Estudo da remoção de Ba2+, Ni2+, Cd2+, Cu3+, Cr3+, Sr2+, Zn2+ por eletrocoagulação em água associada à produção de petróleo

Among the waste generated in the petrochemical industry water associated with oil production is the most important. It is considered one of the great challenges due to the presence of considered toxic chemicals present in this composition. The presence of these substances difficult to reuse the water associated with the enhanced recovery processes, so that prior to their reuse or disposal, treatment is necessary. This paper aimed to study the removal efficiency of chemical species: Ba2+, Ni2+, Cd2+, Cu2+, Cr3+, Sr2+ and Zn2+, present in the composition of the water associated with oil production by electrocoagulation. The evaluation of removal of these chemical species was performed by laboratory tests using electrochemical batch reactors and continuous flow. Initial tests were performed with electrocoagulation of synthetic wastewater in batch reactor using iron electrode. Results of removal of Zn2+ and Ni2+ were 78 % and 59 % respectively. While the percentage of removed Ba2+ was 19 % by 30 minutes of treatment and by applying current of 1.10 A. The tests were performed on effluent batch reactor applying the electrochemical technique with stainless steel electrodes 304, the objective was to remove part of the dispersed oil and also of organic compounds in the effluent. Under the experimental conditions used, the maximum result was obtained TOG was 60 % and TOC was approximately 50 % compared to the initial concentration. In the experiments carried out in continuous reactor, with effluent semisynthetic, have been used electrodes of iron and aluminum and the results were 100 % removal of Cd2+, Cu2+, Cr3+ and Zn2+ and 77 % of Sr2+. These percentages were only attainable through the use of the iron electrode. However, when the electrode was replaced by aluminum, there was a reduction in the percentage of removal to 65 %, using the same flow rate and current. Therefore according to the results obtained using the iron electrode was more effective in removing these metals and the conditions of lower current and lower flow rate was satisfactory, as observed in the experimental design adopted

Vermiculitas tratadas quimicamente na obtenção de sólidos microporosos como precursores para híbridos inorgânico-orgânicos com aplicações adsortivas

ALVES, Ana paula Melo. Vermiculitas tratadas quimicamente na obtenção de sólidos microporosos como precursores para híbridos inorgânico-orgânicos com aplicações adsortivas. 2009. 124 f. Tese (Doutorado em Quimica) - Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, PB, 2009.

Utilização de sílica gel organofuncionalizada para adsorção de íons metálicos em solução aquosa

In this work the organosilanes aminopropyltriethoxysilane, 3-mercaptopropyltryethoxisilane and n[-3-(trimetoxisilyl)propyl]ethylenetriamine, as well as tetraethylortosilicate (TEOS), were employed to produce, by sol-gel method, organofuncionalized silicon samples. The prepared samples were characterized by elementar analys by thermogravimetry and infrared spectroscopy. Those samples were employed to adsorb Cd2+, Pb2+, Ni2+ and Zn2+ from aqueous solutions (10, 20, 40, 60 and 80 mg L-1). In typical experiments, 50 mg of the organometrix was suspended in 20 mL of metal cation solutions at four different contact times: 30, 60, 90 and 120 minutes. The total amount of adsorbed cations were measured by atomic absorption spectrometry. To all investigated matrices, the following adsorption capacity was observed: Ni2+ > Zn2+ > Cd2+ > Pb2+. Such sequence is closely related with the cation radius, as well as the cation hardness

Aplicação de argila branca comercial pura e modificada para adsorção de sulfeto de hidrogênio

In this work were synthesized matrix-based commercial white clay in its composition having large amounts of kaolinite and quartz, with a certain percentage of iron oxide for use as an adsorbent for hydrogen sulfide (H2S). To characterize the effect of initial matrix techniques were used to characterize XRD, FTIR, XRF and TG. The initial clay mineral matrix was placed in contact with 0.1 molar solutions of the salts of Co2+, Ni2+, Cr3+ and a solution 0.1 g / 100ml rhodamine B. During the synthesis process, the solutions were placed in contact with the initial matrix for a period of 48 hours in order to have ion exchange with the clay mineral. To check the amount of exchanged metals, we used the technique of X-ray Fluorescence (XRF). After synthesis was initiated the process of adsorption of H2S, where the arrays were placed in the reactor, then by passing a stream of hydrogen sulfide. The matrix along with the reactor was weighed before and after to measure the amount of gas adsorbed. Based on the gravimetric data the matrix which had the highest performance of the adsorption matrix was exchanged with Ni2+ ions, obtaining a result of 11.13 mg H2S / g matrix, then the matrix coated with rhodamine B which was reached 10.13 mg H2S / g matrix

