Trace impurities such as organic compounds and carbon monoxide in reactive
fluids such as ammonia, hydrogen chloride, hydrogen bromide, and chlorine
are reduced to sub-ppb levels using gas purifying systems that contain a
preconditioned ultra-low emission (P-ULE) carbon. P-ULE is capable of
removing impurities from a reactive fluid down to parts-per-billion (ppb)
and sub-ppb levels without concurrently emitting other impurities such as
moisture or carbon dioxide into the purified reactive fluid. The P-ULE
carbon is prepared by heating a carbon material to temperatures from
300.degree. C. to about 800.degree. C. in an ultra-dry, inert gas stream,
to produce an ultra-low emission (ULE) carbon material, subjecting the ULE
carbon to a second activation process under a reactive gas atmosphere to
produce a P-ULE carbon and storing the P-ULE carbon in an environment that
minimizes contamination of the P-ULE prior to its use in a gas purifier
system.
