关键词: 磁性微球, 微胶囊, 表征, 脱氮性能

Abstract: In order to solve the water pollution caused by eutrophication, Fe₃O₄ nanoparticles modified with SiO₂ and chitosan(CS)was used for immobilizing functional strain, so that the strain can denitrify the contamination in water more efficiently. The morphology, structure and magnetic properties of Fe₃O₄ nanoparticles were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), thermogravimetric analysis(TGA) and vibrating sample magnetometer(VSM), and the functions for removing ammonia nitrogen and nitrate nitrogen from water were investigated. The results showed that Fe₃O₄ nanoparticles exhibited highly ordered crystallinity, regular crystalline morphologies and excellent magnetism. The adsorption rate for the bacteria was up to 85.00% and the numbers of adsorption strain achieved (2.1—2.2)×10⁶cfu/mL at 20min during the adsorption process. Furthermore, when the non-immobilized strain was added into the media(liquid), the removal rate of ammonia nitrogen and nitrate nitrogen was 54.13% and 59.17%, respectively. However, when the immobilized strain was added into the media, the removal rate of ammonia nitrogen and nitrate nitrogen increase to 72.26% and 74.56%. Experimental results showed that the modified Fe₃O₄ nanoparticles had strong adsorption capacity for the strain. In the mean time, the microcapsule structure could make the immobilized strain have better performance and longer life cycle of Fe₃O₄ nanoparticles compared with the non-immobilized strain.

Key words: magnetic microspheres, microcapsules, representation, denitrification performance