title: Transport, retention, and size perturbation of graphene oxide in saturated porous media: effects of input concentration and grain size.
abstract: Accurately predicting the fate and transport of graphene oxide (GO) in porous media is critical to assess its environmental impact. In this work, sand column experiments were conducted to determine the effect of input concentration and grain size on transport, retention, and size perturbation of GO in saturated porous media. The mobility of GO in the sand columns reduced with decreasing grain size and almost all GO were retained in fine sand columns for all of the tested conditions. This result can be explained with colloid filtration and XDLVO theories. Input concentration also influenced the retention and transport of GO in the sand columns because of the 'blocking' mechanism that reduces the particle retention rate. After passing through the column, average GO sizes increased dramatically. In addition, the sizes of GO retained in the sand also increased with travel distance. These results suggested that transport through the porous media induced GO aggregation. A mathematical model based on the advection-dispersion equation coupled with the second-order kinetics to reflect the blocking effect simulated the experimental data well.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Surficial Geochemisty, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing 210093, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Sun
authors.forename: Bin
authors.initials: B
authors.lastname: Gao
authors.forename: Scott A
authors.initials: SA
authors.lastname: Bradford
authors.forename: Lei
authors.initials: L
authors.lastname: Wu
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Shi
authors.forename: Jichun
authors.initials: J
authors.lastname: Wu
mesh_terms: D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis; D006108:Graphite / Q000032:analysis*; D007700:Kinetics; D008962:Models, Theoretical; D010087:Oxides / Q000032:analysis*; D010316:Particle Size; D016062:Porosity; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010087:Oxides; D014874:Water Pollutants, Chemical; D006108:Graphite