Enhanced adsorption removal of anionic dyes via a facile preparation of amino-functionalized magnetic silica.
A novel amino-functionalized magnetic silica (Fe3O4@SiO2-NH2) was easily prepared via a one-step method integrating the immobilization of 3-aminopropyltriethoxysilane with a sol-gel process of tetraethyl orthosilicate into a single process. This showed significant improvement in the adsorption capacity of anionic dyes. The product (Fe3O4@SiO2-NH2) was characterized with scanning electron microscopy, Fourier transform infrared spectroscopy, energy dispersive X-ray spectrometry, zeta potential and vibrating sample magnetometry. The adsorption performance of Fe3O4@SiO2-NH2was then tested by removing acid orange 10 (AO10) and reactive black 5 (RB5) from the aqueous solutions under various experimental conditions including initial solution pH, initial dye concentrations, reaction time and temperature. The results indicated that the maximum adsorption capacity of AO10 and RB5 on Fe3O4@SiO2-NH2was 621.9 and 919.1 mg g-1at pH 2, respectively. The sorption isotherms fit the Langmuir model nicely. Similarly, the sorption kinetic data were better fitted into the pseudo-second order kinetic model than the pseudo-first order model. In addition, the thermodynamic data demonstrated that the adsorption process was endothermic, spontaneous and physical. Furthermore, Fe3O4@SiO2-NH2could be easily separated from aqueous solutions by an external magnetic field, and the preparation was reproducible.
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China E-mail: shihuaqi@cug.edu.cn.
Xiao-Shui
XS
Li
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China E-mail: shihuaqi@cug.edu.cn.
Yu-Han
YH
Fan
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China E-mail: shihuaqi@cug.edu.cn.
Shou-Wen
SW
Zhang
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China E-mail: shihuaqi@cug.edu.cn.
Shi-Hua
SH
Qi
D000327:Adsorption; D000838:Anions / Q000302:isolation & purification; D001391:Azo Compounds / Q000302:isolation & purification; D004396:Coloring Agents / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D060328:Magnetic Phenomena; D008855:Microscopy, Electron, Scanning; D009282:Naphthalenesulfonates / Q000302:isolation & purification; D011437:Propylamines / Q000737:chemistry*; D015203:Reproducibility of Results; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D013696:Temperature; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification
D000838:Anions; D001391:Azo Compounds; D004396:Coloring Agents; D009282:Naphthalenesulfonates; D011437:Propylamines; D012821:Silanes; D012996:Solutions; D014874:Water Pollutants, Chemical; C008710:Orange G; D012822:Silicon Dioxide; C477625:amino-propyl-triethoxysilane; C063421:Remazol black B