Adsorptive Removal of Acid Blue 80 Dye from Aqueous Solutions by Cu-TiO 2

The adsorption performance of a Cu-TiO2 composite for removing acid blue 80 (AB80) dye from aqueous solutions was investigated in terms of kinetics, equilibrium, and thermodynamics. The effect of operating variables, such as solution pH, initial dye concentration, contact time, and temperature, on AB80 adsorption was studied in batch experiments. AB80 adsorption increased with increasing contact time, initial dye concentration, and temperature and with decreasing solution pH. Modeling of adsorption kinetics showed good agreement of experimental data with the pseudo-second-order kinetics model. The experimental equilibrium data for AB80 adsorption were evaluated for compliance with different two-parameter, three-parameter, and four-parameter isotherm models. The Langmuir isotherm model best described the AB80 adsorption equilibrium data. The thermodynamic data revealed that the AB80 adsorption process was endothermic and nonspontaneous. Kinetics, equilibrium, and thermodynamic results indicate that Cu-TiO2 adsorbs AB80 by a chemical sorption reaction

Contaminación con micotoxinas en alimento balanceado y granos de uso pecuario en México en el año 2003

A quantitative and qualitative description is made of the natural presence of mycotoxins in grains and feed used in poultry, swine and cattle production in Mexico during 2003. A total of 133 samples were analyzed to determine content of aflatoxin B1 (AF), ocratoxin A (OTA), citrinin (CIT), T2 toxin (T2) and/or zearalenone (ZEA). A total of 312 analyses were performed: 92 for AF, 45 for OTA, 43 for CIT, 83 for T2, and 49 for ZEA. A total of 57.0 % of the samples contained detectable quantities of at least one of the five mycotoxins, 11.2 % of these had mycotoxin concentrations higher than the maximum concentrations established in current regulations. Ocratoxin A had the highest incidence, with concentrations ranging from 1 to 353 µg kg-1, presence in 15 of the 45 analyzed samples, of which 60 % had an OTA concentration above established maximum concentrations. ascomycotoxins (AF, OTA and CIT) had a natural occurrence of 51.1 %, generally less abundant than the 65.2 % of fusariotoxins (T2 and ZEA). None of the analyzed samples from 2003 had mycotoxins concentrations that would cause mortality in animal populations, though even low concentration mycotoxins contaminations can cause drastic reductions in farm productivity parameters.El presente trabajo describe cuantitativa y cualitativamente la presencia natural de micotoxinas en alimentos balanceados y granos, empleados en la producción de aves, cerdos y ganado en México durante el aÅ„,,o 2003. Se analizaron 133 muestras en su contenido de 1 a 5 micotoxinas, aflatoxina B1 (AF), ocratoxina A (OTA), citrinina (CIT), toxina T2 (T2), y zearalenona (ZEA). En total, se realizaron 312 análisis, 92 de AF, 45 de OTA, 43 de CIT, 83 de T2 y 49 de ZEA. Los resultados muestran que el 57.0 % de las muestras analizadas presentaron alguna cantidad detectable de micotoxinas. Del total de las muestras contaminadas, el 11.2 % contení­an niveles por arriba de las normas de regulación para cada micotoxina. En particular, la micotoxina que presentó la mayor incidencia fue OTA, con un rango de contaminación de 1 a 353 µg kg-1, con una ocurrencia en 15 de 45 muestras analizadas y un porcentaje de 60 % de muestras contaminadas por arriba de la norma. En general, las ascomicotoxinas (AF, OTA y CIT) mostraron menor incidencia que las fusariotoxinas (T2 y ZEA) con 51.1% y 65.2 %, respectivamente. En ninguno de los análisis realizados durante el estudio, se registraron niveles de micotoxinas que representaran riesgo de mortalidad, sin embargo, se discute la importancia de los valores encontrados en función de las reducciones que se pueden observar en los parámetros productivos de las especies de explotación pecuaria

Biodegradation of Methyl Tertiary Butyl Ether (MTBE) by a Microbial Consortium in a Continuous Up-Flow Packed-Bed Biofilm Reactor: Kinetic Study, Metabolite Identification and Toxicity Bioassays - Fig 2

<p>Scanning electron micrographs of <i>tezontle</i> stones (A) without biofilm (60×) and (B–D) with biofilm (60×, 5000×, and 8000×).</p

Dependence of specific removal rate on volumetric loading rate.

<p>(A) MTBE; (B) COD.</p

Relative germination percentage (RG%), relative growth index (RGI) and germination index (GI) averages and toxicity categories of influent and effluent samples.

<p>Relative germination percentage (RG%), relative growth index (RGI) and germination index (GI) averages and toxicity categories of influent and effluent samples.</p

Toxicity tests on bacterial strains of influent and effluents at different hydraulic retention times.

<p>Toxicity tests on bacterial strains of influent and effluents at different hydraulic retention times.</p

Relative abundance of bacterial strains that constitute IPN-120526 consortium in the inoculum and in the packed-bed bioreactor

<p>Relative abundance of bacterial strains that constitute IPN-120526 consortium in the inoculum and in the packed-bed bioreactor</p

Biomass immobilized on <i>tezontle</i> stone particles and MTBE and COD concentrations of effluents at different hydraulic retention times.

<p>Biomass immobilized on <i>tezontle</i> stone particles and MTBE and COD concentrations of effluents at different hydraulic retention times.</p

Dependence of volumetric removal rate on volumetric loading rate.

<p>(A) MTBE; (B) COD.</p

MTBE- and COD-removal efficiency at different hydraulic retention times.

<p>MTBE- and COD-removal efficiency at different hydraulic retention times.</p