Preparation Of Novel Antibacterial Polymer Microcapsules And Application In Soil Conditioner

In recent decades,various types of soil conditioners have been widely used to improve soil quality,but the application of traditional soil conditioners has been limited due to many reasons,such as low utilization rate,single performance,poor antibacterial property and so on.Microcapsule soil conditioner provides a new solution to improve crop yield,promote nutrient absorption,adjust soil pH value and reduce soil erosion.Therefore,it is very important to develop the new microcapsule soil conditioner with excellent performance for agricultural production.At present,studies have shown that the ferrous sulfate(FS)and urea(Urea),which could promote the absorption of nutrients,plant growth and capillary root development of crops,can achieve the purpose of breeding and strengthening seedlings.Therefore,the antibacterial polymer microcapsule soil conditioners of core-shell structure were prepared to achieve the purpose of sustained release of nutrients.The main research contents were as follows:First,a new type of antibacterial microcapsule soil conditioner AG-GL/CQAS/β-CDFS was successfully prepared by complex coacervation method and saturated solution method,chitosan quaternary ammonium salt(CQAS)and β-cyclodextrin(β-CD)were used as shell materials,natural polymer materials Arabic gum(AG)and gelatin(GL)were used as carriers which could load ferrous sulfate(FS).The structure and morphology of the microcapsules were characterized by Fourier transform infrared spectroscopy(FTIR),synchronous thermal analyzer(TGA),polarizing microscope(POM)and field emission scanning electron microscope(SEM).The sustained release,water retention,heavy metal ions adsorption and antibacterial properties of the microcapsules were also tested.The results showed that the particle size of the microcapsules ranged from 14 to 17 μm.After 250 h,the sustained-release amount was only 70-85% of the embedding amount,which was in line with the Ritger-Peppas sustained-release mechanism model.The microcapsules could effectively lock water molecules,thus effectively reducing the water consumption of agricultural production.At different pH values,the microcapsules had good performance for different heavy metal ions.The microcapsules can also effectively reduce the proliferation of bacteria and fungi in the soil,and avoid capillary root erosion,and has a wide application value and prospect in agriculture.Second,FeOOH prepared by chemical reaction was loaded on 1250 mesh pickling zeolite(PZ),PZ(Fe)/GL microcapsules were prepared by gelatin(GL)via emulsion crosslinking method.Sodium alginate(SA)was used as the outermost shell materials to prepare PZ(Fe)/GL-SA-Urea soil conditioner sustained-release microcapsules.Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),synchronous thermal analyzer(TGA),field emission scanning electron microscope(SEM)and polarizing microscope(POM)were used to characterize the structure and morphology of the microcapsules.The sustained release,water retention,antibacterial and degradation properties of the microcapsules were also tested.The results showed that the sustained release of PZ(Fe)/GL-SA-Urea microcapsule soil conditioner was only 68% of the total content in 100 h,which could effectively prolong the release time of nutrients.When the GL content in the solution was 0.5%,the microcapsules had good water retention and swelling properties.The antibacterial experiment showed that the microcapsules could effectively reduce the growth and reproduction of bacteria.The microcapsules can also be biodegraded,which provide a healthy microenvironment for the growth of crops.