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This work reports the catalysis of bare silica materials (MCM-41, SBA-15, and silica gel) for the complete hydrolyses of bis(2,4-nitrophenyl)phosphate (BDNPP) and bis(4-nitrophenyl)phosphate (BNPP)...

In this work, we describe the synthesis of N doped carbon nanomaterials from mesoporous silica impregnated with iron (10 wt%), using acetonitrile as carbon and nitrogen source by CVD process at 600, 650, 700 and 800 °C. The obtained materials showed a N/C content between 8.3–10.1% and a carbon content between 14 and 31%. Results of TEM, TG, elemental analysis, Raman spectroscopy and XRD showed that higher temperatures synthesis has led to the formation of high content and more organized carbon nanostructures, i.e., carbon nanotubes and bamboo-like structures with higher nitrogen contents in their structure. On the other hand, XPS results showed that the carbon structures obtained at 800 °C have preferential the presence of less reactive nitrogen species, i.e. graphitic nitrogen, while the materials obtained at 600 and 650 °C preferentially have the presence of more reactive nitrogen groups such as pyridine. These materials were used as catalysts for the sulfides oxidation. The type of nitrogen group present in the carbon structure influenced directly the activity of the materials. The catalysts obtained at lower temperatures showed the best kinetics of oxidation sulfides, which was related to the presence of a higher content of more reactive nitrogen groups.

Este trabalho descreve a preparacao e os estudos fotofisicos dos complexos [Ru(H 2 dcbpy) 2 (L 1 )](PF 6 ) 2 (1a) , [Ru(Et 2 dcbpy) 2 (L 1 )](PF 6 ) 2 (1b) , [Ru(H 2 dcbpy) 2 (L 2 )](PF 6 ) 2 (2) e [(Et 2 dcbpy) 2 Ru(µ-L 3 )Ru(Et 2 dcbpy) 2 ](PF 6 ) 4 (3) , onde H 2 dcbpy = 4,4'-dicarboxi-2,2'-bipiridina; Et 2 dcbpy = 4,4'-dicarbetoxi-2,2'-bipiridina; L 1 = 1,10-fenantrolino-5,6-diona; L 2 = dipiridina[1,4]dioxino-monofenazina e L 3 = tetrapiridina[1,4]dioxino-difenazina. Os novos complexos 2 e 3 , e os ja conhecidos 1a e 1b , foram completamente caracterizados por tecnicas espectroscopicas e fisico quimicas. Foram realizados os estudos fotofisicos de todos os complexos sintetizados e e notavel a hidrossolubilidade observada e a fluorescencia em todos os solventes utilizados, incluindo a agua, o que indica que podem ser bons candidatos como corantes sensibilizadores para celulas solares (DSSCs).

An immobilized p-sulfonic acid calix[4]arene was synthesized on the surface of silica-coated Fe3O4 nanoparticles. Due to the combination of the magnetic recovery and the acid properties, it acted as a robust, safe and environmentally friendly catalyst for the one-pot synthesis of Biginelli adducts under microwave irradiation and solvent-free conditions. A series of Biginelli adducts were obtained in moderate to excellent yields, and most importantly, the catalyst could be easily recovered by an external magnet and reused five times without significant loss of catalytic activity (ca. 80% yield for all reuses using 0.64 mol% of the catalyst). Keywords: Fe3O4 nanoparticles, p-sulfonic acid calix[4]arene, Magnetic acid catalyst, Biginelli adducts

The current manuscript describes the catalysts in click chemistry reactions, mechanism insights and use of other metals beyond copper associated with Azide-Alkyne Cycloadditions (AAC). Due to their biological importance and several applications in various areas of science, significant efforts have been devoted to devise robust methods for the synthesis of triazoles. Among these approaches, azide-alkyne cycloadditions strategy has been consolidated as a powerful tool for preparing this class of heterocycles. Herein, click reactions involving catalysis with metals other than copper are presented and critically discussed.

