Extração de metais (K, Mg, Ba, Ca, Cr, Mn, Li, Fe) de água produzida utilizando sistema microemulsionado

The produced water is a byproduct formed due to production of petroleum and carries with it a high amount of contaminants such as oil particles in suspension, organic compounds and metals. Thus, these latter pollutants are very difficult to treat because of its high solubility in water. The objective of this work is to use and evaluate a microemulsioned system to remove metals ( K , Mg , Ba , Ca , Cr , Mn , Li , Fe ) of synthetic produced water. For the extraction of metals, it was used a pseudoternary diagram containing the following phases: synthetic produced water as the aqueous phase (AP), hexane as organic phase (OP), and a cosurfactant/surfactant ratio equal to four (C/S = 4) as the third phase, where the OCS (saponified coconut oil) was used as surfactant and n-butanol as cosurfactant. The synthetic produced water was prepared in a bench scale and the region of interest in the diagram for the removal of metals was determined by experimental design called. Ten points located in the phase Winsor II were selected in an area with a large amount of water and small amounts of reagents. The samples were analyzed in atomic absorption spectrometer, and the results were evaluated through a statistical assesment, allowing the efficiency analysis of the effects and their interactions. The results showed percentages of extraction above 90% for the metals manganese, iron, chromium, calcium, barium and magnesium, and around 45% for metals lithium and potassium. The optimal point for the simultaneous removal of metals was calculated using statistical artifact multiple response function (MR). This calculation showed that the point of greatest extraction of metals occurs was the J point, with the composition [72% AP, 9% OP, 19% C/S], obtaining a global extraction percentage about 80%. Considering the aspects analyzed, the microemulsioned system has shown itself to be an effective alternative in the extraction of metals on synthetic produced water remediation

Adsorção de Mn (II) e Zn (II) em soluções aquosas usando perlita expandida revestida com quitosana

In this work, chitosan was used as a coating of pure perlite in order to increase the accessibility of the groups OH- e NH2+the adsorptionof ions Mn2+ e Zn2+.The characterization results of the expanded perlite classified as microporous and whose surface area 3,176 m2 g-1after the change resulted in 4,664 m2g-1.From the thermogravimetry(TG) it was found that the percentage of coating was34,3%.The infrared analysis can prove the presence of groups Si-OH, Si-O e Al-O-Siresulting from the perlite and C=O, NH2and OH characterization of chitosan. The experiments on experiments on the adsorption of Mn and Zn were performed in the concentration range of10 a 50 mgL-1and the adsorption capacity inpH 5,8 e 5,2 was 19,49 and 23,09 mgg-1to 25 oC,respectively.The adsorption data were best fitted to Langmuir adsorption model to Langmuir adsorption model for both metalionsisindicative of monolayer adsorption. The kinetics of adsorption were calculated from the equation of Lagergren fitting the model pseudo-second-order for all initial concentrations, suggesting that adsorption of ions Mn2+ and Zn2+ follows the kinetics of pseudo-second-order and whose constant Speedk2(g/mg.min) are 0,105 e 3,98 and capacity and maximum removal qe 4,326 e 3,348,respectively.In this study we used a square wave voltammetry cathodic stripping voltammetry to quantify the adsorbed ions, and the working electrode glassy carbon, reference electrode silver / silver chloride and a platinum auxiliary electrode. The attainment of the peaks corresponding to ions Mn2+ and Zn2+ was evaluated in and electrochemical cell with a capacity of 30 mL using a buffer system (Na2HPO4/NaH2PO4)at pH 4 and was adjusted with solutionsH3PO4 0,1molL-1and NaOH 0,1 molL-1and addition of the analyte has been a cathodic peak in- 0,873 Vand detection limit of2,55x10-6molL-1para Zn.The dough used for obtaining the adsorption isotherm was 150 mg and reached in 120 min time of equilibrium for both metal ions.The maximum adsorption for 120 min with Mn concentration 20 mgL-1 and Zn 10 mgL-1,was91, 09 e 94, 34%, respectively

Estudo do desempenho de catalisadores tipo Ni/CexM1-xO2 (M = Zr ou Mn) na reação de oxidação parcial do metano

