Nuevos métodos de tratamiento de muestra para la preconcentración, estabilización y determinación de pesticidas por cromatografía de gases

Tesis de la Universidad Complutense de Madrid, Facultad de Ciencias Químicas, Departamento de Química Analítica, leída el 06-07-2001Depto. de Química AnalíticaFac. de Ciencias QuímicasTRUEpu

New perspectives for the application of diatomaceous earth to the remediation of polluted waters and soils

Se realizaron investigaciones acerca de la remediación de aguas residuales para prevenir daños, tanto de las reservas de aguas subterráneas como superficiales. Con este propósito, las tierras de diatomeas, un barato, disponible y no contaminante material, fue ensayado para la retención de contaminantes persistentes, tales como los metales pesados (cadmio) y pesticidas (antracita y cloropirifos). Esto ha sido utilizado en la prevención de la contaminación de aguas subterráneas debido a su gran movilidad reportada y a la irrigación y limpieza de suelos destinados a la agricultura. Variables tales como profundidad, espesor, etc. de los suelos quedaron cuidadosamente establecidos para simular una explotación casi real de suelos potencialmente contaminados. Los resultados preliminares presentados aquí muestran porcentajes de retención de cadmio mayores del 75 % y del 50 % para la antracita. Estos enfatizan el potencial uso como limpiador y remediador de las tierras de diatomea para contaminantes persistentes, tales como los metales pesados y los pesticidas, en particular, los utilizados en este estudio. La adsorción por las tierras de diatomeas es válida para todos los suelos ensayados. Luego, existe la posibilidad de prevenir la contaminación por cadmio en aguas subterráneas por deposición de una capa de las tierras de diatomeas bajo la superficie de los suelo

Repeated exposure of jacket plum (Pappea capensis) micro-cuttings to indole-3-butyric acid (IBA) improved in vitro rooting capacity

The objective of the trial was to determine an effective propagation protocol for jacket plum (Pappea capensis) tree species. Experiments on in vitro propagation and rooting of stem cuttings were carried out. Dipping stem cuttings in half strength Murashige and Skoog (MS) media for 12 h prior to application of rooting hormones improved bud break and prolonged survival of stem cuttings on a mist bed. Early leaf loss was observed for stem cuttings planted without MS treatment. However, rooting was poor (11% for cuttings pre-treated in MS and 0% for those not pre-treated). For micro-propagation, significant differences (P < 0.05) in shoot multiplication and root regeneration were found. MS media supplemented with 2.0 mg l–1 benzylaminopurine was superior in the number of micro-shoots produced. Rooting capacity of micro-cuttings was improved from 42% to 64% when MS media supplemented with 0.5 mg l–1 IBA were repeated for the micro-cuttings that initially failed to root. There was 70% survival rate of plantlets after hardened off.The financial support from the Federal Ministry of Economic Cooperation (BMZ/GTZ), Germany through the World Agroforestry Centre (ICRAF) Southern Africa Regional Programme, Agro-Forest and Bio Energy Association and Invest North West, South Africa is acknowledged

Advances in nanocatalysts design for biofuels production

The exploitation of nanocatalysts, at the boundary between homogeneous and heterogeneous catalysis, is tracking new efficient ways to produce renewable biofuels in environmentally friendly conditions. Their solid state makes them recyclable, and their nanomateric particle size enables high activities approaching those offered by homogeneous catalysts, as well as novel and unique catalytic behaviors not accessible to solids above the nanometer range. Furthermore, the use of magnetically active materials has led to the development of nanocatalysts easily recoverable through the application of magnetic fields. In this mini-review, latest achievements in the production of advanced biofuels using stable, highly active, cheap and reusable nanocatalysts are described. Specifically, biodiesel and high density fuels have been chosen as major topics of research for the design of catalytic nanomaterials

