PEI@Mg2SiO4: an efficient carbon dioxide and nitrophenol compounds adsorbing material

Abstract

The PEI@Mg₂SiO₄ hybrid composite is readily synthesized for adsorbing carbon dioxide (CO₂) and nitrophenol compounds (NACs), in which more than 11% PEI is embedded. By the removal rate of 4-nitrophenol (10 mg L⁻¹) and the capture capacity of CO₂, the Mg²⁺ : PEI : SiO₃²⁻ optimal mole ratio of the PEI@Mg₂SiO₄ is 1 : 0.6 : 1.5. The composite shows the highest adsorption amounts of 0.94 mmol g⁻¹ CO₂ at 50 °C. The heat treatment regeneration exhibits a good stability, e.g. the CO₂ capture capacity decreases by only 20% after four cycles, and the desorption rate of CO₂ remains more than 91%. It also exhibites a fast adsorption and high capacity for 4-nitrophenol (NP), 2,4-dinitrophenol (DNP) and 2,4,6-trinitrophenyl group (TNP). The adsorption capacity of NP, DNP and TNP is 2.40 mmol g⁻¹, 2.66 mmol g⁻¹ and 4.85 mmol g⁻¹ respectively, which is more than that of the conventional sorbents. This work presents the higher capacity and eco–friendly sorbent for CO₂ and nitrophenol compounds.