直接耐酸性枣红在脱硅稻壳活性炭上的吸附热力学与动力学特性  

Kinetic and thermodynamic characteristics of direct fast bordeaux adsorption on activated carbon from silicon-freed rice hull

作　　者：姚超[1] 秦泽勇[1] 吴凤芹[1] 李锦春[1] 王茂华[1] 魏科年[1] 

机构地区：[1]常州大学化工学院,江苏常州213164

出　　处：《化工学报》2011年第4期977-985,共9页CIESC Journal

基　　金：江苏省科技支撑计划项目(BE2009099);江苏省高校自然科学研究项目(09KJA430002);江苏省自然科学基金项目(BK2009748)~~

摘　　要：以稻壳为原料,磷酸为活化剂制备了脱硅稻壳活性炭。探讨了浸渍比、磷酸浓度、活化温度和活化时间对活化效果影响。结果表明,制备脱硅稻壳活性炭的合适工艺条件为:浸渍比为2∶1、磷酸浓度为50%、活化温度为500℃、活化时间为1 h。通过X射线衍射、比表面、Fourier红外光谱、X射线能谱和高分辨透射电子显微镜等技术对脱硅稻壳活性炭进行了表征,并从热力学和动力学角度,研究了脱硅稻壳活性炭对水溶液中直接耐酸性枣红的吸附行为。热力学研究表明:脱硅稻壳活性炭对直接耐酸性枣红的吸附符合Langmuir等温吸附方程,吸附焓变为61.31 kJ.mol-1,吸附自由能变为-39.99^-28.71 kJ.mol-1,吸附熵变为297 J.mol-1.K-1,该吸附过程是一个自发的吸热过程。动力学研究表明:脱硅稻壳活性炭对直接耐酸性枣红的吸附动力学符合颗粒内扩散方程,测得其表观活化能为33.34 kJ.mol-1。The activated carbon was prepared from silicon-freed rice hull by using phosphoric acid as activating agent.The effects of impregnation ratio,concentration of phosphoric acid solution,calination temperature and calination time were studied.The experimental results showed that the suitable condition for preparation of the activated carbon was impregnation ratio 2∶1,concentration of phosphoric acid solution 50%,calination temperature 500℃,and calination time 1 h.The activated carbon was characterized by means of X-ray diffraction（XRD）,Brunauer-Emmett-Teller（BET）,Fourier transform infrared spectra（FTIR）,X-ray energy dispersive spectrum（EDS）and high resolution transmission electron microscopy（HRTEM）techniques.The kinetic and thermodynamic parameters for the absorption of direct fast bordeaux in aqueous solution by the activated carbon were studied.The study on the thermodynamic behavior indicates that the absorption of direct fast bordeaux obeys the Langmuir isotherm model.The adsorption enthalpy is 61.31 kJ·mol-1,the Gibbs free energy is-39.99—-28.71 kJ·mol-1,and the entropy is about 297 J·mol-1·K-1,so the adsorption process is endothermic and spontaneous. The study on kinetic parameters shows that the absorption is best described by the intra-particle diffusion model,and the apparent activation energy is determined to be 33.34 kJ·mol-1.

关 键 词：稻壳 活性炭 直接耐酸性枣红 吸附热力学 吸附动力学 

分 类 号：X131.2[环境科学与工程—环境科学]