A process is presented for separating and removing acid gases or base gases from
a feed gas by use of a gas permeable membrane and a permeate comprising a treatment
solution. The treatment solution in the permeate is caustic or acidic and reacts
with the base or acid gases respectively to form salts so as to facilitate their
removal from the feed gas. The acid gas in an acid feed gas may include HCN, H2S,
CO2, COS and/or NOx. The base gas in a base feed gas may
include NH3. In another aspect of the present invention, an apparatus
for treating a feed gas containing an acid or a base gas comprises a feed gas passage;
a treatment solution container containing a treatment solution; and a gas permeable membrane.
