Characterization of activated carbon synthesized at low temperature from cocoa shell (Theobroma cacao) for adsorbing amoxicillin

Abstract

 The aim of this research was synthesize and characterize activated carbon obtained at low temperature from cocoa peel (Theobroma cacao), modified with zinc chloride (ZnCl2) for its subsequent use in the removal of amoxicillin. The bio­mass was characterized by elemental analysis and the activated carbon was characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Surface Area Analysis (BET) in order to determine the chemical composition, mor­phological and structural characteristics. For the assays of amoxicillin molecular adsorption, was used an aqueous solution of contaminant at 20 ppm, with pH 6 and 9, to which was added 5 g of adsorbent material impregnated with ZnCl2 at 1:3 and 1:4 ratios. These carbons reached surface areas of 287.5 m2/g and 205.4 m2/g, respectively, with average pore sizes from 3 to 4 nm. The percentage of amoxicillin removal was influenced by the pH of the solution to be treated, reaching the highest percentages of adsorption when the pH was acid; removal values achieved for activated carbon 1:3 were 75.4 % and 67.2 %, while for the activated carbon 1:4 were 65.2 % and 56.7 % for solutions at pH 6 and 9, correspondingly. It concludes that the activated carbon obtained at low temperature has potential to remove amoxicillin in aqueous solution and becomes a good alternative due to the availability of the residue.