The adsorption of Pd(II) onto graphene oxide shows optimum pH at 6.0, whereas GO with quaternary ammonium salt shows optimum pH around 3-4.
Attachment for graphene oxide on Pd(II)
This is the explanation why Pd(II) adsorps at higher pH, suggestion taken from the reference you attached. Could you provide the later reference?
""It is reported that GO remains negatively charged in a wide pH range from 2 to 11.36 Therefore, with the increase of pH, the negative charge associated with GO increases. At lower pH values, the major interaction may be coordination between GO and metals. Due to the high availability of chloride anions, the main species of Au(III), Pd(II), and Pt(IV) in lower pH values are AuCl4 −, PdCl42−, andPtCl62−, respectively. Therefore, there is electrostatic repulsionbetween GO and metals, resulting in lower adsorption
capacities. Meanwhile, at higher pH values, because of thelower availability of chloride anions, the ionic species ofAu(III), Pd(II), and Pt(IV) are subject to hydration. As a result,
the electrostatic interaction between GO and metals increases,leading the increase in adsorption capacity.""
Thank you sir but my question is that why along with quaternaryammonium salt it is showing optimum pH around 3-4?
"It is reported that GO wii remain negatively charged from 2 to 11.5 and with the increase in the pH of medium, the negative charge associated with GO will increase. At lower pH values, the interaction may be coordination between GO and metals halides especially. For example the species of Au(III), Pd(II), and Pt(IV) in lower pH value these species will be AuCl4 −, PdCl42−, andPtCl62−, respectively. Therefore, there will be purely electrostatic repulsion between GO and metals, resulting in lower adsorption percentage.. Whereas, at higher pH values, because of the lower availability of chloride anionsand the ionic species of Au(III), Pd(II), and Pt(IV) are subject to hydrated. As a result, electrostatic interaction between GO and metals increases,leading the increase in adsorption capacity.""
- Badges
- Science topic
- Similar topics
- Biological Science
- Biochemistry
- Biochemical Techniques
- Analytical Chemistry
- pH