木聚糖酶前處理對於尤加利硫酸鹽漿氧漂去木質素之影響

Abstract

在製漿工業上，人們一直努力尋找新的漂白程序，在不影響或提高紙張性質為前提，降低化學漂白劑的使用，以及對環境的污染。而到目前為止，以酵素的在預漂上的應用較為有效。 在本次的研究，酵素添加於尤加利硫酸鹽漿氧漂前，探討對其日後助漂的效果。漿料分為高卡巴值和低卡巴值，在進入氧漂階段前，分別以木聚醣酶 (每克絕乾重漿料添加10 IU，反應溫度為65oC，反應時間為60分鐘) 為前處理。在99oC下，分別經過0、15、30、45、60分鐘的氧漂處理，以60分鐘處理後的效果為最佳，可以有效去減少卡巴漿料和高卡巴漿料中的卡巴值，並提高低卡巴漿料和高卡巴值漿料的黏度，分別為6.4o/o和1.3o/o；移除殘餘木質素的能力分別為17o/o和13o/o，並且增加了紙漿的可漂性和選擇性。 如何有效去除己烯糖醛酸，也得到多方關注。由於在製漿的蒸煮過程中會產生己烯糖醛酸，它將會與過錳酸鉀反應，提高卡巴值的測定，使的在漂白時添加過多二氧化氯漂白劑。在這次的實驗樣本中，己烯糖醛酸對於卡巴值分別有18.0o/o和13.1o/o的影響。由此可知，去除己烯糖醛酸可減少漂白劑的使用，進而降低對環境的汙染。

The pulp industry was trying to change and improve the old bleaching sequences to decrease the dosage of bleaching chemicals and environmental pollution furthermore increase the pulp properties. Currently the most important application of enzymes is in the pre-bleaching of kraft pulp. Xylanase enzymes have been found to be most effective for that purpose. The purpose of this study was to investigate the effect of xylanase (Pulpzyme HC) pre-treatment and oxygen bleaching time on Eucalyptus globules kraft pulp. Unbleached pulps, divided into low kappa number and high kappa number, were pre-treated with xylanase (10 IU/g of oven-dried pulp, 65oC) before oxygen delignification stage. After varying oxygen bleaching time, ranges from 0, 15, 30, 45, and 60 min and the temperature maintained at 99oC, it enhanced the removal of the kappa number of low and high kappa number pulps after 60 min reaction, besides, the viscosity of those can be enhanced to 6.4o/o and 1.3o/o at final oxygen delignification, respectively; the residual lignin can be removed 17o/o and 13o/o, respectively. Besides, it enhanced the bleachability and selectivity of pulp. The removal of hexenuronic acid (HexA) has attracted a lot of concerns, because HexA will react with potassium permanganate so that increase the consumption of bleaching chemical agents. The HexA contents in the low kappa number and high kappa number contribute kappa number about 18.0o/o and 13.1o/o. The result showed that the dosage of bleaching agent will be reduced as the removal of hexenuronic acid.