The textile industry is required to execute water conservation and contamination management techniques owing to increasingly serious water scarcity and pollution. Herein, a novel salt-tolerant chitosan-based flocculant (CT-CTA-BGE3) with high charge density was synthesized through chitosan (CT) etherification with 2,3-epoxypropyl trimethylammonium chloride (CTA) and butyl glycidyl ether (BGE). The H-bond hydration effect between BGE segments and water molecules weakens the salt-induced polyelectrolyte effect, allowing CT-CTA-BGE3 to chains keep an extended conformation in high-salty aqueous solution and thus endowing excellent salt-tolerant properties. Meanwhile, the incorporation of CTA segments offers a high positive charge on the flocculant surface. Thus, the beneficial effect of satisfying color removal was obtained by CT-CTA-BGE3 in a highly saline system because it would render the more exposed active sites with strong positive charges along stretched polymer chains. The outstanding flocculability of CT-CTA-BGE3 (3054 mg/g) for the reactive brilliant red 2 (a widely commercial grade dye) could be obtained within 5 min (pH = 6). As expected, because the CT-CTA-BGE3 impurities can be reduced in reclaimed water via the pH-mediated hydrophilicity-hydrophobicity switch of polymer, the obtained clarified saline wastewater after flocculation can be recycled in a new dyeing bath without sacrificing fabric quality (ΔE*less than1), and over 88 % of NaCl can be regenerated for each cycle. This work develops an alternative strategy for the fabrication of salt-tolerant flocculants through enhancing H-bond hydration, revealing the promising application prospects in treating and recycling highly saline textile wastewater.

由于日益严重的缺水和污染，纺织行业需要执行节水和污染管理技术。在此，通过壳聚糖（CT）与2,3-环氧丙基三甲基氯化铵（CTA）和丁基缩水甘油醚（BGE）的醚化反应，合成了一种新型的高电荷密度耐盐壳聚糖絮凝剂（CT-CTA-BGE3）。BGE链段与水分子之间的氢键水合作用减弱了盐诱导的聚电解质效应，使CT-CTA-BGE3链在高盐水溶液中保持延伸构象，从而赋予优异的耐盐性能。同时，CTA 链段的加入在絮凝剂表面提供了高正电荷。因此，CT-CTA-BGE3 在高盐体系中获得了令人满意的颜色去除的有益效果，因为它会使更多暴露的活性位点沿着拉伸的聚合物链具有强正电荷。CT-CTA-BGE3 (3054 mg/g) 对活性艳红 2（一种广泛商业级染料）的出色絮凝性可在 5 分钟内（pH = 6）获得。正如预期的那样，由于 CT-CTA-BGE3 杂质可以通过聚合物的 pH 介导的亲水性 - 疏水性转换减少再生水中的杂质，因此絮凝后获得的澄清盐水可以在新的染色浴中循环使用，而不会牺牲织物质量（ΔE *小于1)，每个循环可再生88%以上的NaCl。