改性木素的絮凝脱色作用

Study on the Flocculation and Decolorization Performances of the Modified Lignin

关键词:  木素  胺化改性  含氮量  品红  脱色

Key Words:lignin  aminating modification  nitrogen content  fuchsin  decolorization

摘要:以造纸黑液中提取的木素为合成原料，通过Mannich反应使木素胺化改性；以氮元素含量来确定木素的改性率；采用正交实验来确定温度、甲醛和己二胺的用量对木素改性率的影响，从而确定最佳工艺条件。比较了超声活化对木素的胺化改性效果的影响。通过红外、电镜对木素和改性木素的结构进行了分析，并用改性木素进行了品红溶液的絮凝脱色实验，研究了脱色时间和改性木素用量对品红溶液脱色效果的影响。结果表明，影响木素改性率的主要因素是甲醛用量和温度，改性木素对品红溶液具有很强的絮凝脱色效果，当脱色时间为100 min、样品用量为10 mg（即0.5 g/L）时脱色率高达93%。

Abstract:The lignin from black liquor was modified through Mannich reaction to prepare a kind of cationic lignin amine. The efficiency of amination of the lignin was determined by the nitrogen content. The orthogonal experiment was employed to study the influence of the temperature, formaldehyde and amine dosage on the modified degree of the lignin, and to get the optimum technological conditions. The effect of ultrasound on aminating modification of lignin was researched too. The structures of lignin and lignin amine were studied through FT-IR and SEM. The test of adsorption decolourization performance of the modified lignin samples was carried out, and the effect of decolourization time and the dosage of the modified lignin on decolorization of magenta were investigated. The results showed that the major parameters of modification were temperature and the amount of formaldehyde. Modified lignin amine samples showed strong flocculation decolorization performance for fuchsin solution, the decolorization rate reached 93% when the reaction time was 100 min, the modified lignin amount was 10 mg（0.5 g/L）.