Herein, the effect of molecular weight (MW) distribution on ultrafiltration (UF) membrane fouling was investigated using humic acids, and the mechanism was explored by the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory. The short-range acid–base (AB) interaction energy was found dominant, followed by van der Waals (LW) energy, whereas electrostatic (EL) interaction energy was negligible. Organic colloid fractions with MW >100 kDa contributed mainly to transmembrane pressure (TMP) increase, whereas the fractions with MW <1 kDa had less influence on membrane fouling due to their strong hydrophilicity, oleophobicity, and polarity. However, no relationship was observed between MW size and its contribution to the TMP increase; this indicated that the total interaction energy between organic colloids and membrane material was a better predictor of membrane fouling than other characteristics of organics. Water from Yangtze River was ozonized prior to UF for fouling control. With the addition of ozone, the proportion of the organic fraction with MW <1 kDa increased, causing decreased absolute value of AB interaction energy between colloid and membrane. The inflection point of interaction energy variation was attained at a 0.8 mg L⁻¹ ozone dosage, corresponding to a slow increase in TMP with the increasing ozone dosage, whereas the least influent organic matter was attained at a 1.2 mg L⁻¹ ozone dosage. This indicated that it was more feasible to optimize ozone dosage according to the interaction energy rather than according to the concentration of the influent organic matter.

中文翻译：

---

从相互作用能看有机分子量分布对臭氧氧化超滤系统中膜污染的影响

在本文中，使用腐殖酸研究了分子量（MW）分布对超滤（UF）膜结垢的影响，并通过扩展的Derjaguin-Landau-Verwey-Overbeek（XDLVO）理论探索了该机理。发现短程酸碱（AB）相互作用能占主导地位，其次是范德华（LW）能量，而静电（EL）相互作用能则可忽略不计。MW> 100 kDa的有机胶体组分主要是促进跨膜压力（TMP）的增加，而MW <1 kDa的有机胶体组分由于其较强的亲水性，疏油性和极性而对膜污染的影响较小。但是，未发现MW大小与其对TMP增长的贡献之间的关系。这表明有机胶体与膜材料之间的总相互作用能比有机物的其他特征更好地预测了膜的结垢。在超滤之前，将来自长江的水进行臭氧处理以控制结垢。随着臭氧的加入，MW <1 kDa的有机部分的比例增加，导致胶体与膜之间AB相互作用能的绝对值降低。相互作用能变化的拐点达到0.8 mg L^-1臭氧剂量，相当于TMP随着臭氧剂量的增加而缓慢增加，而在1.2 mg L ^-1臭氧剂量下，流入的有机物最少。这表明根据相互作用能而不是根据流入有机物的浓度优化臭氧剂量更为可行。