In this work is reported the synthesis, characterization, luminescent properties and positronium formation yields of europium(III) and terbium(III) complexes of stoichiometric formula Ln(dpm)3(2-pyr), where: Ln = Eu and Tb, dpm = 2,2,6,6-tetramethyl-3,5-heptanedionato (dipivaloylmethanate) ion, a β-diketonate ligand, and 2-pyr = 2-pyrrodilidone, a γ-lactam. The crystal structures were determined by single-crystal X-ray diffraction. The complexes crystallize in the space group Pī with one complex in the asymmetric unit. The Eu(III) and Tb(III) ions are seven-coordinated by six O atoms of three β-diketonate ligands, and one O atom of γ-lactam molecule. We present and discuss experimental intensity parameters of 4f-4f transitions in the Eu(III) complexes under UV excitation. The photoluminescent properties of the complexes depend on the energy positions of the ligand-to-metal charge transfer (LMCT) states. The temperature dependence of the Eu(III) 5D0 relaxation rate of the Eu(III) complexes are presented. Positronium formation in Ln(dpm)3 and Ln(dpm)3(2-pyr) (Ln = Eu and Tb) complexes were investigated. A correlation between the parameters of luminescence and positron annihilation spectroscopies has been observed. The results, which strongly evidence the participation of molecular excited states in the positronium formation, were then discussed in terms of the recently proposed Ps formation mechanism, named cybotactic correlated system kinetic mechanism (CCSKM).

The preparation and photoluminescent properties of the new [Eu(FOD)3(2-Pyr)2] complex (FOD = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octadionate; 2-Pyr = 2-pyrrolidone) are reported. The obtained complex was characterized by elemental analysis, complexometric titration using EDTA, infrared spectroscopy, and single-crystal X-ray diffraction studies. The coordination polyhedron of the complex is described as a distorted square antiprismatic with both 2-Pyr monodentate ligands coordinated to Eu(III) via the oxygen atoms, in neutral form, while the three FOD molecules are coordinated in the anionic form. Structural modeling at the PBE1PBE/SVP/MWB52 level of theory provided a geometry in excellent agreement with the one obtained experimentally. Spectroscopy properties such as intensity parameters (Ω2 and Ω4), radiative emission rate (Arad), and chemical partition of Arad for [Eu(FOD)3(2-Pyr)2] and [Eu(FOD)3(H2O)2] were calculated by using the QDC model with help of the semiempirical wavefunctions. The modeling of the ligand-to-metal energy transfer for both complexes was performed, allowing to obtain the theoretical emission quantum yield and to characterize the most relevant molecular orbitals involved.

O presente estudo de cunho quantitativo, teve como objetivo analisar a suplementação nutricional e a sua relação com a saúde e composição corporal de praticantes de musculação em uma academia da cidade de Castanhal-PA, bem como avaliar as mudanças antropométricas ocasionadas em decorrência da reeducação alimentar dos sujeitos pesquisados. Participaram deste estudo 20 indivíduos, sendo 10 homens e 10 mulheres, com idade entre 20 e 35 anos. Foram aplicados dois questionários recordatários, um sobre como era a alimentação do indivíduo antes de iniciar seu período de treinamento e um sobre sua alimentação após três meses de treinamento, e um terceiro questionário relacionado à suplementação alimentar. Os resultados apontaram melhoras significativas na reeducação alimentar dos sujeitos. Quanto a suplementação alimentar, os suplementos mais consumidos foram os ricos em proteínas (60% dos homens e 83% das mulheres) e aminoácidos ramificados, sendo estes consumidos por 30% dos homens e 67% das mulheres. A maior parte dos suplementos foi consumida por iniciativa própria para 38% dos homens. Os benefícios observados e relatados com a suplementação foram o ganho de força e de massa muscular - em que 50% dos homens e 60% das mulheres apresentaram esses ganhos. Sendo que também uma minoria da amostra relatou alguns efeitos colaterais que foram associados ao suplemento alimentar. Mudanças positivas na antropometria também foram observadas. Conclui-se que existe uma forte relação entre exercícios físicos e mudanças de hábitos alimentares, e a associação com uso de suplementos alimentares.

