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Tratamento de fenol em reator anaeróbio horizontal de leito fixo (RAHLF) sob condições mesofílicas / Phenol degradation in horizontal-flow anaerobic immobilized biomass (HAIB) reactor under mesophilic conditionsMaria Lyda Bolaños Rojas 20 April 2001 (has links)
Um reator anaeróbio horizontal de leito fixo foi operado a escala de laboratório, visando verificar sua capacidade de degradação de fenol. O RAHLF foi construído em vidro de borosilicato com 100 cm de comprimento e 5,04 cm de diâmetro, preenchido com lodo anaeróbio imobilizado em matrizes de espuma de poliuretano. Prévio à realização do experimento o reator foi operado com substrato sintético, contendo como fontes de carbono glicose, ácido acético e ácido fórmico, atingida a estabilização da matéria orgânica para uma carga orgânica de 1028 mg/L, correspondente a uma remoção de DQO de 98%, foi iniciada a adição de fenol começando com uma concentração de 50 mg/L como única fonte de carbono. A concentração de fenol adicionada variou de 50 a 1200 mg/L e sua degradação foi avaliada através de determinação cromatográfica, utilizando cromatografia gasosa e parâmetros físico-químicos como pH, ácidos voláteis, alcalinidade e DQO. O RAHLF foi operado com um tempo de detenção hidráulica (TDH) de 12,3 horas. Com 50 mg/L, após 33 dias o reator atingiu uma remoção de fenol de 97%. Com 100 mg/L e depois de 148 dias de operação não foi detectado fenol no efluente do reator. Com 300 mg/L e após 58 dias de operação o reator apresentou 99% de remoção e uma concentração no efluente de 0,85 mg/L. Com 600 mg/L, 900 mg/L e 1200 mh/L, após 47, 29 e 7 dias de operação o reator alcançou remoções de 99%. Em todas as concentrações foi observado o predomínio de Methanosaeta, Methanobacterium e cocosmetanogênicos. Em relação à bactéria oxidadora de fenol foi observado o predomínio de coco-bacilos. As altas remoções de fenol observadas neste trabalho são devidas provavelmente à utilização de células imobilizadas. / A bench-scale horizontal-flow anaerobic immobilized biomass (HAIB) reactor was assayed aiming to verify its potential use for phenol degradation. The HAIB reactor consisted of a bore-silicate tube (100 cm long; 5.04 cm diameter) filled with polyurethane foam matrices containing immobilized anaerobic sludge. Before being subjected to phenol, the reactor was fed with synthetic substrate at the influent chemical oxygen demand (COD) of 1,028 mg/L achieving 98% of COD removal efficiency. Thereafter, phenol as the sole carbon source was added under step-increasing concentrations from 50 to 1,200 mg/L. Phenol degradation was evaluated by gas chromatographic analysis of influent and effiuent samples. Process monitoring included determinations of pH, volatile acids, alkalinity and COD. The HAIB reactor was operated at a constant hydraulic detention time (HDT) of 12,3 hours. After 33 days with 50 mg/L of phenol in the influent, the reactor achieved 97% of phenol removal efficiency. Successful phenol degradation (efficiency removal of 99%) occurred for influem concentrations of 100, 300, 600, 900 and 1,200 mg/L after 148, 58, 47, 29 and 7 days, respectively. The predominance of Methanosaeta, Methanobacterium and methanogenic cocci could be observed in all the operating conditions, besides the presence of phenol-oxidizing microorganisms as irregular rods. The results indicate that phenol degradation at very high rates can be accomplished in HAIB reactors containing acclimatized biomass.
