Synthesis of Colloidal Suspension Based on Porous Silica Nanospheres and Its CO2 Absorption

Abstract

It is urgent to reduce CO2 emissions for minimizing the consequences of the greenhouse effect and carbon capture material is one of the key factors for CO2 capture technology. In this work, colloidal suspension were prepared as sorbents by dispersing porous silica nanospheres modified by polyethylenimine (PEI-PSNs) in dimethyaminoethoxyethanol (DMEE). Porous silica nanospheres (PSNs) synthesized via an emulsion method had high surface area (874.58 m2/g) and uniform morphology. The absorption of CO2 was studied over a wide range of CO2 pressure (0-200 kPa), temperature (25-55 °C) and PEI-PSNs concentration (0-50 wt%). Compared to DMEE and PSNs/DMEE, PEI-PSNs/DMEE have much more CO2 absorption capacity, resulting from that DMEE could improve reaction of amino and CO2. It was also found that the absorption amount increased firstly and then decreased with PEI-PSNs concentration increasing and the maximum absorption capacity was 1.056 mmol/g at 30 wt% PEI-PSMs at 25 °C and 150 kPa. The regeneration efficiencies of the solutions at 80 °C were higher than 92 % in 5 absorption-desorption circles. The novel sorbents showed an advantage of a higher regeneration efficiency at relatively lower temperature and had great energy-saving potential.