直接染料染色废水的脱色及其回用

Decoloration of direct dyeing wastewater and its reuse

使用还原型脱色剂对直接染料染色废水进行脱色处理,重点研究了脱色剂用量、反应温度、pH和时间等因素对脱色反应的影响。并且将脱色后的染色废水回用于织物染色中,在染色织物的颜色特征和牢度方面进行了比较。结果表明,脱色温度的升高有利于染料的脱色,尤其对于水溶性较差的品种,脱色剂用量的增加能够促进染料的脱色率的升高。另外三种染料在自来水和回用水中的的染色织物的染色表面深度和牢度比较接近,而且染色织物之间的色差较小,这说明脱色废水可以回用于直接染料的染色中。

The decoloration of aqueous solution containing direct dyes with twocomponent reductant has been investigated. Some factors affecting the decoloration such as reductant dosage, temperature, pH, time and concentration of sodium chloride on decolouration are discussed. The spent dyebath water containing these direct dyes is decolorized and used for the dyeing of fabrics with direct dyes again. A comparison between color characteristics and fastness of dyed fabrics has been done respectively in fresh tap water and the recycled water as the dyeing medium are made. The results of experiment indicate that high temperature can improve decoloration of directing dyeing wastewater, especially in case of the presentation of direct dyes, which have low solubility in water. The rate of decoloration of direct dyeing wastewater increases with increasing reductant dosage in the solution. It is found that the cotton fabrics dyed with direct dyes respectively in fresh tap water and the recycled water are well matched in respect of color strength and fastness. There is little color difference between the two dyeings mentioned above. Therefore, it comes to the conclusion that the decolorized wastewater may be reused for direct dyeing of cotton fabric. 