Action mechanism of iron on the carbon dioxide emission reduction and methyl methacrylate generation during anhydrous cleaning process for waste glass recovery.

Abstract

Reducing CO₂ and pollutant emissions is a global priority. Waste glass recycling is more effective in achieving this goal compared to producing new glass. A crucial step in waste glass recycling is removing adhesive impurities from the glass surface. Hydraulic cleaning generates organic wastewater, leading to its gradual replacement in China by anhydrous cleaning, a novel technology that avoids wastewater generation. However, CO₂ and pollutant methyl methacrylate are still produced during anhydrous cleaning, and their formation mechanisms were previously unclear. This study explores these mechanisms and finds that the existence of glass interface increases the length of C≡N bond of binder by 0.239 Å, which promotes the bond's fracture and the formation of methyl methacrylate in exhaust gas. Iron in waste glass increases the length of C = O bond by 0.263 Å, facilitating the bond's fracture and reducing the proportions of methyl methacrylate and CO₂ by 7.31 % and 18.01 %, respectively. Therefore, it is recommended to modify the existing recycling process of waste glass by arranging iron removal after anhydrous cleaning to reduce CO₂ and methyl methacrylate production. This paper is the first time to report the mechanisms and approaches for reducing CO₂ emission and controlling gaseous pollutant in waste glass recycling.