Phenol adsorption onto coffee waste - granular activated carbon: kinetics and equilibrium studies in aqueous solutions

abstract In this research, the production of granular activated carbon from coffee waste (CW) by chemical activation with zinc chloride was studied by using a 23 factorial design with the three responses (surface area, yield, and hardness) and studying three factors (the activation temperature, activation time, and impregnation ratio). The findings expose that after the experimental design, the highest response values were achieved at an activation temperature of 600°C, an activation time of 40 min, and an impregnation ratio of 1.5 g ZnCl2 g–1 CW. At these conditions, the experimental tests produced a surface area of 1,279 m2 g–1. Batch studies of phenol adsorption onto coffee waste-activated carbon (CW-GAC) were performed at different solution pH, stirring speeds, and initial phenol concentrations. The maximum phenol adsorption capacity onto CW-GAC was 160.52 mg g−1 at pH 7. The adsorption kinetics was affected by stirring speed, the required time to achieve equilibrium decreased from 150 to 120 min when stirring speed varied from 200 to 400 min–1. Film and intraparticle diffusion mechanisms controlled the adsorption of phenol onto CW-GAC. Finally, the porous material developed in this research is capable of sequestering phenol from aqueous solutions to a higher extent than similar lignocellulosic-based activated carbons. Keywords: Adsorption; Coffee; Factorial experimental design; Granular activated carbon; Lignocellulosic wast

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Determinación de las condiciones óptimas para la producción de carbón activado granular a partir de residuos de café para la eliminación de fenol en solución acuosa.

Próposito y Método de Estudio: El interés de este estudio se centra en establecer las condiciones de operación óptimas para el proceso de producción de carbón activado granular a partir de residuo de café por activación química con ZnCl2 con y sin carboximetilcelulosa como aglutinante, por medio de un diseño factorial 23 , tomando como factores la temperatura, el tiempo, la relación de impregnación y la relación de aglutinación, y como variables a estudiar el área superficial, el rendimiento y el porcentaje de carbón activado granular. El carbón producido se estudió en el proceso de adsorción de fenol en solución acuosa. La sustentabilidad de esta investigación radica en la conversión de residuos en materiales útiles y valiosos, en este caso como adsorbentes, para remover contaminantes de soluciones acuosas. Contribuciones y Conclusiones: En este estudio se demostró la factibilidad técnica de utilizar residuos de café como precursor para la obtención de carbón activado granular sin o con aglutinante. Los mejores valores de rendimiento, área superficial y porcentaje de carbón activado granular se obtuvieron en las condiciones experimentales de 600 ºC, 40 min y una relación de impregnación de 1.5 g ZnCl2/ g de residuo de café, dichas condiciones fueron obtenidas mediante el análisis de superficie de respuesta. El carbón activado granular obtenido presentó una superficie preferentemente ácida, dada la mayor cantidad de sitios ácidos en su superficie. Se determinaron los parámetros de los modelos de Langmuir, Freundlich y Redlich Peterson, resultando que el modelo de Freundlich para dosificación alta es el que mejor describe el comportamiento de los datos experimentales. En el estudio cinético de adsorción de fenol en el carbón activado, el modelo de pseudo segundo orden resultó con mejor ajuste, pero debido que no describe el mecanismo de difusión. Se realizó el ajuste por el modelo de difusión intraparticula de Weber y Morris, presentando una multilinealidad en las curvas de los datos experimentales. La primer sección lineal es debido a la adsorción superficial externa o etapa de adsorción instantánea, la segunda sección lineal corresponde a la etapa de adsorción gradual, donde la difusión intraparticula es la velocidad controlante, y la última sección lineal es la etapa final de equilibrio, donde la difusión intraparticula comienza a disminuir, debido a la concentración baja del adsorbato en la solución. Este modelo presenta una muy buena correlación de ajuste

Active Surveillance of Antimicrobial Resistance and Carbapenemase-Encoding Genes According to Sites of Care and Age Groups in Mexico: Results from the INVIFAR Network

We analyzed the antimicrobial resistance (AMR) data of 6519 clinical isolates of Escherichia coli (n = 3985), Klebsiella pneumoniae (n = 775), Acinetobacter baumannii (n = 163), Pseudomonas aeruginosa (n = 781), Enterococcus faecium (n = 124), and Staphylococcus aureus (n = 691) from 43 centers in Mexico. AMR assays were performed using commercial microdilution systems (37/43) and the disk diffusion susceptibility method (6/43). The presence of carbapenemase-encoding genes was assessed using PCR. Data from centers regarding site of care, patient age, and clinical specimen were collected. According to the site of care, the highest AMR was observed in E. coli, K. pneumoniae, and P. aeruginosa isolates from ICU patients. In contrast, in A. baumannii, higher AMR was observed in isolates from hospitalized non-ICU patients. According to age group, the highest AMR was observed in the ≥60 years age group for E. coli, E. faecium, and S. aureus, and in the 19–59 years age group for A. baumannii and P. aeruginosa. According to clinical specimen type, a higher AMR was observed in E. coli, K. pneumoniae, and P. aeruginosa isolates from blood specimens. The most frequently detected carbapenemase-encoding gene in E. coli was blaNDM (84%)