Formation of dissolved high molecular organic substances in the bleaching of softwood kraft pulp

摘要

This study focused on the possibility of influencing the formation of dissolved high molecular substances after D(EP)DD and D(EP)bleaching of softwood kraft pulp.In laboratory experiments,we used ultra-filtration to separate molecules of different sizes from the generated filtrates.We knew that the biological degradation rate in the receiving water decreased with increasing molecular weight.The cut-off for the membranes used were 1000,3000,and 10,000 g/moMDalton).We used COD and ultraviolet absorbance at 280 nm to analyze total organic substance and the amount of dissolved lignin.