Ning Wu,  You might try high pressure steam oxidation, you could achieve
several bar at reasonable temperatures.  Steam is a very aggressive oxidant,
and something as simple as a pressure cooker might do your job.  Easy and
cheap to try.  Gary

Gary Hillman
Service Support Specialties, Inc.
PO Box 365
9 Mars Court
Montville, NJ 07045
Telephone 973-263-0640 extension 35
Fax 973-263-8888