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The performance of Co3Mo3N, Co3Mo3C, and Co6Mo6C for ammonia synthesis has been compared. In contrast to Co3Mo3N, which is active at 400 °C, a reaction temperature of 500 °C, which was preceded by an induction period, was necessary for the establishment of steady state activity for Co3Mo3C. Co6Mo6C was found to be inactive under the conditions tested. During the induction period, nitridation of the Co3Mo3C lattice was found to occur, and this continued throughout the period of steady state reaction with the material transforming in composition toward Co3Mo3N. Taken together, these observations demonstrate that ammonia synthesis activity in ternary cobalt molybdenum systems is associated with the presence of N in the 16c Wyckoff lattice site.

Please cite this article as: C. Rico, N. Muñoz, J. Fernández, J.L. Rico, High-load anaerobic co-digestion of cheese whey and liquid fraction of dairy manure in a one-stage UASB process: limits in co-substrates ratio and organic loading rate, Chemical Engineering Journal (2014), doi: http://dx. AbstractCheese whey is considered an important pollutant in dairy wastewaters and an environmental problem to solve. This study aimed to develop a treatment process that combines the advantages of co-digesting cheese whey with manure and the short hydraulic retention time of a high-load anaerobic treatment system by using liquid fractions of dairy manure as a co-substrate. The proposed co-digestion process consists of a one-stage UASB reactor with an external settler and effluent recycling for alkalinity supplementation. Under a constant hydraulic retention time of 2.2 days and increasing proportion of cheese whey in the feed, the system demonstrated stable operation up to a 75% cheese whey fraction in the feed, with an applied organic loading rate of 19.4 kg COD m -3 d -1 , obtaining a 94.7% COD removal and a volumetric methane production rate of 6.4 m 3 CH 4 m -3 d -1 . Critical biomass washout was experienced when the cheese whey fraction in the feed was 85%.Operation at a constant 60% cheese whey fraction in the feed mixture enabled stable operation under an organic loading rate of 28.7 kg COD m -3 d -1 and 1.3 days HRT, with 95.1% COD removal and a volumetric methane production rate of 9.5 m 3 CH 4 m -3 d -1 . This new high-load co-digestion method proposed is a promising solution for areas where cheese factories and intensive livestock farming are responsible for environmental pollution caused by unsuitable cheese whey and manure management practices.

Partially sulfided nanostructures were synthesized by direct sulfurization of alpha-MoO(3) nanorods using a mixture of H(2)S/H(2), 15 vol%, at several temperatures (400, 500, 600, 700, and 800 degrees C). These materials were tested as catalysts in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and characterized by specific surface areas using the expression developed by Brunauer, Emmett, and Teller (BET equation), x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The TEM images show a gradual evolution from a smooth surface to a rough material, presenting some type of holes all over the particles, but keeping their rod-like structure throughout sulfidation. The results of evaluating the catalysts in the HDS of DBT showed that the best temperature for sulfidation is 500 degrees C. In all samples, a higher selectivity for hydrogenation over sulfur removal was observed.

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