Recovery of graphite from anode in spent lithium-ion battery as an efficient peroxymonosulfate (PMS) activator: Performance and mechanism

The recovery of anode graphite as catalysts is rarely reported in the published works. In this study, a simple method was used to recover anode graphite from spent lithium-ion battery (LIB) as catalyst to activate peroxymonosulfate (PMS) for the degradation of carbamazepine (CBZ). Graphite catalyst exhibited excellent catalytic performance with the mineralization efficiency of CBZ of 81% in the graphite/PMS system. This system was highly effective in a wide pH range of 3.0–11.0. Inorganic ions (Cl - , HCO 3 - , K + , etc) and natural organic matter (HA) exhibited some influences on the degradation of CBZ. The electron-donating groups of C O and C-OH were identified in the recovered graphite, which transferred electrons to activate PMS generating sulfate radical (SO 4 - •), hydroxyl radical (HO•), and singlet oxygen ( 1 O 2 ). Under the attack of multiple reactive species, five intermediates were detected in the degradation of CBZ and disappeared quickly after 1 min. Particularly, the graphite/PMS system was effective for CBZ degradation in real water matrix, showing a higher degradation efficiency of 93% in tap water (TW). This study provides a green and efficient approach for recovering graphite catalyst from spent LIB as PMS catalyst to degrade organic pollutants in wastewater.