The effects of surface chemistry of mesoporous silica materials and solution pH on kinetics of molsidomine adsorption

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

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.

Surface-functionalized silica aerogels and alcogels for methylene blue adsorption

Surface-functionalized silica aerogels and alcogels preparedviaa two-step sol–gel process through the combination of different silicon precursors were used in the adsorption of methylene blue dye molecules from aqueous media.