One-step synthesis of ZIF-8 and anchoring it on SCB for rapid and high-capacity capture of mercury from aqueous solution

Developing a special kind of material for rapid and efficient capture of Hg(II) in an emergency pollution event or industrial wastewater has always been a headachy task. Herein, porous ZIF-8 with a high surface area was prepared via a facile method for the ultra-fast removal of Hg(II) from diverse water bodies, and anchoring it on SCB could address its separation problem. The ZIF-8 was wider pH adaptable (2-8), of which the conspicuous adsorption performance was insensitive to ionic strength (Cl - , SO 4 2- , NO 3 - ) even at an extremely high level (25000 mg/L, R e >95.40%). ZIF-8 can efficaciously enrich a large amount of Hg(II) in a short period (1 min, 519.6 mg). The theoretical maximum adsorption capacity of ZIF-8 estimated from the Langmuir isotherm was 2195.10 mg/g, which was endowed by that the Hg(II) with higher ionization energy was capable of replacing the Zn(II) to form more stable metal-ligand complexes with dimethylimidazole. Meanwhile, ZIF-8 can also achieve excellent affinity to Hg(II) in binary and multi-metal mixed solutions, and it can maintain high performance (86.25%) after 5 cycles, the leaking Zn(II) in the treated water could be utilized as the raw material to synthesize ZIF-8. Noteworthy, the as-preparing ZIF-8 can efficiently capture Hg(II) in complex environments such as natural water and artificial industrial wastewater in a short time (t<60 min, R e >99.63%). Therefore, the as-prepared material possesses outstanding adsorption performance and could be a promising candidate in the broad practical applications for ultra-fast and high-capacity capture of high mercury level. • A facile and easy-to-operate method to synthesize ZIF-8 was proposed. • Anchoring ZIF-8 onto SCB to achieve rapid separation. • The adsorption performance was broad pH and ionic strength adaptable. • The theoretical adsorption capacity of ZIF-8 was evaluated to be 2195.10 mg/g. • ZIF-8 achieved ultra-fast capture of mercury in artificial wastewater.