The overlooked role of the association between 2-methylisoborneol and natural organic matters in the nanofiltration treatment of authentic water

The presence of natural organic matter (NOM) in surface water and its significance for removing pollutants during nanofiltration (NF) are overlooked since most previous studies were conducted in synthetic water rather than real water. In this paper, using raw water collected from Lake Tai (the third largest lake in China), we investigate the removal of 2-methylisoborneol (2-MIB, one of the most concerned off-flavor compounds in raw water) by NF and analyze the binding behaviors between 2-MIB and NOM, which affect their corresponding migration and removal behaviors of 2-MIB during NF. The results show that the removal of 2-MIB in real raw water is 12.2 ∼ 22.0 % higher than that in pure water (PW). Additionally, we evaluate the increment of the removal of 2-MIB under different backgrounds, which follow the order NOM (17.2 %∼22.0 %) > bovine serum albumin (BSA 16.0 %∼19.1 %) > intracellular organic matter (IOM) of M. aeruginosa (8.3 %∼9.4 %) > sodium carboxymethyl cellulose (CMC 3.9 %∼6.5 %) > humic acid (HA 0.28 %∼0.31 %). These findings demonstrate that the protein-like components in raw water play a major role in binding to 2-MIB, while humic-like components exhibit a weak association with 2-MIB. Overall, the conclusion and findings in this study provide a new perspective on the NOM effect on micropollutant removal during water treatment.