Development of a trajectory model for predicting attachment of submicrometer particles in porous media: stabilized NZVI as a case study.
A new trajectory simulation algorithm was developed to describe the efficiency of a single collector (pore) to catch submicrometer particles moving through saturated porous media. A constricted-tube model incorporating the deterministic (interception, hydrodynamic retardation, van der Waals force and gravitational sedimentation), stochastic (Brownian diffusion), and thermodynamic (electrostatic and steric repulsion force) mechanisms was established to predict the transport and deposition of surface modified nanoscale zerovalent iron (NZVI) particles by applying Lagrangian trajectory analytical approach. The simulation results show good agreement with the results predicted by existing energy-barrier-free models except for the particle size less than 100 nm at low approach velocity. The number of realizations per start location could be decreased down to 100 with the simulations still exhibiting acceptable relative standard deviation for engineering purposes. With the consideration of energy barriers, the model successfully describes the breakthrough curve of polymer-modified NZVI in a benchtop soil column as well. The novel simulation scheme can be a useful tool for predicting the behavior of the nanoscale colloidal particles moving through filter beds or saturated soil columns under conditions with repulsion and attraction forces among surfaces.
Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Road, Taipei 106, Taiwan, ROC.
Yu-Ting
YT
Wei
Shian-chee
SC
Wu
D000327:Adsorption; D003102:Colloids / Q000737:chemistry; D005374:Filtration; D057446:Hydrodynamics; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008956:Models, Chemical; D010316:Particle Size; D016062:Porosity; D013499:Surface Properties; D014873:Water Pollutants / Q000737:chemistry
D003102:Colloids; D014873:Water Pollutants; D007501:Iron