entails pH increase and iron sludge production. The integration of an IE procedure using Lewatit TP 207 resin was found to be able to overcome this important environmental shortcoming. The resin showed higher affinity toward Fe3+ than to Fe2+. However, the iron removal efficiency of an effluent coming from Fenton's was independent of the type of the initial iron used in the process. The presence of organic matter had no significant effect over the resin iron removal efficiency. Even if some efficiency decrease was observed when a high initial iron load was applied, the adsorbent mass quantity can be easily adapted to reach the desired iron removal. The use of IE is an interesting industrial approach able to surpass Fenton's peroxidation drawback and will surely boost its full-scale application in the treatment of bio-refractory effluents.


Assuntos
Resíduos Industriais/análise , Ferro/análise , Olea , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Análise da Demanda Biológica de Oxigênio , Peróxido de Hidrogênio , Concentração de Íons de Hidrogênio , Troca Iônica , Oxirredução
14.
Environ Technol ; 39(13): 1658-1669, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28539105

RESUMO

Diclofenac (DCF) and Sulfamethoxazole (SMX) are two of the most frequently detected pharmaceutical compounds in water and are hardly removed by biological treatment systems. The presence of H2O2 was investigated in the ozonation of these two compounds. Experiments were carried out with both using distilled water and secondary effluent from a municipal wastewater treatment plant spiked with pharmaceuticals. Chemical oxygen demand (COD) abatement rate improved when H2O2 was added at the beginning of the ozonation process and when the ozone inlet concentration increased, attaining a maximum value of 91% and simultaneously a lower ozone waste for a H2O2 initial concentration of 5 mM and an ozone inlet concentration of 20 g Nm-3. For these operation conditions, the water matrix has no significant impact on SMX and DCF removal, which were totally degraded in 45 and 60 min, respectively. Nevertheless, lower COD degradation and ozone usage were obtained when the secondary effluent was used. Inorganic ions such as chloride, sulphate and nitrate and short-chain organic compounds were detected as by-products of the SMX and DCF oxidation. Vibrio fischeri luminescence inhibition tests revealed that simultaneous use of ozone and H2O2 reduced acute toxicity.


Assuntos
Diclofenaco/análise , Sulfametoxazol/análise , Poluentes Químicos da Água/análise , Peróxido de Hidrogênio , Ozônio , Eliminação de Resíduos Líquidos , Águas Residuárias , Água , Purificação da Água
15.
Sci Total Environ ; 609: 329-340, 2017 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-28753508

RESUMO

Conventional wastewater treatments are inefficient for the removal of parabens. The aim of this study was finding a suitable solution using ozone and UVA irradiation combined with TiO2 catalysts doped with different noble metals (Ag, Pt, Pd, Au). Photocatalytic ozonation required lower amounts of ozone for higher efficiency on the removal of parabens, chemical oxygen demand (COD) and total organic carbon (TOC). The best catalyst for the initial contaminants degradation was 0.5% Ag-TiO2 leading to total parabens removal using 46mgO3/L. Due to the relative low mineralization achieved, the toxicity of the treated solutions was still compared with the initial one over several species (Vibrio fischeri, Lepidium sativum and Corbicula fluminea). All the treatments applied led to a clear decrease on the toxicity compared with initial mixture of parabens. From an economical point of view, it was concluded that the presence of UVA irradiation increased the energy consumption compared with catalytic ozonation with these catalysts but it can decrease the time of reaction. From the by-products analysis, it was concluded that hydroxylation appears to be the most significant reaction pathway and the main responsible for parabens degradation.

16.
Can J Physiol Pharmacol ; 95(9): 1058-1063, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28654763

RESUMO

The application of tetraethylammonium (TEA), a blocker of voltage-dependent potassium channels, can induce long-term potentiation (LTP) in the synaptic systems CA3-CA1 and mossy fiber-CA3 pyramidal cells of the hippocampus. In the mossy fibers, the depolarization evoked by extracellular TEA induces a large amount of glutamate and also of zinc release. It is considered that zinc has a neuromodulatory role at the mossy fiber synapses, which can, at least in part, be due to the activation of presynaptic ATP-dependent potassium (KATP) channels. The aim of this work was to study properties of TEA-induced zinc signals, detected at the mossy fiber region, using the permeant form of the zinc indicator Newport Green. The application of TEA caused a depression of those signals that was partially blocked by the KATP channel inhibitor tolbutamide. After the removal of TEA, the signals usually increased to a level above baseline. These results are in agreement with the idea that intense zinc release during strong synaptic events triggers a negative feedback action. The zinc depression, caused by the LTP-evoking chemical stimulation, turns into potentiation after TEA washout, suggesting the existence of a correspondence between the observed zinc potentiation and TEA-evoked mossy fiber LTP.


Assuntos
Região CA3 Hipocampal/citologia , Fibras Musgosas Hipocampais/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Sinapses/efeitos dos fármacos , Tetraetilamônio/farmacologia , Tolbutamida/farmacologia , Zinco/metabolismo , Animais , Região CA3 Hipocampal/efeitos dos fármacos , Feminino , Canais KATP/metabolismo , Potenciação de Longa Duração/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Gravidez , Ratos , Ratos Wistar , Sinapses/metabolismo
17.
Gen Physiol Biophys ; 36(3): 289-296, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28471347

RESUMO

The hippocampal mossy fibers contain a substantial quantity of loosely-bound zinc in their glutamatergic presynaptic vesicles, which is released in synaptic transmission processes. Despite the large number of studies about this issue, the zinc changes related to short and long-term forms of potentiation are not totally understood. This work focus on zinc signals associated with chemically-induced mossy fiber synaptic plasticity, in particular on postsynaptic zinc signals evoked by KCl depolarization. The signals were detected using the medium affinity fluorescent zinc indicator Newport Green. The application of large concentrations of KCl, 20 mM and 60 mM, in the extracellular medium evoked zinc potentiations that decreased and remained stable after washout of the first and the second media, respectively. These short and long-lasting enhancements are considered to be due to zinc entry into postsynaptic neurons. We have also observed that following established zinc potentiation, another application of 60 mM KCl only elicited further enhancement when combined with external zinc. These facts support the idea that the KCl-evoked presynaptic depolarization causes higher zinc release leading to zinc influx into the postsynaptic region.


