Enzymatic deinking effectiveness and mechanisms
Enzymatic deinking effectiveness and mechanisms
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发表时间：
1996-10
影响因子：
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通讯作者：
Thomas Welt;R. Dinus
中科院分区：
文献类型：
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作者：
Thomas Welt;R. Dinus
酶法脱墨是一种将废纸加工成高质量产品的新方法。本研究的目的是阐明纤维素酶处理效果的影响因素的作用，并确定油墨去除的机制。使用商业纤维素酶制剂从由17%半漂白硫酸盐浆（SBKP）和83%热磨机械浆（TMP）组成的新纸中对高度交联的大豆油基油墨进行脱墨。通过酶处理水控制分离油墨，并在标准实验室浮选槽中从纸浆悬浮液中除去常规化学脱墨。在部分析因试验中研究了各种工艺参数的影响。根据浮选前后的手抄纸亮度、残留油墨计数和油墨面积来评价有效性。几个工艺参数证明是重要的，但最重要的是崩解时间和酶浓度。纤维素酶处理增加了亮度，并将墨水计数和面积减少到显着低于水对照的值。然而，脱墨结果与通过化学脱墨获得的结果不匹配。显然，酶处理通过加速和增加被大面积油墨覆盖的纤维材料的分离来促进大油墨颗粒的去除。未印刷纸的试验证实，纤维素酶处理加速了纤维材料的分离。扫描电子显微镜照片，纯SBKP和TMP纸处理后制备的，表明SBKP纤维的纤维素酶处理的影响最大，观察到一些局部降解，但外部原纤没有以任何大的频率被删除。纤维素酶处理对TMP纤维的影响较小，主要限于偶尔缩短和/或去除原纤维。在新纸纤维的显微照片中观察到类似的效果。基于这些发现，纤维素酶在脱墨中的主要作用似乎涉及油墨-纤维附聚物的分离，以及当纤维材料响应于崩解期间的机械作用而分离时油墨颗粒的简单移位或破碎。然而，要了解纤维素酶在脱墨中的作用，需要清楚地了解它们对废纸中不同类型纤维的影响。虽然在本研究中没有研究，但由于它们在油墨纤维团聚体中的显著存在，两种纸浆类型的细粉也被涉及。鉴于其高比表面积，细粉易于受到纤维素酶的优先攻击。细粉在酶促分离油墨-纤维附聚物中的作用是未来研究的主题。
Enzymatic deinking represents a new approach for processing waste paper into quality products. The objectives of the present research were to clarify the role of factors affecting effectiveness of cellulase treatment and to identify the mechanisms underlying ink removal. A commercial cellulase preparation was used to deink a highly crosslinked soybean oil-based ink from a newsheet consisting of 17% semibleached kraft pulp (SBKP) and 83% thermomechanical pulp (TMP). Ink detached via enzymatic treatment water controls, and conventional chemical deinking was removed from pulp suspensions in a standard laboratory flotation cell. Effects of various process parameters were investigated in fractional factorial trials. Effectiveness was evaluated in terms of handsheet brightness, residual ink counts, and ink areas before and after flotation. Several process parameters proved significant, but the most important were disintegration time and enzyme concentration. Cellulase treatment increased brightness and reduced ink counts and areas to values significantly lower than those of water controls. Deinking results, however, did not match those obtained via chemical deinking. Apparently enzymatic treatment fostered removal of large ink particles by hastening and increasing the separation of fibrous materials covered by large areas of ink. Trials with unprinted paper confirmed that cellulase treatment accelerated separation of fibrous materials. Scanning electron micrographs, prepared after treatment of pure SBKP and TMP papers, showed that SBKP fibers were most affected by cellulase treatment Some localized degradation was observed, but external fibrils were not removed with any great frequency. Effects of cellulase treatment on TMP fibers were lesser, and restricted primarily to occasional shortening and/or removal of fibrils. Similar effects were noted in photomicrographs of fibers from newsheet Based on these findings, the primary role of cellulases in deinking appears to involve separation of ink-fiber agglomerates, and simple dislodging or breaking of ink particles as fibrous materials separate in response to mechanical action during disintegration. Understanding the role of cellulases in deinking, nonetheless, requires clear appreciation of their effects on the different types of fibers present in waste paper. Although not investigated during the present research, fines of both pulp types are also involved by virtue of their significant presence in ink-fiber agglomerates. Given their high specific surface area, fines are subject to preferential attack by cellulases. The role of fines in enzymatically enhanced separation of ink-fiber agglomerates is the subject of future research.