Effects of temperature on graphene oxide deposition and transport in saturated porous media

Laboratory batch sorption and sand column experiments were conducted to examine the effects of temperature (6 and 24 degrees C) on the retention and transport of GO in water-saturated porous media with different combination of solution ionic strength (IS, 1 and 10 mM), sand type (natural and acid-cleaned), and grain size (coarse and fine). Although results from batch sorption experiment showed that temperature affected the sorption of GO onto the sand grains at the low IS, the interactions between GO and the sand were relatively weak, which did make the temperature effect prominent. When the IS was 1 mM, experimental temperature showed little effect on GO retention and transport regardless of the medium properties. GO was highly mobile in the sand columns with mass recovery rates ranged from 77.3% to 92.4%. When the IS increased to 10 mM, temperature showed notable effects on GO retention and transport in saturated porous media. For all the combinations of sand type and grain size, the higher the temperature was, the less mobile GO particles were. The effects of temperature on GO retention and transport in saturated porous media were further verified though simulations from an advection-dispersion-reaction model. (C) 2017 Elsevier B.V. All rights reserved.