ＳＣＰ廃液について ＩＶ 廃液中のキシラン

Abstract

In the previous paper, the toxicity characteristics of NSSCP spent liquor were examined using killifish for bioassay, and it was found that the suspended substances in spent liquor played an important role for its toxicity. These suspended substances gave xylose after hydrolysis, and it was considered to be xylan origin.This paper deals with yield pattern and chemical composition of the three fractions separated from the spent liquor as shown in Fig. 1. Precipitate A corresponds to the above mentioned toxic substances.1) Yield of precipitate A showed a linear relationship with the pentosan content of chips, the keeping time at maximum cooking temperature, and organic matter concentration of the spent liquor. This suggested that the toxicity of NSSCP spent liquor would be increased under these conditions.2) Purity of precipitate A as xylan is not so high. Precipitate A isolated from the spent liquor of domestic wood species mainly consist of xylan and lignin. On the other hand, that of white lauan mainly consists of lignin.3) Xylan dissolved from chips into digestion liquor during NSSCP cooking cannot be recovered at most 50% in the spent liquor. Rest of the dissolved xylan may be converted to other types of substance which is difficult to be determined by Somogyi's. method.