Avaliação de diferentes processos oxidativos avançados no tratamento de resíduos de petróleo

The petroleum industry deals with problems which are difficult to solve because of their relation to environmental issues. This is because amounts of residue are generated which vary in type and danger level. The soil contamination by non aqueous liquid phase mixtures, specifically hydrocarbon petroleum has been a reason for great concern, mainly the aromatic and polycyclic aromatic, which present risk to human health due to its carcinogenic and mutagenic character. The Advanced Oxidative Processes (AOP) are efficient technologies for destruction of organic compounds of difficult degradation and, often, they are present in low concentrations. They can be considered clean technologies, because there is no formation of solid by-products or the transfer of pollutor phases. This work focuses on the study of the degradation of petroleum industrial waste, by Advanced Oxidation Processes. Treatments tackling petroleum residues, contaminated soil, and water occurring in the production of petroleum reached the following Polycyclic Aromatic Hydrocarbons (PAH) degradation levels: solid residues 100% in 96 treatment hours; water residue - 100% in 6 treatment hours; soil contamination (COT degradation) - 50.3% in 12 treatment hours. AOP were effective in dealing with petroleum residues thus revealing themselves to be a promising treatment alternative

Estudo da produção eletroquímica de espécies de cloro ativo para tratamento de efluentes sintéticos

The treatment of wastewater is essential to human health. One of the most important steps is the disinfection treatment which uses chlorine to eliminate bacteria as required by environmental agencies. However, the identification of potentially toxic byproducts generated by this method, such as trihalomethanes, has stimulated the development of new alternative disinfection technologies. Among them, heterogeneous photocatalysis, TiO2 photocatalysis and electrochemical disinfection are considered suitable alternatives to the chlorination method. Thus, the present dissertation analyzes the evolution of active chlorine species in a synthetic NaCl solution and it is tested to treat a synthetic solution of the dye Reactive Blue 19 using boron-doped diamond (BDD) and ruthenium oxide (Ti/Ru0.3Ti0.7O2) as anodes. The indirect electrochemical process was discussed in terms of mineralization of the total organic load and percentage of color removal in order to evaluate the applicability of electrochemical technology. Electrochemical experiments were carried out with different current densities (25, 50 and 75 mA.cm-2) during 120 minutes. On the other hand, other important parameter in this study was the influence of the proportion sp3/sp2 on BDD anode on the performance of the evolution of active chlorine species which was investigated by electrolytic techniques (linear polarization), with the intention of determining the related training oxidizing species and consumption energy to chemical or electrochemical reactions. From the results, it can be noted that the BDD electrode showed better efficiency throughout the electrochemical process.

Estudo da produção eletroquímica de espécies de cloro ativo para tratamento de efluentes sintéticos

The treatment of wastewater is essential to human health. One of the most important steps is the disinfection treatment which uses chlorine to eliminate bacteria as required by environmental agencies. However, the identification of potentially toxic byproducts generated by this method, such as trihalomethanes, has stimulated the development of new alternative disinfection technologies. Among them, heterogeneous photocatalysis, TiO2 photocatalysis and electrochemical disinfection are considered suitable alternatives to the chlorination method. Thus, the present dissertation analyzes the evolution of active chlorine species in a synthetic NaCl solution and it is tested to treat a synthetic solution of the dye Reactive Blue 19 using boron-doped diamond (BDD) and ruthenium oxide (Ti/Ru0.3Ti0.7O2) as anodes. The indirect electrochemical process was discussed in terms of mineralization of the total organic load and percentage of color removal in order to evaluate the applicability of electrochemical technology. Electrochemical experiments were carried out with different current densities (25, 50 and 75 mA.cm-2) during 120 minutes. On the other hand, other important parameter in this study was the influence of the proportion sp3/sp2 on BDD anode on the performance of the evolution of active chlorine species which was investigated by electrolytic techniques (linear polarization), with the intention of determining the related training oxidizing species and consumption energy to chemical or electrochemical reactions. From the results, it can be noted that the BDD electrode showed better efficiency throughout the electrochemical process.

