In digital printing, a high salt content in dye solutions is detrimental, which calls for effective strategy for dye/salt fractionation. In this study, a loose nanofiltration (NF) membrane Sepro 2A was employed to desalinate diverse dye species (2 reactive dyes and 4 cationic dyes). This membrane, with a molecular weight cutoff of 490 Da, showed consistently high rejections to all the reactive and cationic dyes (>97.7%). Operational conditions such as dye concentrations and applied pressures have limited effects on the rejection of the membrane. An integrated NF-diafiltration process, involving a pre-concentration and a diafiltration step, was specifically designed for the fractionation of dye/NaCl mixtures. This loose NF membrane showed >99.7% rejection to reactive dyes (reactive blue 2 and reactive orange 16) and ca. 99.3% salt removal with ca. 2.0% dye loss after 5.0 diavolumes. However, the NF membrane experienced a 15.9% loss to methylene blue due to the lower rejection to this model cationic dye (97.2%). The current study provides important insights into dye/salt fractionation by loose NF membranes for digital ink-jet printing.

在数字印刷中，染料溶液中的高盐含量是有害的，这要求染料/盐分馏的有效策略。在这项研究中，使用了松散的纳滤（NF）膜Sepro 2A来淡化各种染料（2种活性染料和4种阳离子染料）。该膜的截留分子量为490 Da，对所有活性染料和阳离子染料表现出始终如一的高排斥率（> 97.7％）。诸如染料浓度和施加的压力之类的操作条件对膜的排斥具有有限的影响。专门设计了集成的NF渗滤工艺，包括预浓缩和渗滤步骤，用于分馏染料/ NaCl混合物。这种疏松的NF膜对活性染料（活性蓝2和活性橙16）和ca的排阻> 99.7％。99。约3％的盐去除率。5.0滴定后染料损失2.0％。但是，由于该模型阳离子染料的排斥率较低（97.2％），因此NF膜的亚甲基蓝损失了15.9％。当前的研究为数字喷墨印刷中松散的NF膜对染料/盐的分馏提供了重要的见识。