麦草亚铵法黑液超滤前后的物化性能

Physical and chemical properties of ammonia sulfite pulping black liquor before and after ultrafiltration

采用超滤法对麦草亚铵法制浆黑液进行处理,并对处理前后的黑液进行物化性能的对比研究;采用凝胶色谱法对黑液和截留液中的木质素分子质量及其分布进行分析。结果表明:超滤纯化了黑液,使其中的木质素含量提高17.42%,灰分减少18.22%;透过液的木质素分子质量主要集中在小于4 950的部分(占82.86%);截留液的木质素分子质量小于4950部分的比例下降了17.33%,高分子质量部分比例增加;截留液中的主要官能团——磺酸基、羧基和酚羟基的含量均比黑液中的高;截留液的表面张力较原液下降了2.2mN/m;净浆流动度提高了45.7%。通过超滤可有限增强黑液的应用性能。

Uhrafihration treatment of the ammonia sulfite pulping black liquor of wheat straw and its effects on chemical structure characteristics and physical properties were studied. The results showed that after uhrafihration the content of lignin in retentate increased by 17. 42% and the content of ash decreased by 18.22%. It was seen that the molecular weight distribution of lignin in black liquor and retentate were determined by Gel Chromatography. The molecular weight of lignin in permeate mainly concentrated in the range less than 4 950 with the occupation of 82.86% , and the molecular weight of lignin in retentate was higher than that in black liquor. The contents of sulfonic, carboxyl, phenolic hydroxyl groups which are the main functional groups in retentate were all more than those in black liquor. Meanwhile, after uhrafihration, the retentate had better performance than black liquor as surfactant, as additive in concrete and as dispersant. Compared with black liquor, its surface tension at 1% was 54. 7 raN/m, and dropped 2.2 mN/m. Clean solution＇ s fluidity improved from 70mm to 102mm. However, the performance of retentate was limited by uhrafihration so that it would be further improved by modification.