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Metab?litos especiais isolados de folhas e galhos de Ouratea ferruginea Engl. (Ochnaceae).Fidelis, Queli Cristina 25 February 2011 (has links)
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Previous issue date: 2011-02-25 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico, CNPq, Brasil. / This work describes the phytochemical study of the stems and leaves of Ouratea
ferruginea Engl., Ochnaceae. The material for study was collected in the campus of Embrapa
in Bel?m, Par? state, and identified by Dra Silvane Taveres Rodrigues. The compounds
described in this phytochemistry investigation were isolated by the solvents partition and
chromatographyc techniques of the extracts obtained by maceration at room temperature with
hexane, ethyl acetate and methanol. The structures were determined through analysis of data
provided by IR, 1H and 13C NMR (1D an 2D techniques), mass spectrometry including GCMS
and HPLC-MS of natural compounds and some derivatives. From the stem
dichloromethane extract friedelin, friedelinol, sitosterol, stigmasterol, campesterol, 3-b-O-Dglucopyranosyl-
stigmasterol, 2,6-dimethoxy?benzoquinine, 2,6-dimethoxy-hydroquinone, the
isoflavones: 5,4'-dihydroxy-7,3',5'-trimethoxy-isoflavone, 5-hydroxy-7,3',4',5'-tetramethoxyisoflavone,
5,4'-dihydroxy-7,3'-dimethoxy-isoflavone, 7,5-dihydroxy-3',4',5'-trimethoxyisoflavone,
7,5,4?-trihydroxy-3?,5?-dimethoxy-isoflavone, and ferulic and syringic aldehyde
were isolated. From the dichloromethane partition of the methanol extract of the stem vanillic
acid, 4 ((1E)-3-hydroxy-1-propenyl)-2-methoxyphenol and 3,5-dimethoxy-4-hydroxydihydrocinamaldehyde
were isolated. From hexane fraction of methanol extract from the
leaves lupeone was isolated, and from the dichloromethane methanol partition were identified
the biflavonoids amentoflavone and 7-methyl-amentoflavone, known as sequoiaflavone,
along with syringic acid. From the ethyl acetate of the methanol extracts partition the
epicatechin which absolute configuration was defined by circular dichroism spectral analysis
was isolated. The sequioflanove is been identified in Ochnaceae for the first time. From the
polar fraction the total phenol were determined by adapted Folin-Denis and precipitation with
casein methods and by NMR spectral analysis. / Este trabalho descreve o estudo fitoqu?mico de caule e folhas da esp?cie vegetal
Ouratea ferruginea Engl, Ochnaceae. O material para estudo foi coletado no campus da
Embrapa em Bel?m do Par? e identificado pela Dra Silvane Tavares Rodrigues. As
subst?ncias descritas nesta investiga??o fitoqu?mica foram isoladas atrav?s de parti??o com
solventes e t?cnicas cromatogr?ficos de extratos obtidos atrav?s de macera??o a frio com
hexano, acetato de etila e metanol. As estruturas foram determinadas atrav?s da an?lise de
dados fornecidos por espectrometria na regi?o do infravermelho, RMN 1H e 13C (t?cnicas 1D
e 2D), de massas incluindo CG-EM e CLAE-EM das subst?ncias naturais e de alguns
derivados. Do extrato em diclorometano do caule foram isolados friedelina, friedelinol,
sitosterol, estigmasterol, campesterol, 3-b-O-D-glicopiranosil-estigmasterol, 2,6-dimetoxi
benzoquinona, 2,6-dimetoxi hidroquinona, as isoflavonas 5,4?-diidroxi-7,3?,5?-trimetoxiisoflavona,
5,4?-diidroxi-7,3?-dimetoxi-isoflavona, 5-hidroxi-7,3?,4?,5?-tetrametoxiisoflavona,
7,5-diidroxi-3?,4?,5?-trimetoxi-isoflavona, 7,5,4?-triidroxi-3?,5?-dimetoxiisoflavona,
al?m dos alde?dos sir?ngico e fer?lico. Da parti??o em diclorometano do extrato
metan?lico do caule foram isolados ?cido van?lico, 4((1E)-3-hidroxi-1-propenil)-2-
metoxifenol e 3,5-dimetoxi-4-hidroxi-diidrocinamalde?do. Das folhas foi isolada a lupeona na
parti??o em hexano do extrato metan?lico; e na parti??o em diclorometano foram
identificados os biflavon?ides amentoflavona e 7-metil-amentoflavona, conhecida como
sequoiaflavona, e o ?cido sir?ngico. Na parti??o em acetato de etila foi isolado a epicatequina
cuja configura??o absoluta foi definida com an?lise do espectro de dicro?smo circular. A
sequioflavona est? sendo registrada pela primeira vez em Ochnaceae. Das fra??es polares
foram determinados o teor de fen?is totais e taninos por m?todos de Folin-Denis e
precipita??o com case?na, adaptados, al?m de an?lise com espectros de RMN.
