Search arXivSearch

arXiv · 2311.11133

Busting the Myth of Spontaneous Formation of H2O2 at the Air-Water Interface: Contributions of the Liquid-Solid Interface and Dissolved Oxygen Exposed

Abstract

Recent reports on the spontaneous formation of H2O2(aq) at the air-water interface and the solid-water interface have been sensational. The speculated mechanism at the air-water interface is based on instantaneous ultrahigh electric fields and the micro-scale of droplets, whereas the solid-water interface is speculated to be the site for oxidation of water (or hydroxide ions) and reduction of the solid surface. We utilized 1H-NMR spectroscopy to investigate the effects of the nebulizing gas, the dissolved oxygen content, and solid substrates on the H2O2(aq) formation (detection limit 50 nM). Experiments revealed that contrary to the sensational claims, the air-water interface is not the site for H2O2(aq) formation; instead, it is the solid-water interface where H2O2(aq) is formed during the reduction of dissolved oxygen and oxidation of the solid surface. Curiously, the tendencies of solid substrates towards forming H2O2(aq) follow the classic Galvanic series. This report advances the current understanding of aquatic chemistry and should be relevant to corrosion science, surface science, and electrochemistry.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Muzzamil Ahmad Eatoo, Himanshu Mishra. 2023-11-18. Busting the Myth of Spontaneous Formation of H2O2 at the Air-Water Interface: Contributions of the Liquid-Solid Interface and Dissolved Oxygen Exposed. https://arxiv.org/abs/2311.11133

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Deformation and organization of droplet-encapsulated soft beads

Many biological, culinary, and engineering processes lead to the co-encapsulation of several soft particles within a liquid interface. In these situations the particles are bound together by the capillary forces that deform them and influence their biological or rheological properties. Here, we introduce an experimental approach to encapsulate a controlled number of soft beads within aqueous droplets in oil. These droplet-encapsulated gels are manipulated in a deformable microfluidic device to merge them and modify the liquid fraction. In the dry limit the contact surface between the hydrogels is found to be determined by the elastocapillary number $E_c$, with the contact radius following a $E_c^{1/3}$ dependence, indicating that the deformation increases for soft or small particles. When multiple beads are co-encapsulated within a single droplet they can be arranged into linear or three-dimensional aggregates that remain at a local energy minimum.

cond-mat.soft

Flexoelectricity-driven softening of bend elasticity leads to spontaneous chiral symmetry breaking in a polar fluid

The origin of the recently observed spontaneous chiral symmetry breaking in polar fluids composed of achiral molecules is an unsolved problem, raising fundamental questions about how heliconical structures emerge in such systems. Here, we investigate the pretransitional fluctuations leading to the formation of the spontaneously chiral twist-bend ferroelectric nematic phase using dielectric spectroscopy, light scattering, and small-angle X-ray scattering. We observe simultaneous softening of the bend elastic constant and the emergence of a collective dielectric mode on approaching the transition. By developing a theoretical model, we show that these phenomena are signatures of a flexoelectricity-driven transition arising from the coupling between electric polarization and bend deformation.

cond-mat.soft

Taylor dispersion in a soft tube

Diffusion of a solute along a tube is enhanced by hydrodynamic flow, a phenomenon known as Taylor dispersion. In microfluidic applications, the compliance of the tube boundaries modifies the hydrodynamic flow and thus solutal transport. Here, we develop the theory of solutal dispersion in a soft, axisymmetric tube where the tube walls respond to the hydrodynamic pressure through a Winkler response. By deriving the modified macro-transport equation for the solutal concentration dynamics based on multiple-time-scale analysis, we explore the influence of softness on solutal transport for steady and pulsatile configurations. Our main finding is that softness enhances the effective advection velocity and dispersion coefficient, which might have practical implication in biology and microfluidic technology.

cond-mat.soft