Study On Preparation And Adsorption Performance Of Activated Carbon From Salix Psammophyla

Activated carbon with high specific surface area and strong adsorption has been used as a quality adsorbent. So far, activated carbon has been widely used in environment protection, chemical industry, food industry, pharmaceutics, etc. The activated carbon is prepared from sailx by chemical activation in the protection of N2. The salix is sand plant which is grown in Northwest Territories and west of Inner Mongolia. The salix resources are plentiful and contain plentiful fixed carbon. It is significant to exploit the application of salix.The studies were carried out on the preparation of salix activated carbon with ZnCl2, H3PO4and KOH as activator, orthogonal test determined the optimum conditions and the ratio, activator concentration, the activate time, the activate temperature and carbonization temperature have been investigated. Under the optimum conditions, the adsorption kinetics and adsorption thermodynamics which three different kinds of salix adsorption capacity on methylene blue have been studied. In adsorption kinetics, the pseudo-first-order model, pseudo-second-order model, Elovich equation and intraparticle diffusion were used for curve fitting. In adsorption thermodynamics, the Langmuir, Freundlich and Temkin adsorption isotherm equation were used for curve fitting. The degree of crystallinity, surface chemical state and surface structural features of salix activated carbon were determined by XRD, FTIR and BET specific surface area. The results are follows:(1) The processing optimum conditions on preparation for activated carbon from salix with ZnCl2were obtained, which was the ratio of1.5:1, activator concentration of45%, activation temperature of500℃and time of60min. The processing optimum conditions on preparation for activated carbon from salix with H3PO4were obtained, which was the ratio of2:1, activator concentration of55%, activation temperature of550℃and time of150min. The processing optimum conditions on preparation for activated carbon from salix with KOH were obtained, which was the ratio of1:1, carbonization temperature of400℃, activation temperature of850℃and time of120min.(2) The degree of graphitization of salix activated carbon was low, the structure is consist of amorphous carbon and a small amount of graphite crystallites. Three different kinds of salix activated carbon contained functional groups which are hydroxyl, carboxide, lactone-based etc. Specific surface area on the preparation of salix activated carbon with ZnCl2 is323.0119m2/g. Specific surface area on the preparation of salix activated carbon with H3PO4is1251.428m2/g. Specific surface area on the preparation of salix activated carbon with KOH is1780.296m2/g.(3) The adsorption capacity of salix activated carbon was increased with increasing adsorption temperature, adsorption time and pH value. The adsorption kinetics obeys the pseudo-second-order model, and the isotherm follows the Langmuir monolayer model.