Estudio de la acción desfoliante de epífitos sobre especies de Quercus

Tesis de la Universidad Complutense de Madrid, Facultad de Biología, Departamento de Biología Vegetal I, leída el 22-04-1999Fac. de Ciencias BiológicasTRUEpu

Optimization of the enzymatic butanolysis of jatropha oil for biodiesel production using Eversa

The use of non‐edible oils for energy production is attracting increasing attention, with a particular focus on those oils that can be produced from plants growing in non‐arable areas. Among the possible alternatives, oils with high free fatty acid content, such as jatropha, have shown great potential. The optimization of jatropha oil in the presence of a bio‐based alcohol (butanol) was investigated for the production of biodiesel using a commercial enzyme (Eversa from Novozymes). The optimization was conducted by changing the reaction temperature and the amount of catalyst, with a 6:1 butanol/oil molar ratio, while the reaction time was set to 60 min. The optimal result was found at the highest reaction temperature (42 °C) and the highest catalyst amount (9.79%), with a biodiesel yield of 83%. A second optimization was conducted, allowing the time to run for up to 8 h. Here the final biodiesel produced was in line with the EU14214 standards, fulfilling all the requirements with the exception of the requirement for oxidation stability. In addition to fulfilling most of the EU14214 standards, the cost of this new enzyme is lower than that of other commercial alternatives. Results show that biodiesel produced using butanol as alcohol in the transesterification process improved cold flow properties in terms of cloud point (CP), pour point (PP), and cold filter plugging point (CFPP). © 2021 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley &amp; Sons LtdDepto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEpu

Sustainable production of jojobyl alcohols and cell viability study

Abstract: An innovative biorefinery approach has been applied to evaluate jojoba oil (JO) in high value-added products. It consists of enzymatic transesterification using short (1-propanol, 1-butanol), medium linear (1-octanol), and branched (2-ethylhexanol) chain alcohols. The proposed biorefinery approach uses an integrated process for the production of jojobyl alcohol (JA) mixtures (11-eicosenol, 13-docosenol and 15-tetracosenol) as products that can be used in pharmaceutical applications. The remaining fraction of fatty acid alkyl esters (FAAE) has a wide range of industrial uses and could be used as a promising alternative to conventional fuels, as it complies with EN14214, the European Biodiesel Norm. The separation of JA from FAAE was carried out by crystallization using a binary mixture of hexane and diethyl ether. After the separation step, the main properties of FAAE were determined. The results showed that the cold flow properties and oxidation stability of the FAAE fraction, obtained as co-product during the process, have been improved with respect to transesterified JO. The use of 2-ethylhexanol as an alcohol in the transesterification reaction increases the amount of the most valuable fraction containing JAs. In vitro cell viability was measured in HEK293T cells using the tetrazolium dye reduction (MTT) assay. The results showed that this oily liquid mixture of JA components (cis-11-eicosenol, cis-13-docosenol, and cis-15-tetracosenol) had a cytotoxic effect at concentrations of 10 and 100 μmol L−1 and no cytotoxic activity at 1 μmol L−1. The concentration of 1 μmol L−1 does not, therefore, modify the cell viability, does not produce toxic effects in the tested cells and could be used as a therapeutic compound.Depto. de Farmacología y ToxicologíaFac. de MedicinaTRUEpu

Natural phosphates and their catalytic applications

The catalytic properties of phosphate rocks (natural phosphates: NP) and their role as a catalyst or catalyst support were discussed in the light of the versatility and potential of phosphate-based catalysts. NP have both acidic and/or basic properties, structure flexibility, capacity to disperse a catalytic active phase (e.g. metal salts), and low cost. Thus, NP have been studied as catalytic materials in several chemical processes, in particular in organic synthesis, with interesting catalytic efficiency. This chapter is dedicated to the study of NP in several application in organic chemistry such as condensation, cross-coupling, alkylation reactions, hydration of aromatic nitriles, hydrogenation, reduction, reforming of methane, etc.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEpu