Kinetics of Cr(VI) Removal from Aqueous Solution with Nanoscale Zero-Valent Iron
FENG Jingwei1,2, LIANG Chenghua1, WANG Li2, ZHANG Xianlong2, ZHANG Siyang2
1. College of Land and Environment, Shenyang Agricultural University, Shenyang 110161, China;2. College of Environmental and Biological Engineering, Shenyang University of Chemical Technology, Shenyang 110142, China
Abstract：A new type of environmental materials, the Nanoscale Zero-Valent Iron(NZVI), was synthesized in aqueous solutions by reduction of Fe3+ with NaBH4 in order to develop a new technology to control or remediate the polluted water containing Cr(VI). The characterization with X-Ray Diffraction(XRD) and Scanning Electron Microscopy(SEM) indicates that the prepared NZVI particles are uniform in distribution and small in diameter with high purity. In the batch removal of Cr(VI) from simulated wastewater, the influences of initial Cr(VI) concentration, temperature and NZVI loading on Cr(VI) reduction on the surface of the NZVI are studied. It is found that each gram of NZVI could remove 198.02 mg of Cr(VI) from the simulated wastewater containing 30.0mg/L of Cr(VI) with an initial pH of 6-7 at room temperature. The kinetics of the Cr(VI) removal is found to follow the pseudo-second-order rate equation. The study reveals that Cr(VI) can be efficiently removed by means of absorption of NZVI in the solution and the key to achieving a high removal rate lies in the appropiate handling of factors involving initial concentration of Cr(VI) and iron loading. The reduction rates are increased with the increase of temperature and iron loading but decreased with the increase of initial Cr(VI) concentration. The experimental data show that the NZVI is very attractive for the removal of Cr(VI) from wastewater.