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林产化学与工业 ›› 2014, Vol. 34 ›› Issue (6): 13-20.doi: 10.3969/j.issn.0253-2417.2014.06.003

• 研究报告 • 上一篇    下一篇

HNO3-H2O2两步法制备Pd/C催化剂及其对木质素改性的催化作用

刘亮, 张盛明, 方桂珍   

  1. 东北林业大学 材料科学与工程学院, 黑龙江 哈尔滨 150040
  • 收稿日期:2013-08-28 出版日期:2014-12-25 发布日期:2015-08-18
  • 通讯作者: 方桂珍,博士生导师,主要从事天然高分子方面的研究及教学;E-mail:Fanggz_0@163.com. E-mail:Fanggz_0@163.com
  • 作者简介:刘亮(1988-),男,陕西咸阳人,硕士生,主要从事天然高分子化学方面研究工作
  • 基金资助:
    国家自然科学基金资助项目(31170542);"十二五"国家科技支撑计划课题 (2012BAD24B04)

The Catalytic Effects of Two-step Pretreatment Actived Carbon Loaded Pd by HNO3-H2O2 on Alkali Lignin

LIU Liang, ZHANG Sheng-ming, FANG Gui-zhen   

  1. College of Material Science and Technology, Northeast Forestry University, Harbin 150040, China
  • Received:2013-08-28 Online:2014-12-25 Published:2015-08-18

摘要: 以HNO3-H2O2处理活性炭载体,以甲醛为还原剂,采用浸渍法制备了Pd/C催化剂,对催化体系进行表征,考察其对碱木质素改性的催化作用,并对木质素抗氧化性能进行研究.研究结果表明,用硝酸预处理,H2O2进行活化后,活性炭羧基含量1.31 mmol/g,较原料提高了5倍;通过原子吸收光谱(AAS)、扫描电子显微镜(SEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)对催化剂进行表征,AAS表明Pd负载量为2.9%,SEM照片显示Pd呈圆球状均匀分布在载体表面;XRD和XPS数据分析表明催化体系中Pd以面心立方结构形式存在,主要为还原态Pd说明还原态Pd是催化的主要物种.反应后碱木质素总羟基、酚羟基和醇羟基分别提高了158.74%, 4.21%和255.96%; 凝胶渗透色谱(GPC)分析结果显示,反应后碱木质素重均相对分子质量(Mw)增大,数均相对分子质量(Mn)降低,分散度降低;抗氧化能力研究结果显示,反应后木质素的抗氧化性能有所提高,随着浓度增大,抗氧化能力提高,但均低于相同浓度条件下2,6-二叔丁基-4-甲基苯酚(BHT)的抗氧化能力.

关键词: 碱木质素, HNO3-H2O2处理活性炭, Pd/C催化剂, 催化活化

Abstract: The Pd/C catalyst was prepared using impregnation method, acidizing pretreatment activated carbon as the carrier, formaldehyde as reducing agent. The catalysts was characterized and its performance on alkali lignin was examined. Finally, the oxidation resistance was explored. That showed that the content of carboxyl functional groups on the surface of activated carbon was 1.31 mmol/g after pretreatment by HNO3 and H2O2. Pd/C catalyst was characterized by AAS, SEM, XRD and XPS. The AAS showed that the content of Pd was 2.9%, and the SEM photos showed that Pd was evenly and globularly distributed on the surface of the active carbon. The XRD and XPS data analysis indicated that Pd existed in the form of face-centered cubic structure, which is the main active species in the reaction. The hydroxyl groups of alkali lignin had significantly been improved after reaction. The content of hydroxy, phenolic hydroxyl and alcoholic hydroxyl increased by 158.74%, 4.21% and 255.96%, respectively. The GPC showed that the Mw of alkali lignin increased while the Mn and Mw/Mn reduced. The antioxidant properties of the lignin increased with concentration increased. It was lower than BHT at the same conditions.

Key words: alkali lignin, HNO3-H2O2 modified active carbon, Pd/C catalyst, catalytic activtion

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