Optimization of mesoporous silica through nano-casting to capture nitrosamines in environment

A new preparative route of Al-containing mesoporous silica is reported in this paper in order to elevate the capability of mesoporous materials in adsorbing small pollutant molecules such as volatile nitrosamines. A mass of aluminum salt additive was used in the synthesis of mesoporous silica for the purposes of both the insertion of Al into the framework and coating on the channel wall via evaporation. After washing products with an acidic solution, most of the aluminum species were removed to create many tiny flaws and artificial defects in the pore wall, whilst some aluminum species, forming acidic sites, survived in the resulting samples. Both the acidic sites and the hierarchical structure can be formed in the mesoporous silica through this nano-casting process, and the resulting samples exhibit a high performance in the adsorption of volatile nitrosamine N-nitrosopyrrolidine (NPYR).