Avaliação físico-química de efluente gerado em biodigestor anaeróbio para fins de avaliação de eficiência e aplicação como fertilizante agrícola

The use of biodigester for basic and environmental sanitation has large demand in Brazil. A biodigester was built to treat conjunctly the human and pig feces and urine, regarding to its future application in rural small towns. The results show that the biodigester can reduce 90% of COD and BOD and, up to 99.99% of thermotolerant coliforms. The treated effluent has variable quantities of macro- and micro-nutrients; and organic matter. However, the concentration variability of the nutrients makes difficult a dosed application into soil. The soluble salts (mainly as Na+ form) make necessary a controlled use to avoid environmental degradation.

Descoloração de corantes industriais e efluentes têxteis simulados por peroxidase de nabo (Brassica campestre)

The removal of important textile dyes by turnip peroxidase (TNP) was evaluated. The textile effluents besides the residual dyes contain also chemical auxiliaries such as salts, dispersing and wetting agents. The effect of these was evaluated in the removal of the dyes reactive blue 21 and reactive blue 19 by TNP in synthetic effluents. A decrease of the efficency decolorization was observed. The action of the enzyme on colour removal of dye mixture was equivalent to the dyes alone. The chemical demand of oxygen in the effluent after enzymatic treatment had a significant increase in relation to the untreated effluent.

Estudo da emissão por fluorescência de ultravioleta na quantificação de um inibidor de corrosão do tipo sal de amônio quaternário em água

Quaternary ammonium salts are the corrosion inhibitors most frequently used by the oil industry. In this study, the ultraviolet fluorescence technique was evaluated for the analysis of a quaternary ammonium salt in water as a corrosion inhibitor. The comparison with standard salt showed that an alkyl aryl quaternary ammonium salt is the main fluorophore, with emission maxima at 306 and 593 nm. The best instrumental parameters were: width of excitation and emission slits of 10 and 15 nm, respectively, and scan rate of 10 nm min-1. The presence of aromatic compounds and biocides affects the analysis of corrosion inhibitors.

Stability-indicating comparative methods using mekc and lc for determination of olmesartan medoxomil

A stability-indicating method using MEKC was validated for the analysis of olmesartan medoxomil in tablets. Successful separation was achieved using a fused silica capillary (40 cm x 50 µm i.d.); background electrolyte consisted of a combination of 10 mmol L-1 borate buffer and 5 mmol L-1 anionic detergent sodium dodecyl sulfate (95:5; v/v) pH 6.5; hydrodynamic mode at 50 mBar for 5 s; 25 kV separation voltage at 25 ºC; and column temperature 25 ºC with detection at 257 nm. The proposed method, validated following ICH guidelines, was applied to the determination of this antihypertensive with good results compared with an LC method.

Síntese e caracterização de hidrogéis compósitos a partir de copolímeros acrilamida-acrilato e caulim: efeito da constituição de diferentes caulins do nordeste brasileiro

Superabsorbent hydrogels based on poly (acrylamide-co-acrylate) and different kaolins, were prepared by free-radical aqueous copolymerization. FTIR and WAXS techniques were employed for characterization of a series of hydrogels, obtained by varying the percentage of clay, crosslinking and constitution of kaolin. The water absorbency at equilibrium (Weq) decreased with increasing clay content and the amount of crosslinking agent. Superabsorbent hydrogel (Weq > 1084 g H2O/g gel) was obtained as 10 wt% of white kaolin and 0.05 mol% of crosslinking agent were used. The hydrogel proved sensitive to pH variation and the presence of salts.

Syntheses, characterization and antifungal activity of tris(1,10-phenanthroline)iron(ii) bis(n-r-sulfonyldithiocarbimate)zincate(ii)

Four new compounds with the general formula [Fe(phen)3][Zn(RSO2N=CS2)2], where phen = 1,10-phenanthroline, R = 4-FC6H4 (1), 4-ClC6H4 (2), 4-BrC6H4 (3) and 4-IC6H4 (4), respectively, were obtained by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimate (RSO2N=CS2K2) and tris(1,10-phenanthroline)iron(II) sulfate, with zinc(II) acetate dihydrate in dimethylformamide. The elemental analyses and the IR data were consistent with the formation of the expected complexes salts. The ¹H and 13C NMR spectra showed the signals for the cationic iron(II) complex and dithiocarbimate moieties. The molar conductance data were consistent with the 1:1 cation:anion complexes in 1-4. The antifungal activities of the compounds were tested in vitro against Candida albicans, Candida tropicalis and Colletotrichum gloeosporioides.

