Mingzhu Yang

High-capacity adsorption of hexavalent chromium from aqueous solution using magnetic microspheres by surface dendrimer graft modification

The magnetic poly-(methyl acrylate-divinyl benzene) (MA-DVB) microspheres with micron size were synthesized by modified suspension polymerization method. Through stepwise reaction with methyl acrylate (MA) and ethylenediamine (EDA), the magnetic poly-(MA-DVB) microspheres with surface dendrimer containing amino groups were obtained. The above mentioned magnetic microspheres were applied for the adsorption of hexavalent chromium from aqueous solution. The effects of solution pH value, adsorption temperature, and adsorption and desorption of Cr(VI) were studied. The results showed that the optimum pH value for Cr(VI) adsorption was found at pH=3, and the adsorption capacity increased with the increase in adsorption temperature. The adsorption equilibrium of Cr(VI) was obtained in about 12 min and more than 98% of adsorbed Cr(VI) were desorbed from the magnetic microspheres in about 30 min using Na(2)SO(4) solution. By fitting the experimental data to Langmuir equation, the maximum capacity for Cr(VI) of magnetic poly-(MA-DVB) microspheres was estimated at 231.8 mg/g.

Micron-sized Magnetic Polymer Microspheres for Adsorption and Separation of Cr(VI) from Aqueous Solution *

Abstract The magnetic poly-(methacrylate-divinyl benzene) microspheres with micron size were synthesized by modified suspension polymerization method. Adsorption of Cr(VI) from aqueous solution by magnetic poly-(MA-DVB) microspheres with surface amination was investigated. The adsorption processes were carried out under diversified conditions of pH value, adsorption time and temperature to evaluate the performance of the magnetic microspheres. The optimum pH value for Cr(VI) adsorption was found as 3. The adsorption capacity increased with adsorption time and attained an optimum at 60 min. The adsorption processes for magnetic microspheres was endothermic reaction, and the adsorption capacity increased with increasing temperature.