RESUMEN
The catalytic activities for benzene oxidation and resistance to SO2 poisoning were tested for a series of Pd/La-Cu-Co-O/cordierite catalysts, which were prepared using a multiple-step impregnation method. The XRD, SEM, and IR characterization techniques were performed to investigate the relationship between the catalytic performance and its physicochemical properties. When Pd/La-Cu-Co-O/cordierite catalysts with Pd loadings of 0.06 and 0.08 % were prepared at a calcination temperature of 500 °C for 5 h, they exhibited similar catalytic activity and sulfur resistance. When the concentration of benzene was 1500 ppm and the GHSV was 20000 h(-1), the benzene conversion was above 95 % at a reaction temperature of 350 °C in SO2 existing at 100 ppm. These results were mainly attributed to the cooperation between La-Cu-Co-O perovskite and the noble metal Pd. Specifically, the addition of copper can strengthen the catalytic activity of La-Co-O/cordierite catalysts by decreasing the crystalline size of the active ingredients. A moderate Pd addition can drastically improve the sulfur resistance and further improve the catalytic activity of the La-Cu-Co-O/cordierite catalyst.
Asunto(s)
Contaminantes Atmosféricos/química , Contaminación del Aire/prevención & control , Benceno/química , Incineración/métodos , Dióxido de Azufre/química , Compuestos de Calcio/química , Cerámica/química , Oxidación-Reducción , Óxidos/química , Titanio/químicaRESUMEN
Lymphomatous involvement of the breast is an uncommon cause of breast masses. A case is presented of a patient with bilateral breast involvement revealed by intense 67Ga uptake. Other foci of involvement were also detected scintigraphically, and confirmed by other imaging modalities. Multiagent chemotherapy resulted in significant clinical and scintigraphic regression of tumor, demonstrating the potential utility of 67Ga imaging in the follow-up of these patients.