Preparation And Study Of Novel Magnetic Or Photodegradable Methylene Blue Molecularly Imprinted Polymers

Molecular imprinting technology is a new technology developed in recent years.It is based on the molecular recognition functions in nature,such as enzymes and substrates,antibodies and antigens,and is synthesized with the target molecule as a template.A technique for molecularly imprinted molecularly imprinted polymers that provides a molecular assembly with the desired structure and properties.It belongs to the subject-guest chemical category in supramolecular chemistry,and it is a frontier science that integrates biochemistry,chemical engineering,materials science,and polymer chemistry.In this paper,based on the molecular imprinting of methylene blue,the magnetic material is added on the one hand,so that the prepared material has superparamagnetic and magnetic separation ability;on the other hand,titanium dioxide is loaded to make it have photodegradability,while adsorbing Decomposes methylene blue into a non-toxic and harmless small molecule.In this paper,magnetic Fe₃O₄ nanoparticles were synthesized by thermal solvent method.After that,a novel form of magnetic methylene blue molecularly imprinted polymer?MMB-MIP?was synthesized by using methylene blue?MB?,acrylic acid and N,N'-methylenebisacrylamide as the imprinting template molecules,monomer and crosslinking agent respectively through bulk polymerization method.It is found that the adsorption capacity of the MMB-MIP to MB increases with increasing of MB's initial concentration,the maximum adsorption value can reach 4865.8 mg·g^-1,its adsorption efficiency is much higher than activated carbon,water-absorbent resin and other adsorbent materials.MMB-MIP also has higher affinity for MB than methylene blue molecular imprinted polymer?MB-MIP?and better selectivity compared to Coomassie brilliant blue G250?CBBG250?and chromium chloride?CrCl₃?.This kind of material with higher adsorption efficient has not been found in the literature so far.In addition,the adsorption performance of MMB-MIP is well represented by pseudo-second order kinetic model.Besides,it is in accord with Langmuir and Freundlich equation,indicating that there are a strong interaction between the MMB-MIP and MB,the adsorption process is a mainly monolayer chemical adsorption reaction and the rate control steps is mainly liquid film diffusion.On the basis of the synthesis of MMB-MIP by bulk polymerization,TiO₂-MB-MIP was prepared by uniformly adding titanium dioxide to MB-MIP by the package carrier method.The morphology and structure of the photodegradable imprinted molecular polymer were characterized by particle size analysis,XRD,scanning electron microscopy,etc.The results showed that the polymer surface was uneven and dispersible,and the titanium dioxide adhered uniformly and firmly to the surface of the imprinted polymer.Through the determination of its repeated utilization rate,it was found that it has good recyclability.The static adsorption experiment shows that the material has good adsorption performance,and the adsorption amount can reach 1202.08 mg g^-1.Through Scatchard analysis,it was found that TiO₂-MB-MIP has different binding sites and different adsorption mechanisms at different concentrations.At the same time,the photodegradation ability of simulated dye wastewater under light conditions was explored.It was found that the concentration of MB in the solution decreased significantly after illumination.By measuring the nitrogen content in the dye wastewater after illumination,it was proved that TiO₂-MB-MIP passed The MB molecules in the dye wastewater are redoxed into non-toxic and harmless small-molecular inorganic substances to achieve photodegradation of MB.