Preparation and characterization of moso bamboo charcoal modified with nitric acid

The surface properties of a commercial moso bamboo charcoal had been selectively modified by means of acidic treatment, using HNO3 with the concentrations of 17%, 34%, and 68% (w/w) respectively at 25 degrees C for 8 hours. The iodine number, moisture content of all samples were tested, and the results showed that the iodine number of modified samples decreased slightly, while the moisture content increased sharply compared with raw sample, the sample modified with 68% HNO3 got the most remarkable change of above parameters. The Boehm titration, FUR and SEM were also introduced to characterize the surface properties of raw and modified samples, the results revealed that the amount of surface functional groups, including various oxygen-containing and a few nitrogen-containing groups increased significantly of modified samples, the surface became more coarse and a large amount of fine fragment was yielded in pore space and vascular bundle of modified samples because of the corrosion behaviour of HNO3 in the modification process.