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Proton-Coupled Electron Transfer from Hydrogen-Bonded PhenolsIrebo, Tania January 2010 (has links)
Proton-coupled electron transfer (PCET) is one of the elementary reactions occurring in many chemical and biological systems, such as photosystem II where the oxidation of tyrosine (TyrZ) is coupled to deprotonation of the phenolic proton. This reaction is here modelled by the oxidation of a phenol covalently linked to a Ru(bpy)32+-moitey, which is photo-oxidized by a laser flash-quench method. This model system is unusual as mechanism of PCET is studied in a unimolecular system in water solution. Here we address the question how the nature of the proton accepting base and its hydrogen bond to phenol influence the PCET reaction. In the first part we investigate the effect of an internal hydrogen bond PCET from. Two similar phenols are compared. For both these the proton accepting base is a carboxylate group linked to the phenol on the ortho-position directly or via a methylene group. On the basis of kinetic and thermodynamic arguments it is suggested that the PCET from these occurs via a concerted electron proton transfer (CEP). Moreover, numerical modelling of the kinetic data provides an in-depth analysis of this CEP reaction, including promoting vibrations along the O–H–O coordinate that are required to explain the data. The second part describes the study on oxidation of phenol where either water or an external base the proton acceptor. The pH-dependence of the kinetics reveals four mechanistic regions for PCET within the same molecule when water is the base. It is shown that the competition between the mechanisms can be tuned by the strength of the oxidant. Moreover, these studies reveal the conditions that may favour a buffer-assisted PCET over that with deprotonation to water solution.
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Topical anesthesia of the tympanic membrane : an experimental animal studySchmidt, Sten-Hermann January 1987 (has links)
Myringotomy plays an important role in otological therapy. The procedure requires an efficient anesthesia, which can be obtained without general anesthesia. However, the use of local anesthetics on the tympanic membrane (TM) has been abandoned in many places, as general anesthesia has been readily available. In the present study the effects of some commonly used topical anesthetics on the TM structure and inner ear were tested in an animal model (rat and guinea pig).Four different anesthetic compounds—Xylocaine®, Bonain's liquid, phenol and Emla®—were applied to the TMs of the animals, which were sacrificed 10 minutes to 5 months after application. Morphological effects regarding time after treatment and number of applications were elucidated. At sacrifice the tissue was fixed and the TMs analysed by light microscopy (LM) and transmission electron microscopy (TEM). In nine animals phenol, Xylocaine® Spray or Emla® was applied to the round window niche and ABR recordings were made at 24 h to 6 months after exposure. After the final ABR evaluation the animals were sacrificed and the cochleae prepared for LM and scanning electron microscopy (SEM).On the TM phenol and Bonain's liquid caused instant destruction of the keratinizing stratified squamous epithelium followed by long-lasting hyperplasia of this epithelium and the underlying connective tissue. A pronounced hyperplasia of these two layers was also noted for the Xylocaine® Spray group, but without immediate destruction of the keratinizing epithelium. The extent of structural changes differed in relation to the extent of spreading of the agent. Emla® showed little, if any, sign of epithelial reaction and had no effect on the connective tissue. Regarding the inner ear Emla®, Xylocaine® Spray and phenol induced significantly impaired ABR thresholds mainly affecting the higher frequencies. However, the impaired ABR thresholds were reversible and at the end of the experiment there was no significant impairment compared to the control data. All agents, except Xylocaine®, damaged the hair cells in the basal part of the cochlea as shown by cytocochleogram and SEM analysis.Instant destruction of the epidermis seems to be necessary for an instant anesthetic effect. All agents caused profound connective tissue reactions. The manner of application, depending on the physical properties of the agent, determined the extent of the structural changes. The changes of the connective tissue were concentrated to the submucosal layer, which seems to be the area for reconstruction of the damaged TM. All agents caused functional inner ear changes. With the exception of Xylocaine® they also caused morphological alterations of the cochlea. The functional changes were partly reversible. Topical anesthetics applied to the TM should be used with caution and when used in an appropriate manner they can be considered safe, especially in an inflamed middle ear, with a thickened round window membrane, which should prevent the agents from reaching the inner ear structures. / digitalisering@umu
