In-situ characterization of the thermal treatment of Zn-Al hydrotalcites with respect to the formation of Zn/Al mixed oxide active in aldol condensation of furfural

Synthesis and evaluation of a Zn–Al layered double hydroxide for the removal of ochratoxin A. Greenness assessment

“…Secondly, another loss of 11% (200°–400 °C), associated with the dehydroxylation of the LDH layers was noticed. 40,43 This is also evidenced in the DTG curve in which two weight losses at maximum temperatures of 175 °C and 255 °C, respectively, can be identified.…”

“…1a shows the characteristic peaks of the hexagonal structure of the Zn–Al layered double hydroxide. 39–41 The Rietveld method in the R 3̄ c space group was performed and crystallographic data as unit-cell parameters, atomic positions, displacement factors and occupation were refined and are summarized in Table 1. From the refined occupation it was possible to obtain the formulae: [Zn 0.73 Al 0.27 (OH) 2 ](CO 3 ) 0.34 and [Zn 0.75 Al 0.25 (OH) 2 ](CO 3 ) 0.34 for the LDH before and after OTA retention assays, respectively.…”

“…1a shows the characteristic peaks of the hexagonal structure of the Zn-Al layered double hydroxide. [39][40][41] The Rietveld method in the R 3c space group was performed and crystallographic data as unit-cell parameters, atomic positions, displacement factors and occupation were rened and are summarized in Table 1.…”

Aplicación del hidróxidos dobles laminares de ZnCuAl modificados con SDS como fotocatalizadores para el tratamiento eficiente de agua contaminada con compuestos orgánicos

“…Los espectros obtenidos del análisis de difracción de rayos X de los materiales ZnCuAl con y sin la adición de dodecilsulfato de sodio (SDS) se presentan en la Figura 2, donde se puede observar para ambos casos, la presencia de las señales características de los hidróxidos dobles laminares [21][22][23] Respecto a los resultados del análisis por espectroscopía IR de las muestras se puede observar la presencia de una banda amplia e intensa alrededor de 3100 a 3600 cm -1 , en la que se encentran englobadas señales correspondientes a vibraciones o estiramientos de diferentes enlaces: una banda observada entre 3100-3300 cm -1 relacionada con el enlace C-H; a 3330 cm -1 podemos localizar vibraciones de O-H y entre 3300-3500 cm -1 la vibración de tensión del enlace -H-N-; la banda a 3500 cm -1 corresponde a los estiramientos de los grupos hidroxilo tanto de las láminas como del agua del espacio interlaminar.…”

Microwave-Assisted Aldol Condensation of Furfural and Acetone over Mg–Al Hydrotalcite-Based Catalysts

“…In industry, aldol condensations are traditionally carried out in alkaline aqueous solution [16], which presents such disadvantages as reaction corrosion and the difficult separation of the products. For this reason, various reports on the cross-condensation of furfural and acetone have focused on heterogeneous catalysis [17][18][19][20][21]. We developed a microwave-assisted batch process for the neat aldol condensation of furfural and acetone over hydrotalcites and derivatives.…”