【作者】 孔凡功；

【导师】 詹怀宇；

【作者基本信息】 华南理工大学 ， 制浆造纸工程， 2006， 博士

【摘要】 纸浆含氯漂白产生的有毒的有机氯化物对环境具有极大的危害。发展无元素氯及全无氯漂白新工艺是实现纸浆漂白清洁生产的关键。电化学介体脱木素（E_M）是一种新型纸浆漂白方法。寻找高效催化电极和催化介体是建立该体系的关键，也是电化学漂白研究的重点和难点。本论文以三倍体毛白杨KP浆为原料，制备和筛选了高效电极和催化介体，建立了高效电化学介体脱木素体系，并对脱木素工艺及漂白和相关机理进行了研究，为其实际应用提供技术和理论依据。 电化学含氯漂白的研究表明：单段漂白的适宜工艺为：初始pH值8.0，温度40℃，电压3.5V，时间120min，NaCl3.5％，浆浓1％，在此条件下能将Kappa值为24.6的浆漂至70％ISO，Kappa值为13.4的浆漂至80％ISO，且废液可循环使用。当改为两段漂在NaCl用量相同情况下，也达到了相同白度。与传统CEH漂白相比，达到80％ISO时，电化学漂白可缩短时间且漂白废液CODcr含量较低。 电极材料需根据电极电位的高低及其催化性能的高低来选择。制备的Ti／SnSbO_x、Ti／SnSbO_x／MnO₂、Ti／RuTiO_x、Ti／SnSbO_x／Pt和Ti／SnSbO_x／PbO₂电极，具有相应的催化晶体或共溶体存在，涂层表面均匀、致密。Ti／SnSbO_x／PbO₂和Ti／SnSbO_x／Pt的阳极电位最高，Ti／RuTiO_x、石墨、不锈钢和Ti／SnSbO_x电极次之，Ti／SnSbO_x／MnO₂：电极电位最低。对紫脲酸（VIO）为介体的电化学脱木素体系，Ti／RuTiO_x电极效果最好，具有最高的催化活性。 合成了多种多金属氧酸盐（POM），且均为Keggin型结构，具有传递电子的能力，氧化电势较高。Na₈[PMo₇V₅O₄₀]（POM-5）和有机介体VIO是优良的电化学脱木素催化介体。 优化了电化学介体脱木素工艺。VIO为介体的电化学脱木素的最优工艺为：VIO1.8mmol／L，电压2.5V，时间5h，pH值4.5，温度50℃，Na₂SO₄0.05mol·L^-1。后续碱处理，能进一步降低纸浆Kappa值，提高白度。E_ME处理使纸浆Kappa值由17.4降至7.8，木素脱除率为55.2％，粘度由1144cm³·g^-1降至1032cm³·g^-1，白度由39.2％ISO升至51.2％ISO。VIO为介体的E_M对不同Kappa值杨木KP浆和其它纤维原料纸浆均具有较好的脱木素效果。POM-5为介体的电化学脱木素较优工艺为：POM-52.5mmol·L^-1，电压2.5V，温度80℃，时间5h，pH值3.0，Na₂SO₄0.1mol／L。电解液可循环使用。后续碱处理，能进一步降低纸浆Kappa值，提高白度。对高Kappa值杨木浆的最优工艺为：POM-54mmol·L^-1，时间5h，温度90℃，电压2.5V，pH值3.0。POM为介体的E_M对不同Kappa值杨木浆均具有较好的脱木素效果，E_ME处理后，木素脱除率高于40％，粘度损失小于15％。 进行了含电化学介体漂段（E_M）的ECF和TCF漂白的研究。VIO为介体的E_M更多还原

【Abstract】 The toxic organochlorine compounds generated in pulp chlorine-containing bleaching have strong damages to environment. In order to resolve this problem and make paper industry in sustained growing, the new elemental chlorine free bleaching （ECF） and totally chlorine free bleaching （TCF） technology must be developed. The electrochemically mediated delignification （E_M） is one of new pulp bleaching methods. To find proper electrodes with high efficiency, high catalysis performance and mediators with high efficiency and high delignification selectivity is the key of setting up the electrochemically mediated delignification system, and it is also a key and difficult point of electrochemical bleaching research. In this thesis, the preparations and choices of different material electrodes and mediators, elecrochemically mediated delignification process, bleaching sequences including E_M stage and their mechanism were investigated, which would offer technical and theoretical support for appliction of this bleaching method in pulp and paper industry.The results of electrochemical chlorine-containing bleaching showed that the optimal technology conditions for one-stage electrochemical bleaching were as follows: initial pH value 8.0, temperature 40℃, voltage 3.5V, time 120min, NaCl 3.5%, pulp consistency 1%. The electrolyte could be recycled. The optimal techology conditions for two-stage electrochemical chlorine-containing bleaching were as follows: first stage: initial pH value 1.0, room temprature, current desity 0.1 A/cm², time 40min, NaCl 1.5%, pulp consistency 1%; second stage: initial pH value 8.0, temperature 40℃, current density 0.06A/cm², time 120min, NaCl 1.5%, pulp consistency 1%. Commpared with CEH bleaching, the electrochemical bleaching could reduce bleaching time when getting the same brightness, 80%ISO. The bleaching effluents from electrochemical bleaching had lower CODcr content than that from CEH.The electrode must be chosen on the basis of electrode potential and catalysis capablity. In this research, all the prepared electrodes with different material such as Ti/SnSbO_x, Ti/SnSbO_x/MnO₂, Ti/RuTiO_x, Ti/SnSbO_x/Pt and Ti/SnSbO_x/PbO₂ had catalysis crystal. The coated layer was smooth and dense. Among these electrodes, the electrodes of Ti/SnSbO_x/PbO₂ and Ti/SnSbO_x/Pt had highest electric potential. The electrode of Ti/SnSbO_x/MnO₂ had lowest electric potential. For violuric acid （VIO） mediated electrochemical delignification the electrode of Ti/RuTiO_x had best更多还原