A Sindrome de Burnout (SB) e uma importante patologia na area da Saude do Trabalhador (ST), marcada por uma resposta psicossocial inerente

Phosphate esters and analogs thereof are well known in chemistry and biology by their formidable stability. We used a porous silica material (PSiM) functionalized with amino groups (8.4%) and lanthanum ions (1.5%) to catalyze the cleavage of bis(2,4-dinitrophenyl)phosphate (BDNPP). The functionalized PSiM attracted the substrate from solution and accelerated its hydrolysis by 38-fold in relation to the uncatalyzed reaction at pH 8.14. After an induction period associated to hydration of the catalyst during the first use, the catalytic activity increased in the first reuse to about 600-fold. Supramolecular effects were proposed to drive the catalytic process. Kinetic studies in different pH's showed that the lanthanum ion and amino groups acted mutually in the BDNPP hydrolysis and a reaction mechanism that took this into account was proposed.

This work reports the use of an iron ore tailings from waste dam as a catalyst and support for carbon nanotubes synthesis and their application in the adsorption of the 17α-ethinylestradiol hormone. The synthesis was carried out by Chemical Vapor Deposition (CVD) in a Fluidized Bed system using: ethylene at temperatures of 500, 600 and 700 °C, and acetonitrile at 500, 600, 700, 800 and 900 °C. The transmission electron microscopy (TEM) results showed that the two higher temperatures in each case favored the formation of nanostructures like carbon nanotubes (CNTs), with good yields. The ethylene source generated classic tubular structures of multiple walls. On the other hand, acetonitrile provided the formation of tubes with less organization, known as bamboo like. This morphology was caused by the insertion of nitrogen into the graphite structure (doping), which originates from the carbon source. The adsorptive capacity of the materials for 17α-Ethinylestradiol removal ranging from 9.2 mg g−1 to 22.3 mg g−1. The kinetic and adsorption isotherm studies were also performed for the systems. As for kinetics, all of them presented pseudo-second order behavior. In relation to the type of isotherm, the systems showed Freundlich behavior, that is, the adsorption occurs in multiple layers. Finally, it was concluded that the use of an iron ore tail as a catalyst in the production of CNTs by CVD is feasible. The materials synthesized still had good adsorptive capacity for an emerging contaminant, thus this study allowed the investigation of two environmental problems.

In this work, supported ionic liquid (IL) phases catalysts were prepared based on Pd dispersed in IL phases supported on magnetic particles of nickel/molybdenum covered with carbon (NiMo/C). The magnetic support was prepared via CVD method at 800 °C. XRD analysis showed the phases of metallic nickel and molybdenum carbide. The presence of carbon in these materials was confirmed by TEM/EDS and thermogravimetric analysis (TG) analysis. Pd particles were dispersed in 1 and 2.5 wt% of the IL 1-butyl-3-methylimidazolium tetrafluoroborate (BMIm·BF4), which were immobilized on the support surface via impregnation method. TG analysis shows a weight loss between 300 and 420 °C attributed to the BMIm·BF4, confirming the existence of IL on the support surface. The prepared materials were investigated in hydrogenations reactions of 1,5-cyclooctadiene and nitrobenzene, and the influence of IL on the activity and selectivity of these catalysts were observed. These materials have great potential for catalysis applications, because they bring together the advantages of the IL in the catalyst surface and the facility of magnetic materials separation.

KOH activation of a mesophase pitch produces very efficient carbons for the removal of sulfide in aqueous solution, increasing the sulfur oxidation rate with the degree of activation of the carbon. These carbons are characterized by their graphitic structures, with domains of sizes of around 20 nm, and a moderate concentration of surface oxygen groups (0.2–0.5 mmol·g–1) dominating the basic groups. Because the activation leads first to a strong development of the micropores and later to a development of the mesopores, the surface area values are always high, reaching values of as high as 3250 m2·g–1 in the most activated carbon, with a volume of mesopores of as high as 44% of the total pore volume. In the presence of this carbon, the sulfide oxidation rate is 100 times higher than that found for a commercial activated carbon, the results indicating that the porosity of the carbon, especially mesoporosity, plays a role more important than the structure or the chemical nature of the carbon in the kinetics of sulfide oxidation to different polysulfides. The authors thank CNPq, CAPES, INCT, PRPq-UFMG, and Prometeo II/2014/004 for financial support.

