Development of a sandwich-type filtration unit packed with MIP nanoparticles for removal of atrazine from water sources

• Development of a sandwich-type fixed bed filtration unit packed with MIP NPs.
• Removal of atrazine from water solutions at very low concentrations (ppb level).
• The atrazine removal rate varied from 0.4 × 10−6 to 4 × 10−6 μmol/g polymer·s.
• Successful regeneration of sandwich-type filtration unit packed with MIP NPs.

Highly specific molecularly imprinted polymer (MIP) nanoparticles (NPs) were synthesized via precipitation and mini-emulsion polymerization in the presence of atrazine, acting as template molecule. The specificity and binding ability of synthesized MIP NPs to remove the target template molecule from polluted water samples were tested in batch-wise experiments. Subsequently, a sandwich-type membrane filtration system packed with highly specific particulate MIPs was developed for the selective adsorption of atrazine from water samples. The sandwich-type fixed bed filtration unit packed with MIP NPs was then tested in continuous filtration experiments for the removal of atrazine from water samples at very low concentrations (i.e., down to 1 ppb). The binding capacity of the regenerated sandwich-type filtration system packed with MIP NPs and its long-term performance was also assessed through a series of experiments. It was found that the sandwich-type fixed bed filtration unit packed with MIP NPs synthesized by mini-emulsion polymerization can efficiently remove atrazine from water samples at very low concentrations and it can be regenerated and reused without loss of the rebinding capacity and “memory effect”. Finally, a simple kinetic model was developed to describe the atrazine adsorption rate from aqueous solutions. Based on the derived kinetic model, it was found that 0.75 g of MIP NPs were required for the removal of 99% of the total atrazine mass from a polluted water quantity of 800 ml (i.e., 1–10 ppb atrazine concentration) flowing through the filtration unit at a rate 4 ml/min.