Zeolites can be used for the adsorption of organic micropollutants (OMPs) from water. In this research, the potential applications of zeolite granules for OMP removal in wastewater treatment plants (WWTPs) were discovered. The adsorption of 18 target OMPs by zeolite granules was fully studied in batch and column experiments. The adsorption capacity and kinetics of OMPs in demineralised water (DW) and secondary effluent from WWTP (WW matrix) were investigated. A prediction model of OMP breakthrough curves in zeolite packed columns was established and evaluated.
It was found that the adsorption of OMPs by zeolite granules in batch and column experiments was influenced by OMP species, water matrices and operational parameters (e.g., superficial velocity and contact time). Positively charged OMPs were better adsorbed by zeolite granules than neutral and negatively charged OMPs. In most cases, the adsorption capacity and kinetics of OMPs were reduced in WW matrix, which led to an earlier breakthrough in columns. On the contrary, WW matrix enhanced the adsorption capacity and kinetics of a few negatively charged OMPs, such as diclofenac and clofibric acid.
Higher zeolite dosage resulted in faster OMP adsorption kinetics.
Column experiments showed that 12 of the 18 target OMPs could be effectively removed at the EBCT of 12 min, achieving removal efficiencies of 50% over 10 days. The mathematic model for the prediction of OMP breakthrough curves was optimized by applying larger kinetic constants obtained from the batch experiment. It was predicted an EBCT of 15 min is an alternative for a 7-day operation to remove OMPs sufficiently by zeolite packed columns.