摘要
在常规工艺下难以制备高白度(>78%)竹材化学机械浆是制约竹类资源在高附加值纸产品领域规模化应用的关键技术瓶颈。使用乙醇-水二元介质碱性过氧化氢漂白体系可以突破当前慈竹机械浆漂白上限,将纸浆白度提升至80%以上。以慈竹机械浆为原料,对比研究了常规过氧化氢用量(90 kg/t)水相体系两段漂工艺、高过氧化氢用量(180 kg/t)水相四段漂工艺和高过氧化氢用量(180 kg/t)乙醇-水二元介质相四段漂工艺中各段处理所得纸浆的发色基团结构特点,以及3种工艺漂白段溶出物的结构特点,以此探索二元体系漂白过程中发色基团形成和溶出规律。结果表明,在漂白过程中,慈竹机械浆中的苯环类共轭结构含量逐渐降低,但在化学品用量较大的漂白段会生成在水相体系无法被破坏和溶出的呋喃类共轭结构。在漂白体系中引入乙醇,可以显著提高呋喃类共轭结构的溶出效率,同时发现浆料中溶出的部分苯环结构发生了开环反应,推测碱性条件下乙醇电离的微量乙氧根离子对呋喃类共轭结构的脱除具有关键性作用。慈竹机械浆发色基团演变及溶出机制可为开发经济上可行的竹类机械浆漂白工艺提供理论基础。
The application of bamboo in high value-added paper products is limited due to the difficulty of preparing high-brightness(>78%)chemical-mechanical pulp.Based on the current bleaching chemi-mechanical pulp manufacturing process,i.e.,alkaline hydrogen peroxide with ethanol-water media bleaching(AHEWB)system,the facile mild bleaching system has been proven to be an effective approach to break through the brightness limitation of the Neosinocalamus affinis mechanical pulp(NAMP)over 80%.In this study,bleached NAMPs(B-NAMPs)were prepared in three different systems,e.g.,two-stage bleaching process with conventional hydrogen peroxide dosage(90 kg/t)in aqueous system,four-stage bleaching process with high hydrogen peroxide dosage(180 kg/t)in aqueous system,and four-stage bleaching process with high hydrogen peroxide dosage(180 kg/t)in AHEWB system,respectively.The UV-Vis and Raman spectra of different B-NAMPs,as well as the 2D-HSQC of their milled wood lignin(MWL)and the pyrolysis gas chromatography mass spectrometry(Py-GCMS)of bleaching residues were carried out to distinguish the characteristics of B-NAMP s chromophores and bleaching residues.The results showed that the content of benzene-conjugated structures in B-NAMP decreased during the bleaching process.However,furan-conjugated structures that could not be disrupted and solubilized in aqueous systems were generated during the bleaching section with high chemical dosages.Moreover,the Py-GCMS results of bleaching residues confirmed that the solubility of furan-conjugated structures was significantly improved in the AHEWB system,while the ring-opening reactions of benzene ring structures were simultaneously boosted.It was hypothesized that the trace amounts of ethoxylate ions from ethanol ionization under alkaline conditions played a key role in selectively severing the chemical bonds within the furan-conjugate structure and NAMP,further achieving its dissolution.The findings of this study may provide a theoretical basis for the development of a feasible cost-effecti
作者
焦健
朱北平
韩善明
梁芳敏
苏晨
房桂干
谢章红
沈葵忠
JIAO Jian;ZHU Beiping;HAN Shanming;LIANG Fangmin;SU Chen;FANG Guigan;XIE Zhanghong;SHEN Kuizhong(Institute of Chemical Industry of Forestry Products,CAF,Key Lab.of Biomass Energy and Material,Jiangsu Province,Co-Innovation Center of Efficient Processing and Utilization of Forest Resources,Jiangsu Province,Key Lab.of Chemical Engineering of Forest Products,National Forestry and Grassland Administration,National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass,Nanjing 210042,China;Shandong Huatai Paper Co.Ltd.,Dongying 257335,China;Yibin Paper Industry Co.Ltd.,Yibin 644109,China;Sichuan Province Engineering Technology Research Center of Bamboo Pulping and Papermaking,Yibin 644109,China)
出处
《林业工程学报》
CSCD
北大核心
2024年第3期77-87,共11页
Journal of Forestry Engineering
基金
国家自然科学基金面上项目(32271974)
宜宾市揭榜挂帅科技项目(2022JB009)
泰山产业领军人才工程专项经费(tscy20200213)
江苏省生物质能源与材料重点实验室重点项目(JSBEM-S-202309)。
关键词
慈竹机械浆
漂白
发色基团
溶出机制
演变机制
Neosinocalamus affinis mechanical pulp
bleach
chromophores
removal mechanism
evolution mechanism
