Mechanisms and application of the IAST-EBC model for predicting 2-MIB adsorption by PAC in authentic raw waters: Correlation between NOM competitiveness and water quality parameters

Highlights: • NOM competitiveness relates to the category and location of the water sources. • Tyrosine-like substances were identified as the major competing substances. • The IAST-EBC model performs well under equilibrium and nonequilibrium conditions. • The model can be simplified under lower 2-MIB concentrations or longer contact time. • Fluorescence index (FI) can be used to estimate the EBC concentration (C_0,EBC). Natural organic matter (NOM) exerts negative impacts on 2-methylisoborneol (2-MIB) removal by powdered activated carbon (PAC), thus adding to the difficulty in accurate PAC dose prediction. Our study investigated the application of the ideal adsorbed solution theory-equivalent background compound (IAST-EBC) model and its simplified version for PAC dose prediction. Four raw water samples were employed, and the corresponding C_0,EBC values, indicating NOM competitiveness, were calculated. The results showed that the IAST-EBC model presented ideal predictive performance in 2-MIB adsorption under both equilibrium and nonequilibrium conditions and the C_0,EBC values of the Huangpu River (8800 ng/L) and Qiantang River (10300 ng/L) were high, representing the higher NOM competitiveness in these two rivers, which may be caused by municipal effluent and industrial wastewater discharge. In contrast, Tai Lake water showed a lower C_0,EBC value (6400 ng/L), which was likely associated with algae and other microbial activities. The fluorescence index (FI, the ratio of E_x/E_m = 370/470 nm to E_x/E_m = 370/520 nm) can be applied to estimate C_0,EBC, thus facilitating prediction. Our study also showed that the IAST-EBC model can be further simplified under lower initial 2-MIB concentrations or longer contact times, which is particularly useful for practical applications.