Preparation Of Modified Dendrimer Sterilization Microspheres And Preliminary Application

The safety of drinking water has been a popular topic of social concern,especially the safety problem caused by microbial contamination.There are two methods to.deal with this problem,one is high temperature sterilization,the other one is chemical disinfection;the former is high energy consumption,high cost,large equipment,which is the risk of secondary pollution.Therefore,the research on the sterilization technology with high efficiency and safety,no residue and low price is one of the important directions of development.The immobilized bactericide technology is a kind of sterilization method which has the bactericidal function based on insoluble carrier,and be sterilized at room temperature,reduce the energy consumption.This paper reviews the research status of the immobilized fungicides functional ligand and dendrimer.With chloromethylated polystyrene microspheres(the chlorine ball)as the carrier,at the same time as the initiator synthesized the 3 generation dendrimer,and explore the optimum synthesis conditions of each generation of microspheres;then the best synthetic microspheres were modified,and obtained the best conditions for modification of the functional ligand;minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of new sterilization microspheres on Escherichia coil and Staphylococcus aureus were tested for screening excellent sterilization microspheres.The preliminary research and application experiments were carried out,which laid the foundation for the development of the immobilized fungicides.The main research contents are as follows:1.To chlorine ball as the initiator core,ethylenediamine and methyl acrylate as molecular chain used divergent method by Micheal addition reaction and repeatedly grafted,synthesis of 3 generation dendrimer microsphere(G3).The optimum reaction conditions of the reaction solvent,temperature and molar ratio were obtained in each generation microspheres for the maximum grafting ratio.Using the element analysis to get the content of each generation microspheres containing nitrogen to calculate the rate of grafting;each generation of the best synthesis results were:G0.5 of the graft was 99%,G1.0 was 95%,G1.5 was 91%,G2.0 was 93%,G2.5 was 93%,G3.0 was 90%.The functional groups of each generation were observed by infrared spectroscopy,and the mechanism was preliminarily obtained.Thermogravimetric analysis further verify the success of the synthesis.2.G3 was modified by quaternary ammonium salt compound as functional reagent,and 4 kinds of new sterilization microspheres were synthesized,their functional group were calculated by the results of elemental analysis.The conversion rates of MEL-R,SA-R,TSC-R and AB-R were 76%,93%,93%,79%,respectively.The synthesis mechanism and thermal stability of the microspheres were investigated by FTIR and TGA.3.The minimal inhibitory concentration(MIC)and minimal bactericidal concentration(MBC)of four kinds of microspheres on Staphylococcus aureus(S.aureus)and Escherichia coli(E.coil)were determined to identify the bactericidal effect of the microspheres.The experimental results showed that the bactericidal effect of four kinds of microspheres was SA-R>TSC-R>MEL-R>AB-R.In order to further explore the application of microspheres,metal ions Cu2+ and food additives on the bactericidal effect of microspheres was studied.The results showed that the effect of Cu2+on bactericidal effect of the microspheres was inhibited.During the study,SA-R and TSC-R have maintained good bactericidal properties.4.SA-R and TSC-R were selected as the representative,scanning electron microscopy,thermogravimetric analysis as a means to study the preliminary mechanism of the microspheres.The metal adsorption capacity and sterilization of two kinds of microspheres were tested.The results showed that two kinds of microspheres can be used as a metal absorbing agent and repeatedly for 5 times.As a fungicide can be reused 2 times and maintain a highly effective bactericidal effect,.5.Determination the growth of bacteria in tap water,bottled water and drinks without heating.And then,by the normal flow rate of water containing bacteria through the sterilization of microspheres,didn’t found the presence of micro-organisms.The test results showed that SA-R had good germicidal efficacy.