High-performance removal of methyl mercaptan by nitrogen-rich coconut shell activated carbon

A series of nitrogen-doped coconut shell activated carbon catalysts were prepared by urea or melamine impregnation followed by heat treatment and used for the removal of methyl mercaptan (CH3SH). The physical and chemical properties of the nitrogen-doped coconut shell activated carbons were evaluated by nitrogen adsorption/desorption, scanning electron microscopy, X-ray photoelectron spectroscopy, elemental analysis, Boehm titration, and thermal analysis. The results show that CH3SH capacity depends on the nitrogen content. Further research indicates that pyridinic nitrogen and quaternary nitrogen are the active sites. Due to the metal-free property of the nitrogen-rich coconut shell activated carbon, the regeneration process can be easily performed and dimethyl disulfide (CH3SSCH3) can be recovered as the main product. Our study indicates that there is a promising prospect for nitrogen-rich coconut shell activated carbon for CH3SH removal because of its high capacity, mild conditions, and easy regeneration.