Synthesis of Novel Composite Membranes Based on Molecularly Imprinted Polymers for Removal of Triazine Herbicides from Water

Abstract

Novel molecularly imprinted polymer (MIP) composite membranes for the selective removal of triazine herbicides from polluted water sources were synthesized using two different approaches. According to the first method, sandwich-type composite membranes were prepared that consisted of a middle packed layer of MIP nanoparticles (NPs) confined between two microfiltration membranes. The highly selective MIP NPs were synthesized in the presence of atrazine, acting as template molecule, via the mini-emulsion polymerization method. In the second approach, MIP thin films, formed via an in situ polymerization method in the presence of the template molecule (desmetryn), were deposited on the top surface of ceramic support membranes using 2,2′-azobis (N,N′-dimethylene) isobutyramidine as initiator. The rebinding capacity of the synthesized MIP-ceramic composite membranes toward the template molecules was initially tested in batch-wise guest binding experiments. Subsequently, the synthesized composite membranes were tested in continuous dead-end filtration experiments to assess their binding efficiency, specificity, and their ability to adsorb the template molecules from water samples, at very low concentrations (i.e., down to 1 ppb). A series of experiments were also carried out to assess the binding capacity of the regenerated composite membranes and their long-term performance. The present results clearly demonstrate that the synthesized MIP composite membranes can remove the triazine herbicides of atrazine and desmetryn from water samples at very low concentrations (i.e., down to 1 ppb). Finally, it was found that the MIP composite membranes could be regenerated and reused without loss of their binding capacity and “memory effect”, which underlines their outstanding stability and reusability features in a continuous filtration process.

Comparative analysis of atrazine molecularly imprinted polymers using acetonitrile and toluene as solvents

“…Atrazine MIPs were first reported by three different research groups in 1995 and 1996 . Since then, lots of studies have been done on triazine MIPs concerning the effects of polymerization conditions on the properties of MIPs, the binding mechanisms between host and guest, and the application to sample pretreatment for herbicide residue determination . From the literature, we can see that the most popular solvents used in the polymerization of atrazine MIPs are acetonitrile and toluene, but there are few works that compare the effects of these two solvents on the properties of MIPs in the same polymerization system.…”

“…[14][15][16] Since then, lots of studies have been done on triazine MIPs concerning the effects of polymerization conditions on the properties of MIPs, 17,18 the binding mechanisms between host and guest, [19][20][21] and the application to sample pretreatment for herbicide residue determination. [22][23][24][25] From the literature, we can see that the most popular solvents used in the polymerization of atrazine MIPs are acetonitrile and toluene, 22,26 but there are few works that compare the effects of these two solvents on the properties of MIPs in the same polymerization system. In this paper, a polarizable continuum model (PCM) was adopted to evaluate the solvent effects, acetonitrile and toluene were used as solvents to prepare atrazine MIPs, and the results were analyzed comparatively.…”

Synthesis of a molecularly imprinted polymer on mSiO2@Fe3O4 for the selective adsorption of atrazine

“…To show the advantages of the MMIP prepared in this study, Table 1 compared it with other previously reported MIPs [4,34,35] for sorption of atrazine in terms of sorption capacity and equilibrium time. As can be seen, the MMIP synthesized in this study revealed the shortest equilibrium time, and a relatively high adsorption capacity as compared to the other imprinted materials, which clearly show the advantages of the MMIP.…”

Research on the Lysozyme imprinted polymers

“…water with 0.05 vol% TFA. Linear gradient for competitive binding tests is from 65 to 10 % A in 10 min, and for real chicken white sample is from 100 to 0 % A in 35 min, with UV detection wavelength at 280 nm, flow rate 0.8 mL/min and injection volume 10ul [5] .…”