Pollution analysis of micro/nano meters glass particles and benzene produced from the friction cleaning process for the recovery of waste glass.

Abstract

Friction cleaning can effectively remove the paint coating (adhesive organic impurities) on the surface of waste glass, and promote the closed-loop recovery of urban silicic acid resources in industrial applications. However, due to a large number of mechanical collisions and wear during use, it is easy to produce powder dust and organic waste gas, and the pollution characteristics and mechanism have not been studied. In this study, the ball milling experiment was designed and the pollutants were tested and evaluated. The results show that a large number of micro/nano meters glass particles with an average size of less than 4.5 μm are generated by low-speed ball milling, and the risk of inhalation is as high as 50.75 mg/kg·m³. Main organic waste gases include cyclopropane, hexane, but-2-ene, and benzene with the value of Incremental lifetime cancer risk reaching 3.4 × 10^-2 indicating definite carcinogenic risks for benzene exposure. The C-C bond between hydroxyl acrylic acid molecules and the C-O bond between phenolic propylene oxide molecules are easily broken to form small molecular chains, and the complex product is due to the complex cross-linking with the silane coupling agent. It is suggested that a special dust collector for micro/nano meters glass particles should be added while adopting an activated carbon catalytic combustion process to treat VOCs in the exhaust gas. This study revealed the contamination of micro/nano meters glass particles and benzene during friction cleaning to remove organic coatings in waste glass recycling.