Aplicação de radiação UV artificial e solar no tratamento fotocatalítico de efluentes de curtume

Tannery effluents are very dangerous for the environment since they contain large amounts of dangerous and biorecalcitrant contaminants (organic matter and Cr(VI)). This paper reports the efficiency of heterogeneous photocatalysis, based on the application of solar and artificial radiation, furnished by UV lamps, using TiO2 fixed on a flat plate, in the treatment of synthetic effluents. The results of COD and Cr(VI) demonstrate that the use of solar radiation is the most efficient way to perform the photocatalytic treatment of these effluents since a minimum removal of 62 and 61% was observed for Cr(VI) and organic matter, respectively.

1,2,3,4-Tetrahydrobenzo[h][1,6]naphthyridines as a new family of potent peripheral-to-midgorge-site inhibitors of acetylcholinesterase: synthesis, pharmacological evaluation and mechanistic studies

A series of 1,2,3,4-tetrahydrobenzo[h][1,6]naphthyridines differently substituted at positions 1, 5, and 9 have been designed from the pyrano[3,2-c]quinoline derivative 1, a weak inhibitor of acetylcholinesterase (AChE) with predicted ability to bind to the AChE peripheral anionic site (PAS), at the entrance of the catalytic gorge. Fourteen novel benzonaphthyridines have been synthesized through synthetic sequences involving as the key step a multicomponent Povarov reaction between an aldehyde, an aniline and an enamine or an enamide as the activated alkene. The novel compounds have been tested against Electrophorus electricus AChE (EeAChE), human recombinant AChE (hAChE), and human serum butyrylcholinesterase (hBChE), and their brain penetration has been assessed using the PAMPA-BBB assay. Also, the mechanism of AChE inhibition of the most potent compounds has been thoroughly studied by kinetic studies, a propidium displacement assay, and molecular modelling. We have found that a seemingly small structural change such as a double O → NH bioisosteric replacement from the hit 1 to 16a results in a dramatic increase of EeAChE and hAChE inhibitory activities (>217- and >154-fold, respectively), and in a notable increase in hBChE inhibitory activity (> 11-fold), as well. An optimized binding at the PAS besides additional interactions with AChE midgorge residues seem to account for the high hAChE inhibitory potency of 16a (IC50 = 65 nM), which emerges as an interesting anti-Alzheimer lead compound with potent dual AChE and BChE inhibitory activities.

1,2,3,4-Tetrahydrobenzo[h][1,6]naphthyridines as a new family of potent peripheral-to-midgorge-site inhibitors of acetylcholinesterase: synthesis, pharmacological evaluation and mechanistic studies

A series of 1,2,3,4-tetrahydrobenzo[h][1,6]naphthyridines differently substituted at positions 1, 5, and 9 have been designed from the pyrano[3,2-c]quinoline derivative 1, a weak inhibitor of acetylcholinesterase (AChE) with predicted ability to bind to the AChE peripheral anionic site (PAS), at the entrance of the catalytic gorge. Fourteen novel benzonaphthyridines have been synthesized through synthetic sequences involving as the key step a multicomponent Povarov reaction between an aldehyde, an aniline and an enamine or an enamide as the activated alkene. The novel compounds have been tested against Electrophorus electricus AChE (EeAChE), human recombinant AChE (hAChE), and human serum butyrylcholinesterase (hBChE), and their brain penetration has been assessed using the PAMPA-BBB assay. Also, the mechanism of AChE inhibition of the most potent compounds has been thoroughly studied by kinetic studies, a propidium displacement assay, and molecular modelling. We have found that a seemingly small structural change such as a double O → NH bioisosteric replacement from the hit 1 to 16a results in a dramatic increase of EeAChE and hAChE inhibitory activities (>217- and >154-fold, respectively), and in a notable increase in hBChE inhibitory activity (> 11-fold), as well. An optimized binding at the PAS besides additional interactions with AChE midgorge residues seem to account for the high hAChE inhibitory potency of 16a (IC50 = 65 nM), which emerges as an interesting anti-Alzheimer lead compound with potent dual AChE and BChE inhibitory activities.

