Preparation And Performance Of Biomass Carbon Materials

Using renewable biomass as raw material to prepare carbon materials,not only can reduce the need for fossil fuels,but also can reduce environment pollution problem.Firstly,the effect of appropriate hydrothermal carbonization on walnut shell and shaddock peel hydrochars was studied;Secondly,used hydrochars as absorbent for the removal of Cr(VI);Lastly,the carbon materials were prepared by a sample activation derived from hydrochars with KOH as active agent,and their supercapacitive properties were studies.The main points were as follows:(1)The optimum preparation conditions of the walnut shell and shaddock peel hydrochars were at 180? and 190? for 12 h,respectively;Under this condition,the yield of hydrochars are 50.69%,50.13% and C are 66.26%,60.22% respectively.The results show that the surface of the hydrochars contain a large amount of oxygen-containing functional groups.(2)The adsorption test of hydrochars for chromium simulated waster results indicate that:the adsorption processs was highly dependent on the pH;with the increase of the hyrdochars mass,the removal percentage improving significantly;with increasing the Cr(VI)concentration,though the removal percentage decrease after increase,the adsorption capacity increase;when reaching the adsorption equilibrium,the removal percentage of walnut shell and shaddock peel hydrochars for Cr(VI)were 98.32%?99.03,respectivally;the adsorption process of walnut shell and shaddock peel hydrochars are better described by the pseudo-second-order model and Freundlich isotherm model.(3)With increasing the activation temperature and alkali/carbon ratio,the specific area and pore volume of walnut shell and shaddock peel porous carbons increased at the beginning and then decreased,while the percentage of mesopores increasde.Compared with walnut shell and shaddock peel pyrolysis carbonization and activated,the specific area increase of 13.62%?16.79%,respectively;the pore volume increase of 14.37%?11.43%,respectively.(4)The result show that the walnut shell and shaddock peel porous carbons show high performance for supercapacitors in 3mol/L KOH,and the maxium mass specificcapacitor are 284F/g?260F/g,respectively.Compared with walnut shell and shaddock peel pyrolysis carbonization and activated,mass specific capacitor increased of36.54%?20.37%,respectively.