In situ synthesis of AgI on the nanosilica surface for potential application as a cloud seeding material

An economical, environmentally friendly, one-step method for applying a water-insoluble silver iodide salt to nanosilica was developed, resulting in formation of composites with nanocrystals (6–45 nm) on the surface. These nanocomposites have demonstrated advanced ice-forming capabilities, even with smaller AgI quantities, comparable to the existing agents.

Abstract

A series of nanosilica/AgI composites was synthesized by in situ reactions between silver nitrate and ammonium iodide deposited on the nanosilica surface using the gas-phase solvate-stimulated mechanosorption modification (GSSMSM) under both dry and wet conditions. The characterization of the synthesized materials was performed by X-ray diffraction (XRD), SEM/EDX (Scanning Electron Microscopy-Energy Dispersive X-ray), thermogravimetric (TGA) and gas sorption methods. As a result of the mechanosorption modification of nanosilica, the bulk density of the samples synthesized in the dry and wet medium increases from 45 g/l for initial nanosilica to 249 g/l and 296 g/l for the modified samples, respectively. The specific surface area of the composites decreased in compared to the nanosilica precursor. The SEM data showed a denser aggregate structure of the nanocomposites compared to the initial nanosilica. The XRD, SEM/EDX and TEM/EDX data indicated the formation of AgI clusters. The AgI particle size was in the range of 6–45 nm. The ice-forming activity of the AgI-containing samples was examined as well. The sample with a smaller size of silver iodide on the surface exhibited superior ice-forming properties, and considering the quantity of utilized AgI, the prepared samples hold promise for application in this field.

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