In this work, it was investigated the conversion of fatty acids into hydrocarbon based on the reaction with NaOH followed by a controlled thermal decomposition. FTIR, Raman, UV–vis, XRD, TG-MS, SEM/TEM, CHN, GC–MS showed that precursors based on NaOH/oleic acid (molar ratios 0.7, 1.0, 1.5 and 2.0) decomposed at 550 °C to produce three fractions, i.e. liquid (5–37 wt%), gas (52–70 wt%) and solid (10–31 wt%). The liquid fraction was composed of a complex mixture containing mainly aromatic compounds. On the other hand, the major gas fraction showed a remarkable selectivity for propane (56–61 wt%) with some C 1 , C 2 , C 4 , H 2 and CO x . The solid fraction showed the presence of Na 2 CO 3 , Na 2 O and particles of amorphous and graphene like carbon. Upon treatment at 800 °C the carbonate decomposes to CO 2 , oxidizes the carbon and regenerated the Na 2 O which can potentially be used for a new reaction cycle. These results are preliminary discussed in terms of a catalytic effect of the basic sodium oxide to promote cracking, dehydrogenation and H-transfer reactions.

Phenazinic ligands and Ru(II)-based complexes were synthesized from natural products lapachol and lawsone and evaluated against T. cruzi, the etiological agent of Chagas disease. These new ruthenium compounds could provide promising trypanocidal drugs. Besides synthesis and trypanocidal activity, this paper reports photophysical features and computational details of the compounds. The fluorescent trypanocidal substances are promising derivatives for further studies aiming to find molecules active against parasites associated with neglected diseases.

In this work, samples of Fe mining tailings from the collapsed Fundão Dam, Brazil, which were retained by the Candonga hydroelectric power plant, were characterized by various techniques. Quartz, hematite, kaolinite, and goethite were identified as the main phases present. The composition, homogeneity, and relatively low (~1%) organic matter content indicate potential for usage of these tailings in civil constructions. The next step of this work is to investigate such applications. If their feasibility is confirmed, the goal is to use this material for construction in the areas affected by the Fundão Dam rupture. This use will lead to positive socio-environmental impacts in these regions, where tailings still need to be removed and damaged infrastructure needs to be repaired. Integr Environ Assess Manag 2020;16:636-642. © 2019 SETAC.Neste trabalho, amostras do rejeito de mineração de ferro, proveniente do rompimento da barragem de Fundão e retidas pela usina hidroelétrica de Candonga, foram caracterizadas por diversas técnicas. Quartzo, hematita, caulinita e ghoetita foram identificadas como as principais fases presentes no rejeito. A composição, homogeneidade e teor de matéria orgânica relativamente baixo, cerca de 1%, indicam uso potencial deste material em construção civil. O próximo passo deste trabalho é investigar tais aplicações. Se a viabilidade for confirmada, o objetivo é utilizar esse material para obras nas áreas afetadas pelo rompimento da barragem de Fundão. Isso contribuirá para reduzir os impactos socioambientais nessas regiões, as quais ainda necessitam da remoção do rejeito e de reparos na infraestrutura danificada. Integr Environ Assess Manag 2020;16:636-642.

