Sibele B. C. Pergher

Materiais magnéticos baseados em diferentes zeólitas para remoção de metais em água

In this work the adsorption features of zeolites (NaY, Beta, Mordenite and ZSM-5) have been combined with the magnetic properties of iron oxides in a composite to produce a magnetic adsorbent. These magnetic composites can be used as adsorbents for contaminants in water and subsequently removed from the medium by a simple magnetic process. The magnetic zeolites were characterized by XRD, magnetization measurements, chemical analyses, N2 adsorption isotherms and Mossbauer spectroscopy. These magnetic adsorbents show remarkable adsorption capacity for metal ion contaminants in water.

Um novo procedimento de síntese da zeólita A empregando argilas naturais

This work proposes the synthesis of zeolite A by IZA standard proceedures starting from a natural clay. The clay was used in its natural form and after calcination at 900oC. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and porosity analysis by nitrogen adsorption. Results showed low surface area for Na-A zeolite in sodium form, but a higher one in CaA based on the nitrogen accessibility. The presence of cubic crystals for the A phase was observed in the SEM micrographies. The new procedure starting from natural clay favors the formation of sodalite while that using the calcinated clay gives A.

Screening of supports for immobilization of commercial porcine pancreatic lipase

The aim of this work is to report the performance of different supports for the immobilization of commercial porcine pancreatic lipase. The immobilization tests were carried out in several types of Accurel, activated alumina, kaolin, montmorillonite, ion exchange resins and zeolites. The characterization of the supports showed differences in terms of specific area and morphology. The characteristics of the supports influenced the amount of enzyme adsorbed, yield of immobilization and esterification activity of the resulting immobilized catalyst. The clays KSF and natural and pillared montmorillonites presented potential for use as support for lipase immobilization in terms of yield and esterification activity. Yields of immobilization of 76.32 and 52.01% were achieved for clays KSF and natural montmorillonite, respectively. Esterification activities of 754.03, 595.51, 591.88 and 515.71 U.g-1 were obtained for lipases immobilized in Accurel MP-100, Amberlite XAD-2, mordenite and pillared montmorillonite, respectively.

Caracterização de argilas bentonitas e diatomitas e sua aplicação como adsorventes

Five samples of natural clays denominated: diatomite, CN-20, CN-29, CN-40 and CN-45 from Alianca Latina LTDA were characterized by differents supplementary techniques such as: XRD, chemical analysis, adsorption N2 measurements, infrared spectroscopy analysis, thermogravimetric analysis. Clays were tested in adsorption of blue methylene. All of isotherms adjust in a model of physics adsorption with formation of multilayers, however in the case of diatomite was a favorable adsorption (type II) and the CNs were a not favorable adsorption (type III). In the case of CNs had flocculation of clay in high concentration of coloring.

Preparación y caracterización de la zeolita MCM-22 y de su precursor laminar

The layered precursor of MCM-22 was prepared with different Si/Al ratios: 15, 25, 50, 100 and ¥. Upon heat treatment these precursors form MCM-22 zeolite. Both layered precursor and MCM-22 zeolite were characterized by several techniques: Chemical Analysis by Atomic Absorption Spectroscopy (AAS), X-Ray Diffraction (XRD), Thermo-gravimetric Analysis (TGA), Pore Analysis by N2 and Ar adsorption, Scanning Electron Microscopy (SEM), Infrared Spectroscopy (IR) and Temperature Programmed Desorption of ammonium (TPD).

Acid treatments of montmorillonite-rich clay for Fe removal using a factorial design method

Montmorillonite clays are of great interest for industrial processes such as catalysis and adsorption. The textural properties of clays can be modified in an attempt to increase their uses. This paper describes the acid treatment of natural montmorillonite clay. The materials were characterized using X-ray diffraction (XRD), atomic absorption spectroscopy (AA) and BET surface area measurements. Three different acids (HCl, HNO3 and H2SO4) were tested, and HCl and H2SO4 were more efficient for removing Fe from the clay. The results indicate that HCl better preserves the material structure because less Al is removed. A central composite design (CCD) 22 was applied to evaluate the treatment using HCl. The temperature and concentration presented positive effects on the removal of Fe, Al and Mg. Combinations of the HCl acid solution concentration and temperature, such as 4 mol.L-1/50 °C and 1 mol.L-1/75 °C, assured that Fe was removed with less damage to the structure.

Synthesis of high value-added zeolitic materials using glass powder residue as a silica source

In this work, zeolite A was obtained using alkaline fusion followed by a hydrothermal treatment of glass powder residue derived from the manufacturing of glass. The following parameters were evaluated: leaching of the stock material (silica source), mineralizing agent, alumina source, and the alkaline fusion and crystallization temperatures. The synthesized materials were characterized by chemical analysis using energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD and SEM results showed that zeolite A was obtained under almost all of the evaluated parameters. The use of pseudoboehmite as an aluminum source led to the formation of zeolite X as a secondary phase and a change in the temperature of fusion, which at 500 °C, there was formation of zeolite A, hydrated sodalite and zeolite X.

Estudo da síntese da zeólita ZSM-5 a partir de argilas naturais

The synthesis of ZSM-5 zeolite was studied by three synthesis methods: standard synthesis, three day synthesis and synthesis employing clays (kaolin and montmorillonite). The raw materials and prepared materials were characterized by Chemical Analysis by X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD). The results show that it is possible to synthesized ZSM-5 zeolite using clays as raw materials. Kaolin gives phases of higher crystalinity than montmorillonite.

Programa de gerenciamento de resíduos dos laboratórios de graduação da Universidade Regional Integrada do Alto Uruguai e das Missões - Campus Erechim

This work presents a proposal for the management of residues from teaching laboratories. The main goals of the proposal are: scale reduction of experiments, reuse of residues as raw materials for new experiments and appropriate treatment and storage of residues. The methodology includes standardized labels for residue classification and registration of experimental classes and their residues in files. The management seemed to be efficient, resulting in a reduction of the amount of reagents utilized and residues generated, and an increase of reutilization of residues. A considerable decrease of needed storage space and suitable methods for correct residue disposal were achieved. We expect that all laboratories, including those exclusively for research activities, become involved, in a near future, in the Residue Management Project of URI - Campus Erechim.

Compósitos magnéticos baseados em hidrotalcitas para a remoção de contaminantes aniônicos em água

In this work the adsorption features of hydrotalcites (Al, Mg- CO3) and the magnetic properties of iron oxides have been combined in a composite to produce a magnetic adsorbent. These magnetic composites can be used as adsorbents for anionic contaminants in water and subsequently removed from the medium by a simple magnetic process. The magnetic hydrotalcites were characterized by XRD, magnetization measurements, N2 adsorption isotherms and Mossbauer spectroscopy. These magnetic adsorbents show remarkable adsorption capacity for anionic contaminants in water.