Digestion phases

A simple and economical method for recovering silver residues by dissolution in used photographic fixer (thiosulfate) solution, then precipitation by addition of zinc powder, is detailed [1]. After the acid digestion phase of silver recovery operations, addition of ammonia followed immediately by addition of ascorbic acid as reducant gives a near-quantitative recovery of silver metal, and avoids the possibility of formation of silver nitride [2],... 

The Bevrox Biotreatment technology consists of three phases the primary contact, or mixing phase the primary digestion phase and the polishing phase. The equipment is mobile and modular a project may require from 2 to 12 reactors. The technology does not treat metals. 

Kossena, G.A. etal. (2005) In uence of the intermediate digestion phases of common formulation lipids on the absorption of a poorly water-soluble drufcj.Pharm. Sci., 94 481-492. 

Vitamin E, like neutral lipids, requires apoB lipoproteins at every stage of its transport (Fig. 27-2). Dietary vitamin E becomes emulsified in micelles produced during the digestive phase of lipid absorption and permeates the intestinal epithelium, similar to fatty acids and cholesterol. Uptake of vitamin E by enterocytes appears to be concentration dependent. Within intestinal cells, vitamin E is packaged into chylomicrons and secreted into lymph. During blood circulation of chylomicrons, some vitamin E may be released to the tissues as a consequence of partial lipolysis of these particles by endothelial cell-anchored lipoprotein lipase. The rest remains associated with chylomicron remnants. Remnant particles are mainly endocy-tosed by the liver and degraded, resulting in the release of fat-soluble vitamins. 

Only relatively small quantities of bile acids are lost from the body approximately 95% of bile acids delivered to the duodenum are absorbed back into blood within the ileum. Venous blood from the Ueum goes straight into the portal vein, and hence through the sinusoids of the liver (enterohepatic circulation). Hepatocytes extract bile acids very efficiently from sinusoidal blood they are re-secreted into canaliculi. The net result of enterohepatic recirculation is that each bUe salt molecule may be reused up to 20 times, and often 2 or 3 times during a single digestive phase (Figure 6.1). 

The case study of the S.E.S.A. facility in Este shows a situation of wet AD combined with composting where the compostable bags skip the digestion phase (Route 1 in Figure 15.3) and go to a complete material recovery (Route 2 in Figure 15.3). 

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