Rapid quantification of residual glyphosate in water treated with layered double hydroxides using liquid chromatography / Quantificação rápida de glifosato residual em água tratada com hidróxidos duplos lamelares usando cromatografia líquida

High performance liquid chromatography and an optimized colorimetric method were applied to determine the residual glyphosate in waters treated with double lamellar hydroxides such as MgxAlyCO3.nH2O. The chromatographic determination was by means of derivatization with 9-fluorenylmethylchloroformiate and running time less than 2 minutes, faster than analogous methods in the literature. The colorimetric method was performed by optimizing the Ruhemann purple method. The chromatographic and colorimetric methods presented LOQ of 1.05 and 2.08 ?g / mL and LOD of 0.31 and 0.84 ?g / mL, respectively. The percentages of recovery of the methods are between 93 to 105% with RSD less than 2.35% for the chromatographic method and 6% for the colorimetric. Both methods depend on the temperature. The double hydroxide Mg1Al1CO3.nH2O has the highest percentage of charge density (5.54 nm2) and the best performance in removing glyphosate from the aqueous medium

Processo para aumentar a porcentagem de geraniol e nerol no óleo essencial de Melissa officinalis

Em 08/08/2014: Anuidade de pedido de patente de invenção no prazo extraordinário.DepositadaA presente invenção provê processo para aumentar a proporção de geraniol e nerol no óleo essencial de Melissa officinalis. As plantas cultivadas in vitro, em meio MS (Murashige e Skoog, 1962) acrescidos de diferentes combinações de citocininas e auxinas, apresentaram aumento significativo nas concentrações de nerol e geraniol no óleo essencial, quando comparadas com as plantas não tratadas com reguladores de crescimento

Produção de biodiesel através de transesterificação in situ de sementes de girassol via catálise homogênea e heterogênea

The objective of this work is to show the results of the in situ transesterification of sunflower seed oil with methanol on basic homogeneous and heterogeneous catalysis for the production of biodiesel. In homogeneous catalysis, the activity of KOH and K2CO3 were evaluated using the same oil:methanol ratio of 1:90. KOH showed to be more active than K2CO3, leading to total conversion in biodiesel after 1h reaction time. In the heterogeneous catalysis the activity of K2CO3/Al2O3 was comparable to the activity of K2CO3 bulk: 53.0 and 66.6% resp. The properties of samples of biodiesel produced by homogeneous and heterogeneous catalysis were evaluated and are in accordance with the recommended fuel properties

Geopolimeros com base em cinzas volantes activadas com naoh y Ca(OH)2: caracterização microestrutural por rmn-mas 29Si y 27Al

In fly-ash alkali-activation technology, depending on the combination of activators, deleterious reactions may result in a drop in resistance with age. This Studiy aimed to evaluate the compressive strength of alkali-activated fly ash from combined solutions of NaOH and Ca(OH)2. Three molar ratio CaO/SiO2 (C/S) were studied: 0.05 (M5), 0.15 (M15) e 0.25 (M25). Resistances order of 21 MPa (M15) and 19 MPa (M25) were reached at the age of 7 days. However, after 28 and 91 days, the resistances were 8 MPa and 7 MPa, respectively. The M5 samples showed rising behavior of resistance with age. Thus, the drop in resistance has conditioned the C/S matrices. In the 29Si NMR spectra of the M25 sample Si has decreased species Q4 (3Al) and Q4 (2Al), those responsible for the mechanical properties of activated samples.Na tecnologia de álcali-ativação de cinzas volantes, dependendo da combinação dos ativadores, reações deletérias poderão resultar em queda na resistência com a idade. Assim, este trabalho teve como objetivo avaliar a resistência à compressão de cinzas volantes álcali-ativadas,a partir de soluções combinadas de NaOH e Ca(OH)2. Três relações molares CaO/SiO2 (C/S) foram estudadas: 0.05 (M5), 0.15 (M15) e 0.25 (M25). Resistências da ordem de 21 MPa (M15) e 19 MPa (M25) foram atingidas na idade de 7 dias. Porém, aos 28 e 91 dias as resistências foram de 8 MPa e 7 MPa, respetivamente. As amostras M5 apresentaramcomportamento ascendente da resistência com a idade. Assim, a queda na resistência está condicionada a relação C/S das matrizes. Nos espectros 29Si RMN da amostra M25 o Si apresenta diminuição das espécies Q4(3Al) e Q4(2Al), estes responsáveis pelas características mecânicas das amostras ativadas