Assuntos
Potenciais da Membrana/fisiologia , Fibras Musgosas Hipocampais/fisiologia , Plasticidade Neuronal/fisiologia , Sinapses/fisiologia , Transmissão Sináptica/fisiologia , Zinco/metabolismo , Animais , Células Cultivadas , Feminino , Potenciação de Longa Duração/efeitos dos fármacos , Potenciação de Longa Duração/fisiologia , Potenciais da Membrana/efeitos dos fármacos , Fibras Musgosas Hipocampais/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Cloreto de Potássio/administração & dosagem , Ratos , Ratos Wistar , Sinapses/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos
18.
J Environ Qual ; 46(2): 436-442, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28380567

RESUMO

The discharge of poorly decontaminated winery wastewater remains a serious environmental problem in many regions, and the industry is welcoming improved treatment methods. Here, an innovative decontamination approach integrating Fenton's process with biofiltration by Asian clams is proposed. The potential of this approach was assessed at the pilot scale using real effluent and by taking an actual industrial treatment system as a benchmark. Fenton peroxidation was observed to remove 84% of the effluent's chemical oxygen demand (COD), reducing it to 205 mg L. Subsequent biofiltration decreased the effluent's COD to approximately zero, well below the legal discharge limit of 150 mg L, in just 3 d. The reduction of the effluent's organic load through Fenton's process did not decrease its toxicity toward , but the effluent was much less harmful after biofiltration. The performance of the treatment proposed exceeded that of the integrated Fenton's process-sequencing batch reactor design implemented in the winery practice, where a residence time of around 10 d in the biological step typically results in 80 to 90% of COD removal. The method proposed is effective and compatible with typical winery budgets and potentially contributes to the management of a nuisance species.


Assuntos
Análise da Demanda Biológica de Oxigênio , Resíduos Industriais , Águas Residuárias , Peróxido de Hidrogênio , Ferro , Oxirredução , Oxigênio , Eliminação de Resíduos Líquidos
19.
Sci Total Environ ; 586: 265-283, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28185729

RESUMO

Due to the shortening on natural water resources, reclaimed wastewater will be an important water supply source. However, suitable technologies must be available to guaranty its proper detoxification with special concern for the emerging pharmaceutical and personal care products that are continuously reaching municipal wastewater treatment plants. While conventional biological systems are not suitable to remove these compounds, ozone, due to its interesting features involving molecular ozone oxidation and the possibility of generating unselective hydroxyl radicals, has a wider range of action on micropollutants removal and water disinfection. This paper aims to review the studies dealing with ozone based processes for water reuse by considering municipal wastewater reclamation as well as natural and drinking water treatment. A comparison with alternative technologies is given. The main drawback of ozonation is related with the low mineralization achieved that may lead to the production of reaction intermediates with toxic features. The use of hydrogen peroxide and light aided systems enhance ozone action over pollutants. Moreover, scientific community is focused on the development of solid catalysts able to improve the mineralization level achieved by ozone. Special interest is now being given to solar light catalytic ozonation systems with interesting results both for chemical and biological contaminants abatement. Nowadays the integration between ozonation and sand biofiltration seems to be the most interesting cost effective methodology for water treatment. However, further studies must be performed to optimize this system by understanding the biofiltration mechanisms.

20.
Environ Sci Pollut Res Int ; 24(8): 7521-7533, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28116623

RESUMO

The electrochemical oxidation (EO) of phenolic wastewaters mimicking olive oil mill effluents was carried out in a batch stirring reactor using Ti/IrO2 anodes, varying the nature (NaCl and Na2SO4) and electrolyte concentration (1.8-20 g L-1), current density (57-119 mA cm-2) and initial pH (3.4-9). Phenolic content (TPh) and chemical oxygen demand (COD) removals were monitored as a function of applied charge and over time. The nature of the electrolyte greatly affected the efficiency of the system, followed by the influence of the current density. The NaCl concentration and the initial pH influenced the process in a lesser extent. The best operating conditions achieved were 10 g L-1 of NaCl, current density of 119 mA cm-2 and initial pH of 3.4. These parameters led to 100 and 84.8% of TPh and COD removal, respectively. Under these conditions, some morphological differences were observed by SEM on the surface of the anode after treatment. To study the potential toxicity of the synthetic effluent in neuronal activity, this mixture was applied to rat brain slices prior to and after EO. The results indicate that although the treated effluent causes a smaller depression of the neuronal reactive oxygen species (ROS) signal than the untreated one, it leads to a potentiation instead of recovery, upon washout. Furthermore, the purification of a real olive mill wastewater (OMW), with the organic load of the synthetic effluent, using the same optimised operating conditions, achieved total phenolic compounds abatement and 62.8% of COD removal.This study demonstrates the applicability of this EO as a pre-treatment process of a real effluent, in order to achieve the legal limit values to be discharged into natural streams regarding its organic load.


Assuntos
Técnicas Eletroquímicas/métodos , Irídio/química , Fenóis , Titânio/química , Poluentes Químicos da Água , Purificação da Água/métodos , Eletrodos , Oxirredução , Fenóis/análise , Fenóis/química , Fenóis/isolamento & purificação , Cloreto de Sódio/química , Sulfatos/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
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