Preparing Surface Molecularly Imprinted Material Of Pesticides Based On Anionic Monomer Surface-initiated Graft-polymerization And Studies On Its Molecular Recognition Character

In the modern agricultural technology, all kinds of highly effective pesticides and herbicides were used widely, but generally these pesticide compounds were difficult to degrade, leading to a large number of residues and accumulating in the soil. The pesticide residues will be transferred to the water through a variety of natural channel, causing pollution of surface water and groundwater, and causing great threat to human health. Therefore, pesticide residues has become an important pollution source of water pollution at present, it is an urgent environmental governance subject to remove pesticide residue from water environment. This subject adopts the novel surface-molecular imprinting technique, preparated high-performance pesticide molecule-imprinted material, and mainly stydied recognition selectivity and fine binding affinity for pesticide molecule. This subject used molecularly imprinting technologyin solid phase extraction to remove pesticide pollutant in the aqueous medium, which has obvious innovation, also it has potential application prospect.First, Micron-sized silica gel particles were surface-modified with coupling agent y-aminopropyltrimethoxysilane(AMPS), obtaining the modified particles AMPS-SiO2. A redox initiating system was constituted by the amino groups on AMPS-SiO2particles and persulfate in the solution, and the surface-initiated graft-polymerization of Sodium styrene sulfonate (SSS) was performed, resulting in the grafted particles PSSS/SiO2, on which anionic polyelectrolyte PSSS was grafted. The effects of different factors on the surface-initiated graft polymerization were investigated in depth, and ultimately determine the optimal grafting condition:temperature is40℃,the concentration of monomer is12%, and concentration of initiator is1.0wt%. Under this condition, the grafting degree of PSSS can get up to22.35g/100g. On the basis of that, the adsorption property and adsorption mechanism of the grafted microspheres for pirimicarb were researched in depth. The results show that the grafted particle PSSS/SiO2has strong adsorption ability for pirimicarb. The driving force of the adsorption is the electrostatic interaction. The adsorption capacity has a maximum value at pH=4for pirimicarb. The reaction temperature can exert great effect on the adsorption property of PSSS/SiO2, and the adsorption capacity is decreased with the increase of the temperature.Then, in the reaction system of aqueous solutions of pH=4, molecularly imprinted polymers of pirimicarb were prepared with Sodium styrene sulfonate as functional monomer, N,N’-Methylenebisacrylamide as crosslinker and pirimicarb as a template molecule. In this work, with propoxur as contrast substances, both static and dynamic methods were adopted to study the binding properties and recognition character of molecularly imprinted polymers of pirimicarb for pirimicarb. The experiment results show that molecularly imprinted polymers of pirimicarb have the binding properties and recognition character for pirimicarb. In relation to propoxur, the selectivity coefficient of molecularly imprinted polymers for pirimicarb is9.373, showing high selectivity of molecular recognition. Besides, molecularly imprinted polymers of pirimicarb has excellent elution property, with a diluted aqueous solution of NaOH as the eluent, the desorption ratios of pirimicarb reach99.67%in16BV. The amount of crosslinker and the amount of template molecule have certain effect on selectivity coefficient of molecularly imprinted polymers. The best molar ratio of amount of functional monomer and amount of crosslinker is5:1, and the best molar ratio of amount of functional monomer and amount of template molecule is4:1.Last, through the experiment, a study has found that grafted particles PSSS/SiO2and atrazine produce maximum electrostatic interaction force in atrazine solutions of pH=2. So in the reaction system of aqueous solutions of pH=2, molecularly imprinted polymers of atrazine were successfully prepared with Sodium styrene sulfonate as functional monomer, N,N’-Methylenebisacrylamide as crosslinker and atrazine as a template molecule. The article also studied the binding properties and recognition character of molecularly imprinted polymers of atrazine for atrazine. In relation to pirimicarb, the selectivity coefficient of NMIP-PSSS/SiO2for atrazine is 1.06, and that of MIP-PSSS/SiO2for atrazine is8.79, showing that atrazine surface molecularly imprinted material MIP-PSSS/SiO2has specific recognition selectivity for atrazine in water medium, but atrazine surface molecularly imprinted material MIP-PSSS/SiO2does not recognize and not binding for the comparison-pirimicarb molecular. Besides, MIP-PSSS/SiO2has excellent elution property.