【作者】 厉悦；

【导师】 李湘洲；

【作者基本信息】 中南林学院 ， 林产化工， 2005， 硕士

【摘要】 活性炭作为一种优质吸附剂,其应用越来越广泛,目前已广泛应用于环境保护、化学工业、食品加工、药物精制、军事化学防护等各个领域。稻壳是稻谷加工的副产品,我国稻壳资源相当丰富,但利用程度较低,大部分作为废物丢弃或作低级燃料用。因此对于稻壳资源的开发和利用一直是人们感兴趣的课题。大量存在的农副产品废弃物—稻壳中含有丰富的固定碳,开发利用稻壳有着重要的意义。活性炭的表面官能团的种类与数量决定了活性炭的表面化学性质,而化学性质决定了活性炭的化学吸附特性。通过表面改性,可以大大改善活性炭对特定吸附物质的吸附能力。 本研究以稻壳为原料,分别采用碱金属氢氧化物活化法、磷酸活化法制备活性炭,考察了活化剂的种类,原材料与活化剂的配比,活化温度和活化时间等因素对活性炭的吸附性能的影响,确立了调控活性炭性能的工艺方法和工艺条件。利用扫描电镜观察了活性炭的形貌特征,利用X射线衍射分析了稻壳活性炭中微晶的晶体结构,并且将所制的稻壳活性炭应用于对水中Cr⁶⁺的吸附,研究了活性炭去除Cr⁶⁺的吸附等温线和适宜的吸附条件。本文还研究了硝酸、硫酸和氨水对活性炭的表面改性,探讨了表面改性对活性炭表面化学性质的影响及其表面化学性质与吸附性能之间的关系。 研究结果表明: ①以稻壳为原料,KOH为活化剂在实验室的马弗炉中制备活性炭的适宜工艺条件为:活化剂/炭为4,活化温度为750℃,活化时间为1h。所制得的活性炭的碘吸附值为1240 mg·g^-1,亚甲基蓝吸附值为150 mL·g^-1。 ②以碱金属氢氧化物作活化剂时,KOH的催化活化性能明显高于NaOH的催化活化性能。 ③以稻壳为原料,磷酸为活化剂在实验室的马弗炉中制备活性炭的适宜工艺条件为:活化剂/炭为3,活化温度为400℃,活化时间为2h.所制得的活性炭的碘吸附值为809 mg·g^-1,亚甲基蓝吸附值为160 mL·g^-1。 ④稻壳为原料制备的活性炭对Cr⁶⁺具有良好的吸附性能,其中磷酸法稻壳活性炭对Cr⁶⁺的吸附量为8.75 mg·g^-1;KOH法稻壳活性炭对Cr⁶⁺的吸附量为9.23 mg·g^-1,NaOH法稻壳活性炭对Cr⁶⁺的吸附量为9.05 mg·g^-1。 ⑤活性炭经过表面改性后,其表面总酸度、总碱度有较大变化,因而对特定目标物质的吸附性能有较大影响。更多还原

【Abstract】 Activated carbon is an important adsorbent, and is extensively used in industry such as environmental protection, chemical industry, food processing, pharmaceutical processing, and military chemistry etc. The rice husk is byproduct of rice processing .The rice husk resources are plentiful in our country, but most of them are discarded as waste material or burned out as fuel. The abundant rice husk as agricultural byproduct contains plentiful fixed carbon. It is significant to exploit the application of rice husk. The surface chemical properties of activated carbons are closely related to the functional groups on their surface,which further determine the chemical absorbing characteristic of the activated carbon..Surface modification can lead to substantial improvement in the activated carbon’ ability to absorb specific absorbates.The activated carbon （AC） is prepared from rice husk by the activation of alkali metal hydroxide and phosphoric acid. The activated agent of different kinds and its ratio, the activate temperature, the activate time; adsorption properties of AC have been investigated. Base on these, the technologic methods and conditions of controlling structure and properties of AC had been established. The morphology of AC is observed by scan electric microscope. X-ray diffraction analyzer analyzes the structure of microcrystalline in AC. Utilizing the activated carbon from rice husk absorb Cr6+ in water, this paper does some study about Cr6+ removal sorption isotherm line and suitable terms of absorbing. In order to improve the carbon dioxide adsorption capacity on activated carbon, its oxidative treatment with nitric acid, sulphuric acid and ammonia water is carried out. The results show that surface modification has important effects on the carbon dioxide adsorption capacity and surface acid groups.The results of this paper are follows:（1）Experiment results show that the best technologic conditions of preparing AC with rice husk by the activation of KOH using muffle furnace in laboratory are the ratio of rice husk and KOH, activation temperature and activation time being 4,750 and 1 hour respectively. Its iodine adsorption value and methylene blue adsorption value are 1240 mg.g^-1and 150 mL.g^-1 respectively.（2）The catalysis activity of KOH is super to NaOH when single alkali metals hydroxide as activated agent.（3）The best technologic conditions of preparing AC with rice husk by the activation of更多还原