A novel combined pretreatment strategy, where the hydrophobicity of feedwater is reduced and the morphology of flocs is optimized by varying the sequence of powdered activated carbon (PAC) adsorption and coagulation, is applied to alleviate membrane fouling. To explore the effects of pretreatment sequence and the role of PAC on the membrane fouling, the combined pretreatments of adsorption followed by coagulation (A-C) and coagulation followed by adsorption (C-A) are investigated with various PAC dosages (10, 20, and 50 mg/L). The results reveal that since PAC directly participates in the growth of flocs as the core during A-C pretreatment, the A-C pretreatment is more conducive than the C-A pretreatment to form flocs with a larger size, higher strength, and smaller fractal dimension. Thus, the flocs can accumulate into a porous cake layer to improve the membrane permeability and fouling reversibility. Moreover, the irreversible fouling is highly linearly correlated SUVA values in the early ultrafiltration cycles (R²_SUVA = 0.9536) and with the floc strength in the late cycles (R²_Strength = 0.9348–0.9763). This finding can be used to make a targeted diagnosis of irreversible fouling in different cycles, providing valuable guidance for prolonging the service life of ultrafiltration membranes.

一种新的组合预处理策略，通过改变粉末活性炭（PAC）吸附和混凝的顺序来降低给水的疏水性并优化絮凝物的形态，以减轻膜污染。为了探索预处理顺序的影响和 PAC 对膜污染的作用，研究了不同 PAC 剂量（10、20 和 50 mg）的吸附后混凝 (AC) 和混凝后吸附 (CA) 组合预处理/L)。结果表明，由于PAC在AC预处理过程中直接参与了以絮体为核心的絮体生长，因此AC预处理比CA预处理更有利于形成尺寸更大、强度更高、分形维数更小的絮体。因此，絮凝物可以积聚成多孔饼层，以提高膜的渗透性和结垢可逆性。此外，在早期超滤循环中，不可逆污染与 SUVA 值高度线性相关（R² _SUVA  = 0.9536）和后期周期的絮凝强度（R ²_强度 = 0.9348–0.9763）。这一发现可用于对不同循环的不可逆污染进行针对性诊断，为延长超滤膜的使用寿命提供有价值的指导。