Patent ID: 7666252

Claim:
A method for purifying large quantities of exhaust gas containing dilute volatile hydrocarbons, wherein adsorption units that comprise a layer loaded with a precoated mesoporous activated carbon as an adsorbent, and that alternatingly perform adsorption and desorption, are used; an exhaust gas containing volatile hydrocarbons is caused to pass through one of the adsorption units; the volatile hydrocarbons are adsorbed on the adsorbent layer inside the adsorption unit; the exhaust gas that contains no volatile hydrocarbons is released from an outlet of the adsorption unit; the other adsorption unit is switched to a desorption operation during this interval; and the previously adsorbed volatile hydrocarbons are extracted from the system; wherein said purification method is characterized in that a pretreatment unit for concentrating the volatile hydrocarbons contained in the exhaust gas in advance is used to increase the concentration before a treatment is performed using said adsorption unit; and said pretreatment unit is a honeycomb-structure rotor or a fixed honeycomb in which a mesoporous activated carbon precoated using the volatile hydrocarbons is used in the adsorbent layer.