Synthesis of mesoporous silica from bottom ash and its application for CO2 sorption

A supernatant solution of silicate species extracted from bottom ash in a power plant was used to prepare a mesoporous silica by the synthesis protocol of SBA-15. XRD, N-2 adsorption-desorption, and TEM confirmed a disordered mesopore structure. The pore volume and average pore size of the product were significantly larger than SBA-15 prepared using pure chemicals, and complementary textural mesoporosity was detected. When the mesoporous silica was tested for carbon dioxide sorption after polyethyleneimine (PEI) impregnation, substantially higher CO2 sorption capacity (169 mg CO2/g-sorbent) was achieved than that of PEI-impregnated pure SBA-15 under the same test conditions. High CO2 sorption capacity was maintained when the gas composition was changed to 15% CO2, and the hybrid material exhibited satisfactory performances during the 10 recycle runs.