title: Modified MODFLOW-based model for simulating the agglomeration and transport of polymer-modified Fe0nanoparticles in saturated porous media.
abstract: The solute transport model MODFLOW has become a standard tool in risk assessment and remediation design. However, particle transport models that take into account both particle agglomeration and deposition phenomena are far less developed. The main objective of the present study was to evaluate the feasibility of adapting the standard code MODFLOW/MT3D to simulate the agglomeration and transport of three different types of polymer-modified nanoscale zerovalent iron (NZVI) in one-dimensional (1-D) and two-dimensional (2-D) saturated porous media. A first-order decay of the particle population was used to account for the agglomeration of particles. An iterative technique was used to optimize the model parameters. The model provided good matches to 1-D NZVI-breakthrough data sets, with R2values ranging from 0.96 to 0.99, and mass recovery differences between the experimental results and simulations ranged from 0.1 to 1.8 %. Similarly, simulations of NZVI transport in the heterogeneous 2-D model demonstrated that the model can be applied to more complicated heterogeneous domains. However, the fits were less good, with the R2values in the 2-D modeling cases ranging from 0.75 to 0.95, while the mass recovery differences ranged from 0.7 to 6.5 %. Nevertheless, the predicted NZVI concentration contours during transport were in good agreement with the 2-D experimental observations. The model provides insights into NZVI transport in porous media by mathematically decoupling agglomeration, attachment, and detachment, and it illustrates the importance of each phenomenon in various situations. Graphical Abstract ᅟ.
authors: Department of Hydrology Engineering, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors: Peyman
authors: P
authors: Babakhani
authors: Department of Earth Sciences, Uppsala University, Villavägen 16, 75236, Uppsala, Sweden.|Center for Experimental Study of Subsurface Environmental Processes, Colorado School of Mines, Golden, CO, USA.
authors: Fritjof
authors: F
authors: Fagerlund
authors: Department of Hydrology Engineering, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran.|Department of Civil Engineering, Sharif University of Technology, Tehran, Iran.
authors: Abolfazl
authors: A
authors: Shamsai
authors: Center for Environmental Implications of Nanotechnology (CEINT) and Department of Civil and Environmental Engineering, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA.
authors: Gregory V
authors: GV
authors: Lowry
authors: Research Unit for Integrated Natural Resources Remediation and Reclamation (IN3R), Department of Civil Engineering, Faculty of Engineering, Naresuan University, Phitsanulok, 65000, Thailand. pomphenrat@gmail.com.|Center of Excellence for Sustainability of Health, Environment and Industry (SHE&I), Faculty of Engineering, Naresuan University, Phitsanulok, 65000, Thailand. pomphenrat@gmail.com.
authors: Tanapon
authors: http://orcid.org/0000-0003-2179-042X
authors: T
authors: Phenrat
mesh_terms: D003198:Computer Simulation; D052918:Environmental Restoration and Remediation; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008956:Models, Chemical; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D011108:Polymers; D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide; D007501:Iron
keywords: Aggregation; MODFLOW; NZVI; Numerical simulation; Saturated porous media; Transport