Comparative study of graphene oxide, activated carbon and carbon nanotubes as adsorbents for copper decontamination

This paper presents a comparative study of Cu(II) decontamination by three different carbonaceous materials, i.e., graphene oxide, multiwalled carbon nanotubes, and activated carbon. The three carbonaceous materials were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, N2-BET surface area analysis, and potentiometric acid-base titrations in detail. Also, Cu(II) adsorption on the three types of carbonaceous materials as a function of pH and Cu(II) ion concentration were investigated. The constant capacitance model was used to determine the appropriate surface reactions of Cu(II) adsorption on carbonaceous materials with the aid of FITEQL 4.0 software. In addition, how the surface area and the total concentration of acidic functional groups influencing the adsorption capacities of the three carbonaceous materials for Cu(II) removal were elucidated. The results have an important role in predicting the adsorption capacity of surface modified carbonaceous materials.