A method of removing trace contaminants, such as mercury, from a flue gas by passing the gas over a sorbent structure on which is coated a renewable layer of sorbent. The sorbent structure can be a tube or plate and can be porous or non-porous and is placed inside a duct through which the flue gas flows. The sorbent particles comprise noble metal or activated carbon particles and can be injected into the gas stream before it passes over the sorbent structures. The sorbent structures can be periodically recoated with sorbent while the gas is still flowing.