Coagulation is a conventional method in water treatment. In recent decades, with the rapid development of membrane filtration, the use of coagulation is facing some new challenges. How to minimize the membrane fouling became a leading-edge topic in the study of coagulation. Here, the performances of three types of titanium coagulants were evaluated in terms of both the coagulation removal of toxic micropollutants and the alleviation of membrane fouling. Three oxysalts and two antibiotics were taken as representatives of inorganic and organic micropollutants. As compared with titanium tetrachloride (TiCl₄) and polytitanium chloride (PTC), titanium xerogel (TXC) with a higher polymerization degree showed much better performances in direct coagulation removal of oxysalts and antibiotics and in pre-coagulation for mitigating membrane fouling in both coagulation-sedimentation-ultrafiltration (CSUF) and in-line coagulation-ultrafiltration (CUF) processes. In the CSUF system, the membrane permeate flux with TXC pre-coagulation (89.5%) was much higher than those of TiCl₄ (56.1%) and PTC (57.4%). After a 5 day continuous operation, the transmembrane pressure in the CUF system with TXC coagulation was increased only to 4.9 kPa, while those of PTC and TiCl₄ were 12.2 and 18.5 kPa, respectively. The results here demonstrate that TXC is a promising coagulant for pollutant removal and membrane fouling alleviation, due to the following merits: better floc properties, weaker pH-dependence, and higher resistance to coordination with organic pollutants. The observation shed new lights on the fabrication and application of coagulants in a wide variety of scenarios.

混凝是水处理中的常规方法。近几十年来，随着膜过滤技术的飞速发展，混凝的使用面临着一些新的挑战。如何最大限度地减少膜污染成为凝结研究的前沿课题。在这里，从有毒微污染物的混凝去除和膜污染的缓解方面评估了三种类型的钛混凝剂的性能。以三种含氧盐和两种抗生素作为无机和有机微污染物的代表。与四氯化钛（TiCl ₄) 和聚氯化钛 (PTC)，具有更高聚合度的钛干凝胶 (TXC) 在直接混凝去除含氧盐和抗生素以及在混凝-沉淀-超滤 (CSUF) 和预混中减轻膜污染方面表现出更好的性能。在线凝固-超滤 (CUF) 工艺。在 CSUF 系统中，TXC 预混的膜渗透通量 (89.5%) 远高于 TiCl ₄ (56.1%) 和 PTC (57.4%)。连续运行 5 天后，具有 TXC 凝固的 CUF 系统的跨膜压力仅增加到 4.9 kPa，而 PTC 和 TiCl ₄的跨膜压力分别为 12.2 和 18.5 kPa。这里的结果表明，TXC 是一种很有前途的污染物去除和膜污染缓解混凝剂，因为具有以下优点：更好的絮凝物特性、更弱的 pH 依赖性以及更高的抗与有机污染物的配位能力。该观察结果为凝结剂在各种情况下的制造和应用提供了新的思路。