Highlights Catalytic resins Pd/WA30 can exchange nitrites and/or reduce them to nitrogen. The performance of the Pd(2%)/WA30 catalyst in a hybrid process (reaction and ion exchange) proved to be very good. The ammonium concentration generated by nitrites over-reduction never exceeded 0.2 mg/L. A new methodology for regenerating the resin makes it possible to eliminate more than 99 % of the nitrites.
Ipomoea es un género diversificado y complejo, compuesto por herbáceas, lianas y enredaderas leñosas, y un pequeño grupo de arbustos y árboles. Llama la atención que todas las especies estudiadas anteriormente presentaron diferentes tipos de variante cambial en sus tallos, independientemente del modo de vida, excepto dos taxones con crecimiento secundario normal, una liana y un árbol. Por ello, en el presente trabajo se planteó el estudio de tres enredaderas nativas de Argentina, Ipomoea cairica, I. purpurea e I. rubriflora, y de I. carnea ssp. fistulosa, árbol con crecimientonormal, con el fin de comparar el desarrollo de sus tallos y aportar datos de interés para dilucidar sus relaciones filogenéticas. Las cuatro especies estudiadas presentaron igual ontogenia y anatomía desus tallos con crecimiento primario, lo que apoyaría sus estrechas relaciones filogenéticas. Por otro lado, las enredaderas presentaron sólo dos tipos de variante cambial, el patrón lobado y el de cámbiumsupernumerario. Se puede inferir que en Ipomoea el tipo de crecimiento secundario, así como los tipos de variante cambial, no estarían directamente relacionados con el hábito; sin embargo, otras características del leño pueden ponerse a consideración como la proporción de tejido parenquimático y características de los vasos.
Fibrous structures present interesting characteristics as catalyst supports for heat-and mass-transfer-limited reactions. This paper investigates the mass and heat transport behavior of ceramic fiber-based catalysts (catalytic ceramic paper) by applying them to the exothermic reaction of CO 2 methanation. Catalytic experiments were carried out to fit the activity of the catalysts with known kinetics. A fixed-bed reactor model was used to determine the efficiency and efficiency losses caused by different transport phenomena, as well as to perform a sensitivity study focused on heat transfer. The results show that heat transfer limitations are the main cause for losses in reactor efficiency, with steep temperature profiles developing inside the reactor. Poor heat transfer limits the development of highly active catalysts, while pressure drop restricts the flow rate and therefore the productivity. The use of ceramic materials with higher thermal conductivity and increasing the fiber diameter are promising approaches to enhance heat transfer, reduce pressure drop, and improve overall reactor performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.