Membrane concentrates nitric acid
15 Jan 2000
An electrically-driven polymer membrane process may offer an economical alternative to distillation for the reconcentration of large volumes of dilute nitric acid.
Researchers have known for a long time that alcohol-water azeotropes can be broken by pervaporation membranes. Robert Field's team has achieved similar success in breaking the nitric acid-water azeotrope with an anion selective membranes in an electrically driven membrane process.
He told PE: `Smaller users of nitric acid might be interested in the process. They wouldn't have to buy expensive distillation equipment or tanker out the acid. It can also clean up contaminated acid.'
The Defence Research Association commissioned Bath to investigate the conversion of 5wt% nitric acid, from a waste stream, into 50wt% concentrate. The waste stream is produced by a novel DRA technique for producing dinitrogen pentoxide.
Greville Bagg, head of Chemical Process Research at the DRA, said collaboration with Bath is a cost-effective way of developing new technologies.
* Field is also involved in research on diffusion dialysis and is seeking industrial contacts .
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