摘要
Graphene oxide(GO) holds great promise for a broad array of applications in many fields,but also poses serious potential risks to human health and the environment.In this study,the adsorptive properties of GO toward Ca^(2+) and Na+were investigated using batch adsorption experiments,zeta potential measurements,and spectroscopic analysis.When pH increased from 4 to 9,Ca^(2+)adsorption by GO and the zeta potential of GO increased significantly.Raman spectra suggest that Ca^(2+)was strongly adsorbed on the GO via –COO Ca~+ formation.On the other hand,Na+was adsorbed into the electrical diffuse layer as an inert counterion to increase the diffuse layer zeta potential.While the GO suspension became unstable with increasing pH from 4 to 10 in the presence of Ca^(2+),it was more stable at higher pH in the NaC l solution.The findings of this research provide insights in the adsorption of Ca^(2+)on GO and fundamental basis for prediction of its effect on the colloidal stability of GO in the environment.
Graphene oxide(GO) holds great promise for a broad array of applications in many fields,but also poses serious potential risks to human health and the environment.In this study,the adsorptive properties of GO toward Ca^(2+) and Na+were investigated using batch adsorption experiments,zeta potential measurements,and spectroscopic analysis.When pH increased from 4 to 9,Ca^(2+)adsorption by GO and the zeta potential of GO increased significantly.Raman spectra suggest that Ca^(2+)was strongly adsorbed on the GO via –COO Ca~+ formation.On the other hand,Na+was adsorbed into the electrical diffuse layer as an inert counterion to increase the diffuse layer zeta potential.While the GO suspension became unstable with increasing pH from 4 to 10 in the presence of Ca^(2+),it was more stable at higher pH in the NaC l solution.The findings of this research provide insights in the adsorption of Ca^(2+)on GO and fundamental basis for prediction of its effect on the colloidal stability of GO in the environment.