1,2,3,4-Tetrahydrobenzo[h][1,6]naphthyridines as a new family of potent peripheral-to-midgorge-site inhibitors of acetylcholinesterase: synthesis, pharmacological evaluation and mechanistic studies

A series of 1,2,3,4-tetrahydrobenzo[h][1,6]naphthyridines differently substituted at positions 1, 5, and 9 have been designed from the pyrano[3,2-c]quinoline derivative 1, a weak inhibitor of acetylcholinesterase (AChE) with predicted ability to bind to the AChE peripheral anionic site (PAS), at the entrance of the catalytic gorge. Fourteen novel benzonaphthyridines have been synthesized through synthetic sequences involving as the key step a multicomponent Povarov reaction between an aldehyde, an aniline and an enamine or an enamide as the activated alkene. The novel compounds have been tested against Electrophorus electricus AChE (EeAChE), human recombinant AChE (hAChE), and human serum butyrylcholinesterase (hBChE), and their brain penetration has been assessed using the PAMPA-BBB assay. Also, the mechanism of AChE inhibition of the most potent compounds has been thoroughly studied by kinetic studies, a propidium displacement assay, and molecular modelling. We have found that a seemingly small structural change such as a double O → NH bioisosteric replacement from the hit 1 to 16a results in a dramatic increase of EeAChE and hAChE inhibitory activities (>217- and >154-fold, respectively), and in a notable increase in hBChE inhibitory activity (> 11-fold), as well. An optimized binding at the PAS besides additional interactions with AChE midgorge residues seem to account for the high hAChE inhibitory potency of 16a (IC50 = 65 nM), which emerges as an interesting anti-Alzheimer lead compound with potent dual AChE and BChE inhibitory activities.

El vehicle elèctric: té problemes de comunicació?

Something on the level of pure electric vehicle communication is failing. If the benefits are so obvious: reducing emissions, existing technology, etc., why not EV, start to lead the global sales? Whose interests may be behind it?

Les captacions d'aigua destinada al consum humà al Principat d'Andorra: Anàlisi del marc jurídic actual, definició del procediment d'autorització i sistema d'informació geogràfic sobre les captacions i els perímetres de protecció associats

RESUM L’aigua és un recurs limitat necessari per a l’establiment de qualsevol forma de vida sobre la Terra. Aquest recurs, es veu regit pel cicle hidrològic i durant les diferents fases del seu cicle, l’aigua pot ser captada per ser aprofitada per l’ésser humà. En els darrers anys, la necessitat d’aigua per a la població ha estat incrementada provocant un impacte negatiu sobre aquest recurs. Per aquest motiu sorgeix la necessitat de crear polítiques globals per protegir l’aigua que vagin encaminades a minimitzar l’efecte negatiu provocat per l’home. Tota captació d’aigua destinada al consum humà ha de garantir uns paràmetres de qualitat i per tal de poder aconseguir aquest objectiu amb eficàcia és imprescindible l’aplicació d’una eina legal molt important: els perímetres de protecció. A l’article 6 de la Llei de policia i protecció de les aigües del 31 de juliol del 1985, s’estableix que tota captació d’aigua potable haurà de quedar aïllada mitjançant un perímetre de protecció, a l’interior del qual no podrà dur-se a terme cap activitat sense prèvia autorització de Govern. Els objectius principals d’aquest estudi son recopilar la informació existent en referència a les captacions d’aigua i els seus respectius perímetres de protecció, elaborar una base de dades que pugui contenir tota la informació existent i elaborar cartografia especifica amb la finalitat de realitzar una diagnosi de la situació actual de les captacions i perímetres associats i identificar els principals riscos potencials existents en aquestes àrees. Entre les conclusions mes rellevants obtingudes amb aquest treball, cal destacar que s’ha constatat que algunes activitats antròpiques potencialment contaminants es troben situades en zones properes a les captacions destinades a consum humà, inclòs dins dels seus perímetres de protecció, amb el conseqüent risc que aquesta situació comporta.

2-fenilbenzotriazóis (PBTA): uma nova classe de contaminantes ambientais

This work is a literature review of PBTAs, the phenylbenzotriazoles generated from the reduction and chlorination of azo dyes. The PBTAs and the non- chlorinated PBTAs were isolated for the first time from river blue rayon organic extracts that showed high mutagenic activity in the Salmonella/microsome genotoxicity assay. To date, 8 PBTAs have been identified and beside their mutagenic activity in bacteria they cause genotoxic effects in fish and mammalian cell cultures. Due to the large number of textile dyeing facilities in Brazil, studies to determine them in the aquatic environment seem to be relevant.