One of the main applications of methane is in the production of syngas, a mixture of hydrogen and carbon monoxide. Procedures used in this process are steam reforming, CO2 reforming, partial oxidation and autothermal reforming. The present study evaluated and compared the behavior of nickel catalysts supported on mixed oxides of cerium and manganese in the partial oxidation of methane with that of nickel catalysts supported on mixed oxides of cerium and zirconium. Mixed oxides of cerium and zirconium or cerium and manganese were synthesized using two different preparation methods, the polymeric precursor based on Pechini method and combustion reaction using a microwave. This was followed by impregnation with nickel content of 15 %. Samples were calcined at 300, 800 and 900 °C and characterized by specific surface area (SSA), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed reduction (TPR) and the reaction of partial oxidation of methane. The specific areas of samples decrease with the rise in calcination temperature and after nickel impregnation. Metal-cerium solid solution was formed and the presence of other manganese species outside the solid solution structure was confirmed in the compound with the highest amounts of manganese oxides showed. With regard to scanning electron microscopy, supports based on cerium and zirconium prepared by Pechini method exhibited agglomerated particles without uniform geometry or visible pores on the surface. However, compounds containing manganese presented empty spaces in its structure. Through synthesis by combustion reaction, morphology acquired independently of the proposed composition demonstrated greater porosity in relation to Pechini synthesis. Although catalysts were prepared using different synthesis methods, the insertion of nickel showed very similar reduction profiles (TPR). In relation to nickel catalysts supported on mixed oxide of cerium and zirconium, there is an initial reduction of NiO species that present certain interaction with the support. This is followed by the reduction of Ce4+ in Ce3+ surface, with subsequent bulk reduction. For catalysts containing manganese, a reduction of nickel oxide species occurs, followed by two stages of reduction for species Mn2O3 in Mn3O4 and Mn3O4 in MnO, with subsequent reduction of bulk. With respect to partial oxidation reactions, the nickel catalyst supported on mixed oxide of cerium and zirconium, prepared using the Pechini method, exhibited CH4 conversion of approximately 80 %, with conversion of 81 % when prepared by combustion. This behavior continued for 10 hours of reaction. Manganese content was also found to directly influence catalytic activity of materials; the greater the manganese oxide content, the faster deactivation and destabilization occurred in the catalyst. In both synthesis methods, the nickel catalyst supported on mixed oxide of cerium and zirconium maintained an H2/CO ratio very close to 2 during the 10 hours of partial oxidation reaction. Samples containing manganese displayed smaller H2/CO ratios and lower performance in partial oxidation.

Adsorção dos gases NH3, NO e H2S em fosfato de vanadila, hidrogeno fosfato de vanadila e fosfatos de vanadila dopados por Al, Co, Mn e Cr

In this work were synthesized the materials called vanadyl phosphate, hydrogen vanadyl phosphate and vanadyl phosphate doped by transition metals with the aim in adsorption the following compounds: ammonia, hydrogen sulfide and nitrogen oxide. To characterize the starting compounds was used DRX, FTIR, FRX and TG analysis. After the characterization of substrates, proceeded de adsorption of NH3 and H2S gases in reactor, passing the gases with continuous flow for 30 min and room temperature. Gravimetric data indicate that the matrices of higher performance in adsorption of ammonia was those doped by aluminum and manganese, obtaining results of 216,77 mgNH3/g and 200,40 mgNH3/g of matrix, respectively. The matrice of higher performance in adsorption of hydrogen sulfide was that doped by manganese, obtaining results of 86,94 mgH2S/g of matrix. The synthesis of substrates VOPO4.2H2O and MnVOPO4.2H2O with nitrogen oxide was made in solution, aiming the final products VOPO4.G.nH2O and MnVOPO4.G.nH2O (G = NO and n = number of water molecules). The thermo analytical behavior and the infrared spectroscopy are indicative of formation of VOPO4.2,5NO.3H2O compound. Results of scanning electron microscopy (SEM) and Energy dispersive spectroscopy (EDS) of materials vanadyl phosphate and vanadyl phosphate modified after reaction in solid state or in solution with the gases show morphology changes in substrates, beyond the formation of orthorhombic sulfur crystals over their respective hosts when these adsorb hydrogen sulfide