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Mejoras en el tratamiento de lixiviados de vertedero de RSU mediante procesos de oxidación avanzada.Primo Martínez, Oscar 21 November 2008 (has links)
Esta tesis doctoral está dirigida a la investigación y desarrollo de Procesos de Oxidación Avanzada (POAs), los cuales basan su capacidad en la generación in-situ de radicales hidroxilo (OH·), especie capaz de oxidar muchos compuestos orgánicos. Esta propiedad es aprovechada para conseguir la completa mineralización de los contaminantes o su degradación en sustancias más fácilmente biodegradables.Se plantean dos grandes objetivos:1) Contribuir al conocimiento científico a través del análisis y modelado del proceso UV/H2O2 aplicado a la degradación y mineralización de fenol. Para ello, se ha realizado una planificación experimental dirigida a estudiar la influencia de las variables de operación sobre parámetros globales del proceso, como el contenido total de materia orgánica o la toxicidad.2) Desarrollar una alternativa eficaz para la eliminación de materia orgánica de corrientes residuales de escasa biodegradabilidad mediante la aplicación de POAs. Se ha seleccionado el tratamiento de lixiviados de vertedero de residuos sólidos urbanos (RSU) como caso de estudio y se ha realizado un análisis comparativo de los procesos Fenton y foto-Fenton. Los experimentos se han realizado tanto a escala de laboratorio como a escala de planta piloto. / The aim of this thesis is the research and development of Advanced Oxidation Processes (AOPs). AOPs are based on the in-situ generation of hydroxyl radicals (OH·). These radicals are able to oxidize many organic compounds with high oxidation rates but in a non-selective way. This is useful to achieve the complete mineralization of the pollutants or its degradation into more easily biodegradable compounds.Two main objectives have been pursued in this thesis:1) To contribute to the scientific knowledge of the UV/H2O2 process through its analysis and modelling. Phenol degradation has been selected as a case of study. An experimental planning was established to study the influence of process variables on parameters such as total organic matter concentration and ecotoxicity.2) Research on new alternative treatments for suitable organic matter removal from recalcitrant waste effluents by AOPs. As study case, the leachate remediation from a municipal solid wastes landfill was selected. Fenton and photo-Fenton processes were compared and the operational conditions to achieve the maximum organic matter reduction and colour removal have been determined. Both laboratory scale and pilot plant experiments were carried out.
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Desenvolupament de mètodes de determinació de compostos fenòlics en aigües i sòls. Caracterització dels processos d'adsorció en diferents tipus de sòls.Sirvent Masias, Gemma 22 April 2005 (has links)
El desenvolupament de mètodes d'anàlisi de compostos fenòlics és una pràctica habitual en molts laboratoris des de l'establiment de mesures legislatives de control de les concentracions d'aquestes substàncies en el medi ambient. Les tècniques cromatogràfiques representen la primera opció per a la determinació de la major part de compostos orgànics, en els que s'inclouen els fenols. Aquests, per les seves propietats de volatilitat i polaritat, poden analitzar-se emprant tant la cromatografia líquida com la cromatografia de gasos i aquesta dualitat s'ha aplicat en aquest treball. / Phenols form a heterogenic compound family that has been found to have a detrimental effect on human health and to alter the taste and odour of water. Given the production of these contaminating compounds has increased considerably, both the EU and the EPA have established limits for the presence in the environment. The strictness of this legislation has made it necessary to develop more sensitive analytical methods to allow the detection of phenols at trace levels and to monitor their distribution in the different environmental contexts in which they are found.