Efeito dos dióxidos de enxofre e de nitrogênio no desempenho de uma célula a combustível de membrana de intercâmbio de prótons

There is presently much interest in the clean and efficient generation of energy by proton exchange membrane fuel cells (PEMFC), using hydrogen as fuel. The generation of hydrogen by the reforming of other fuels, anaerobic fermentation of residual waters and other methods, often produce contaminants that affect the performance of the cell. In this work, the effect of gaseous SO2 and NO2 on the performance of a H2/O2 single PEMFC is studied. The results show that SO2 decreases irreversibly the performance of the cell under operating conditions, while NO2 has a milder effect that allows the recovery of the system.

Treatment of oily wastewater by ultrafiltration: The effect of different operating and solution conditions

In many industries, such as petroleum production, and the petrochemical, metal, food and cosmetics industries, wastewaters containing an emulsion of oil in water are often produced. The emulsions consist of water (up to 90%), oils (mineral, animal, vegetable and synthetic), surfactants and other contaminates. In view of its toxic nature and its deleterious effects on the surrounding environment (soil, water) such wastewater needs to be treated before release into natural water ways. Membrane-based processes have successfully been applied in industrial applications and are considered as possible candidates for the treatment of oily wastewaters. Easy operation, lower cost, and in some cases, the ability to reduce contaminants below existing pollution limits are the main advantages of these systems. The main drawback of membranes is flux decline due tofouling and concentration polarisation. The complexity of oil-containing systems demands complementary studies on issues related to the mitigation of fouling and concentration polarisation in membranebased ultrafiltration. In this thesis the effect of different operating conditions (factors) on ultrafiltration of oily water is studied. Important factors are normally correlated and, therefore, their effect should be studied simultaneously. This work uses a novel approach to study different operating conditions, like pressure, flow velocity, and temperature, and solution properties, like oil concentration (cutting oil, diesel, kerosene), pH, and salt concentration (CaCl2 and NaCl)) in the ultrafiltration of oily water, simultaneously and in a systematic way using an experimental design approach. A hypothesis is developed to describe the interaction between the oil drops, salt and the membrane surface. The optimum conditions for ultrafiltration and the contribution of each factor in the ultrafiltration of oily water are evaluated. It is found that the effect on permeate flux of the various factors studied strongly depended on the type of oil, the type of membrane and the amount of salts. The thesis demonstrates that a system containing oil is very complex, and that fouling and flux decline can be observed even at very low pressures. This means that only the weak form of the critical flux exists for such systems. The cleaning of the fouled membranes and the influence of different parameters (flow velocity, temperature, time, pressure, and chemical concentration (SDS, NaOH)) were evaluated in this study. It was observed that fouling, and consequently cleaning, behaved differently for the studied membranes. Of the membranes studied, the membrane with the lowest propensity for fouling and the most easily cleaned was the regenerated cellulose membrane (C100H). In order to get more information about the interaction between the membrane and the components of the emulsion, a streaming potential study was performed on the membrane. The experiments were carried out at different pH and oil concentration. It was seen that oily water changed the surface charge of the membrane significantly. The surface charge and the streaming potential during different stages of filtration were measured and analysed being a new method for fouling of oil in this thesis. The surface charge varied in different stages of filtration. It was found that the surface charge of a cleaned membrane was not the same as initially; however, the permeability was equal to that of a virgin membrane. The effect of filtration mode was studied by performing the filtration in both cross-flow and deadend mode. The effect of salt on performance was considered in both studies. It was found that salt decreased the permeate flux even at low concentration. To test the effect of hydrophilicity change, the commercial membranes used in this thesis were modified by grafting (PNIPAAm) on their surfaces. A new technique (corona treatment) was used for this modification. The effect of modification on permeate flux and retention was evaluated. The modified membranes changed their pore size around 33oC resulting in different retention and permeability. The obtained results in this thesis can be applied to optimise the operation of a membrane plant under normal or shock conditions or to modify the process such that it becomes more efficient or effective.

