Superior selectivity for efficiently reductive degradation of hydrophobic organic pollutants in strongly competitive systems

Highly toxic halo-/nitro-substituted organics, often in low concentrations and with high hydrophobicity, make it difficult to obtain electrons for reduction when strongly electron-competing substances (e.g., O₂, H⁺/H₂O, NO₃^-) coexist. To address this barrier, we devised a new strategy to modify microscale zero-valent aluminum (mZVAl) with graphene (GE) by one-pot ball-milling for GE@mZVAl, which exhibits 99 % selective removal of halo-/nitro-substituted organic pollutants (e.g., carbon tetrachloride (CT), trichloroethylene (TCE), p-nitrophenol (PNP) and p-nitrochlorobenzene (p-NCB)) in the presence of multiple competing inorganics (O₂, H⁺/H₂O, Cr(VI), NO₃^- and BrO₃^-) and interfering ions (Cl^-, CO₃^2-, SO₄^2- and PO₄^3-). Notably, due to the fact that the side-reaction of H₂ evolution and second-passivation are significantly suppressed, the electron utilization efficiency for organics degradation reaches an impressive 96 %, even under harsh pH conditions (3−11). GE@mZVAl contains an Al-C interface with a high concentration of C-O, which can form active sites for organics and perform selective electron transfer. Meanwhile, the organophilic catalyst GE also hinders the exposure of AlOH⁺/Al⁰ sites to shield the competing and interfering of inorganic substances. As a highly selective reduction system, this work may yield innovative insights for the selective removal of hydrophobic refractory pollutants in complex water matrices.