The transport of graphitic carbon nitride in saturated porous media: Effect of hydrodynamic and solution chemistry

Abstract

Understanding transport behavior of graphitic carbon nitride (g-C3N4) in porous media plays an important role in preventing its possible causing the underground environmental problems. The transport behavior of g-C3N4 in porous media were investigated by packed column experiments at different flow rates, ionic strengths (ISs), pHs and multivalent cations. The experimental results showed that the transport ability of g-C3N4 decreased with the IS increasing, and most of the g-C3N4 was retained in the sand column for the IS greater than 0.0001 M. The flow rate had little effect on the transport behavior of g-C3N4, and the recovery of g-C3N4 increased slightly with increasing flow rate. In addition, the migration ability of g-C3N4 under acidic conditions was drastically reduced compared with neutral alkaline conditions. Moreover, it was found that 1.51%, 30.33%, 34.91%, and 60.54% of g-C3N4 was retained in the column when g-C3N4 was leached through the quartz sand column at Al3+, Ca2+, Mg2+, and K+, which was consistent with the Schulze-Hardy rule. Finally, FTIR spectrum showed that the infrared absorption peak of the g-C3N4 mixed quartz sand were shifted to certain degrees under different conditions, which confirmed that hydrogen bond was formed in the transport of carbon nitride with the quartz sand surface. This study provides a new perspective on the role of hydrogen bond in the transport and fate of nanomaterials.