Tandem Efficient Bromine Removal and Silver Recovery by Resorcinol-Formaldehyde Resin Nanoparticles

Halogen wastewater greatly threatens the health of human beings and aquatic organisms due to its severe toxicity, corrosiveness, and volatility. Efficient bromine removal is therefore urgently required, while existing Br₂-capture materials often face challenges from limited water stability and possible halogen leaking. We report a facile and efficient aqueous Br₂ removal method using submicron resorcinol-formaldehyde (RF) resin nanoparticles (NPs). The abundant aromatic groups dominate the Br₂ removal by substitution reactions. An excellent Br₂ conversion capacity of 7441 mg g_RF^-1 was achieved by RF NPs that outperform state-of-the-art materials by ∼2-fold, along with advantages including good water stability, low cost, and easy fabrication. Two recycling-coupled (electrochemical or H₂O₂-involved) Br₂ removal routes further reveal the feasibility of in-depth halogen removal by RF NPs. The brominated resin can be downstream upcycled for silver recovery, realizing the harvesting of precious metal, reducing of heavy-metal pollution, and resource utilization of brominated resin.