Mechanisms of safranin O interaction with 1:1 layered clay minerals

Using Earth materials for the removal of environmental contaminants attracted great attention. In this study, the mechanism of safranin O (SO) removal by 1:1 layered clay minerals was investigated. The specific surface area and cation exchange capacity of the minerals played a key role, while solution pH and ionic strength had less influences on SO removal. The sorption of counterion Cl(-)on halloysite nano clay (HNC) at high loading levels resulted in bilayer SO formation on HNC surfaces. Lack of Cl(-)sorption on kaolinite (KAO) suggested monolayer SO formation on KAO surfaces. These speculations were confirmed by molecular dynamic simulation.

Automated summary

The study found that the specific surface area and cation exchange capacity of 1:1 layered clay minerals play a key role in the removal of safranin O, while solution pH and ionic strength have less influence. Experimental results suggested that bilayer SO formation occurs on halloysite nano clay surfaces at high loading levels, while monolayer SO formation occurs on kaolinite surfaces.