Synthesis,Characterization Of Amino-functionalized Polymer Materials And Their Adsorption Properties Of Phosphate In Aqueous Solution

In this work, amino-functionalized polymer materials have been synthesized by co-polymerization and ring-opening reactions.22kinds of amino-functionalized polymer materials (NH2-PMs) were synthesized by varying the kinds of amino agents, the usage amount of Fe3O4, and the usage amount of monomers, i.e., glycidylmethacrylate (GMA), divinylbenzene (DVB) and styrene (St). The morphologies, magnetic properties, contents and structures of amino-functionalized polymer materials have been characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), elementary analysis (EA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the materials were micro-spheres, with an average diameter of around0.5～1.0μm. The effects of the removal of phosphate by NH2-PMS were systematicly investigated via batch tests. The effects of some important factors, i.e., the effects of pH value, contacting time, contacting temperature, initial concentration of phosphate, and ionic strength were intensively investigated. The adsorption mechanism of phosphate onto NH2-PMS was discussed. The results showed that the adsorption properties of NH2-PMS were highly pH dependent. The adsorption efficiency of phosphate initially increased with the increase of the pH value of the aqueous solution, then it gradually decreased and reached a plateau; the optimized pH values were at2.5-3.0. The kinetic studies showed that the adsorption process reached equilibrium in30min and fitted the pseudo-second-order rate equations well. Thermodynamic studies indicated that the process of the phosphate adsorbing onto NH2-PMS was exothermic, spontaneous and entropy unfavored in nature. The adsorption efficiency was increased with the increase of the initial concentration and reached equilibrium. The adsorption data were well correlated with Langmuir isotherm model and the process might be monolayer adsorption. The effectiveness of the adsorption was decreased with the increase of ionic strength in the aqueous solution. The adsorption mechanism studies showed that the adsorption of phosphate could be mainly related with electrostatic attraction. Under the alkaline conditions, the post-absorbed materials can be recycled and the adsorption efficiency remained79～89%after5cycles.