Avaliação do comportamento de argila ativada na presença de água destilada, soluções salinas e inibidores de hidratação catiônicos

The clay swelling is today one of the major problems during the well drilling. Nearly 50% of clays that constitute shale expand easily in the presence of water molecules. During the drilling of a geological formation containing swelling clays, when is feasible the use of water base fluids, it is necessary to apply clay inhibitors. This avoids the incorporation of the cutting to the drilling fluid which is responsible for the wall swelling and crumbling. The aim of this work was to evaluate the synergistic behavior that occurs when swelling clay inhibitors are associated to NaCl and KCl salts. Three swelling clay inhibitors samples, INIB A, INIB B and INIB C, were analyzed. Each inhibitor was characterized by the amount of chlorides and active matter content. For the water-clay interaction evaluation in the presence of various fluids, it was used the Capillary Suction Timer (CST, Fann) and Linear Swell Meter (LSM 2000, Fann). For better interpretation of results, a Design of Experiments (DOE, Umetrics MODDE 7.0 TM) through Result Surface Methodology (RSM) was employed, taking into account the type, the swelling inhibitors concentration and the contact time with the clay. The results showed different efficiencies among the inhibitors employed, and the salt-inhibitors mixtures were more efficient than those products alone. However, for field operation, other parameters should be taking into account, as operational cost, environmental requests and time of application for each product

Avaliação do potencial anticorrosivo de tiossemicarbazonas solubilizadas em sistemas microemulsionados

In this work thiosemicarbazones [4-N-cinnamoyl-thiosemicarbazone (CTSC), 4-N-(2'-methoxycinnamoyl)-thiosemicarbazone (MCTSC), and 4-N-(4'-hydroxy-3'-methoxybenzoyl)-thiosemicarbazone (HMBTSC)] were solubilized in an microemulsion system (ME_OCS) which is rich in aqueous phase (O/W system). The system ME_OCS was obtained with saponified coconut oil (OCS) as (surfactant), butanol (cosurfactant), and kerosene as oil phase (Fo), using 40% of C/T (cosurfactant/surfactant), 5% of Fo and 55% of aqueous phase. The microemulsions systems CTSC_ME_OCS, MCTSC_ME_OCS and HMBTSC_ME_OCS effectiveness on a AISI 1020 carbon steel corrosion inhibition process were evaluated in a saline solution (NaCl 0.5%), using a galavostatic method. The tested thiosemicarbazones (TSC) showed highest inhibitors effects (85.7% for CTSC_ME_OCS, 84.0% for MCTSC_ME_OCS, and 83.3% HMBTSC_ME_OCS) at lower concentrations [0.19% of CTSC, 0.07% (MCTSC), and 0.26% (HMBTSC)]. Comparatively, the surfactant OCS (solubilized in H2O) as well as the system ME_OCS showed lower efficacy [71% for OCS (at 0.20 - 0.25% of concentration) and 74% for ME_OCS (at 0.5% of concentration)]. Since the microemulsion systems ME_OCS showed satisfactory interfacial adsorption, the greatest inhibitory effect of those TSC_ME_OCS systems could be correlated to both chemical composition of each tested TSC (which is rich in heteroatoms and aromatic ring) and also the presence of the surfactant OCS

Diagnóstico ambiental das águas do estuário Jundiaí-Potengi pela determinação dos índices de qualidade da água e toxidez

This study is an environmental diagnosis of the Jundiaí-Potengi/RN estuarine system waters, using calculations of pollution indicator indices such as the Water Quality Index (WQI) and the Toxicity Index (TI). The samples were collected at twelve points on the estuary, at high and low tide, between August and November 2007, over four campaigns. The study area, located in a high impact region, has various activities on its banks such as: discharge of untreated or undertreated domestic and industrial sewage, shrimp farming, immunizer stabilization lakes, riverside communities, etc. All the parameters analyzed were compared to the limits of CONAMA Resolution No. 357 of 2005 for healthy and saline Class 1 waters. The results found prove the impact caused by various activities, mainly the parameters related to the presence of organic material, such as DQO, DBO, COT and thermotolerant colliforms. The IQA for most of the collection points was of medium quality. For the metals, although values above the Resolution limits were found, most of them were lower than the detection limits of ICP-OES used, indicating that they tend to be transported by the dynamic of the tides or rainfall and are deposited in bottom sediments, resulting in a TI of 1.0 in this water, when they are absent, which occurs in most cases, or 0.0, when heavy metals are found in these waters

