Experimental and theoretical approaches for the surface interaction between copper and activated sludge microorganisms at molecular scale.
Interactions between metals and activated sludge microorganisms substantially affect the speciation, immobilization, transport, and bioavailability of trace heavy metals in biological wastewater treatment plants. In this study, the interaction of Cu(II), a typical heavy metal, onto activated sludge microorganisms was studied in-depth using a multi-technique approach. The complexing structure of Cu(II) on microbial surface was revealed by X-ray absorption fine structure (XAFS) and electron paramagnetic resonance (EPR) analysis. EPR spectra indicated that Cu(II) was held in inner-sphere surface complexes of octahedral coordination with tetragonal distortion of axial elongation. XAFS analysis further suggested that the surface complexation between Cu(II) and microbial cells was the distorted inner-sphere coordinated octahedra containing four short equatorial bonds and two elongated axial bonds. To further validate the results obtained from the XAFS and EPR analysis, density functional theory calculations were carried out to explore the structural geometry of the Cu complexes. These results are useful to better understand the speciation, immobilization, transport, and bioavailability of metals in biological wastewater treatment plants.
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry.
Hong-Wei
HW
Luo
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry.
Jie-Jie
JJ
Chen
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry.
Guo-Ping
GP
Sheng
Department of Modern Physics, University of Science and Technology of China, Hefei. 230026, China.
Ji-Hu
JH
Su
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei. 230029, China.
Shi-Qiang
SQ
Wei
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry.
Han-Qing
HQ
Yu
D015502:Absorptiometry, Photon; D003300:Copper / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D013499:Surface Properties; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology
D003300:Copper; D012722:Sewage; D062065:Wastewater