Abstract Vermiculite clays are adsorbent materials that have good chemical adsorption capacity, which makes them applicable in the removal of drugs from aqueous solutions. Their lamellar structure can be easily expanded and organophilized. To assess the efficacy and environmentally-tolerant capacity of the adsorption method, the organophilized vermiculite clay was compared to both natural and expanded vermiculite clays. To prepare the organophilized clays, a natural clay sample was expanded at 900 °C. The expanded clay was thus treated by immersion in a 1.0 M NaCl solution and organophilized using a cetyltrimethylammonium bromide (CTMA-Br) surfactant, for 24 h at 50 °C. Natural, expanded, and organophilized samples were characterized using the techniques of XRD, FTIR, TG/DSC, and SEM to observe structural changes after expansion and organophilization. These characterizations indicated that there was an increase in the interlamellar space of the expanded and organophilized sample. In addition, a study of the point of zero charge was performed to determine the surface changes of the samples and the amount of doxazosin adsorption in the samples was determined by the time adsorption test. Further, the organophilized sample showed potential adsorption of the drug doxazosin and high performance in relation to the expanded and natural samples.

Abstract The physical and mechanical properties of foamed geopolymers were determined. The geopolymers were made with two different metakaolins (from Metacaulim do Brasil - MB, and Pantano Grande/RS - MPG) as precursors, with NaOH and Na2SiO3 as activators, and with the addition of foam, which was produced with the foaming agent diethanolamide of coconut fatty acid with a minimum of 80% concentration. Also, two times (2.5 and 4 h) were used for the calcination of MPG at 750 °C. The results showed that all factors (precursors type, alkali content, silica modulus, and foam content) had a significant influence on the response variables, which presented the following variations: compressive strength of 0.36 to 3.23 MPa; thermal conductivity from 0.22 to 0.42 W/(m.K); saturated bulk density from 1176 to 1364 kg/m3; dry bulk density of 619 to 864 kg/m3; air void from 46.4% to 62.5%; and water absorption from 55.7% to 95.4%. It was also concluded that the precursor type was the factor that had the most influence on the properties of foamed geopolymers, with MPG calcined for 4 h being the best, as greater compressive strength and low thermal conductivity were obtained.

Resumo Relatamos a primeira ocorrência de Panstrongylus megistus (Burmeister, 1835) (Hemiptera, Reduviidae, Triatominae) na Região Metropolitana de São Paulo, Brasil. Em 2018, espécimes adultos foram enviados por residentes e a pesquisa na propriedade constatou a presença de um grande foco associado a um ninho marsupial. Este achado reforça a importância da espécie no estado de São Paulo, serve de alerta para a vigilância epidemiológica e amplia a área de colonização da espécie no estado de São Paulo.

Abstract We report the first known occurrence of Panstrongylus megistus (Burmeister, 1835) (Hemiptera, Reduviidae, Triatominae) in the Metropolitan Region of São Paulo, Brazil. In 2018, adult specimens were sent by residents to the competent authorities and, in the inspection of the property, a large focus associated with a marsupial nest was found. This finding reinforces the importance of the species in the state of São Paulo, serves as an alert for epidemiological surveillance and extends the species colonization area in the state of São Paulo.

The capability of natural and modified-Illite/kaolinite for zinc adsorption from aqueous solution was investigated in the present paper. The new hybrid material was composed of the natural clay using the intercalation process with dimethyl sulfoxide. The objective of this study was to examine the adsorption behavior of Brazilian phyllosilicate sample and hybrid material, towards a divalent metal has been studies by a batch technique. The phyllosilicate sample and hybrid material were characterized by x-ray diffractometry (XRD) and elemental analysis. The Avrami, Lagergren, Elovich, and Intra-particle diffusion models for adsorption isotherms were applied for analyses experimental data in order to determine the adsorption capacity to form a monolayer and the constant related to the adsorption intensity. The adsorption equilibrium was established in 140 minutes for natural and 120 minutes for modified clay. The maximum number of moles adsorbed was determined to be 12.55 and 22.89 mmolg-1 for systems Zn²+-(kaolinite/ilite) and Zn²+-(kaolinite/ilite + dimethyl sulfoxide), respectively.

Conversores catalíticos ou catalisadores automotivos são formados por metais nobres como platina, paládio, ródio e molibdênio, suportados em filmes de alumina depositados em cordierita, um material cerâmico poroso, os quais convertem gases poluentes em dióxido de carbono, água e nitrogênio, produtos não poluentes. Neste trabalho, é discutida a desativação de catalisadores automotivos devido às altas temperaturas de operação e por contaminação inorgânica originária dos combustíveis e óleos utilizados. Catalisadores novos e usados foram analisados por adsorção gasosa, picnometria, difração de raios X, e microscopia eletrônica de varredura para caracterizações texturais, morfológicas e estruturais. Microssonda eletrônica foi utilizada para detectar a composição dos catalisadores e dos seus contaminantes.

Catalytic converters or automotive catalyst are formed by noble metals such as platinum, rhodium, palladium, and molybdenum supported in cordierite, a porous ceramic materials which convert the pollutant gases in carbon dioxide, water and nitrogenous, no-pollutant products. In this work, we discuss the deactivation of automotive catalyst due to the high operation temperature and by inorganic contaminants originating in engine oil and fuel. New and used catalysts were analyzed by gas adsorption, picnometry, X-ray diffraction, thermal analyses and scanning electron microscopy for textural, morphological and structural characterization. EDS and WDS electron microprobe were used to detect the composition of the catalysts and their contaminants.

We investigate an extension of the Perard and Bishop (PB) model. In the studied model we get a harmonic one dimensional lattice chain with an additional Morse potential on site. The rotation and vibration motion of each component of the lattice are considered and the coupling for these motions is introduced by a resonance condition. Thermodynamics and structural properties of the system are explored.

A influência da concentração de Al nas transformações de fase em ligas de Cu-Al-Ag foi estudada por análise térmica diferencial clássica (ATD), microscopia óptica (MO) e difratometria de raios X (DRX). Os resultados indicaram que o aumento no teor de Al e a presença de Ag diminuem a velocidade da reação de decomposição da fase <FONT FACE=Symbol>b</font>1 e contribuem para o aumento da temperatura desta transição, diminuindo assim o intervalo de estabilidade da fase perlítica, resultante da reação de decomposição.

The influence of the Al content on the phase transformations in Cu-Al-Ag alloys was studied by classical differential thermal analysis (DTA), optical microscopy (OM) and X-ray diffractometry (XRD). The results indicated that the increase in the Al content and the presence of Ag decrease the rate of the <FONT FACE=Symbol>b</font>1 phase decomposition reaction and contribute for the raise of this transition temperature, thus decreasing the stability range of the perlitic phase resulted from the b1 decomposition reaction.