麦草碱木质素三甲基季铵盐对酸性染料溶液的絮凝性能影响

摘要

The trimethyl quaternary ammonium salt of wheat-alkali-lignin was synthesized in the Mannich reaction using wheat straw alkali lignin as raw material which is extracted from black liquo of paper and pulp industry. The decolorization rate of the trimethy quaternary ammonium salt of wheat-alkali-lignin was detected by Acid Black ATr dye, Acid red B, and Orange G in aqueous solu- tion to evaluate flocculation function. The results showed that decolorization rate of 0. 15g/L Acid Black ATY dye with pH values of 2 in aqueous solution increased with increasing concentration of the trimethyl quaternary ammonium salt of wheat-alkali-lignin between 0 -3500 mg/L; the decolorization rate of 0. 15g/L Acid Black ATr dye increased with decreasing pH value between 1 -4 when the concentration is 2884 mg/L. There were similar results for Orange GG and Acid Red B dye. According to the above conclusions and the structure of the trimethyl quaternary ammonium salt of wheat-alkali-lignin and the acid dye, the flocculation mechanism was that there was hydrogen bonds to attract the ammonium ion from the trimethyl quaternary ammonium salt of wheat-alkali-lignin and sulfonate from the acid dye, and acid dye particles played a ＂bridging＂ role, then acid dye was netted and swept by alkali lignin with the three- dimensional network structure.%以从造纸黑液中提取的麦草碱木质素为原料，通过曼尼希反应合成麦草碱木质素三甲基季铵盐，以脱色率为指标检测其对酸性黑ATT、酸性橙GG和酸性红B的絮凝性能。实验结果表明：对于0．1g／l酸性黑ATT溶液，pH为2，麦草碱木质素三甲基季铵盐使用浓度在O-3500mg／l范围内时，脱色率随浓度增大而升高；麦草碱木质素三甲基季铵盐使用浓度为2884mg／l时，在pH为1～4范围内，脱色率随pH降低而增加。酸性橙GG和酸性红B也有类似的规律。由上述结论结合麦草碱木质素三甲基季铵盐和酸性染料的结构特点，认为絮凝过程先是麦草碱木质素三甲基季铵盐中的铵离子与酸性染料中的磺酸根之间氢键吸引，然后染料间产生“架桥”现象，具有三维网状结构的碱木质素分子继续网捕和卷扫脱除染料。