Estudo da modificação de bentonita para a remoção de fenol em águas produzidas na indústria de petróleo

This study evaluates the inclusion of quaternary ammonium salt, bromide hexadecyl trimethyl ammonium (HDTMA-Br) on sodium bentonite to evaluate their performance on the adsorption of phenol present in produced water. It was observed an increase in d001 samples modified with HDTMA-Br by diffraction of X-rays, showing the intercalation of quaternary ammonium cations in the interlamellar layers of clay. Through the adsorption isotherms could be abserver adsorption behavior of sodium bentonite and organophilic bentonite produced in three different concentrations of HDTMA-Br for adsorption of phenol, which is the main phenolic compound found in the product water. Different concentrations of synthetic solutions of phenol were placed in contact with these adsorbents under the same conditions of agitation and temperature. The adsorbent showed adsorptive favorable, especially the clay modified with the highest concentration of HDTMA-Br, 150% CEC of clay, BEN30-14, with higher amounts of phenol adsorbed per gram of adsorbent (mg.g-1)

Desenvolvimento de componentes nanométricos para aplicação em células a combustível à base de sólidos estruturados e filmes finos

The present work aims the preparation of filmes of strontium-doped lanthanum manganite (perovskita) yttria-stabilized zirconia (LSM-SDC) films deposited on substrate of YSZ by means of spin coating technique having as principal objective their application to solid oxide fuel cells of intermediate temperature. La0,8Sr0,2MnO3 and Ce0,8Sm0,2O1,9 were obtained by modified Pechini method by use of gelatin which act as polymerization agent. The powders obtained were characterized by Xray fluorescence, X ray diffraction, electronic scanning microscopy and the superficial area by BET method. The results obtained by X-ray fluorescence showed that the route adopted for obtention of powders was effective in the obtention of the compositions with close values to the stoichiometrics. Ethyl cellulose was used as pore-forming agent and mixed with the LSM-SDC powders in weight proportions of 1:24, 2:23 and 1:9. The films were sintered at 1150 °C for 4 h and characterized by X-ray diffraction and scanning electron microscopy technique (SEM) and atomic force. The phases quantification of the precursory powders and of the obtained films was carried through Rietveld method. According with the analysis of SEM, as the content of ethyl cellulose was increased, the pore distribution in films become more uniform and the pore size reduced. The methodology used for the obtention of the films was very efficient, considering a material was obtained with characteristics that were proper to the application as electrolyte/cathode system to solid oxide fuel cells

Degradação catalítica de polietileno de alta densidade sobre a zeólita HZSM

In last years it has talked a lot about the environment and the plastic waste produced and discarded. In last decades, the increasing development of research to obtain fuel from plastic material, by catalytic degradation, it has become a very attractive looking, as these tailings are discarded to millions worldwide. These materials take a long time to degrade themselves by ways said natural and burning it has not demonstrated a viable alternative due to the toxic products produced during combustion. Such products could bring serious consequences to public health and environment. Therefore, the technique of chemical recycling is presented as a suitable alternative, especially since could be obtain fractions of liquid fuels that can be intended to the petrochemical industry. This work aims to propose alternatives to the use of plastic waste in the production of light petrochemical. Zeolites has been widely used in the study of this process due to its peculiar structural properties and its high acidity. In this work was studied the reaction of catalytic degradation of high-density polyethylene (HDPE) in the presence HZSM-12 zeolites with different acid sites concentrations by thermogravimetry and pyrolysis coupled with GC-MS. The samples of the catalysts were mixed with HDPE in the proportion of 50% in mass and submitted to thermogravimetric analyses in several heating rates. The addition of solids with different acid sites concentrations to HDPE, produced a decrease in the temperature of degradation of the polymer proportional the acidity of the catalyst. These qualitative results were complemented by the data of activation energy obtained through the non-isothermal kinetics model proposed by Vyazovkin. The values of Ea when correlated to the data of surface acidity of the catalysts indicated that there is a exponential decrease of the energy of activation in the reaction of catalytic degradation of HDPE, in function of the concentration of acid sites of the materials. These results indicate that the acidity of the catalyst added to the system is one of the most important properties in the reaction of catalytic degradation of polyethylene

