Effect of cations composition on transport of graphene oxide in saturated porous media

This study was conducted on one-dimensional seepage in saturated porous media fixed on packed bed columns to investigate the fate of graphene oxide (GO) in the subsurface environment. In the present experiments, the fate of grapheme oxide (GO) was investigated as a function of cations composition (sodium absorption ratios, SAR) at 10 mmol·L −1 constant ionic strength (IS). To analyze the migration deposition mechanism of GO, the deposition kinetics curve was determined by mathematical model and interface chemistry theory. When SAR increased from zero to ∞, maximum effluent concentration of sand columns and recovery of GO increased, however, deposition rate, removal efficiency and attachment efficiency of the breakthrough experiments decreased respectively from 0.356 min −1 to 0.039 min −1 、1.04×10 −2 to 1.1×10 −3 and 0.054 to 0.003. Accordingly, it was proposed that Brownian diffusion was the major mechanism which resulted in contacting between GO particles and quartz sand particles, and the change of Ca 2+ concentration was the predominant factor which caused GO different migration behavior at different SAR. The charge neutralization and bridging between Ca 2+ and GO could be responsible for the balance of electrostatic repulsion and attraction between the particles, which affected the size and shape of GO particles and strengthened the retention effect of sand column on GO.