The Iranian athlete lost to his South Korean rival In Kyo-don in the +80kg final.
Mardani failed to book an Olympic berth despite winning the silver medal.
Arman Hadipour in men's under-58 kilograms and Mirhashem Hosseini in under-68kg failed to win medal but qualified for the Olympics thank to their rankings.
A total of 128 athletes from 42 countries competed at the Dynamo Sports Palace on December 6 and 7.