Green treatment of concentrated sulfuric acid: mercury ion removal using adsorption with activated carbon

BACKGROUND The mercury (Hg) content in technical concentrated sulfuric acid must be strictly controlled for industrial applications, particularly in water treatment, fertilizer production, etc. This study explores the removal of Hg(II) ions directly from concentrated sulfuric acid (93–98%) using granular activated carbon. While adsorption processes are well established in aqueous systems, their application in concentrated sulfuric acid matrices has received limited attention due to the highly aggressive chemical media. RESULTS Adsorption performance was evaluated through equilibrium studies, kinetic modeling and continuous‐flow fixed‐bed column experiments. Scanning electron microscopy, Fourier transform infrared spectroscopy and X‐ray fluorescence spectroscopy with energy‐dispersive X‐ray analysis confirmed the chemical stability of activated carbon under strongly acidic conditions and the adsorption of Hg(II) on the activated carbon. The Sips isotherm model provided the best description of equilibrium data ( R 2 = 0.996), while Avrami kinetics adequately fitted the adsorption process ( R 2 = 0.968). CONCLUSION Fixed‐bed column results further demonstrated practical feasibility, suggesting that the use of granular activated carbon offers a promising approach for Hg control in sulfuric acid production.