This work is reports the luminescent properties and positronium formation yields of the Eu(dpm)3 and Eu(dpm)3(2-pyr) complexes, where dpm = 2,2,6,6-tetramethyl-3,5-heptanedionato (dipivaloylmethanate) ion and 2-pyr = 2-pyrrodilidone. We present and discuss experimental intensity parameters of 4f-4f transitions in the Eu3+ complexes under UV excitation. Positron annihilation lifetime spectroscopy (PALS) and Doppler broadening of annihilation radiation lineshape (DBARL) measurements were also performed. It was observed that the photoluminescent properties and Ps formation yields of the complexes are related to intramolecular processes, such as a ligand-to-metal charge transfer (LMCT). The results, which strongly evidence the participation of molecular excited states in the positronium formation, were then discussed in terms of the recently proposed Ps formation mechanism, named cybotactic correlated system kinetic mechanism (CCSKM).This work is reports the luminescent properties and positronium formation yields of the Eu(dpm)3 and Eu(dpm)3(2-pyr) complexes, where dpm = 2,2,6,6-tetramethyl-3,5-heptanedionato (dipivaloylmethanate) ion and 2-pyr = 2-pyrrodilidone. We present and discuss experimental intensity parameters of 4f-4f transitions in the Eu3+ complexes under UV excitation. Positron annihilation lifetime spectroscopy (PALS) and Doppler broadening of annihilation radiation lineshape (DBARL) measurements were also performed. It was observed that the photoluminescent properties and Ps formation yields of the complexes are related to intramolecular processes, such as a ligand-to-metal charge transfer (LMCT). The results, which strongly evidence the participation of molecular excited states in the positronium formation, were then discussed in terms of the recently proposed Ps formation mechanism, named cybotactic correlated system kinetic mechanism (CCSKM).

The cement normally applied in carbon capture and storage sites as well lining or plugs may undergo degradation due to carbon dioxide (CO2) exposure, increasing the risk of CO2 gas leakage to the surface. Thus, finding a substitute is urgently necessary. This study reports the application of geopolymers produced with fly ash and rice husk ash as an adsorbent material for the capture of CO2. Different geopolymer formulations were used to produce mechanical resistance and CO2 adsorption capacity materials. The quantification of the reactive oxides in the precursor materials was carried out to obtain a better degree of geopolymerization. The geopolymers were characterized by X-ray diffraction (XRD), Brunauer - Emmett – Teller (BET), Scanning electron microscopy (SEM) and compressive strength analysis. Calcined rice husk ash activated by NaOH was found to be the most suitable precursor material to produce a geopolymer for CO2 adsorption, with a capacity 24.4% higher than the best geopolymer adsorbent reported in the literature to date.

Quinonoid compounds based on 5-iodo-1,4-disubstituted-, 1,4- and 1,5-disubstituted-1,2,3-triazoles were synthesized using simple methodologies and evaluated against T. cruzi, the etiological agent of Chagas disease, and cancer cell lines PC3, HCT-116, HL-60, MDA-MB-435 and SF-295. The cytotoxic potential of the lapachones was also assayed against peripheral blood mononuclear cells (PBMC). Two compounds 6 and 12 were identified as potential hits against T. cruzi. β-Lapachone-based 1,5-disubstituted-1,2,3-triazole (12) displayed an IC50/24 h = 125.1 μM, similar to benznidazole, the standard drug. Compound 12 was also more active than the precursor β-lapachone against the cancer cell lines. These compounds acting as multitarget quinoidal systems could provide promising new leads for the development of trypanocidal and/or anticancer drugs.

