草酸处理竹材的水解液pH值与水解得率的关系

Relationship of pH of the Hydrolysate and the Yield of Bamboo in Oxalic Acid Treatment

中文关键词:  竹子  草酸  预水解  得率  pH值

Key Words:bamboo  oxalic acid  yield of hydrolysis  pH

中文摘要:

      以硫酸盐法生产溶解浆时，需先用预水解的方式去除原料中的半纤维素。实验探讨了以竹材为原料进行水预水解及草酸预水解过程中，水解液终点pH值与水解得率的变化规律。实验结果表明，在水预水解过程中，水解液的pH值与得率均会达到一个相对稳定值，而且，温度越高，达到相对稳定值越快；在草酸预水解过程中，草酸用量为1%时，水解液pH值变化不大，基本维持在3.2~3.3之间，但是得率随水解时间的延长而下降；草酸用量≥3%时，随水解反应的进行，pH值逐渐增大、得率逐渐降低，而后趋于稳定，而且，草酸用量越高，pH值及得率相对稳定值越低。在这2种水解过程中，水解液pH值与水解得率有很好的线性关系；温度对直线斜率影响不大；草酸用量越高，斜率越小。

Abstract:

      In this study, the pH of the hydrolysate and the yield of bamboo in oxalic acid pretreatment of bamboo chips with various oxalic acid concentration were investigated and the relationship between pH of hydrolysate and bamboo yield were explored. pH and yield would reach to a level-off value in the course of hot water treatment, while the higher temperature was favored to a level-off value in short time. pH of hydrolysate was almost stable with the addition of 1% oxalic acid, whereas the yield of bamboo decreased. When the oxalic acid amount exceeded 3%, pH increased and yield decreased gradually, furthermore both of them tended to be level-off. The final values were depended on the initial oxalic acid addition. The higher of oxalic acid addition, the lower of both level-off values. pH and yield bad good linear relationship in hot water treatment, its slope was more or less independent on temperature. Similarly, pH and yield also had linear relationship when oxalic acid was added, its slope was related to oxalic acid addition, the higher of oxalic acid addition, the lower of the slope.