Síntese e Caracterização de Titanatos de Cobalto e Níquel, dopados com Praseodímio, obtidos a partir da decomposição de Nitrilotriacetatos

In recent years, studies about the physicochemical properties of mixed oxides, call attention of the scientific community, properties like as piezoelectricity, photoluminescence, or applications as catalysts, arise in these compounds, when their chemical compositions are modified, in this context some routes are employed in the synthesis of these materials, among which can be cited these methods: ceramic, combustion, co-precipitation, Pechini or polymeric precursor method, hydrothermal, sol-gel; these routes are divided into traditional routes or chemical routes. In this work were synthesized oxides with variable composition, from the thermal decomposition of titanium, cobalt, nickel and praseodymium nitrilotriacetates. The nitrilotriacetates were characterized by IR Spectroscopy (FTIR), Thermogravimetric (TG/ DTG) and Differential Scanning Calorimetry (DSC), while oxides have been characterized by X-ray diffraction (XRD), Spectrofluorimetry and IR Spectroscopy (FTIR). From FTIR data, it was demonstrated that the displacement of the band corresponding to the carboxylate group (νCOOH) at 1712 cm-1, present in nitrilotriacetic acid (H3NTA), for 1680-1545 cm-1, these stretches are characteristics of coordinated nitrilotriacetates, By thermal analysis (TG/DTG /DSC), it was suggested, that in an oxidizing atmosphere (air) oxides are obtained at lower temperatures than in an inert atmosphere N2(g). By results from X-ray Diffraction (XRD), it was determinated that the oxides are crystalline and the predominant phases obtained are summarized titanate phases rutile and ilmenite. By fluorimetry was observed that the intensity of emission bands are directly proportional to the concentration of ions Ni2+, Co2+ and Pr3+, and IR spectroscopy (FTIR) from oxides, demonstrated the disappearance of characteristic bands by nitrilotriacetates, determining the complete decomposition of the nitrilotriacetates in oxides

Complexos metálicos de cobalto, níquel e cobre com a Pirazina-2-carboxamida e 4- hidrazida ácida piridincarboxílica: síntese e caracterização

This work involved the synthesis, characterization and proposing the molecular structure of coordination compounds involving ligands pyrazine-2-carboxamide (PZA) and 4- hydrazide acidic pyridine carboxylic (INH) and metals of the first transition series (M = Co2+, Ni2+ and Cu2+). For the characterization of the compounds used were analytical techniques such as infrared absorption spectroscopy average (FT-IR) molar conductivity measurements, CHN elemental analysis, EDTA Complexometric, measurement of melting point, X-ray diffraction by powder method, Thermogravimetry (TG) and Differential Thermal Analysis (DTA) and Simultaneous Differential Scanning Calorimetry (DSC). The absorption spectra in the infrared region suggested that the ligand coordination to the metal center occurs through the carbonyl oxygen atom and nitrogen alpha pyrazine ring to those complexes formed with PZA. For INH complexes with metal-ligand coordination is through the carbonyl oxygen and nitrogen of the terminal hydrazide grouping. The conductivity measurements of the complexes in aqueous solution they suggest to all behavior of the type 1:2 electrolytes, and conduct of non-electrolytes in acetonitrile. The results obtained by CHN elemental analysis and EDTA Complexometric allowed to infer the stoichiometry of the compounds synthesized. For all of the complexes obtained was possible to record the melting points, neither of which melted near the melting temperature of the free ligands. The X-ray diffraction showed that the complexes of pyrazinamide exhibited diffraction lines, suggesting that these compounds are crystalline, while compounds of isoniazid, with the exception of cobalt, exhibited diffraction lines, indicating that they are crystalline. The results from the TG-DTA and DSC allowed information regarding the dehydration and thermal decomposition of these complexes

Avaliação da poatencialidade da perlita natural e expandida na adsorção de metais

