title: Reduction of hexavalent chromium by Pannonibacter phragmitetus LSSE-09 coated with polyethylenimine-functionalized magnetic nanoparticles under alkaline conditions.
abstract: A novel cell separation and immobilization method for Cr (VI)-reduction under alkaline conditions was developed by using superparamagnetic Fe(3)O(4) nanoparticles (NPs). The Fe(3)O(4) NPs were synthesized by coprecipitation followed by modification with sodium citrate and polyethyleneimine (PEI). The surface-modified NPs were monodispersed and the particle size was about 15 nm with a saturation magnetization of 62.3 emu/g and an isoelectric point (pI) of 11.5 at room temperature. PEI-modified Fe(3)O(4) NPs possess positive zeta potential at pH below 11.5, presumable because of the high density of amine groups in the long chains of PEI molecules on the surface. At initial pH 9.0, Pannonibacter phragmitetus LSSE-09 cells were immobilized by PEI-modified NPs via electrostatic attraction and then separated with an external magnetic field. Compared to free cells, the coated cells not only had the same Cr (VI)-reduction activity but could also be easily separated from reaction mixtures by magnetic force. In addition, the magnetically immobilized cells retained high specific Cr (VI)-reduction activity over six batch cycles. The results suggest that the magnetic cell separation technology has potential application for Cr (VI) detoxification in alkaline wastewater.
authors: Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors: Lin
authors: L
authors: Xu
authors: Liangrong
authors: L
authors: Yang
authors: Mingfang
authors: M
authors: Luo
authors: Xiangfeng
authors: X
authors: Liang
authors: Xuetuan
authors: X
authors: Wei
authors: Junmei
authors: J
authors: Zhao
authors: Huizhou
authors: H
authors: Liu
mesh_terms: D020561:Alphaproteobacteria / Q000378:metabolism*; D002857:Chromium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission / Q000379:methods; D036103:Nanotechnology / Q000379:methods; D011094:Polyethyleneimine / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D055672:Static Electricity; D013818:Thermogravimetry / Q000379:methods; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification / Q000379:methods
chemical_list: D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D011094:Polyethyleneimine