Abstract: "Thin stillage", discharged from a centrifuge in which relatively large >10 .mu.m insoluble solids in an ethanol stillbottoms stream are separated from "whole stillage", is separated in a step-wise membrane separation process to recover lactic acid and glycerol, together. In each step, the permeate recovery is at least 50%. In a first step, an ultrafiltration (UF) membrane means produces a UF permeate stream in which not only essentially all the insoluble portion of said thin stillage >0.0.05 .mu.m is removed as UF concentrate, but also at least 50% of solubles having a molecular weight >2.times.10.sup.5 Daltons, including dissolved proteins in said thin stillage. In a second step to which the UF permeate is fed, a nanofiltration (NF) membrane produces a NF permeate with a rejection of less than 30% of both the lactic acid and the glycerol, preferably less than 25%. Essentially all molecules larger than lactic acid or glycerol are removed in the NF concentrate.

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: A method for reducing the acidity and moisture content of used organophosphate functional fluids. The used functional fluid is contacted with a solid composite adsorbent and then separated from the adsorbent. The composite adsorbent is preferably a powder having an average particle size of about 20-500 microns and total pore volume of at least about 0.40 cm.sup.3 /g and it comprises about 40-90 wt % alumina and about 10-60 wt % Y zeolite wherein the molar ratio of SiO.sub.2 to Al.sub.2 O.sub.3 is about 4.5-6.0. The adsorbent is produced by agglomerating particles of activated alumina and Y zeolite into a composite agglomerate, aging the agglomerate, activating at an elevated temperature, and then comminuting to form a powder.

Abstract: The process of the present invention for preparing granules of alumina includes pretreating an alumina powder by admixing with cold water in a mixer at a temperature below room temperature, e.g., such as below about 20.degree. C., to form a pretreated alumina having a pore volume saturated with water and further having a surface area of gel structure, and agglomerating the pretreated alumina in a fluidized bed to form granules. The process is particularly suited to producing activated alumina in macroporous granules. The process in one aspect further includes a cold hopper for cooling alumina powder prior to the pretreating step.

Abstract: A composite HCl adsorbent comprising about 50-95 wt % alumina and about 5-50 wt % Y zeolite wherein the molar ratio of SiO.sub.2 to Al.sub.2 O.sub.3 is about 4.5-6.0. The adsorbent is produced by admixing particles of alumina and acid-treated Y zeolite, agglomerating, aging and activating. The activated composite adsorbent has improved dynamic adsorption behavior for HCl compared with both the alumina and Y zeolite starting materials.

Abstract: A composite adsorbent useful for reducing the acidity and moisture content of used organophosphate functional fluids. The adsorbent is a powder having an average particle size of about 20-500 microns and total pore volume of at least about 0.40 cm.sup.3 /g and it comprises about 40-90 wt % alumina and about 10-60 wt % Y zeolite wherein the molar ratio of SiO.sub.2 to Al.sub.2 O.sub.3 is about 4.5-6.0. The adsorbent is preferably produced by agglomerating particles of activated alumina and Y zeolite into a composite agglomerate, aging the agglomerate and then comminuting to form a powder.

Abstract: In accordance with the invention, an improved process is provided for the efficient removal and recovery of silver from an impure solution containing silver ions which comprises contacting the silver-containing solution with an activated alumina adsorbent to selectively adsorb the silver ions from the solution and the lower the subsequent effluent discharge to less than 1 ppm silver, treating the activated alumina with a regeneration fluid to recover the silver ions from the adsorbent, and reducing the recovered silver ions to metallic silver.

Abstract: Water contaminated with a trihalocarbon is passed through a first or second bed containing particles of an activated composite adsorbent comprising alumina and zeolite. The trihalocarbon is adsorbed onto the particles, thereby reducing trihalocarbon concentration in the water. The adsorbed trihalocarbon is reacted with air or steam at an elevated temperature in order to regenerate the adsorbent particles for reuse. Gaseous HCl produced in the reaction with air or steam may be adsorbed in a third bed containing adsorbent agglomerates.

Abstract: An improved process is disclosed for the simultaneous removal of ammonia, sulfides and organic impurities from an impure aqueous stream from a tanning process which comprises contacting the impure stream with an adsorbent comprising a mixture of alumina and a Y zeolite.

Abstract: The process of the present invention for preparing granules of alumina includes pretreating an alumina powder by admixing with cold water in a mixer at a temperature below room temperature, e.g., such as below about 20.degree. C., to form a pretreated alumina having a pore volume saturated with water and further having a surface area of gel structure, and agglomerating the pretreated alumina in a fluidized bed to form granules sized in the range of about 1-3 mm. The process is particularly suited to producing activated alumina in macroporous granules. The process in one aspect further includes a cold hopper for cooling alumina powder prior to the pretreating step.