Green Synthesis of Nano-Zero Valence Iron with Green Tea and It's Implication in Lead Removal

The nano-zero valence iron (nZVI) via green synthesis for heavy metal remediation has attracted many attentions due to its low-cost, environmental-safety, relative reproductivity, and high stability. However, influence of synthesis conditions on the physiochemical properties of nZVI via green tea extracts and the responding suspensibility, which is required for high reactivity, has not been fully elucidated. In this study, we investigated the zeta potentials, sedimentation and lead (Pb²⁺) removal capacity of various nZVIs synthesized using green tea extracts. The results showed that the tea extracts extracted at 80^oC presented an excellent activity, which contributed to the outstanding suspensibility and reaction activity of nZVI synthesized in a volume ratio of 1:1 (tea extraction versus Fe²⁺ solution). Thus, the optimized nZVI was successfully prepared with a Pb²⁺ removal capacity (377.3 mg/g), which was seven times stronger than 50.31 mg/g of traditional chemical synthesized nZVI.