RESUMEN

Spent methanol-to-propylene (MTP) catalysts have a large specific surface area and high porosity but are usually disposed of in landfills directly, and recycling has rarely been reported. In this study, the spent MTP catalyst was moderately dealuminized with organic acids and etched with alkali solvent to increase its specific surface area, further silanized by octyl triethoxy silane (OTS). A novel superhydrophobic adsorbent covered with -Si(CH2)7CH3 groups was obtained. The characterization of XRD, SEM, FTIR and XPS shows that the adsorbent maintains a typical ZSM-5 zeolite structure, and the -Si(CH2)7CH3 group is successfully grafted into the sample, not only on the surface but also in some pore space. Taking high chemical oxygen demand (COD) wastewater as the object, the influence of contract time, pH and temperature on COD removal was investigated. The removal process could be better depicted by the Langmuir isotherm model and the pseudo second-order dynamic model. Furthermore, the results of the thermodynamic study (∆G is - 79.35 kJ/mol, ∆S is 423.68 J/mol K, and ∆H is 46.91 kJ/mol) show that the adsorption was a spontaneous and endothermic process. These findings indicate that the modified spent MTP catalyst has potential application for the removal of COD from wastewater.

Asunto(s)

Aguas Residuales , Contaminantes Químicos del Agua , Adsorción , Alquenos , Análisis de la Demanda Biológica de Oxígeno , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Cinética , Metanol , Contaminantes Químicos del Agua/química

RESUMEN

Deposition of carbonaceous compounds was used to improve the propylene selectivity of ZSM-5 by deactivating some acid sites meanwhile maintaining the high activity for methanol conversion. The carbonaceous species of pre-coked samples before and after MTP reactions were investigated by elementary analysis and thermogravimetric analysis (TGA). The results showed that pre-coke formed at low temperature (250°C) was unstable and easy to transform into polyaromatics species at the high reacting temperature, while combining 5% pre-coking process with 95% steam treatment at high temperature (480°C) was effective in inhibiting the formation of coke deposits and presented a significant improvement in the propylene selectivity.

RESUMEN

The basic leucine zipper (bZIP) transcription factors comprise a family of transcriptional regulators present extensively in plants, involved in regulating diverse biological processes such as flower and vascular development, seed maturation, stress signaling and pathogen defense. Castor bean (Ricinus communis L. Euphorbiaceae) is one of the most important non-edible oilseed crops and its seed oil is broadly used for industrial applications. We performed a comprehensive genome-wide identification and analysis of the bZIP transcription factors that exist in the castor bean genome in this study. In total, 49 RcbZIP transcription factors were identified, characterized and categorized into 11 groups (I-XI) based on their gene structure, DNA-binding sites, conserved motifs, and phylogenetic relationships. The dimerization properties of 49 RcbZIP proteins were predicted on the basis of the characteristic features in the leucine zipper. Global expression profiles of 49 RcbZIP genes among different tissues were examined using high-throughput sequencing of digital gene expression profiles, and resulted in diverse expression patterns that may provide basic information to further reveal the function of the 49 RcbZIP genes in castor bean. The results obtained from this study would provide valuable information in understanding the molecular basis of the RcbZIP transcription factor family and their potential function in regulating the growth and development, particularly in seed filling of castor bean.

Asunto(s)

Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Regulación de la Expresión Génica de las Plantas , Genómica , Ricinus communis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/clasificación , Sitios de Unión , Ricinus communis/crecimiento & desarrollo , Bases de Datos Genéticas , Dimerización , Endospermo/genética , Endospermo/crecimiento & desarrollo , Euphorbiaceae/genética , Euphorbiaceae/crecimiento & desarrollo , Evolución Molecular , Perfilación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , Familia de Multigenes , Especificidad de Órganos , Filogenia , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Proteínas de Plantas/clasificación , Proteínas de Plantas/genética , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Semillas/genética , Semillas/crecimiento & desarrollo , Análisis de Secuencia de ADN

RESUMEN

Highly ordered SBA-16-type mesoporous silica materials were synthesized by using poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) triblock copolymer (EO(132)-PO(50)-EO(132), Pluronic F108) as template through a two-step pathway under mildly acidic conditions (pH 2.15-4.50). The highly ordered cage-like mesoporosity of the prepared SBA-16-type mesoporous silica materials having Im3m cubic mesostructure was proved by the well-defined X-ray diffraction patterns combined with transmission electron microscopy. Scanning electron microscopy shows a variation from the spherical agglomerations to the randomly shaped ones with an increase of pH value. The nitrogen adsorption-desorption analysis reveals that the prepared SBA-16-type mesoporous silica materials have a uniform small-sized pore diameter (3.37-4.24 nm) and very thick pore wall (8.84-10.2 nm). These features may make the SBA-16-type mesoporous silica materials synthesized in this study favor the incorporation of catalytically active heteroatoms in silica frameworks, and the functionalization of organic groups for applications in catalysis, sensor and separation. The two-step synthetic method under the mildly acidic conditions can also be extended to the production in the industrial scale as an environmentally friendly way.