Measurements using positron annihilation lifetime (PALS) and Doppler broadening annihilation radiation lineshape (DBARLS) spectroscopies were performed in several lanthanide dipivaloylmethanate complexes, Ln(dpm) 3 where Ln = Sm 3+ , Gd 3+ , Tb 3+ , Ho 3+ , Er 3+ , Yb 3+ and dpm = 2,2,6,6-tetramethyl-3,5-pentanedionate, and also on their binary solid solutions and mechanical mixtures, biphasic systems, of the general formula Ln 1− x Eu x (dpm) 3 . Expressive positronium formation was observed in all Ln(dpm) 3 complexes, except in Eu(dpm) 3 complex. The results indicate formation of solid solutions in the Sm 3+ , Gd 3+ and Tb 3+ systems, where total inhibition of positronium formation was observed. A Stern–Volmer type equation, I 3 0 / I 3 = 1 + kx , was used to fit the data, enabling the calculation of the inhibition constants, k . A mechanical mixture behavior, with linear variation of I 3 between the I 3 values of the pure complexes, was observed in systems containing Ho 3+ , Er 3+ and Yb 3+ complexes, where no effective solid solution formation occurred due to differences between the crystalline structures of these complexes and Eu(dpm) 3 . No positronium quenching reactions were observed in the solid solutions. DBARLS results confirmed those of PALS, evidencing that the positron annihilation spectroscopies are useful techniques to characterize the formation of solid solutions. PALS measurements at 80 K were performed in the Sm 1− x Eu x (dpm) 3 and Gd 1− x Eu x (dpm) 3 solid solutions. The results indicate that, despite a contraction in the crystalline structures, the solid solution structure remains intact at low temperatures. The temperature dependence of the inhibition constant do not seem to be understood from the positronium formation spur model and might be related to intra and intermolecular energy and charge transfer processes in the solid solutions, which is currently being studied.

In this work, the coordination compounds presenting the formulas [Eu(acac)(NO3)2 (phen)2]⋅H2O (Eu1) and [Eu(bzac)(NO3)2(phen)2]⋅H2O (Eu2), acac: acetylacetonate, bzac: benzoylacetonate and, phen: 1,10-phenantroline, were successfully synthesized and some spectroscopic properties were investigated by theoretical and experimental methods. These compounds were characterized via elemental analysis, FTIR spectroscopy and thermogravimetric analysis (TGA). The X-ray diffraction data revealed that the compound Eu1 crystallizes in the monoclinic space group P2/n. Spectroscopic data showed that ligand-to-metal charge transfer states (LMCT) in the [Eu(β-dik)(NO3)2(phen)2]⋅H2O complexes (β-dik: acac or bzac) are redshift as compared with [Eu(β-dik)3(phen)] complexes. These data showed that LMCT states play the most important role on the luminescence quenching in the complexes Eu1 and Eu2, which only exhibit high luminescence intensities at low temperatures. Furthermore, the role of changes in the chemical environment on the intensity parameters Ωλ (λ = 2 and 4) have been investigated from the theoretical point of view for the complexes Eu1 to Eu2, and from these to tris β–dik complexes. Interestingly, the theoretical intensity parameters ratio Ω2/Ω4 calculated are in a good agreement with those experimental ones.

O presente artigo teve como objetivo avaliar os benefícios da prática do exercício físico sistematizado em mulheres que sofrem com os sintomas incomodativos da menopausa na cidade de Castanhal-PA, comparando dados de mulheres menopáusicas fisicamente ativas com de mulheres também menopáusicas, porém sedentárias, mediante aplicação do questionário da Escala de Avaliação da Menopausa (MRS - Menopause Rating Scale), do Índice de Massa Corpórea (IMC) e da Circunferência da Cintura (CC). O desenho deste estudo é descritivo e transversal, e avaliou 33 mulheres menopáusicas, sendo 17 fisicamente ativas e 16 sedentárias. O MRS avaliou as participantes em três domínios: sintomas somato-vegetativos, sintomas psicológicos e sintomas urogenitais. As fisicamente ativas apresentaram menor severidade em todos os domínios. De acordo com o IMC, observou-se que das sedentárias 38% estavam com obesidade grau I e 6% com obesidade grau II enquanto que apenas 6% das fisicamente ativas com obesidade grau I e nenhuma na condição de obesidade grau II. Em relação a CC, de todas as participantes da pesquisa 29% das fisicamente ativas apresentaram sem risco, por outro lado somente 6% das sedentárias se mostraram sem risco para doenças associadas à obesidade. No presente estudo o exercício físico aeróbio regular de intensidade controlada influenciaram positivamente a qualidade de vida e a intensidade da sintomatologia climatérica.

