Enhanced abatement of organic contaminants by zero-valent copper and sulfite

Sulfate radicals (SO 4 ·− ) are highly efficient for the degradation organic pollutants. SO 4 ·− can be produced by activation of sulfites, yet actual heterogeneous activators exhibit a lower reactivity for activation of sulfite to SO 4 ·− at pH 7.0–8.0. Here we hypothesized that zero-valent copper can activate sulfite under mild conditions. We tested the reaction with iohexol, diatrizoate, atrazine, benzoic acid, and p -chlorobenzoic acid contaminants. Reactive radicals were identified by electron paramagnetic resonance, fluorescence spectrometry, and radical scavenging experiments. Results show up to 90% abatement of contaminants by combining sulfite with zero-valent copper at pH 8.0. Moreover, zero-valent copper maintains a crystalline stability and satisfactory reusability with iohexol abatement efficiency up to 80% after five runs.