Dft theoretical study of energetic nitrogen-rich C4N6H8-n(NO2)n derivatives

Density functional theory (DFT) calculations at the B3LYP/6-31G** theoretical level were performed for a series of guanidine-fused bicyclic skeleton derivatives C4N6H8-n(NO2)n (n = 1 - 6). The heats of formation (HOFs) were calculated by isodesmic reactions, and the detonation properties were evaluated using the Kamlet - Jacobs equations. The bond dissociation energies were also analyzed to investigate the thermal stability and sensitivity of the compounds. The results show that all of the derivatives have high positive HOFs, compound G has the highest theoretical density, and compound F1 has the highest detonation velocity and detonation pressure. Considering both the detonation properties and thermal stabilities, compounds D1 and D4 (3 nitro substituents), E1 - E6 (4 nitro substituents), and G (6 nitro substituents) can be regarded as potential candidates for high-energy density materials.

Influencia de variables de formulación en la viscosidad de emulsiones de surfactante aniónico-aceite-agua

Phase transition and viscosity behavior of emulsified systems were studied after modifying their physicochemical formulation. Effects of concentration and nature of salts and n-alcohols, and water/oil relation on the rheological properties of emulsions were also studied. Pre-equilibrated systems were emulsified according to an agitation procedure, and the viscosity (cP) was measured at different shear rates ranging from 1 to 300 s-1. The phase behavior, as well as the emulsion type based on electrolytic conductivity, was observed. Several interpretations of the flow and viscosity curves of emulsions were made through the estimation of rheological parameters such as consistency index "k" and behavior index "n".

Avaliação da lixiviação do cádmio e níquel provenientes da degradação de baterias níquel-cádmio em uma coluna de solo

Spent nickel-cadmium (Ni-Cd) batteries and salts of nickel and cadmium were placed in two different columns of soil for a period of two years. A leaching solution was passed through them at ambient temperature in this period. The behavior of metals in each column was then evaluated. Under the conditions of the experiment, cadmium and nickel demonstrated the potential to contaminate and affect the natural cycles of soil. The disposal of Ni-Cd batteries directly to the soil also increased the concentration of nickel (349 mg kg-1) and cadmium (2890 mg kg-1), sometimes exceeding the intervention values defined in CONAMA resolution 420/09.

CONSTRUÇÃO DE UM DISPOSITIVO DE PRESSURIZAÇÃO A VÁCUO PARA A PREPARAÇÃO DE FASES ESTACIONÁRIAS MONOLÍTICAS VIA PROCESSO SOL-GEL

The filling of capillaries via the sol-gel process is growing. Therefore, this technical note focuses on disseminating knowledge acquired in the Group of Analytical Chemistry and Chemometrics over seven years working with monolithic stationary phase preparation in fused silica capillaries. We believe that the detailed information presented in this technical note concerning the construction of an alternative high pressurization device, used to fill capillary columns via the sol-gel process, which has promising potential for applications involving capillary electrochromatography and liquid chromatography in nano scale, may be enlightening and motivating for groups interested in developing research activities within this theme.

FASES ESTACIONÁRIAS DE LÍQUIDOS IÔNICOS EM CROMATOGRAFIA GASOSA: FUNDAMENTOS, AVANÇOS RECENTES E PERSPECTIVAS

Since their original discovery in 1914, ionic liquids (IL) have been widely examined and explored in chemistry due to their unique physical and chemical properties. Ionic liquids are collectively known as organic salts and have melting points of 100 °C or under. The molten salts most employed in analytical chemistry, including gas chromatography (GC), consist of an organic cation paired with an organic or inorganic anion. This class of materials exhibits negligible vapor pressure and may have their properties (e.g.thermal stability and selectivity) structurally tuned by imparting different moieties to the cation/anion. Currently, there are an estimated 1018possible combinations of IL. In this context, the prospection of highly selective IL-based stationary phases for gas-liquid chromatography has enabled high peak capacity and efficient separations of many critical pairs in complex samples. In this review, we present and discuss fundamental characteristics of ionic liquids and introduce important solvation models for gas-liquid systems. In addition, recent advances and applications of IL in conventional and multidimensional gas chromatography are outlined.

