阔叶木蒸煮黑液中木素溶解性能的研究

发布时间：2018-05-28 08:08

本文选题：黑液 + 木素　；参考：《天津科技大学》2015年硕士论文

【摘要】：木素具有胶体的特性。本文采用聚焦光束反射测定仪(FBRM)、激光粒度仪、膜分离与紫外分光光度计(UV)相结合的方法,研究了电解质对黑液体系中硫酸盐木素溶解性能的影响。根据研究结果,可采取相应的措施来减缓某些电解质对原料的蒸煮、浆料的洗涤以及纸浆漂白所产生的不良影响；也可将金属离子对于木素溶解性能影响的研究结果应用于盐析法提取木素。电解质对桉木硫酸盐法黑液中木素溶解性能影响的研究结果表明,Ca2、Mg2+、 Mn2+、Fe3+和Fe2+的临界聚沉浓度分别为50.10 mmol/L、64.9mmol/L、12.5mmol/L、 1.87 mmol/L和1.56 mmol/L。在黑液中的金属离子浓度达到临界浓度之前,木素颗粒数增加不大,但黑液的UV吸光度(205nm处)减少百分比会随着黑液中金属离子浓度的增加而略有增大。当黑液中的金属离子浓度超过临界浓度时,木素的吸光度减少百分比和颗粒数量都急剧增加。黑液残余有效碱浓度在范围内变化时,A13+的临界聚沉浓度随着黑液中残余有效碱浓度的增加而减小,其它几种金属离子的临界聚沉浓度随着黑液残碱浓度的增加变化较小。随着原黑液中金属离子浓度的增加,纳米级木素颗粒的粒径逐渐增大。NaCl对残碱浓度为3.54 g/L到17.89 g/L之间的黑液体系中木素的溶解性能影响不大,几种酸根离子(SO42-、NO3-、SiO32-、CO32-)对黑液中木素溶解性能的影响较小。pH值对桉木硫酸盐法黑液中木素溶解性能影响的研究结果表明,当黑液的pH值在13.2-10.6之间时,木素的颗粒数和吸光度减少百分比随着pH值的降低变化很小；当黑液的pH值在10.6-9.3范围内时两者随着pH值的降低都急剧增加；当其小于9.3时随着pH值的降低两者增加缓慢。Ca2+和Mg2+随着桉木硫酸盐法黑液中固形物含量的减小,其临界浓度逐渐降低；Mn2+和Fe3+的临界浓度随着黑液中固形物含量的减小先增加后降低。增加桉木硫酸盐法蒸煮和洗涤过程所用水中电解质的含量会使蒸煮后和洗涤后纸浆的卡伯值增大。研究了电解质对桦木硫酸盐法黑液中木素溶解性能的影响。实验得出,Ca2+和A13+的临界聚沉浓度较大,分别为40.5 mmol/L和31.5 mmol/L, Mg2+和Mn2+的临界聚沉浓度较小,分别为7.80 mmol/L和4.10 mmol/L。NaCl以及几种酸根离子对有效碱浓度为7.94 g/L(以NaOH计)的黑液中木素的溶解性能几乎没有影响。
[Abstract]:Lignin has colloidal properties. In this paper, the influence of electrolyte on the solubility of lignin sulfate in black liquor system was studied by means of focusing beam reflectometry, laser particle size analyzer, membrane separation and ultraviolet spectrophotometer (UV). According to the results, some measures can be taken to slow down the adverse effects of some electrolytes on raw material cooking, pulp washing and pulp bleaching. The effect of metal ions on the solubility of lignin can also be applied to the extraction of lignin by salting-out method. The effect of electrolytes on the solubility of lignin in eucalyptus sulfate black liquor was studied. The results showed that the critical concentration of Ca _ 2mg _ 2, Mn2 Fe _ 3 and Fe2 were 50.10 mmol / L ~ 64.9 mmol / L ~ (12.5) mmol 路L ~ (-1), 1.87 mmol/L and 1.56 mmol 路L ~ (-1) 路L ~ (-1) respectively. When the concentration of metal ions in black liquor reached the critical concentration, the number of lignin particles increased little, but the UV absorbance of black liquor increased slightly with the increase of concentration of metal ions in black liquor. When the concentration of metal ions in black liquor exceeds the critical concentration, the absorbance of lignin decreases by percentage and the number of particles increases sharply. When the residual effective alkali concentration of black liquor changes in range, the critical concentration of A13 decreases with the increase of residual effective alkali concentration of black liquor, while the critical concentration of other metal ions changes slightly with the increase of residual alkali concentration of black liquor. With the increase of metal ion concentration in the original black liquor, the particle size of nano-lignin particles increased gradually. NaCl had little effect on the solubility of lignin in the black liquor with residual alkali concentration of 3.54 g / L to 17.89 g / L. The effect of pH value on the solubility of lignin in eucalyptus sulfate black liquor was studied. The results showed that when the pH value of eucalyptus sulfate black liquor was between 13.2-10.6, the effect of pH value on the solubility of lignin in eucalyptus sulphate black liquor was found to be between 13.2-10.6. The number of lignin particles and the percentage of decrease in absorbance of lignin changed little with the decrease of pH value, and when the pH value of black liquor was in the range of 10.6-9.3, both of them increased sharply with the decrease of pH value. When it is less than 9.3, the increase of Ca 2 and Mg2 is slow with the decrease of pH value. The content of solid substance in eucalyptus sulfate black liquor decreases with the decrease of pH value. The critical concentration of MNO _ 2 and Fe3 decreased gradually with the decrease of solid content in black liquor, and then decreased. The Kappa number of pulps after cooking and washing was increased by increasing the content of electrolytes in the water of eucalyptus Kraft cooking and washing process. The effect of electrolytes on the solubility of lignin in birch sulfate black liquor was studied. The experimental results show that the critical concentration of Ca 2 and A 13 are 40.5 mmol/L and 31.5 mmol / L, respectively, and the critical concentration of Mg2 and Mn2 are smaller. The solubility of lignin in black liquor with effective alkali concentration of 7.94 g / L (in NaOH) was almost unaffected by several acid ions at 7.80 mmol/L and 4.10 mmol/L.NaCl, respectively.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X793

【相似文献】