Study On The Source And Enhancement Of Basicity Of Activated Carbon And Its Catalysis To The Reaction Of Hydrogen Peroxide Decomposition

The basicity of activated carbon is fundamental to the applications in adsorption, catalysis,electrochemistry and other fields. To understand the fundamental on basicity of activated carbon surface, the methods including acid washing, oxidation and ammonination were used to modify the surface property of activate carbon. The surface functional groups were characterized by the methods such as Boehm titration, TG-IR, XPS, et al, and pore structure was analyzed by nitrogen adsorption in an effort to investigate the effect of ash, oxygen and nitrogen containing functional groups on the basicity of activated carbon. Finally, the catalytic ability of the ammonia modified activated carbon to the reaction of hydrogen peroxide decomposition was studied to explore the application of the basic activated carbon. The main conclusions are obtained as follows:(1) The activated carbon prepared by steam activation present to be basic mainly due to the existence of the basic inorganics in ash. After acid washing, the commercial activated carbon become weak basic, even neutral or weak acidic in the water. The heat treated activated carbon above 700 o C in inert atmosphere present a basici nature, which is attributed to the existence of a benzopyrone structure on the activated carbon surface.(2) In the processing of HNO3 oxidation, the species of the oxygen containing funcational groups caused by HNO3 oxidation are ether, phenol, quinone, carbonyl, at a lower oxidation degree, and then gradually shifted to the ones such as anhydride, lactones, which possess stronger acidity. The HNO3 oxidation led to the decrease in the basicity of activated carbon because the more acidic functional groups produced a shielding role in the basic groups on the activated carbon. However, oxidation by air or steam oxidation produced a negligible effect on the basicity of activated carbon because they does’ t change activated carbon surface functional groups obviously(3) The major species of the nitrogen containing functional groups generated by ammonia treatment at 900 o C included pyridinic, pyrrolic and quaternary functional groups, with the minor ones of nitrogen oxide. The pre-oxidation of activated carbon by HNO3 benfited the formation of the nitrogen containing functional groups, especially of nitrogen oxides.(4) The activated carbon modified by ammonia can catalyze significantly the reaction of hydrogen peroxide decomposition. The main reason is that the pyridinic, pyrrolic and quaternary functional groups have a potential to lower the apparent activation energy the reaction...