O objetivo deste trabalho foi analisar a participação do gênero feminino em cursos técnicos da Rede Federal no Brasil e no Amapá em 2018, por faixa etária. A abordagem deste estudo é de natureza quanti-qualitativa. Os dados coletados foram oriundos do banco de dados Plataforma Nilo Peçanha. Os resultados mostraram que tanto no Brasil quanto no Estado do Amapá houve um predomínio de mulheres matriculadas nos institutos de ensino, no ano de 2018. A nível nacional, os dados mostraram que mulheres com menos de 20 anos são maioria nos Institutos Federais de ensino, enquanto que no Estado do Amapá verificou-se o inverso. Nacionalmente, na faixa etária de 20 a 34 os matriculados se igualam. No Amapá, na faixa etária de 20 a 34 anos há um leve predomínio das mulheres. Os dados mostram ainda que há uma diferença (queda) significativa na porcentagem de mulheres com 50 anos ou mais no ensino técnico. Embora se observe um avanço, ainda existe muita desigualdade entre homens e mulheres e um longo caminho para alcançar a equidade entre os gêneros.

The diversity of whole rice grains with black and red pericarp has been valued in Brazil due to its different characteristics of color, texture, and also due to the association with health benefits. This work aimed to evaluate the physicochemical, cooking, and textural characteristics of different samples of polished and whole rice grains from different varieties marketed in Brazil. A total of 28 samples were collected and divided into 6 groups: polished white rice, white polished parboiled rice, whole white rice, whole red rice, whole black rice, and whole wild rice. Moisture content, crude protein, ash, mineral content, hardness, and adhesiveness were analyzed. The cooking quality was evaluated through the determination of cooking time, swelling ratio, and volume expansion ratio. A strong correlation between the protein content and the hardness value of cooked grains was observed. The polished samples showed the lowest ash and mineral values and the shortest cooking time. A strong correlation was also observed for the volume expansion ratio and hardness of cooked samples. The data obtained contribute to a better understanding of the quality of the rice marketed in Brazil and demonstrate a large variation among samples in terms of physicochemical, cooking, and texture properties. La diversidad del arroz integral con pericarpio negro y rojo se ha valorado en Brasil debido a las diferentes características de color, textura y también por la asociación con los beneficios para la salud. El objetivo de este trabajo fue evaluar las características físico-químicas, de cocción y de textura de muestras de arroz pulido y integral de diferentes variedades vendidas en Brasil. Se realizó un muestreo exploratorio y aleatorizado, con el objetivo de adquirir el mayor número de marcas. Se recolectaron 28 muestras y se dividieron en 6 grupos: arroz blanco pulido, arroz blanco precocido, arroz integral blanco, arroz integral rojo, arroz integral negro y arroz integral silvestre. Se analizaron los contenidos de humedad, proteínas, cenizas, minerales, dureza y adhesividad. La calidad de cocción se evaluó determinando el tiempo de cocción, el índice de absorción de agua y el índice de expansión. Se observó una fuerte correlación entre el contenido de proteína y el valor de dureza de los granos cocidos. Las muestras de arroz pulido mostraron los valores más bajos de cenizas y minerales y el tiempo de cocción más corto. Se observó una fuerte correlación entre el índice de expansión y el valor de dureza de las muestras cocidas. Los resultados obtenidos contribuyen a una mejor comprensión de la calidad del arroz vendido en Brasil y demuestran una gran variación entre las muestras en términos de propiedades físico-químicas, cocción y textura. As diversidades de arroz integral de pericarpo preto e vermelho têm sido valorizadas no Brasil devido às diferentes características de cor, textura e também pela associação com benefícios à saúde. Esse trabalho teve como objetivo avaliar as características físico-químicas, de cozimento e textura de amostras de arroz polido e integral de diferentes variedades comercializadas no Brasil. Foi realizada uma amostragem exploratória e aleatorizada, objetivando adquirir o maior número de marcas, sendo coletadas 28 amostras e divididas em 6 grupos: arroz branco polido, arroz branco parboilizado polido, arroz branco integral, arroz vermelho integral, arroz preto integral e arroz selvagem integral. Foram analisados os teores de umidade, proteína, cinzas, minerais, dureza e adesividade. A qualidade de cozimento foi avaliada através da determinação do tempo de cozimento, índice de absorção de água e índice de expansão. Foi observada uma forte correlação entre o teor de proteína e o valor de dureza dos grãos cozidos. As amostras de arroz polido apresentaram os menores valores de cinzas e minerais e menor tempo de cozimento. Foi observada uma forte correlação entre o índice de expansão e o valor de dureza das amostras cozidas. Os resultados obtidos contribuem para uma melhor compreensão da qualidade do arroz comercializado no Brasil e demonstram uma grande variação entre as amostras em termos de propriedades físico-químicas, cozimento e textura.