Expression of Grapevine leafroll-associated virus 3 coat protein gene in Escherichia coli and production of polyclonal antibodies

Grapevine leafroll-associated virus 3 (GLRaV-3), the main viral species of the grapevine leafroll complex, causes yield and quality reduction in grapes (Vitis spp.). The coat protein gene was RT-PCR-amplified from total RNA extracted from infected grapevine leaves and the amplified fragment was cloned and completely sequenced. The fragment was subsequently subcloned into the pRSET-C expression vector. The recombinant plasmid was used to transform Escherichia coli BL21:DE3 and express the capsid protein. The coat protein, fused to a 6 His-tag, was purified by affinity chromatography using an Ni-NTA resin. The identity of the purified protein was confirmed by SDS-PAGE and Western blot. The in vitro-expressed protein was quantified and used for rabbit immunizations. The antiserum was shown to be sensitive and specific for the detection of GLRaV-3 in grapevine extracts in Western blot and DAS-ELISA assays, with no unspecific or heterologous reactions against other non-serologically related viruses being observed.

Resultados científicos do cruzeiro do "Baependi" e do "Vega" à Ilha da Trindade: o gênero Firoloida, Prosobranchia Heteropoda

From the Jaseur Bank, off the Brazilian coast at 20º 30' S - 35º 50' W, were collected a few specimens of one of the less known species of the Heteropoda: Firoloida lesueuri (d'Orbigny). A detailed anatomical description follows aiming at the elucidation of some obscure points in the litterature on the subject and at showing the identity of most of the previously described "species" of the genus Firoloida. Special care was taken with the study of the nervous system of which most of the descriptions found were discordant. The author arrived at the conclusion that the pleural ganglia are either missing of fused to the cerebral ganglia, that the supraintestinal ganglion (left parietal ganglion) is present in the posterior region and is close to the subintestinal or right parietal ganglion, being both located near the rear end of the body. The innervations are described and discussed as well as the fusion of extensive tracts of the connectives. The present material is shown to be identical to F. kowalewskyi, well described by Vayssière and Tesch; F. desmaresti (Lesueur 1817) is shown to be undistinguishable from F. blainvilleana and F. gracilis. F. aculeata and F. gaimardi are here considered as "nomina nuda". F. liguriae Issel 1907 is admitted as separate species in spite of its insufficient description and, finally, F. vigilans (Troschel 1855), unsatisfactorily described from only one specimen is perhaps a valid species. A table is presented to show the slight differences between the 4 species which are undoubtedly very similar. F. desmaresti is found only in the Atlantic north of the line and a few points south and close to it as well as in dependent seas, while F. lesueuri is common to the south Atlantic, south Indie and south Pacific oceans, extending north only up to the Azores Islands. F. liguriae is from the south western Atlantic. ?F. vigilans would be an endemic species from Messina (Mediterranean).

Extraction and spectrophotometric determination of Hg2+ as complex anion HgI3-

A method has been developed for the extraction and spectrophotometric determination of Hg2+ in a concentration range of 0.2-1.0 mg L-1; following the Lambert-Beer's law using high molecular weight quaternary ammonium salts dissolved in chloroform. The metal complex anion was determined in the extract in the region UV (260 nm).

Magnetic, thermal and spectral characterization of 2,6-dimethoxybenzoates of Co(II), Ni(II) and Cu(II)

The complexes of 2,6-dimethoxybenzoic acid anion with ions of Co(II), Ni(II), and Cu(II) have been synthesized as polycrystalline solids, and characterized by elemental analysis, spectroscopy, magnetic studies, and also by X-ray diffraction and thermogravimetric measurements. The analysed complexes have following colours: pink for Co(II), green for Ni(II), and blue for Cu(II) compounds. The carboxylate group binds as monodentate, and bidentate bridging and chelating ligands. On heating in air to 1173 K the complexes decompose in four, three or two steps. At first, they dehydrate in one or two steps to anhydrous salts, that next decompose to oxides of the respective metals. The solubility of the investigated dimethoxybenzoates in water at 293 K is of the order of 10-2 mol/dm3. Their magnetic moments were determined in the temperature range of 76-303 K. The results reveal the compounds of Co(II) and Ni(II) to be high-spin complexes and that of Cu(II) to form dimer.