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Influence of pH and NOM on Sorption of Phenols onto Aquifer MaterialAmiri, Fariba 02 March 2005 (has links) (PDF)
Geosorption processes play an important role as retardation mechanism in subsurface transport of organic water constituents. Geosorption behaviour of Ionisable Hydrophobic Organic compounds (IHOCs) especially influence of dissolved natural organic materials on their sorption coefficients is poorly investigated. In this study influence of pH and NOM on the sorption of three different phenols (2-methyl-4,6-dinitrophenol, 2,4,6-trichlorophenol and pentachlorophenol) on a natural sandy aquifer material collected from a bank filtration site was studied in flow through column experiments. In first step the sorption coefficients of investigated phenols from NOM-free solutions with different pH values were determined. Single as well as multi (mixed) solutes experiments confirmed that there was no competition effect among the phenols investigated. An increasing sorption/retardation was observed with decreasing pH. A linear model was used to resolve the apparent sorption coefficient into an ionised species and neutral species component. This model allows a prediction of apparent sorption coefficients for any pH value. Analysis of data also revealed that the anion of 2-M-4,6-DNP show no significant sorption and a simple model based on the neutral form sorption coefficient was useful in predicting the apparent sorption coefficient over the entire pH range investigated. For 2,4,6-TCP and PCP, the anion sorption is much lower than that of the neutral species but cannot be neglected completely. For PCP, the anion sorption is even as high as the sorption of neutral 2,4,6-TCP. Thus for such hydrophobic phenols prediction of sorption based only on the partitioning of non-dissociated species may lead to an error, especially at high pH values (> pKa), where ionised form is present predominantly. On the other hand prediction of sorption based on the partitioning of non-dissociated species is useful at pH < pKa or in cases where the anion sorption can be neglected. The advantage of this prediction is that it allows predicting the pH-dependent sorption only on the basis of LFER correlations. It was shown that the organic carbon normalized sorption coefficients of the neutral forms of the phenols can be predicted better by solubility based regression correlations than by n-octanol-water partition coefficient based correlations. In second step the apparent sorption coefficients of investigated phenols from NOM-containing solutions (mixed solution of phenols dissolved in natural river water) with different pH values were determined; the sorption coefficients obtained from this step were compared with the results of the first step examinations. Analysis of data revealed that binding of 2-M-4,6-DNP by dissolved humic substances (DHS) reduces the sorption coefficient significantly. In contrast to it, the sorption of the more hydrophobic chlorinated phenols was not affected by DHS. A strong reduction of sorption onto aquifer material caused by complex formation with DHS was also observed for a second nitrophenol (2,4-DNP) and seems to be typically for nitrophenols. A combined sorption and complex formation model was proposed which could be used successfully to describe the effect of pH and NOM concentration on sorption reduction and to estimate binding constants. The binding constant found for 2-M-4,6-DNP is much higher than those reported by Ohlenbusch and Frimmel, 2001, for chlorophenols associated with Aldrich humic acid. This can be interpreted as a result of specific interactions between the nitrophenol and DHS. This phenomenon may cause an increase of the amount of nitrophenols, which can be transported with the groundwater flow and has to be considered in transport modelling, especially in cases where pH is lower than pKa. The models developed here are a useful tool to describe the influence of pH and NOM on geosorption processes and to estimate the Kd values which have to be used in transport models.
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Rubber Toughening Of Phenolic Resin By Using Nitrile Rubber And Amino SilaneCagatay, Onur 01 July 2005 (has links) (PDF)
The aim of this study was to investigate rubber toughening of resol type phenol-formaldehyde resin. For this purpose, phenolic resin was first modified by only acrylonitrile butadiene rubber, and then by using nitrile rubber together with 3-aminopropyltriethoxysilane.
Test specimens were prepared by mixing and casting of liquid phenolic resin in three groups. In the first one, neat phenolic resin specimens were produced. In the second group, phenolic resin was modified with 0.5, 1, 2, and 3 wt.% nitrile rubber, while in the last group modification was carried out by using 0.5 wt.% nitrile rubber together with 1, 2, and 4wt.% amino silane (with respect to nitrile rubber). All specimens were heat cured in the oven.
In order to observe behaviors of the specimens, Three-Point Bending, Charpy Impact, Plane-Strain Fracture Toughness, and Dynamic Mechanical Analysis tests were conducted according to the related ISO standards for all specimens groups. Scanning Electron Microscopy was also used for the fractographic analysis of some samples.
