Dear researchers

I am working on the activated carbon, which synthesized by sulfuric acid impregnation. From EDS , 3% sulfur content attached to the AC. I studied the this material for Pb2+ uptake, and it can remove up to 100 mg/L initial concentration of lead solution. But, when studied, the selectivity by mixing Pb 2+ with Mg2+. Cu2+ and Zn2+ the material was not selective. May I know the reason.

Here is the supporting data related to the coexisting ions :

Ion Ionic radius Type of acid

Cu2+ 73 Borderline

Mg2+ 79 Hard

Pb2+ 119 borderline

Zn2+ 74 borderline

Thank you all. :)