【摘要】 <正> 制浆造纸废水含有包括酚类化合物在内的多种有毒物质,是一种很重要的污染源。由于对这些酚类化合物的组成缺乏足够的数据,83年开始执行的造纸工业污染物排放标准中没有设限制挥发酚排放的指标。酚类化合物是木素在蒸煮过程中降解的产物,制浆原料的木素结构的不同其降解产物可能是不同的。我国是一个以草类植物为主要制浆原料的国家,固此搞清草浆黑液中酚类化合物的组成已受到造纸工业部门和环保部门的日益重视。目前国内对制浆废水中酚类的研究主要限于挥发酚,但从木素结构可以推知其蒸煮产物还包括了不挥发酚和多元酚,甚至还有许多二苯环物。造纸工业比较发达的北欧、北更多还原

【Abstract】 Results from determinations of phenolics in black liquors with gas chromatography (G.C.) were presented.A Chinese made SP-2308 gas chromatography equipped with a flame detector was employed for the purpose. 17 phenolics, with some volatile phenolics,low volatile phenolies and polyphenols inclusive, were effectively separated on a packed column coated with a SP-2250 stationary phase. 10 phenolics in wheat straw kraft black liquor (sp. gr. 8.2～9.2 Be’) were identified by means of GC technique and further confirmed through GC/MS studies. Among these 8 phenolics existing in greater amounts were quantified by internal standard methods using 2.6-dichlorophenol as reference. The quantitative results are shown in Table 3,with Ci, Gi and Wi expressing weight of phenolic‘i’per litre of black liquor, weight of phenolic‘i’produced per ton pulp and weight persentage of phenolic‘i’in total contents respectively. Black liquor samples were prepared by laboratory wheat straw cooks typical of kraft mill pulping practices. It could be safe to assume that data shown in Table 1 were representative of what could have been obtained in commercial pulping processes.Such data might serve as a guide for the estimation phenolics concentrations in actual mill effluents or black liquors Black liquor samples were pretreated by acidification filtration, extraction and extractive evaporation. Then, the sample were directly injected and GC analysed. This procedure employed was comparatively simple. Recoveries of phenolics determined were between 0.33 and 0.78, (for phenols 0.78, and for syringaldehyde 0.33, with standard deviations of about 0.1). The same procedure was evidently applicable for all black liquor samples, regardless of their origin with respect to raw material species and their, methods of processing. Current procedures employed for determining phenolic pollutants in industrial wastewater in cluded 4-AAP colorimetry and regular GC (designated as GC (Ⅱ) in this paper). Modified GC procedure employed by the present authors (designated as GC(Ⅰ) in this paper) served advantageously for attacking pulp mill effluents. Since phenolic pollutants in pulp mill effluent were generally degradation products. of lignin, they were usually compounds with guacacyl, syringyl or hydroxybenzenoid groups being their structures. Furthermore, the hydroxyl group in the para position of such compounds may be substituted by aldehyde or ketone groups or alkyl groups. Some of those compounds were only slightly volatile, some did not react with 4-AAP. Total phenolics in wheat straw black liquor determined by GC (Ⅱ) alone was found to be only 11.3% of that by GC(Ⅰ)’ and with 4- AAP colorimetry only results about 6.03% of those from GC(Ⅰ)’ were obtained, as shown in Table 4. Apparently, 4-AAP and regular GC methods were not suitable for the monitoring of phenolic pollutants in pulp and paper mill effluents. Determinations of phenolic compounds in larch kraft black liquor were also carried out with GC techniques. phenolics of similar structures as found with wheat straw were confirmed. But for Larch, more guaiacyl and/or dihydroxybenzenoid and Less syringyl groups were found. As a result, it may be observed that total phenolics in wheat straw black liquor were far more abundant than those in larch black liquor. Such analytical results conformed very well with the current knowledge of the proposed structure for lignin and the mechanism of delignification in kraft pulping.更多还原