"Molecular Imprinting" is a method for preparation of functional polymers exhibiting selective recognition towards specific target molecules (templates). This technique involves the interaction of the template with polymerizable monomers having functional moieties. Due to this interaction, functional monomers are linked to the template and a pre-determined orientation of functional moieties is achieved around it. The addition of cross-linker during the polymerization process allows to prepare imprinted cross-linked polymers with enhanced stability and rigidity. Subsequent extraction of the template leaves imprinted sites capable to selectively rebind the template [1]. In the last years the imprinting technique has been used to develop molecularly imprinted membranes (MIMs) capable to separate the target molecule from mixture solutions [2-4]. Among the different strategies used to prepare imprinted membranes, the employment of the phase inversion technique to produce hybrid systems based on the dispersion of cross-linked imprinted polymers into commonly used polymer matrices had great influence on the separation performance of these systems. This method, known as hybrid molecular imprinting has been described in some papers dealing with the preparation of hybrid polymeric membranes for application in different fields [5,6]. In the present study we firstly developed hybridized membranes made of polyvinylidene fluoride (PVDF) with polymer powder imprinted with 4,4'-methylendianiline (MDA). In particular, polyacrylonitrile (PAN) molecularly imprinted copolymer was synthesized for the preparation of hybrid membranes with recognition properties for template molecule. Acrylic acid (AA) and ethylene glycol dimethacrylate (EGDMA) were used as functional co-monomer and cross-linker, respectively. The polymer synthesis was carried out by water phase precipitation polymerization.. The obtained imprinted co-polymer powder was ground by pestle and mortar and granules were sieved through 100 micron aperture sieve. The polymer powder was dispersed in a 15 wt. % PVDF solution in N-methyl-2-pyrrolidone (NMP) and hybrid membranes were prepared by phase inversion process [2] using the dry-wet method through partial evaporation of the solvent. The recognition properties of the membranes were evaluated by performing binding experiments by filtration of MDA and its structural analogue 4,4'-ethylendianiline in isopropanol as the solvent. The performance of the membranes was evaluated as a function of the amount of polymer present in the hybrid system and of the initial feed concentration. Best results in terms of binding capacity, recognition factor and selectivity were obtained with membrane containing 33wt.% of imprinted polymer and using an initial feed concentration of 10 mg/L. A computational molecular modelling was also performed in order to provide more information on the properties of the novel hybrid membranes. References [1] Samuel García Del Blanco, Laura Donato, Enrico Drioli, Development of molecularly imprinted membranes for selective recognition of primary amines in organic medium, Separation and Purification Technology 87 (2012) 40-46 [2] L. Donato; F. Tasselli; E. Drioli, Molecularly Imprinted Membranes with Affinity Properties for Folic Acid, Separation Science and Technology 45(2010) 2273-2279 [3] Trotta, F.; Baggiani, C.; Luda, M.P.; Drioli, E.; Massari, T. A molecular imprinted membranes for molecular discrimination of tetracycline hydrochloride. Journal of Membrane Science 254 (2007) 13-19 [4] L. Donato, M. C. Greco, E. Drioli, Preparation of molecularly imprinted membranes and evaluation of their performance in the selective recognition of dimethoate, Desalination and Water Treatment 30 (2011) 171-177 [5] Donato, L.; Figoli, A.; Drioli, E. (2005) Novel composite poly(4-vinylpiridine)=polypropylene membranes with recognition properties for (S)-naproxen. J. Pharmaceut. Biomed. Anal., 37: 1003-1008 [6] F. Tasselli, L. Donato, E. Drioli. Evaluation of molecularly imprinted membranes based on different acrylic copolymers. Journal of Membrane Science 320 (2008) 167-172.
Solvent Resistent Hybrid Molecularly Imprinted Membranes
2012
Abstract
"Molecular Imprinting" is a method for preparation of functional polymers exhibiting selective recognition towards specific target molecules (templates). This technique involves the interaction of the template with polymerizable monomers having functional moieties. Due to this interaction, functional monomers are linked to the template and a pre-determined orientation of functional moieties is achieved around it. The addition of cross-linker during the polymerization process allows to prepare imprinted cross-linked polymers with enhanced stability and rigidity. Subsequent extraction of the template leaves imprinted sites capable to selectively rebind the template [1]. In the last years the imprinting technique has been used to develop molecularly imprinted membranes (MIMs) capable to separate the target molecule from mixture solutions [2-4]. Among the different strategies used to prepare imprinted membranes, the employment of the phase inversion technique to produce hybrid systems based on the dispersion of cross-linked imprinted polymers into commonly used polymer matrices had great influence on the separation performance of these systems. This method, known as hybrid molecular imprinting has been described in some papers dealing with the preparation of hybrid polymeric membranes for application in different fields [5,6]. In the present study we firstly developed hybridized membranes made of polyvinylidene fluoride (PVDF) with polymer powder imprinted with 4,4'-methylendianiline (MDA). In particular, polyacrylonitrile (PAN) molecularly imprinted copolymer was synthesized for the preparation of hybrid membranes with recognition properties for template molecule. Acrylic acid (AA) and ethylene glycol dimethacrylate (EGDMA) were used as functional co-monomer and cross-linker, respectively. The polymer synthesis was carried out by water phase precipitation polymerization.. The obtained imprinted co-polymer powder was ground by pestle and mortar and granules were sieved through 100 micron aperture sieve. The polymer powder was dispersed in a 15 wt. % PVDF solution in N-methyl-2-pyrrolidone (NMP) and hybrid membranes were prepared by phase inversion process [2] using the dry-wet method through partial evaporation of the solvent. The recognition properties of the membranes were evaluated by performing binding experiments by filtration of MDA and its structural analogue 4,4'-ethylendianiline in isopropanol as the solvent. The performance of the membranes was evaluated as a function of the amount of polymer present in the hybrid system and of the initial feed concentration. Best results in terms of binding capacity, recognition factor and selectivity were obtained with membrane containing 33wt.% of imprinted polymer and using an initial feed concentration of 10 mg/L. A computational molecular modelling was also performed in order to provide more information on the properties of the novel hybrid membranes. References [1] Samuel García Del Blanco, Laura Donato, Enrico Drioli, Development of molecularly imprinted membranes for selective recognition of primary amines in organic medium, Separation and Purification Technology 87 (2012) 40-46 [2] L. Donato; F. Tasselli; E. Drioli, Molecularly Imprinted Membranes with Affinity Properties for Folic Acid, Separation Science and Technology 45(2010) 2273-2279 [3] Trotta, F.; Baggiani, C.; Luda, M.P.; Drioli, E.; Massari, T. A molecular imprinted membranes for molecular discrimination of tetracycline hydrochloride. Journal of Membrane Science 254 (2007) 13-19 [4] L. Donato, M. C. Greco, E. Drioli, Preparation of molecularly imprinted membranes and evaluation of their performance in the selective recognition of dimethoate, Desalination and Water Treatment 30 (2011) 171-177 [5] Donato, L.; Figoli, A.; Drioli, E. (2005) Novel composite poly(4-vinylpiridine)=polypropylene membranes with recognition properties for (S)-naproxen. J. Pharmaceut. Biomed. Anal., 37: 1003-1008 [6] F. Tasselli, L. Donato, E. Drioli. Evaluation of molecularly imprinted membranes based on different acrylic copolymers. Journal of Membrane Science 320 (2008) 167-172.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
