Abstract: Thermally stable transitional alumina particulates retaining high specific surface area after calcination at 1000° C. suitable for the use as catalysts or catalysts supports are produced by treating an aqueous solution containing Al3+ and optionally a doping amount of La3+ (e.g., 0.3 mol. %) with an anion-exchange resin to give a stable hydroxide sol followed by freeze drying of the sol and further thermal dehydration. The resultant stabilized transitional alumina retains high specific surface area at 1000° C., and additionally stabilization is achieved at very low levels of added La.

Abstract: Thermally stable transitional alumina particulates retaining high specific surface area after calcination at 1000° C. suitable for the use as catalysts or catalysts supports are produced by treating an aqueous solution containing Al3+ and optionally a doping amount of La3+ (e.g., 0.3 mol. %) with an anion-exchange resin to give a stable hydroxide sol followed by freeze drying of the sol and further thermal dehydration. The resultant stabilized transitional alumina retains high specific surface area at 1000° C., and additionally stabilization is achieved at very low levels of added La.

Abstract: A dry flocculant powder comprises an inorganic substrate consisting essentially of metal oxide/hydroxide particles having an average particle size of less than about 30 microns, said substrate having a cationic or anionic polyelectrolyte coated onto its outer surface, preferably under other than high shear conditions. A method for coating or adhering polyelectrolytes to the outermost surface of inorganic particles comprises dispersing a polyelectrolyte in a substantially non-aqueous solvent, preferably having a low boiling point and a low to intermediate polarity relative to the polyelectrolyte; adding the inorganic particles to the solvent to form a slurry; mixing the slurry under low to moderate shear conditions; and removing excess solvent from the slurry. There is also disclosed a method for removing clay, clay-like materials, humic acids, yeast, biological cells and/or other cell debris from an aqueous stream through contact with the aforementioned dry flocculant powder.

Abstract: A method is disclosed for reducing the amount of a first contaminant and second contaminant in a solution to environmentally safe levels, said solution having a substantially greater amount of the first contaminant than the second contaminant. The method comprises: contacting the solution with an activated or calcined product of a compound having the formula A.sub.6 B.sub.2 (OH).sub.16 C.4H.sub.2 O, wherein A is a divalent metal cation, B is a trivalent metal cation and C is a mono- to tetravalent anion. The method further comprises separating the solution from the contacted product. The method is particularly useful for removing both selenium and sulfate, arsenic and sulfate, or arsenic and phosphate from a waste water stream. An unpredicted preference for selenium and arsenic, in the presence of other contaminants including sulfate and phosphate, was also shown herein.

Abstract: Disclosed is a method of separating organic or organometallic materials under supercritical fluid conditions, the method comprising the steps of providing a bed of packing material selected from a metal oxide/hydroxide support material having phsophorous-containing organic molecules bonded to reactive sites on said support material, alumina and alumina-containing mixtures. The materials are introduced to the bed and a fluid is added to the bed under supercritical fluid conditions. The fluid removes one of the materials from the bed.

Abstract: An improved process is disclosed for the purification of an impure aqueous solution containing heavy metal ions which comprises passing the impure solution through a bed of activated alumina adsorbent. The heavy metal ions are removed from the impure aqueous solution by adsorption onto the activated alumina adsorbent. The adsorbent may be regenerated for reuse and the adsorbed metals recovered by subsequently stripping the metal ions from the adsorbent and recycling the metal ions back to the process of origin. The pH of the effluent may be monitored to determine when the capacity of the adsorbent has been reached and regeneration of the adsorbent should be commenced. In a preferred embodiment, a portion of the activated alumina is pretreated with acid before passing the impure solution through the adsorbent to enhance the chromium ion adsorption of the acid-treated activated alumina and a portion of the regenerated activated alumina is again treated with acid after each regeneration cycle.

Abstract: Disclosed is a method of separating organic or organometallic materials under supercritical fluid conditions, the method comprising the steps of providing a bed of packing material selected from a metal oxide/hydroxide support material having phosphorous-containing organic molecules bonded to reactive sites on said support material, alumina and alumina-containing mixtures. The materials are introduced to the bed and a fluid is added to the bed under supercritical fluid conditions. The fluid removes one of the materials from the bed.

Abstract: A chromatographic packing material is disclosed comprising a metal oxide/hydroxide particle having chemically bonded to reactive sites on a surface thereof, a monolayer of one or more phosphonic acids. The bond to the metal oxide/hydroxide surface is formed by reaction of the phosphorous-containing group of the phosphonic acid with the metal oxide/hydroxide surface, so that the carbon-containing or non-polar group of the phosphonic acid is oriented away from the metal oxide/hydroxide surface.

Abstract: A method for bonding aluminum and aluminum alloys to refractory materials. A body of metal is heated to an elevated temperature at a total pressure above the vapor pressure of aluminum but less than atmospheric pressure. Oxygen partial pressure is maintained sufficiently low to prevent substantial oxidation of the metal. The heated body is contacted with a mass of refractory material and cooled, thereby forming a composite.