A proposal to the supervision of processes in an industrial environment with heterogeneous systems

SOUZA, Rodrigo B. ; MEDEIROS, Adelardo A. D. ; NASCIMENTO, João Maria A. ; GOMES, Heitor P. ; MAITELLI, André L. A Proposal to the Supervision of Processes in an Industrial Environment with Heterogeneous Systems. In: INTERNATIONAL CONFERENCE OF THE IEEEOF THE INDUSTRUI ELECTRONICS SOCIETY,32., Paris, 2006, Paris. Anais... Paris: IECON, 2006

Características estruturais e fotocatalíticas do compósito oxihidróxido de nióbio/vermiculita

The preparation of nanostructured materials using natural clays as support, has been studied in literature under the same are found in nature and consequently, have a low price. Generally, clays serve as supports for metal oxides by increasing the number of active sites present on the surface and can be applied for various purposes such as adsorption, catalysis and photocatalysis. Some of the materials that are currently highlighted are niobium compounds, in particular, its oxides, by its characteristics such as high acidity, rigidity, water insolubility, oxidative and photocatalytic properties. In this scenario, the study aimed preparing a composite material oxyhydroxide niobium (NbO2OH) / sodium vermiculite clay and evaluate its effectiveness with respect to the natural clay (V0) and NbO2OH. The composite was prepared by precipitation-deposition method and then characterized by X-ray diffraction, infrared spectroscopy (XRD), energy dispersive X-ray (EDS), thermal analysis (TG/DTG), scanning electron microscopy (SEM), N2 adsorption-desorption and investigation of distribution of load. The application of the material NbO2OH/V0 was divided in two steps: first through oxidation and adsorption methods, and second through photocatalytic activity using solar irradiation. Studies of adsorption, oxidation and photocatalytic oxidation monitored the percentage of color removal from the dye methylene blue (MB) by UV-Vis spectroscopy. The XRD showed a decrease in reflection d (001) clay after modification; the FTIR indicated the presence of both the clay when the oxyhydroxide niobium to present bands in 1003 cm-1 related to Si-O stretching bands and 800 cm-1 to the Nb-O stretching. The presence of niobium was also confirmed by EDS indicated that 17 % by mass amount of the metal. Thermal analysis showed thermal stability of the composite at 217 °C and micrographs showed that there was a decrease in particle size. The investigation of the surface charge of NbO2OH/V0 found that the material exhibits a heterogeneous surface with average low and high negative charges. Adsorption tests showed that the composite NbO2OH/V0 higher adsorption capacity to remove 56 % of AM, while the material removed from V0 only 13 % showed no NbO2OH and adsorptive capacity due to the formation of H-aggregates. The percent removal of dye color for the oxidation tests showed little difference from the adsorption, being 18 and 66 % removal of dye color for V0 and NbO2OH/V0 respectively. The NbO2OH/V0 material shows excellent photocatalytic activity managing to remove just 95,5 % in 180 minutes of the color of MB compared to 41,4 % and 82,2 % of V0 the NbO2OH, proving the formation of a new composite with distinct properties of its precursors.

Síntese e caracterização de catalisadores baseados em vermiculita modificada com ferro: aplicação em processos do tipo foto-fenton

Clays are materials with specific properties that make them promising for various studies. In this work we used the vermiculite clay as support for iron compounds, in order to obtain promising materials for application in the heterogeneous type photo-Fenton process. In all, the study included six solid, starting from the vermiculite (V0) was obtained calcined vermiculite (V0-C), the mixed material (V0/β-FeOOH) formed by vermiculite more akaganeite, exchanged vermiculite (v0t-C), vermiculite impregnated Wet (V0u-C) and V0u-CL that is the solid obtained by impregnating with a back washing. The solids of the study had their physical and chemical characteristics investigated by the following characterization techniques: X-Ray Diffraction (XRD), Infrared Spectroscopy (IR), Energy Dispersive Spectroscopy (EDS), X-Ray Fluorescence Spectroscopy (XRF), UV-Vis by Diffuse Reflectance (DR UV-Vis), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The V0 material showed three distinct phases, which are the very vermiculite, hidrobiotite and biotite, the last two phases are part of the geological of formation process vermiculite. The solids obtained after the modification showed an increase in the amount of iron present in the clay, these being quantities important for application in photocatalysis. The micrographs and EDS data, show that after treatment of addition of the metal , the iron was intercalary in structure of vermiculite for solid V0t-C and V0u-C, however, this did not occur with mixed material. In the photoFenton process, was observed a maximum removal of 88.8% of the dye methylene blue coloring for the catalyst V0/β-FeOOH, while for the other solids was obtained values between 76.8 and 62.6%, compared to 37.8% of discoloration without the presence of catalyst. Therefore, it is concluded that the vermiculite clay presents as a good catalyst and iron support for the, beyond of presenting a low cost because of its high abundance.

A proposal to the supervision of processes in an industrial environment with heterogeneous systems

SOUZA, Rodrigo B. ; MEDEIROS, Adelardo A. D. ; NASCIMENTO, João Maria A. ; GOMES, Heitor P. ; MAITELLI, André L. A Proposal to the Supervision of Processes in an Industrial Environment with Heterogeneous Systems. In: INTERNATIONAL CONFERENCE OF THE IEEEOF THE INDUSTRUI ELECTRONICS SOCIETY,32., Paris, 2006, Paris. Anais... Paris: IECON, 2006