The contamination by metal ions has been occurring for decades through the introduction of liquid effluent not treated, mainly from industrial activities, rivers and lakes, affecting water quality. For that the effluent can be disposed in water bodies, environmental standards require that they be adequately addressed, so that the concentration of metals does not exceed the limits of standard conditions of release in the receptor. Several methods for wastewater treatment have been reported in the literature, but many of them are high cost and low efficiency. The adsorption process has been used as effective for removal of metal ions. This paper presents studies to evaluate the potential of perlite as an adsorbent for removing metals in model solution. Perlite, in its natural form (NP) and expanded (EP), was characterized by X-ray fluorescence, X-ray diffraction, surface area analysis using nitrogen adsorption (BET method), scanning electron microscopy and Fourier transform infrared spectroscopy. The physical characteristic and chemical composition of the material presented were appropriate for the study of adsorption. Adsorption experiments by the method of finite bath for model solutions of metal ions Cr3+, Cu2+, Mn2+ and Ni2+ were carried out in order to study the effect of pH, mass of the adsorbent and the contact time on removal of ions in solution. The results showed that perlite has good adsorption capacity. The NP has higher adsorption capacity (mg g-1) than the EP. According to the values of the constant of Langmuir qm (mg g-1), the maximum capacity of the monolayer was obtained and in terms of proportion of mass, we found the following order experimental adsorption: Cr3+ (2.194 mg g- 1) > Ni2+ (0.585 mg g-1) > Mn2+ (0.515 mg g-1) > Cu2+ (0.513 mg g-1) and Cr3+ (1.934 mg g-1)> Ni2+ (0.514 mg g-1) > Cu2+ (0.421 mg g-1) > Mn2+ (0.364 mg g-1) on the NP and EP, respectively. The experimental data were best fitted the Langmuir model compared to Freundlich for Cu2+, Mn2+ and Ni2+. However, for the Cr3+, both models fit the experimental data

Eficiência de extração de cobre e níquel utilizando sistemas microemulsionados bifásicos e trifásicos

The environmental impact due to the improper disposal of metal-bearing industrial effluents imposes the need of wastewater treatment, since heavy metals are nonbiodegradable and hazardous substances that may cause undesirable effects to humans and the environment. The use of microemulsion systems for the extraction of metal ions from wastewaters is effective when it occurs in a Winsor II (WII) domain, where a microemulsion phase is in equilibrium with an aqueous phase in excess. However, the microemulsion phase formed in this system has a higher amount of active matter when compared to a WIII system (microemulsion in equilibrium with aqueous and oil phases both in excess). This was the reason to develop a comparative study to evaluate the efficiency of two-phases and three-phases microemulsion systems (WII and WIII) in the extraction of Cu+2 and Ni+2 from aqueous solutions. The systems were composed by: saponified coconut oil (SCO) as surfactant, n-Butanol as cosurfactant, kerosene as oil phase, and synthetic solutions of CuSO4.5H2O and NiSO4.6H2O, with 2 wt.% NaCl, as aqueous phase. Pseudoternary phase diagrams were obtained and the systems were characterized by using surface tension measurements, particle size determination and scanning electron microscopy (SEM). The concentrations of metal ions before and after extraction were determined by atomic absorption spectrometry. The extraction study of Cu+2 and Ni+2 in the WIII domain contributed to a better understanding of microemulsion extraction, elucidating the various behaviors presented in the literature for these systems. Furthermore, since WIII systems presented high extraction efficiencies, similar to the ones presented by Winsor II systems, they represented an economic and technological advantage in heavy metal extraction due to a small amount of surfactant and cosurfactant used in the process and also due to the formation of a reduced volume of aqueous phase, with high concentration of metal. Considering the reextraction process, it was observed that WIII system is more effective because it is performed in the oil phase, unlike reextraction in WII, which is performed in the aqueous phase. The presence of the metalsurfactant complex in the oil phase makes possible to regenerate only the surfactant present in the organic phase, and not all the surfactant in the process, as in WII system. This fact allows the reuse of the microemulsion phase in a new extraction process, reducing the costs with surfactant regeneration

Vermiculitas tratadas quimicamente na obtenção de sólidos microporosos como precursores para híbridos inorgânico-orgânicos com aplicações adsortivas

ALVES, Ana paula Melo. Vermiculitas tratadas quimicamente na obtenção de sólidos microporosos como precursores para híbridos inorgânico-orgânicos com aplicações adsortivas. 2009. 124 f. Tese (Doutorado em Quimica) - Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, PB, 2009.