Abstract: A reversible adsorbent for carbon dioxide, which can be used as a decontaminant of closed environments, has been devised. It consists of a novel material formed by a surface modified silica gel with active sites for the chemisorption of CO.sub.2 at room temperature combined with a clay which acts as an agglomerant in a preferred weight ratio of 80/20. The carbon dioxide is liberated under heating at 110.degree. C. The surface area of the material ranges between about 120 and about 240 m.sup.2 /g with a total pore volume between about 0.4 and about 0.8 cc/g where about 80% of the total pore volume contains pores of a diameter between about 60 .ANG. and about 180 .ANG.. The material is capable of adsorbing between about 7.5 and 11.7 cc of dry CO.sub.2 per gram and can be regenerated between about 70.degree. and about 150.degree. C. without losing any adsorptive capacity. Dry carbon dioxide is chemisorbed as a surface ammonium carbamate which becomes a surface bicarbonate in the presence of water.

Abstract: A natural active stable catalyst for use in the hydrodemetallization (HDM) and the hydroconversion (HC) of heavy crudes and residues and, in particular, a method for the preparation of the catalyst from natural clay and a process for the treatment of heavy crudes and residues with the catalyst. The catalyst is free of hydrogenating metals of Groups VIB and VIII of the Periodic Table and comprises primarily iron, silica and alumina derived from the composition of the natural clay. The catalyst possesses a surface area of between 20 to 100 m.sup.2 /g, a total pore volume of between 0.20 to 0.90 cc/g, where 50 to 100% of the total pore volume contains pores of diameter greater than 400 .ANG.. The catalyst has a ratio I(Fe)/I(Si+Al) of between 0.2 to 0.9 as determined by XPS.

Abstract: A natural active stable catalyst for use in the hydrodemetallization (HDM) and the hydroconversion (HC) of heavy crudes and residues and, in particular, a method for the preparation of the catalyst from natural clay and a process for the treatment of heavy crudes and residues with the catalyst. The catalyst is free of hydrogenating metals of Groups VIB and VIII of the Periodic Table and comprises primarily iron, silica and alumina derived from the composition of the natural clay. The catalyst possesses a surface area of between 20 to 100 m.sup.2 /g, a total pore volume of between 0.20 to 0.90 cc/g, where 50 to 100% of the total pore volume contains pores of diameter greater than 400 .ANG.. The catalyst has a ratio I(Fe)/I(Si+Al) of between 0.2 to 0.9 as determined by XPS.