Electrochemical Oxidation of Transition Metal-Based Mediators for Pulp Delignification
Electrochemical Oxidation of Transition Metal-Based Mediators for Pulp Delignification
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DOI：
10.1149/1.1427077
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发表时间：
2002
影响因子：
3.9
通讯作者：
D. Rochefort;R. Bourbonnais;D. Leech;S. Renaud;M. Paice
中科院分区：
文献类型：
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作者：
D. Rochefort;R. Bourbonnais;D. Leech;S. Renaud;M. Paice
为了在制浆过程之后脱木素和去除残留在纸浆中的木质素，纸浆必须漂白。环境考虑和系统关闭要求已经产生了替换传统使用的氯漂白技术的需要。漆酶介导氧化纸浆中的残余木质素在过去的10年里得到了广泛的应用，可以被认为是一种很好的替代漂白方法。导致介导的木质素氧化的机制仍然不清楚。为了阐明介体在介体法硫酸盐浆脱木素过程中的作用并提高系统的效率，我们研究了介体K4Mo（CN）8（MoCn）在与纸浆反应之前在电解槽中的氧化。电化学氧化的MoCN得到类似的脱木素水平酶促氧化在类似的条件下，而铁基介质得到更好的脱木素比酶促氧化。电脱木素装置使我们能够研究pH和氧气对木质素降解的影响。我们还报告了高形式的潜在介质的使用和效率，这些介质被怀疑是良好的木质素氧化剂，但不容易被漆酶氧化。通过研究转移到溶液中以实现介体氧化的电荷，我们能够表明介体充当催化剂，即，在整个过程中连续再生，以进行有效的纸浆脱木质素。
In order to depolymerize and remove the lignin that remains in paper pulp following the pulping process, the pulp must be bleached. Environmental considerations and system closure requirements have created a need for replacement of the traditionally used chlorine bleaching technologies. Mediated laccase oxidation of residual lignin in pulp has gained in popularity during the last 10 years and could be considered as a good alternative bleaching method. The mechanisms leading to mediated lignin oxidation are still unclear. To clarify the role of the mediator during mediated kraft pulp delignification and to increase the efficiency of the system, we have studied the oxidation of K 4 Mo(CN) 8 (MoCn) mediator in an electrolysis cell prior to its reaction with pulp. The electrochemical oxidation of MoCN gave similar delignification levels to enzymatic oxidation under similar conditions, while the iron-based mediators gave better delignification than enzymatic oxidation. The electrodelignification setup allowed us to study the effect of pH and oxygen on the lignin degradation. We also report on the use and efficiency of high formal potential mediators that are suspected to be good lignin oxidants hut which are not readily oxidized by the laccase. By studying the charge transferred to the solution to achieve mediator oxidation we were able to show that the mediator acts as catalyst, i.e., is being continuously regenerated throughout the process, to perform efficient pulp delignification.