Activated carbon impregnated with copper to remove l-cysteine in an aqueous medium

Abstract

In this work, the surface of commercial activated carbon was modified with the copper sulfate salt by impregnation method, aiming at the removal of reduced sulfur compounds from aqueous media. The materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy with energy dispersion spectroscopy, and using nitrogen gas as adsorbent, the apparent specific surface areas were determined. In addition, the semiquantitative analysis to explore the surface area was performed using methylene blue a ‘molecular probe.’ For the adsorption, was used l-cysteine as the model adsorbate. After the impregnation of activated carbon, the presence of copper in the forms of copper oxide and metallic copper was confirmed. The mapping of functional groups demonstrated the carbonaceous characteristic of the material. The photomicrographs showed crystals on the surface of the activated carbon impregnated with copper and revealed a copper atomic content of 16.8% w/w. However, the impregnation caused a reduction in the apparent specific surface, probably due to the clogging of the pores with the impregnation salt. On the other hand, the results of adsorption tests showed an increase in l-cysteine removal with impregnation, ranging from 76 to 93%. The results suggest that the adsorbent impregnated with copper is considered promising for the removal of compounds with reduced sulfur.