Preparation And Application Of Functionalized Magnetic Suspension

This paper systematically studies the two parts content: preparation, characterization and application of FA-conjugated Fe₃O₄ magnetic nanoparticles and IDA-functionalized Fe₃O₄ magnetic P（St-GMA） microspheres.（1） The folic acid（FA）-conjugated Fe₃O₄ magnetic nanoparticles（MNPs） were synthesized by co-precipitation of Fe³⁺ and Fe²⁺ solution followed by surface modification with carboxymethyl dextran（CMD） to form carboxymethyl group terminated MNPs, then FA was conjugated with the carboxyl group functionalized MNPs. The morphology and properties of obtained nanoparticles were characterized by X-ray powder diffraction（XRD）, Fourier transform infrared spectroscopy（FT-IR）, UV-visible spectra（UV-vis）, transmission electron microscopy（TEM）, dynamic light scattering（DLS）, vibrating sample magnetometer（VSM） and thermogravimetric analysis（TGA）. The FA-conjugated MNPs exhibited relatively high saturation magnetization and fast magneto-temperature response which could be applied to hyperthermia therapy. To determine the accurate targeting effect of FA, we chose FA-conjugated MNPs as MRI contrast enhancement agent for detection of KB cells with folate receptor over-expression in vitro and in vivo. The results show that these magnetic nanoparticles appear to be the promising materials for local hyperthermia and MRI.（2） The iminodiacetic acid（IDA）-functionalized Fe₃O₄ magnetic poly（styrene-glycidyl methacrylate）（Fe₃O₄/P（St-GMA）-IDA） microspheres were synthesized by magneto-template miniemulsion polymerization to obtain the epoxy groups terminated magnetic（Fe₃O₄/P（St-GMA）） microspheres followed by modification with IDA to form the IDA chelation groups on the surface. The morphology and properties of the as-prepared magnetic polymer microspheres were characterized.The Fe₃O₄/P（St-GMA）-IDA microspheres exhibited relatively high saturation magnetization and chelated metal ions through coordination bond which could be applied to copper ions(Cu²⁺) removal. Different factors such as p H value, temperature, contact time and initial concentration were investigated to determine the adsorption behavior of Cu²⁺ from aqueous solution. The adsorption equilibrium isotherms was evaluated by the Langmuir and Freundlich models, the kinetics was analyzed using the pseudo-first-order and pseudo-second-order models. The results show that the functionalized microspheres appear to be the promising adsorbent for Cu²⁺ removal from wastewater.