Mechanism of Hydrogen Peroxide Formation on Sprayed Water Microdroplets

How is H2O2 formed in sprayedwater is notwell understood. It is believed to involve the association of HO center dot radicals spontaneously generated from HO- ions by internal electric fields on the surface of neutral microdroplets.Spraying water actually creates charged microdroplets carrying eitherexcess OH- or H+ intrinsic ions thatrepel each other toward the very surface. The requisite electron transfer(ET) takes place between surface-bound ions: HOS (-) + H-S (+) = HOS (center dot) +H-S (center dot), during encounters between positiveand negative microdroplets. The ET endothermicity in bulk water (Delta H = 448 kJ mol(-1)) is reversed in low-densitysurface water by the destabilization of the strongly hydrated reactantions: Delta H (hydration)(H+ +OH-) = -1670 kJ mol(-1),relative to neutral radical products: Delta H (hydration)(HO center dot + H-center dot) = -58kJ mol(-1). The formation of H2O2 is driven by the energy supplied for spraying water, and causedby restricted hydration on microdroplet surfaces.

Automated summary

The formation of H2O2 in sprayed water is not well understood. It is believed to involve the association of HO center dot radicals generated from HO- ions by electric fields on microdroplet surfaces. Charged microdroplets with excess OH- or H+ ions are created during spraying, and electron transfer occurs between these surface-bound ions to form H2O2. The energy supplied for spraying water and restricted hydration on microdroplet surfaces drive the formation of H2O2.