【摘要】 以稻壳为原料,采用水热法制备稻壳炭,将稻壳炭用于吸附印染废水中亚甲基蓝。利用XRD、SEM、TG、FT-IR等手段对稻壳炭进行表征分析,探究炭化温度和炭化时间对稻壳炭理化性质和亚甲基蓝吸附性能的影响。结果表明,炭化温度是影响稻壳炭吸附性能的重要因素。炭化时间为4 h,炭化温度为180～220℃,稻壳炭对亚甲基蓝去除率大于90%,亚甲基蓝的吸附量大于6.27 mg/g,其中,炭化温度为200℃、炭化时间为8 h,即(RH-200-8)的稻壳炭结构完整,稻壳炭产率较高为65.20%,亚甲基蓝的去除率和吸附能力分别为93.04%和6.62 mg/g。炭化温度为180～220℃,纤维素未完全分解,孔隙结构良好,孔径适中,有利于亚甲基蓝分子的扩散与吸附,含氧官能团数量较多,吸附活性点位较多,对亚甲基蓝吸附性能较好。炭化温度大于220℃,随着炭化温度的升高,纤维素和富氧官能团的分解加速,吸附活性点位减少,稻壳炭结构发生改变,比表面积增加,但最可几孔径减小,不利于亚甲基蓝分子的扩散,导致稻壳炭对亚甲基蓝的去除率和吸附能力降低。RH-200-8稻壳炭再生循环使用实验表明,RH-200-8稻壳炭再生次数增加,稻壳炭对亚甲基蓝去除率略有下降,RH-220-8-3(即稻壳炭使用第3次)的亚甲基蓝去除率达82.20%(10 h)。更多还原

【Abstract】 Rice husk carbon was prepared by hydrothermal method from rice husk, and used to adsorb methylene blue from printing and dyeing wastewater. Rice husk carbon was characterized by X-ray diffraction(XRD), Scanning Electron Microscope(SEM), Thermo Gravimetric(TG), Fourier Transform Infrared Spectrometer(FT-IR), and the effects of hydrothermal temperature and hydrothermal time, respectively, on the physicochemical properties and adsorption properties of methylene blue in rice husk carbon were investigated. The results showed that hydrothermal temperature was the important factor to affect the adsorption performance of rice husk carbon. In this study, when the hydrothermal time was 4 h and the hydrothermal temperature was 180-220 ℃, the removal rate of methylene blue in rice husk carbon was more than 90% and the adsorption capacity of rice husk carbon to methylene blue was more than 6.27 mg/g. Among them, the hydrothermal temperature was 200 ℃ and the hydrothermal time was 8 h(RH-200-8), the structure of rice husk carbon was intact and the yield of rice husk carbon was 65.20%. Besides, the removal rate and adsorption capacity of methylene blue in rice husk carbon were 93.04% and 6.62 mg/g in the same condition, respectively. The phenomenon was due to the cellulose was not completely decomposed, the pore structure of rice husk carbon was better and the pore diameter of rice husk carbon was moderate when the hydrothermal temperature was 180-220 ℃. In addition, the structure of rice husk carbon was conducted to the methylene blue molecule diffusion and adsorption, and rice husk carbon has more oxygen-containing functional groups with more adsorption active points, so the adsorption performance of rice husk carbon on methylene blue was better. When the hydrothermal temperature was greater than 220 ℃, with the increase of hydrothermal temperature, the cellulose would be accelerated decomposition, the oxygen-enriched functional groups were decomposed quickly, the adsorption activity points of rice husk carbon were reduced, the rice husk carbon structure was also changed and the specific surface area was increased, but most probable pore sizes of rice husk carbon were decreased, the phenomenon was not conducted to the methylene blue molecule diffusion in rice husk carbon, so the removal rate and adsorption ability of methylene blue in rice husk carbon decreased. The experiment of rice husk carbon(RH-200-8) regeneration and recycling showed that the removal rate of methylene blue in rice husk carbon decreased slightly with the number of rice husk carbon regeneration increased, and the maximum methylene blue removal rate of RH-220-8-3(Rice husk charcoal use 3 rd) reached 82.20%(10 h).更多还原