Aplicação da espectroscopia de absorção de raios X no estudo do comportamento do íon Cu2+ em micelas inversas

This work deals with the application of X-Ray Absorption Spectroscopy on the study of the behavior of Cu2+ ions in inverse micelles. The formation of copper nanoparticles in water-in-oil microemulsions in pseudo-ternary systems of cetyl trimethylammonium Bromide (CTAB) surfactant, butanol co-surfactant, heptane as oil phase and aqueous solutions of CuSO4.5H2O, and NaBH4. The microemulsions were prepared with a fixed percentage (60 %) of oil phase and a variable water to tensoative proportion. It was observed an increase on Cu2+ reduction by the sodium borohydride in microemulsions with 13 % of aqueous phase, independent of the reaction time. For the microemulsions in which the aqueous phase is composed only by the CuSO4 solution, it was observed that the color of the solution depends on the water to surfactant ratio. These changes in color were attributed to a competition for the hidratation water between the polar head of the tensoative and Cu2+ ions with the eventual substitution of oxygen by bromine atoms in the first coordination shell of Cu2+ ions

Influência espaço-temporal e fisiológica na absorção de nutrientes e elementos tóxicos por Eichhornia crassipes visando o uso adequado da sua biomassa: o caso do Rio Apodi/Mossoró - RN

This study aims to determine the amount of nutrients and toxic elements in aquatic macrophytes of species Eichhornia crassipes present in River Apodi/Mossoró - RN and check some of the possibilities of using the biomass produced, based on the influence of space - temporal and physiological absorption of nutrients by plants. For this, was determined: Leaf area, Leaf wet mass, Leaf dry mass, Real humidity, Apparent humidity, Ash, Total nitrogen, Crude protein, Calcium, Magnesium, Potassium, Total phosphorus, Sodium, Iron, Copper, Manganese, Zinc, Nickel, Cobalt, Aluminum, Cadmium, Lead and Total chromium at different times, 2 sampling points and 2 parts of plants (leaves and roots). The results show that the levels of nutrients, protein and toxic elements present in plant tissue of Eichhornia crassipes are influenced by spatial, temporal and physiological variability. In general, because the maximum values in the dry matter for total nitrogen (4.4088 g/100g), crude protein (27.5549 g/100g), total phosphorus (0.642 g/100 g), calcium (1.444 g/100g), magnesium (0.732 g/100 g), potassium (7.51 g/100 g), copper (4.4279 mg/100g), manganese (322.668 mg/100g), sodium (1.39 g/100g), iron (194.169 mg/100g) and zinc (3.5836 mg/100g), there was the possibility of using biomass of Eichhornia crassipes for various purposes such as in food animal, products production for human consumption, organic fertilizers, fabrication of brick low cost, and crafts. For all these applications requires a control of the levels of substances in plant tissue. Based on the levels of nutrients and crude protein, the younger plants (0 Month) would be best to have their biomass used. Moreover, one factor that contributes to the use of larger plants (6 Months), the levels of toxic elements which have significantly small or below the detection limit. Therefore, further studies quantifying the biomass produced/m2 at 0 and 6 months are needed for a more correct choice for the best time of harvest

Análise de sedimento de fundo: uma amostragem representativa do estuário Potengi/RN

The aim of this study is to quantify the presence of major and minor elements in the sediments of estuary Potengi. Four georeferenced sampling points were used in the study, at which sediment samples were collected in the channel of the river and on the right and left banks. In addition, dissolved oxygen, salinity and water conductivity were taken in situ at the time of sample collection. The percentage of organic matter, determined by gravimetry, and granulometric analysis of the sediment samples were conducted in the laboratory. To quantify the major and minor elements a prior test to open the sample was conducted with standard NIST 1646ª estuarine sediment to choose the best methodology to be adopted. The sediment samples were dissolved in microwaves with nitric acid and chloridric acid, according to methodology proposed by US EPA 3051ª. Quantitative analyses of the elements Al, Fe, Cd, Cr, Cu, Mn, Ni, Pb and Zn were conducted by inductively coupled plasma optical emission spectrometry (ICPOES). The results showed that the partial concentrations of the elements analyzed are below average worldwide shale levels, the standard described by Turekian and Wedepohl (1961)

