Key role of Phyllanthus emblica L. fruit extract promotes ZVI/H2O2 process: rich titratable acid, suitable chelating ability, and antioxidant capacity.

Phyllanthus emblica L. fruit extract (PFE) was introduced to improve ZVI/H₂O₂ technology, and the efficiency and mechanism of PFE promoting ZVI/H₂O₂ technology were explored. With the introduction of PFE, the Norfloxacin (NOR) removal rate and k_obs of the process were improved by 41.17% and 5.08 times, respectively. In the ZVI/H₂O₂/PFE process, the degradation of NOR by the attack of ROS is the main pathway for decontamination and is dominated by the heterogeneous reaction on the catalyst surface. PFE contains 13.92 g/L titratable acid and has good complexing ability and antioxidant ability. The mechanism of PFE promoting ZVI/H₂O₂ technology was based on lowering the pH, complemented by chelation and antioxidant capacity. With the introduction of PFE, the utilization rate of the reagent was significantly increased (7.56 times for ZVI and 3.21 times for H₂O₂), the applicable pH range was widened (6–9) and the iron sludge was reduced (32.80%). Meanwhile, the concept of UPR is proposed for the first time. The result is the key role to the selection of green promoters in the ZVI/H₂O₂ process depends on the abundance of titratable acid, followed by a certain chelating ability and antioxidant capacity. [ABSTRACT FROM AUTHOR]