The aim of this study was to evaluate the effects of oxidation on humic-acid-enhanced gypsum scaling in different nanofiltration phases, including the short-term membrane flux behaviors and the long-term ones. On the basic of correlation analysis between the changing physicochemical properties of feed solution and membrane fouling, the inner mechanisms were revealed from aspects of bulk crystallization (interaction between humic acid and inorganic ions) and surface crystallization (compositions and morphologies of surface crystallization). Furthermore, the reliability of applicating differential log-transformed absorbance spectroscopy for predicting membrane fouling was also systematically evaluated. There was an upward trend in short-term membrane fouling with increasing dosage of NaClO, while long-term membrane fouling decreased after an initial increase. During short-term filtration, the enhanced combination between inorganic ions and the humic acid with stronger density of carboxyl groups, which was generated more easily under stronger oxidation conditions, favored the earlier appearance of flux decline. During long-term filtration, the size of bulk crystallization depended on the total content of carboxyl groups in feed solution. Both of them increased firstly and then decreased with increasing oxidation. The terminal fouling layer resistance also shared a similar tendency with them, because the deposition of bulk crystallization on membranes and the formation of dense scaling layer were the direct reasons for the long-term membrane fouling. Furthermore, the differential log-transformed absorbance spectroscopy was proven to be an efficient approach to predict short-term membrane fouling, especially in the wavelength range of 260 to 280 nm. This research could not only provide guidance on alleviating oxidation-enhanced membrane fouling in nanofiltration but also propose an efficient way to predict the membrane fouling which was influenced by the interaction between organic matters and inorganic ions.

这项研究的目的是评估在不同的纳滤阶段，氧化对腐殖酸增强石膏结垢的影响，包括短期的膜通量行为和长期的膜通量行为。在进料溶液的理化性质变化与膜污染之间的相关性分析的基础上，从本体结晶（腐殖酸与无机离子的相互作用）和表面结晶（表面结晶的组成和形态）方面揭示了内部机理。此外，还系统地评估了应用差分对数变换的吸收光谱法预测膜污染的可靠性。随着NaClO剂量的增加，短期膜污染呈上升趋势，最初增加后，长期膜污染减少了。在短期过滤过程中，无机离子和腐殖酸之间的结合增强，具有更强的羧基密度，在更强的氧化条件下更容易产生，有利于通量下降的更早出现。在长期过滤期间，本体结晶的大小取决于进料溶液中羧基的总含量。它们都先增加，然后随着氧化的增加而减少。终端结垢层的电阻也与它们具有相似的趋势，这是因为在膜上沉积大量结晶和形成致密的结垢层是长期膜结垢的直接原因。此外，事实证明，差分对数转换吸收光谱是预测短期膜污染的有效方法，尤其是在260至280 nm波长范围内。这项研究不仅可以为减轻纳滤膜中的氧化膜结垢提供指导，而且可以为预测受有机物与无机离子相互作用影响的膜结垢提供一种有效的方法。