Initial transport and retention behaviors of ZnO nanoparticles in quartz sand porous media coated with E. coli biofilm
Xujia Jiang a, Xueting Wang a,b, Meiping Tong a,b,*, Hyunjung Kim c
a The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China
b School of Environment and Urban Studies, Shenzhen Graduate School of Peking University, Shenzhen 518055, PR China
c Department of Mineral Resources and Energy Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea
Initial transport and retention of zinc oxide nanoparticles through porous media of quartz and sand coated with E. coli biofilms was studied by Jiang and Wang et al. The transport and deposition behavior of zinc oxide nanoparticles with varying conditions of ionic strengths covering the range of environmental range and with different fluid velocities were studied.
A suspension of nanoparticles was prepared. The porous media for ZnO nanoparticles was irregular quartz sand. Zeta potentials of suspension and porous media were measured at different ionic strengths of NaCl and CaCl2. Porous media and quartz microbalance with dissipation (QCM-D) experiments were performed. To study the transport of nanoparticles through the prepared porous media particle tracking model was used and DLVO interaction forces were measured.
The study of Jiang and Wang et al., showed the impact of biofilm on the retention and transport of zinc oxide nanoparticles in the initial stage. Biofilms affected the breakthrough curves of zinc oxide nanoparticles and also the shape of retained nanoparticles. The higher deposition of nanoparticles in biofilm coated porous media was due to the DLVO and non-DLVO interaction of nanoparticles with the biofilm and the morphology of biopolymers. The profiles with extra exponential retained profiles were observed with coated as well as uncoated films. The deviations were observed from CFT model in the columns coated with biofilms. In the presence and as well as in the absence of biofilms, the concentration of zinc oxide nanoparticles have a sharp decrease with the increase of ionic strength.
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