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La presente invención describe un procedimiento para la preparación de un catalizador de Pt soportado sobre carbón, que comprende la preparación de una solución acuosa ácida de una sal de Pt, y la impregnación con dicha solución de un carbón con marcado carácter básico o neutro, el cual que presenta una desorción de CO{sub,2} inferior a 100 {mi}moles/gramo de carbón, así como un catalizador obtenible según dicho procedimiento y el uso de dicho catalizador en el tratamiento de efluentes gaseosos residuales contaminados con clorometanos., Depto. de Ingeniería Química y de Materiales, Fac. de Ciencias Químicas, pub

Laboratory-prepared Pd/C catalysts have been investigated in the deep gas-phase hydrodechlorination (HDC) of monochloromethane (CH3Cl), dichloromethane (CH2Cl2) and trichloromethane (CHCl3). The catalysts were found to be active in HDC, the reactivity following the order CHCl3 > CH2Cl2 > CH3Cl. Selectivities to non-chlorinated compounds were found to be higher than 90% in most cases. The results obtained with the catalyst prepared from PdCl2 suggest that all the reaction products are primary products. The CH4, CH3Cl and CH2Cl2 come from the hydrogenation of the corresponding adsorbed chloride radical, while hydrocarbons of more than one carbon atoms are formed by reaction and subsequent hydrodechlorination of two radicals adsorbed in neighbouring active centers. The catalyst undergoes a significant deactivation which appears to be due to the poisoning of active centers with chlorinated hydrocarbons. The use of Pd(NO3)2 as Pd precursor leads to a decrease in the activity due to its lower Pd dispersion and a lower proportion of electrodeficient Pd species., Depto. de Ingeniería Química y de Materiales, Fac. de Ciencias Químicas, TRUE, pub

A method for quantitative mineralogical analysis by ATR-FTIR [1] has been used first time for analysis of historical mortars. Mixtures of different minerals and gypsum were used in order to measure the minimum band intensity that must be considered for calculations and the detection limit. In this way, the molar absorptivity coefficient in the Lambert–Beer law and the components of a mixture in mol percentage can be calculated. The GAMS equation modeling environment and the NLP solver CONOPT (©ARKI Consulting and Development) were used to correlate the experimental data in the samples considered. The characterization of the vernacular mortars by FTIR analysis identifies the predominant minerals of the samples, and in conjunction with XRF and XRD, shows the exact composition of historical mortars, which will optimize the restoration and conservation of monuments, preserving our heritage.

Four precious metals supported on activated carbon are compared as catalysts in the gas-phase hydrodechlorination (HDC) of chloromethanes. The intrinsic activity or turnover frequency (TOF) of the catalysts follows the order Pd/C > Rh/C > Pt/C > Ru/C in the HDC of dichloromethane (DCM) while the sequence Pd/C > Pt/C > Rh/C > Ru/C was found for the HDC of chloroform (TCM). High selectivities to non-chlorinated products were obtained in all cases except for the HDC of TCM with Rh/C and Ru/C where the selectivity to DCM greatly depends on the operating conditions. A wider diversity of non-chlorinated hydrocarbons was obtained as reaction products with these two catalysts, especially in the HDC of TCM, favoring the formation of carbonaceous deposits which provoked a marked deactivation of the catalysts. In contrast, CH4 was the only non-chlorinated product obtained with the Pt/C catalysts which showed by far the highest stability. Different reaction pathways were found depending on the catalyst and the starting chloromethane. The different reactivity of the metals is explained in terms of their different electronic structure and the physicochemical properties of the catalysts., MINECO, Depto. de Ingeniería Química y de Materiales, Fac. de Ciencias Químicas, TRUE, pub

Tests were carried out on samples prepared from ceramic clay containing 0 + 0, 1 + 15, 2 + 20, 3 + 25, 4 + 30 and 5 + 35 wt%, respectively, of municipal solid waste and marble sludge residue obtained from marble plants in Alicante, Spain. Test bodies were prepared by pressing at 40 MPa to form 20 mm diameter discs which were subjected to representative industry firing cycles at temperatures up to 975, 1 000, 1 025 and 1 050 degrees C. The water absorption capacities of the samples were measured and bend strength tests carried out on both dried and heated samples. The results showed that the added waste residue reacted easily with the clay minerals and quartz in the ceramic clay, providing better sintering of the original powders. A linear relationship was observed between the water absorption capacity and the content of waste residue, but the addition of the residue reduced the bending strength. Provided the content of wastes was controlled, it was possible to obtain products that were close in quality to conventional ceramic products., Tests were carried out on samples prepared from ceramic clay containing 0 + 0, 1 + 15, 2 + 20, 3 + 25, 4 + 30 and 5 + 35 wt%, respectively, of municipal solid waste and marble sludge residue obtained from marble plants in Alicante, Spain. Test bodies were prepared by pressing at 40 MPa to form 20 mm diameter discs which were subjected to representative industry firing cycles at temperatures up to 975, 1 000, 1 025 and 1 050 degrees C. The water absorption capacities of the samples were measured and bend strength tests carried out on both dried and heated samples. The results showed that the added waste residue reacted easily with the clay minerals and quartz in the ceramic clay, providing better sintering of the original powders. A linear relationship was observed between the water absorption capacity and the content of waste residue, but the addition of the residue reduced the bending strength. Provided the content of wastes was controlled, it was possible to obtain products that were close in quality to conventional ceramic products.

About 70% of the processing wastes generated by the natural stone industry in Alicante, Spain, are disposed of locally. Industries involved in cutting marble dump the wastes upstream of the Vinapolo river and the dust is carried by rain water to form sediments in the Pantano de Elche lagoon, the eventual dredging of which will present high economic and environmental costs. Investigations were carried out in which lagoon sediment was added in amounts of 15, 20, 25 and 30% to four ceramic clays in a ceramic body. The clay bodies were dried, ground and sieved, pressed at 40 MPa in a laboratory uniaxial press, shaped into discs and fired using industrial firing cycles at up to 1 050 degrees C. The most suitable products were selected on the basis of their mineralogical composition and the properties of the ceramic product, including water absorption and bending strength. An increase in water absorption was observed with increasing waste residue content. Addition of the residue resulted in a decrease in the bending strength. Selection of suitable sediment additions can be made by applying the relevant industry standards for specific construction materials., About 70% of the processing wastes generated by the natural stone industry in Alicante, Spain, are disposed of locally. Industries involved in cutting marble dump the wastes upstream of the Vinapolo river and the dust is carried by rain water to form sediments in the Pantano de Elche lagoon, the eventual dredging of which will present high economic and environmental costs. Investigations were carried out in which lagoon sediment was added in amounts of 15, 20, 25 and 30% to four ceramic clays in a ceramic body. The clay bodies were dried, ground and sieved, pressed at 40 MPa in a laboratory uniaxial press, shaped into discs and fired using industrial firing cycles at up to 1 050 degrees C. The most suitable products were selected on the basis of their mineralogical composition and the properties of the ceramic product, including water absorption and bending strength. An increase in water absorption was observed with increasing waste residue content. Addition of the residue resulted in a decrease in the bending strength. Selection of suitable sediment additions can be made by applying the relevant industry standards for specific construction materials.