Monoethanolamine Impregnation of Titanosilicate Zeolite ETS-10

Abstract

ETS-10, a mixed octahedral/tetrahedral titanosilicate molecular sieve, has a unique architecture where its 0.8 nm pores are lined exclusively with silicon which imparts a high degree of chemical stability, yet the anionic framework can be modified by cation exchange. In this work, the hydrogen-exchanged form of ETS-10 was impregnated with monoethanolamine and the thermal stability and CO2 adsorption characteristics were analyzed. The surface area of the material was characterized by N2 physisorption, the thermal stability of the material assessed through TG-MS experiments, the CO2 capacity was measured via static volumetric adsorption experiments, and the influence of moisture as a carbamate promoter was investigated through a series of gravimetric CO2 adsorption/desorption cycling experiments. Several measurements converge on ~7 wt% monoethanolamine loading which occupies about half of the available pore volume of the sieve. The results suggest that the monoethanolamine is so effectively retained by the molecular sieve that, while the amine is effectively immobilized, under both humid and dry process streams the monoethanolamine is either chemically or sterically hindered and is unable to react measurable quantities of CO2.

Carbon dioxide capture with zeotype materials

“…146 Although amine modification of zeolites enhances their CO 2 adsorption strength, it often reduces the CO 2 capacity due to partial pore blockage and amine loss, as demonstrated in many literature. 95,132,133,137,138,140,142,[147][148][149][150][151][152] To overcome the reduction of capacity with the amine-modified zeolites, several alternative approaches (Fig. 9) were developed to solve these difficulties and allow for amine modification of zeolites with smaller pore sizes.…”