It can be concluded that, although there were problems in mixing and casting of liquid resol type phenolic resin, its toughness could be improved by using nitrile rubber and amino silane. Modification by using nitrile rubber and amino silane together was much more effective than by using only nitrile rubber. In this synergistic case for instance, Charpy impact strength and fracture toughness values of the neat phenolic specimens were increased 63% and 50%, respectively. SEM studies indicated that the main rubber toughening mechanism was shear yielding observed as deformation lines especially initiated at the domains of nitrile rubber and amino silane.
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Uso de argilominerais e diatomita como adsorvente de fen?is em ?guas produzidas na ind?stria de petr?leoBraga, Renata Martins 06 October 2008 (has links)
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Previous issue date: 2008-10-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The oil production in Brazil has been increasing each year. Consequently, increasing volumes of water produced are generated with large quantities of contaminants, which brings many problems in disposing of these waters. The concern that the concentrations of contaminants in water produced meet existing laws for disposal of effluents, has been extremely important for the development of different techniques for treatment of water produced. The study of clay minerals as adsorbents of organic contaminants has grown considerably so in order to combine the low cost with the efficiency of environmental preservation and health issues. Thus, this study aims to understand the characteristics of vermiculite clay, sodium bentonite, calcium bentonite and diatomite and evaluate their performance as adsorbents for phenol in the water produced. Through adsorption isotherms it was possible to observe the behavior of these adsorptive clay and diatomite for adsorption of phenol, the main phenolic compound found in water produced. Different concentrations of synthetic solutions of phenol were put in touch with these adsorbents under same conditions of agitation and temperature. The adsorbents were composted adsorptive favorable, but the vermiculite and diatomite showed little capacity for absorption, being suggested for absorbs small concentrations of phenol in the balance isothermal / A produ??o de petr?leo no Brasil vem aumentando a cada ano. Em conseq??ncia, volumes crescentes de ?gua de produ??o s?o gerados com grandes quantidades de contaminantes, o que traz v?rios problemas no descarte dessas ?guas. A preocupa??o para que as concentra??es dos contaminantes da ?gua produzida atendam as legisla??es vigentes para descarte de efluentes, tem sido extremamente importante para o desenvolvimento de diferentes t?cnicas de tratamentos da ?gua produzida. O estudo de argilominerais como adsorventes de contaminantes org?nicos tem crescido de forma consider?vel, a fim de se aliar o baixo custo com a efici?ncia da preserva??o ambiental e sa?de publica. Assim, este trabalho
tem como objetivo conhecer as caracter?sticas dos argilominerais vermiculita, bentonita s?dica, bentonita c?lcica e da diatomita e avaliar seus desempenhos como adsorventes de
fen?is na ?gua produzida. Atrav?s das isotermas de adsor??o p?de-se abservar os comportamentos adsortivos desses argilominerais e da diatomita para adsor??o do fenol,
principal composto fen?lico encontrado na ?gua produzida. Diferentes concentra??es de solu??es sint?ticas de fenol foram postas em contato com estes adsorventes sob agita??o e mesmas condi??es de temperatura. Os adsorventes apresentaram comportamento adsortivo favor?vel, por?m a vermiculita e diatomita apresentaram pequena capacidade de adsor??o, sendo sugeridas para adsorver pequenas concentra??es de fenol no equil?brio isot?rmico
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Estudo de reatores eletroqu?micos para remo??o de Cu2+ , Zn2+, Fenol e BTEX em ?gua produzidaRamalho, Adriana Margarida Zanbotto 01 August 2008 (has links)
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Previous issue date: 2008-08-01 / The production of water has become one of the most important wastes in the petroleum industry, specifically in the up stream segment. The treatment of this kind of effluents is complex and normally requires high costs. In this context, the electrochemical treatment emerges as an alternative methodology for treating the wastewaters. It employs electrochemical reactions to increase the capability and efficiency of the traditional chemical treatments for associated produced water. The use of electrochemical reactors can be effective with small changes in traditional treatments, generally not representing a significant additional surface area for new equipments (due to the high cost of square meter
