title: Investigation on efficient adsorption of cationic dyes on porous magnetic polyacrylamide microspheres.
abstract: We report here the preparation of porous magnetic polyacrylamide microspheres for efficient removal of cationic dyes by a simple polymerization-induced phase separation method. Characterizations by various techniques indicate that the microspheres show porous structures and magnetic properties. They can adsorb methylene blue with high efficiency, with adsorption capacity increasing from 263 to 1977 mg/g as the initial concentration increases from 5 to 300 mg/L. Complete removal of methylene blue can be obtained even at very low concentrations. The equilibrium data is well described by the Langmuir isotherm models, exhibiting a maximum adsorption capacity of 1990 mg/g. The adsorption capacity increases with increasing initial pH and reaches a maximum at pH 8, revealing an electrostatic interaction between the microspheres and the methylene blue molecules. The microspheres also show high adsorption capacities for neutral red and gentian violet of 1937 and 1850 mg/g, respectively, as well as high efficiency in adsorption of mixed-dye solutions. The dye-adsorbed magnetic polyacrylamide microspheres can be easily desorbed, and can be repeatedly used for at least 6 cycles without losing the adsorption capacity. The adsorption capacity and efficiency of the microspheres are much higher than those of reported adsorbents, which exhibits potential practical application in removing cationic dyes.
authors: State Key Laboratory of Materials-Oriented Chemical Engineering and College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing 210009, PR China.
authors: Tong
authors: T
authors: Yao
authors: State Key Laboratory of Materials-Oriented Chemical Engineering and College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing 210009, PR China.
authors: Song
authors: S
authors: Guo
authors: State Key Laboratory of Materials-Oriented Chemical Engineering and College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing 210009, PR China.
authors: Changfeng
authors: C
authors: Zeng
authors: State Key Laboratory of Materials-Oriented Chemical Engineering and College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing 210009, PR China.
authors: Chongqing
authors: C
authors: Wang
authors: State Key Laboratory of Materials-Oriented Chemical Engineering and College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing 210009, PR China. Electronic address: lixiongzhang@yahoo.com.
authors: Lixiong
authors: L
authors: Zhang
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000327:Adsorption; D002412:Cations; D004396:Coloring Agents / Q000737:chemistry*; D008280:Magnetics; D008863:Microspheres; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D002412:Cations; D004396:Coloring Agents; D000099166:Polyacrylamides
keywords: Adsorption; Cationic dyes; Complete removal; Magnetic PAM microspheres; Wastewater treatment