Mesoporous carbon spheres loading with ionic liquids for adsorption of low-concentration SO2

• The mesoporous carbon beads (MCBs) in millimeter size were prepared by a suspension polymerization combined with a hard template, and loaded with two kind of ionic liquids, which exhibited extremely high SO 2 adsorption capacity, especially in the case of [Emim][OAc]. • The MCBs loaded with ionic liquids exhibit high adsorption efficiency for low-concentration SO 2 and extremely low air resistance. • MCBs loaded with ionic liquids demonstrate the feasibility of effective removal of SO 2 at low concentrations for ultra-clean rooms, which will be a new absorption material in the field of air-cleaning. Biomass-activated carbon is generally used in ultra-clean rooms to remove sulfur dioxide (SO 2 ) molecular impurities. However, its high air resistance and excessive chemical residues needs resolution. In this study, we have developed millimeter-sized mesoporous carbon beads (MCBs) using a silica sol and reverse-phase suspension polymerization. The microstructure of MCBs was characterized by various techniques, including X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The MCBs were categorized into three distinct groups based on particle size and were loaded with tetramethyl guanidine lactate (TMGL) or 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), respectively. It was found that the MCBs exhibit a perfect spherical shape, smooth surface, high strength, and effectively reduce air resistance. Notably, the MCBs loaded with [EMIM][OAc] demonstrated a remarkable SO 2 adsorption capacity of up to 36.7 mg/ml, and the feasibility to remove SO 2 as a new absorption material for ultra-clean room.