Predição da demanda química de oxigênio em chorume maduro contendo reagente de Fenton, por meio de modelo matemático empírico gerado com planejamento fatorial completo

COD is an important parameter to estimate the concentration of organic contaminants. The closed system technique with the use of K2Cr2O7 is the most important one, however, it has the inconvenience to suffer positive chemical interferences from inorganic compounds such as Fe2+ and H2O2 (not enough reported in the literature). This paper considers a statistical-experimental set capable to validate a empirical mathematical model generated from a 23 experimental design, in the presence of Fe2+ and H2O2. The t test shows that mathematical model has 99,99999% confidence degree and the experimental validation test indicates absolute mean error of 4,70%.

Elementos-traço e sódio em suco de uva: aspectos nutricionais e toxicológicos

Eight trace elements were determined in 20 Brazilian brands of grape juice, distributed over the country. Highest measured concentrations (As: 0.016; Cd: 0.010; Cr: 0.060; Cu: 1.28; Ni: 0.032; Pb: 0.016; Sb: 0.0040 and Zn: 1.44 mg L-1) comply with Brazilian maximal tolerance levels for inorganic contaminants (As: 0.5; Cd: 0.5; Cr: 0.1; Cu: 30; Ni: 3; Pb: 0.4; Sb: 1 and Zn: 25 mg L-1). Determination of arsenic species has shown inorganic As(V) as predominant in most samples. Sodium concentrations, nowadays a major public health concern, were also measured, showing an average of 149 mg L-1. Analytical results for this element were much higher than label concentrations, showing the need for better quality control.

Síntese de poliestireno sulfonado para aplicações no tratamento de água produzido a partir de copos e bandejas descartadas de poliestireno

In the present paper, the use of poly(styrene sulfonate) (PSS), produced from discarded polystyrene materials through heterogeneous and homogeneous processes, was investigated. The use of PSS for water treatment, using a kaolin suspension as wastewater model, reduced water turbidity for all the employed materials when compared to the blank analysis, without PSS. The most efficient polyelectrolyte was PSS cups obtained by homogeneous route. The same behavior was observed for real system. The homogeneous PSS cups showed a balance between a moderate molecular weight and high anionic character that improved flocks formation and water removal turbidity.

Formação de micelas mistas entre o sal biliar colato de sódio e o surfactante aniônico dodecanoato de sódio

Mixed-micelle formation between sodium chlolate (NaC) and the anionic surfactant sodium dodecanoate (SDoD) in Tris-HCl buffer solutions, pH 9.00, varying the molar fraction of the surfactants, was investigated by means of electrical conductivity and steady-state fluorescence of pyrene. The critical micelar concentration (cmc) was measured from the equivalent conductance versus the square root of the molar surfactant concentration plots and the regular solution theory (RST) was used to predict the mixing behavior. The I1/I3 pyrene ratio-surfactant concentration plots were used as an additional technique to follow the behavior and the changes in the micropolarity of the mixed micelles.

Quimiossensores cromogênicos e fluorogênicos para a detecção de analitos aniônicos

The detection of anionic species is a field which is currently attracting increasing interest. Research is carried out not only to gain a better understanding of biological events that anions participate in, but also to ascertain the potential contribution of the anionic chemosensors to the qualitative and quantitative analysis of species of interest in the areas of industry, medicine, the environment, and chemistry. This review summarizes several aspects related to the main strategies used in anion sensing. Each strategy discussed is illustrated with its potential applications citing recent examples. The prospects for their use in several areas are also described.

Degradação de fármacos residuais por processos oxidativos avançados

The concern about aquatic ecosystems and the potential risk of drinking water contamination by pharmaceuticals have stimulated the study of processes for the efficient degradation of these contaminants, since the conventional treatment have been inefficient on that purpose. The advanced oxidation processes (AOPs) appear as viable alternatives due to their efficiency on the degradation of different classes of organic contaminants. This review presents an overview of the main AOP (O3, H2O2/UV, TiO2/UV, Fenton and photo-Fenton) which have been applied to the degradation of different pharmaceuticals. The main results obtained, intermediates identified and toxicity data are presented.