Novel approach for membrane modification to improve separation performance and antifouling stability was proposed. It involves using of 0.1–0.3 wt.% aqueous solutions of Praestol 859 (cationic polyelectrolyte based on copolymer of acrylamide and 2-acryloxyethyltrimethylammonium chloride) as coagulants upon membrane preparation via non-solvent induced phase separation. It was shown that the addition of small amounts (0.1–0.3 wt.%) of Praestol 859 into the coagulation bath leads to an increase in membrane pure water flux from 51 up to 68 L m⁻² h⁻¹ without decreasing membrane retention. Contact angle for modified membranes decreased from 64° down to 55°. Immobilization of Praestol 859 on the surface of a selective membrane layer was confirmed by FTIR spectroscopy. It was found that the addition of Praestol 859 into the coagulation bath suppressed the macrovoid formation in the membranes supporting layer due to the decrease of “solvent-non-solvent” exchange rate which is attributed to the significant increase of viscosity of the coagulation bath. The separation performance of modified membranes for fractionation of thermomechanical pulp mill process water, for concentration and purification of hemicellulose for further processing was studied. It was found that membrane modification by Praestol 859 leads to 2–6 times increase of flux, increase of fouling recovery ratio and improvement of cleaning efficiency without decreasing membrane rejection with regard to hemicelluloses (91.5–93%) and lignin (21–22%) as reference components.

提出了一种新的膜改性方法，以提高分离性能和防污稳定性。它涉及通过非溶剂诱导的相分离制备膜时，使用0.1-0.3 wt。％的Praestol 859（基于丙烯酰胺和2-丙烯酰氧基乙基三甲基氯化铵的共聚物的阳离子聚电解质）水溶液作为凝结剂。结果表明，在凝结浴中添加少量（0.1–0.3 wt。％）的Praestol 859可使膜纯水通量从51增加到68 L m ^-2  h ^-1而不会减少膜的保留。改性膜的接触角从64°降至55°。通过FTIR光谱证实了Praestol 859固定在选择性膜层的表面上。发现在凝结浴中添加Praestol 859抑制了在膜支撑层中大孔的形成，这归因于“溶剂-非溶剂”交换速率的降低，这归因于凝结浴的粘度的显着增加。研究了改性膜的分离性能，该膜用于热机械制浆厂工艺用水的分馏，浓缩和纯化半纤维素以进行进一步处理。发现使用Praestol 859进行膜改性可导致通量增加2至6倍，