Abstract This study aimed to investigate the oxalate formation mechanism during chlorine dioxide ( ClO 2 {\mathrm{ClO}_{2}}) bleaching of bamboo kraft pulp, and thus explore favourable ClO 2 {\mathrm{ClO}_{2}} bleaching conditions to better control oxalate formation. The amount of oxalate formed varied linearly with ClO 2 {\mathrm{ClO}_{2}} dosage within the whole research range, while it rose exponentially within the first 90 mins of pulp bleaching. Then the actual bleaching process was simulated by reacting ClO 2 {\mathrm{ClO}_{2}} with three representative lignin model compounds and comparatively studied. The rule of oxalate formation in the simulated reaction system was identical to that in pulp bleaching by ClO 2 {\mathrm{ClO}_{2}}, except for oxalate production by veratraldehyde with prolonged reaction time. Under identical conditions, vanillin formed the highest amount of oxalate, while veratraldehyde formed the least. Furthermore, the amount of oxalate formed increased by 19.59 mg/kg when the kappa number of the delignified pulp was reduced by one unit. Considering the satisfactory pulp brightness and decreased oxalate formation, the recommended conditions for ClO 2 {\mathrm{ClO}_{2}} bleaching of bamboo kraft pulp were a ClO 2 {\mathrm{ClO}_{2}} dosage of 4 %, 60 °C and 70 mins.

中文翻译：

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竹牛皮纸浆二氧化氯漂白过程中草酸盐的形成

摘要 本研究旨在探讨竹硫酸盐浆二氧化氯（ClO 2 {\mathrm{ClO}_{2}}）漂白过程中草酸盐的形成机理，从而探索有利的ClO 2 {\mathrm{ClO}_{2} } 漂白条件以更好地控制草酸盐的形成。在整个研究范围内，草酸盐的形成量随 ClO 2 {\mathrm{ClO}_{2}} 剂量呈线性变化，而在纸浆漂白的前 90 分钟内呈指数增长。然后通过使 ClO 2 {\mathrm{ClO}_{2}} 与三种代表性木质素模型化合物反应来模拟实际漂白过程并进行比较研究。模拟反应体系中草酸盐的形成规律与ClO 2 {\mathrm{ClO}_{2}}漂白纸浆的规律相同，只是藜芦醛反应时间延长，产生草酸盐。在相同条件下，香草醛形成的草酸盐含量最高，而藜芦醛形成的含量最少。此外，脱木素纸浆的卡伯值每减少一个单位，草酸盐的生成量增加了19.59 mg/kg。考虑到令人满意的纸浆白度和减少草酸盐的形成，推荐的 ClO 2 {\mathrm{ClO}_{2}} 漂白竹牛皮纸浆的条件是 ClO 2 {\mathrm{ClO}_{2}} 用量为 4 %，60 °C 和 70 分钟。