Whether or not you believe in global warming, nitrogen-oxides, or NOx, definitely does contribute to acid rain and smog, which are not debatable. Because NOx is emitted in large quantities from the exhaust of diesel engines, something needs to stop it from entering our atmosphere. One way to do this is with urea, which is being used in the Bluetec systems installed by various automakers. Because people don't like to think about carrying around a container of urea (think urine, although it is usually created chemically, not gathered "naturally"), it is often referred to as Adblue, and because it is a source of ammonia, must be metered properly as ammonia is rather toxic by itself. Are there any other solutions?

The Chemical Engineering Division of Argonne National Laboratory in the U.S. has come up with a possible alternative to ammonia and urea. Their process uses Cu-ZSM-5, a zeolite with copper ions attached within its micropore structure, "with an external coating of cerium oxide", according to Christopher Marshall, who helped develop the technology. The technology also does not contain platinum, which is expensive and not compatible with the older diesel fuels which contained high amounts of sulphur.

This catalyst is currently under testing, but is proving to work out well enough that Argonne is expecting to have the product commercially available in as little as two years. I think it sounds pretty promising myself, because while I don't mind using urea at all, I think it is good that the consumer would not be left in charge of being sure that the Adblue tank was not empty.

[Source: Argonne National Laboratory]

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