In this work, it was studied the interaction of the hazardous antibiotic amoxicillin (AMX) molecules inside the mesocavities of a composite MCM-41/cetyltrimethylammonium (MCTA). MCTA with low surface area (5 m2 g−1) showed high sorption efficiency of AMX (55 mgAMX g−1) comparable with high surface area activated carbon (980 m2 g−1). Positron annihilation spectroscopy and isosteric heats suggested that the AMX molecules are not adsorbed by a classical surface process but are attracted and trapped by the CTA C18 hydrophobic chains inside the MCM-41 mesocavities. Preliminary kinetic data suggests that the AMX sorption process takes place in three stages, the external adsorption, interaction with the CTA molecules and diffusion inside the mesocavities.

In this work, the effect of crystallite size, defects, and surface area of iron oxyhydroxide particles supported on mesoporous MCM-41 on the adsorption of hazardous β-lactamic antibiotics was investigated. Different adsorbents were prepared by impregnation of 5, 10, 20, and 50 wt% of Fe followed by treatment at 150–400 °C. Mossbauer, XRD, BET, TG, FTIR, and Raman analyses suggested that treatment at 150 °C produced a mixture of α-Fe2O3, FeOOH, and highly dispersed Fe3+ species. At higher temperatures, different phases were gradually converted to hematite with crystallite sizes varying from 1 to 5 nm. Both, Fe content and temperature, strongly affected the amoxicillin, cephalexin, and ceftriaxone adsorption at pH 5, 7, and 9, with the best results obtained for the sample 20Fe150 (20% Fe treated at 150 °C), ca. 25 mgAMX g−1 which decreased to 17, 6, and 4 mgAMX g−1 (AMX = amoxicillin) upon treatment at higher temperatures. These results combined with competitive adsorption using AMX/phosphate and H2O2 decomposition experiments suggested that the antibiotic molecules are likely adsorbing by complexation on Fe3+ surface species of poorly crystallized small particles of Fe oxyhydroxide phases. It was observed that below a critical crystallite size of 3 nm, the AMX adsorption was very sensitive and strongly increased.

BACKGROUND Remediation of oil spillage accidents requires efficient and low cost floating absorbents to remove small amounts of contaminant oil. In this work, a highly hydrophobic floating magnetic macroporous structure based on silica encapsulated Fe nanoparticles was prepared and used for oil absorption from water. RESULTS The magnetic macroporous materials were prepared by silica encapsulation of iron oxide/hydroxide nanoparticles followed by a thermal treatment with H2. Mossbauer, XRD, SEM/TEM, CHN, IR, TG/DTA and contact angle analyses showed that the Fe oxides nanoparticles are reduced by H2 to form Feo cores protected by silica which sinters to form a macroporous network. The surface reaction with octadecyltrimethoxysilane (Si(CH3O)3C18H37) was used to produce highly hydrophobic materials. CONCLUSIONS The materials obtained showed very high oil absorption capacities for different model contaminants, i.e. petroleum, soy bean oil, diesel, gasoline and xylene removal. The results are discussed in terms of a macroporous structure with strong capillarity combined with a very hydrophobic surface. © 2015 Society of Chemical Industry