on offshore platforms) and also it can use almost the same equipments, in continuous or batch flow, without others high costs investments. Electrochemical treatment causes low environmental impact, because the process uses electrons as reagent and generates small amount of wastes. In this work, it was studied two types of electrochemical reactors: eletroflocculation and eletroflotation, with the aim of removing of Cu2+, Zn2+, phenol and BTEX mixture of produced water. In eletroflocculation, an electrical potential was applied
to an aqueous solution containing NaCl. For this, it was used iron electrodes, which promote the dissolution of metal ions, generating Fe2+ and gases which, in appropriate pH, promote also clotting-flocculation reactions, removing Cu2+ and Zn2+. In eletroflotation, a
carbon steel cathode and a DSA type anode (Ti/TiO2-RuO2-SnO2) were used in a NaCl solution. It was applied an electrical current, producing strong oxidant agents as Cl2 and HOCl, increasing the degradation rate of BTEX and phenol. Under different flow rates, the
Zn2+ was removed by electrodeposition or by ZnOH formation, due the increasing of pH during the reaction. To better understand the electrochemical process, a statistical protocol factor (22) with central point was conducted to analyze the sensitivity of operating
parameters on removing Zn2+ by eletroflotation, confirming that the current density affected the process negatively and the flow rate positively. For economical viability of these two electrochemical treatments, the energy consumption was calculated, taking in account the kWh given by ANEEL. The treatment cost obtained were quite attractive in comparison with the current treatments used in Rio Grande do Norte state. In addition, it could still be reduced for the case of using other alternative energy source such as solar, wind or gas generated directly from the Petrochemical Plant or offshore platforms / A produ??o de ?gua tem sido a maior corrente de res?duos da ind?stria do petr?leo no segmento de Explora??o e Produ??o E&P. O tratamento deste efluente al?m de ser complexo, requer um alto custo. Neste contexto, surge o tratamento eletroqu?mico como uma metodologia alternativa que empregando rea??es de eletr?lise possibilita aumentar a capacidade e a efici?ncia do tratamento f?sico-qu?mico tradicional da ?gua produzida. A implanta??o de reatores eletroqu?micos pode ser efetivada com pequena modifica??o numa esta??o de tratamento tradicional, sem demandar ?rea significativa (tendo em vista o alto custo do metro quadrado nas plataformas em alto mar), aproveitando os equipamentos existentes, podendo realizar tratamento cont?nuo ou em bateladas, sem a necessidade de investimentos elevados. O tratamento eletrol?tico causa baixo impacto ambiental, pois o processo utiliza el?trons como reagente e gera poucos res?duos. Neste trabalho foram estudados dois tipos de reatores eletroqu?micos: um eletrofloculador e um eletroflotador, tendo como objetivo a remo??o de Cu2+, Zn2+ , fenol e BTEX presentes na ?gua produzida.
No eletrofloculador aplicou-se um potencial el?trico a uma solu??o aquosa contendo NaCl, atrav?s de eletrodos de ferro, que promovendo a dissolu??o deste metal com a gera??o de ?ons Fe2+ e gases que em pH apropriado formou rea??es de coagula??o-flocula??o removendo Cu2+ e Zn2+. No eletroflotador utilizou-se c?todo de a?o carbono e ?nodo do tipo DSA de Ti/TiO2-RuO2-SnO2, em solu??o contendo NaCl, que atrav?s de uma corrente
el?trica produziu agentes oxidantes fortes como Cl2 e HOCl que ajudaram a degradar o BTEX e fenol em diferentes vaz?es; o Zn2+ foi removido por eletrodeposi??o ou pela forma??o de ZnOH devido ao aumento de pH durante a rea??o. Para compreender o
processo eletroqu?mico foi realizado um planejamento fatorial 22 com ponto central para avaliar a sensibilidade dos par?metros operacionais que influenciaram no processo de remo??o de Zn2+ na eletroflota??o, de forma que a densidade de corrente influenciou positivamente e a vaz?o negativamente. Como indicador da viabilidade econ?mica do tratamento eletroqu?mico foram analisados os consumos energ?ticos dos reatores tomando como base o valor kWh cobrado pela ANEEL. Os custos dos tratamentos desta pesquisa foram mais atrativos quando comparados ao utilizado atualmente no Rio Grande do Norte, podendo ser reduzidos caso seja utilizada fontes de energia alternativas, como solar, e?lica
ou a g?s gerada no pr?prio P?lo Petroqu?mico ou plataformas
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