Avaliação da estabilidade térmica e oxidativa dos biodieseis de algodão, girassol, dendê e sebo bovino

The search for new sources of environmentally friendly energy is growing every day. Among these alternative energies, biodiesel is a biofuel that has had prominence in world production. In Brazil, law 11.097, determine that all diesel sold in the country must be made by mixing diesel/biodiesel. The latter called BX, , where X represents the percent volume of biodiesel in the diesel oil, as specified by the ANP. In order to guarantee the quality of biodiesel and its mixtures, the main properties which should be controlled are the thermal and oxidative stability. These properties depend mainly of the chemical composition on the raw materials used to prepare the biodiesel. This dissertation aims to study the overall thermal and oxidative stability of biodiesel derived from cotton seed oil, sunflower oil, palm oil and beef tallow, as well as analyze the properties of the blends made from mineral oil and biodiesel in proportion B10. The main physical-chemical properties of oils and animal fat, their respective B100 and blends were determined. The samples were characterized by infrared and gas chromatography (GC). The study of thermal and oxidative stability were performed by thermogravimetry (TG), pressure differential scanning calorimeter (PDSC) and Rancimat. The obtained biodiesel samples are within the specifications established by ANP Resolution number 7/2008. In addition, all the blends and mineral diesel analyzed presented in conformed withthe ANP Regularion specifications number 15/2006. The obtained results from TG curves data indicated that the cotton biodiesel is the more stable combustible. In the kinetic study, we obtained the following order of apparent activation energy for the samples: biodiesel from palm oil > sunflower biodiesel > tallow biodiesel > cotton biodiesel. In terms of the oxidative stability, the two methods studied showed that biodiesel from palm oil is more stable then the tallow. Within the B100 samples studied only the latter were tound to be within the standard required by ANP resolution N° 7. Testing was carried out according to the EN14112. This higher stability its chemical composition

Análise dos Processos de Flotação e Oxidação Avançada para o Tratamento de Efluente Modelo da Indústria do Petróleo

The generation of wastes in most industrial process is inevitable. In the petroleum industry, one of the greatest problems for the environment is the huge amount of produced water generated in the oil fields. This wastewater is a complex mixture and present great amounts. These effluents can be hazardous to the environmental without adequate treatment. This research is focused in the analysis of the efficiencies of the flotation and photo-oxidation processes to remove and decompose the organic compounds present in the produced water. A series of surfactants derivated from the laurilic alcohol was utilized in the flotation to promote the separation. The experiments have been performed with a synthetic wastewater, carefully prepared with xylene. The experimental data obtained using flotation presented a first order kinetic, identified by the quality of the linear data fitting. The best conditions were found at 0.029 g.L-1 for the surfactant EO 7, 0.05 g.L-1 for EO 8, 0.07 g.L-1 for EO 9, 0.045 g.L-1 for EO 10 and 0.08 g.L-1 for EO 23 with the following estimated kinetic constants: 0.1765, 0.1325, 0.1210, 0.1531 and 0.1699 min-1, respectively. For the series studied, the most suitablesurfactant was the EO 7 due to the lower reagent consumption, higher separation rate constant and higher removal efficiency of xylene in the aqueous phase (98%). Similarly to the flotation, the photo-Fenton process shows to be efficient for degradation of xylene and promoting the mineralization of the organic charge around 90% and 100% in 90 min

Comparação entre metodologias de extração de HPAs em água utilizando um planejamento fatorial com quantificação no CG/EM

