Highly efficient removal of methyl iodide gas by recyclable Cu⁰-based mesoporous silica

Developing recyclable adsorbents for co-capture of I₂ and CH₃I gas is a meaningful and challenging topic. Herein, Cu⁰-based mesoporous silica (C-S) materials were synthesized and applied for CH₃I capture for the first time. Factors (Cu⁰ content, temperature, contact time and CH₃I concentration) affecting the adsorption behavior were investigated. The results demonstrated that the CH₃I adsorption capacity of the obtained C-S materials reached up to 1060 mg/g at 200 ℃. Furthermore, the C-S material exhibited excellent reusability (91.3 %, 5 cycles). It was found that Cu⁰ could cleave the carbon iodine bonds, causing CH₃I to dissociate into •CH₃ and I^-. Then the Cu⁺ converted from Cu⁰ reacted with I^- to achieve the purpose of CH₃I capture. The adsorption mechanism of CH₃I on the C-S materials could be concluded that Cu⁰ reacted with CH₃I form CuI (Cu + CH₃I → CuI + •CH₃). This work suggested that the obtained C-S materials could be promising adsorbents for CH₃I capture.