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

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 C0,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 C0,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 C0,EBC value (6400 ng/L), which was likely associated with algae and other microbial activities. The fluorescence index (FI, the ratio of Ex/Em = 370/470 nm to Ex/Em = 370/520 nm) can be applied to estimate C0,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.