PAHs (Polycyclic Aromatic Hydrocarbons) are a group of organic substances which receive considerable attention because of the carcinogenic and mutagenic properties of some of them. It is therefore important to determine the PAHs in different environmental matrices. Several studies have shown the use of gas chromatography coupled to mass spectrometry as a technique for quantification of PAHs by presenting excellent detection limits. This study aimed to develop an analytical methodology for the determination of 16 PAHs listed by the USEPA, test two methods for extraction of PAHs in water from a 23 factorial design, quantify them through the analytical technique coupled to gas chromatography mass spectrometry (GC/MS) using the method developed, and finally apply the results in chemometrics. The sample was synthesized and subjected to tests of the 23 factorial design, which has the factors: the type of extraction technique (ultrasound and digester), the ratio solvent / sample (1:1 and 1:3) and the type of solvent (dichloromethane / hexane and acetone / dichloromethane). The responses of eight combinations of the factorial design were obtained from the quantification by external calibration in GC/MS. The quantification method was developed from an optimized adaptation of the USEPA Method 8270. We used the full scan mode as a way of acquiring the mass spectra of 16 PAHs. The time in which the samples were subjected to ultrasound was fixed at 10 min and held an investigation to establish the conditions of power and time in the digester. We had the best response in the investigation of the digester power of 100 watts and the time of six minutes. The factorial design of liquid-liquid extraction showed that the most representative factors were: the use of the digester as extraction technique, the ratio solvent / sample 1:1 and the use of a 1:1 mixture of dichloromethane / hexane as a solvent more suitable. These results showed that the 1:1 mixture of dichloromethane / hexane is an excellent mixture to recover the extraction of PAHs an aqueous sample using the microwave digester. The optimization of the method of separation, identification and quantification of PAHs in the GC/MS was valid for 16 PAHs present in each chromatogram of the samples

Monitoramento das águas da bacia hidrográfica pirangi pela determinação dos índices de qualidade da água-iqa e índice de toxidez-it

The problems of water supply in Northeast Brazil are severe and require more focused studies. This work was intended to assess water quality in the watershed Pirangi, located in the Northeastern state of the newborn using the Water Quality Index, AQI associated with the Index of Toxicity-IT. The data presented in this study were collected in November 2008, June 2009 and March 2010 at eight sampling stations distributed throughout the basin. The study covered nine parameters, based on guidelines established by CETESB, and seven members of Metal Toxicity index-IT. These waters are framed in the classification between GOOD and BAD showing AQI 41.34 minimum and a maximum of 76.23. Virtually all seven metals analyzed were below the detection limits of ICP-OES giving IT a water equal to one when they are absent and 0 when there are levels of trace metals

Tratamento eletroquímico de água produzida sintética para remoção de hidrocarbonetos policíclicos aromáticos

The aim of this work is the treatment of produced water from oil by using electrochemical technology. Produced water is a major waste generated during the process of exploration and production in the oil industry. Several approaches are being studied aiming at the treatment of this effluent; among them can be cited the biological process and chemical treatments such as advanced oxidation process and electrochemical treatments (electrooxidation, electroflotation, electrocoagulation, electrocoagulation). This work studies the application of electrochemical technology in the treatment of the synthetic produced water effluent through the action of the electron, in order to remove or transform the toxic and harmful substances from the environment by redox reactions in less toxic substances. For this reason, we used a synthetic wastewater, containing a mixture H2SO4 0,5M and 16 HPAs, which are: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo (a) anthracene, chrysene, benzo(b)fluoranthene, benzo(k) fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenzo(a, h)anthracene, benzo(g, h, i)perylene. Bulk electrochemical oxidation experiments were performed using a batch electrochemical reactor containing a pair of parallel electrodes, coupled with a power supply using a magnetic stirrer for favoring the transfer mass control. As anodic material was used, a Dimensionally Stable Anode (DSA) of Ti/Pt, while as cathode was used a Ti electrode. Several samples were collected at specific times and after that, the analysis of these samples were carried out by using Gas Chromatography Coupled to Mass Spectrometry (GC - MS) in order to determine the percentage of removal. The results showed that it was possible to achieve the removal of HPAs about 80% (in some cases, more than 80%). In addition, as an indicator of the economic feasibility of electrochemical treatment the energy consumption was analyzed for each hour of electrolysis, and based on the value kWh charged by ANEEL, the costs were estimated. Thus, the treatment costs of this research were quite attractive

Deposição de filmes de ZrO2 modificados sobre substratos metálicos

This work makes use of the Pechini process for synthesis of the solutions and the dip-coating process for the addition of zirconium oxide films pure and doped cerium metal substrates. The metals with ceramic substrates were subjected to severe conditions of salinity. The x-ray fluorescence of the substrate showed a great diversity of chemical elements. The x-ray diffraction of the samples showed the phase of iron substrate because the thickness of nano-thin film. Tests using an LPR probe showed that the film presents with zirconia corrosion independent of film thickness. The substrates of ZrO2-doped ceria showed low chemical attack of the salt in films with less than 15 dives. The results imply that ultrathin films are shown in protecting metallic substrates