Oxidation-stable amine-containing adsorbents for carbon dioxide capture

Abstract

Amine-containing solids have been investigated as promising adsorbents for CO2 capture, but the low oxidative stability of amines has been the biggest hurdle for their practical applications. Here, we developed an extra-stable adsorbent by combining two strategies. First, poly(ethyleneimine) (PEI) was functionalized with 1,2-epoxybutane, which generates tethered 2-hydroxybutyl groups. Second, chelators were pre-supported onto a silica support to poison p.p.m.-level metal impurities (Fe and Cu) that catalyse amine oxidation. The combination of these strategies led to remarkable synergy, and the resultant adsorbent showed a minor loss of CO2 working capacity (8.5%) even after 30 days aging in O2-containing flue gas at 110 °C. This corresponds to a ~50 times slower deactivation rate than a conventional PEI/silica, which shows a complete loss of CO2 uptake capacity after the same treatment. The unprecedentedly high oxidative stability may represent an important breakthrough for the commercial implementation of these adsorbents.

Oxidation‐Resistant, Cost‐Effective Epoxide‐Modified Polyamine Adsorbents for CO2 Capture from Various Sources Including Air

“…The heat of adsorption was also lowered by the addition of the epoxide . A following paper by the same group also showed the good stability of these adsorbents under oxidative conditions . In parallel, Lee and co‐workers also studied the same adsorbent materials based on BPEI and BO on silica .…”

“…This is a good indication that the addition of PO increases the stability of the adsorbent under oxidative conditions. Choi and co‐workers observed a similar improvement in stability when BPEI with a molecular weight of 1200 was modified with BO …”

Oxidatively‐Stable Linear Poly(propylenimine)‐Containing Adsorbents for CO2 Capture from Ultradilute Streams

“…functionalized branched PEI with 1,2‐epoxybutane, which incorporates hydrogen bonding groups directly onto the aminopolymer, to simultaneously suppress urea formation and oxidative degradation of amines by reducing the fraction of primary amines . The same group extended their work to incorporate metal chelating groups on the silica support to help remove ppm levels of residual oxidation‐catalyzing metal ions that remain from the polymer synthesis …”

Piperazine‐modified activated alumina as a novel promising candidate for CO2 capture: experimental and modeling

“…Carbon dioxide adsorption using amine modified adsorbents involves a chemical reaction that occurs between amino groups and CO 2 . 41,42 Although piperazine is not an alkanolamine, its reaction with CO 2 can be explained according to the zwitterion mechanism. 43,44 This mechanism includes the reaction of CO 2 with piperazine to form an ionic middle compound of zwitterion (PZH + COO − ).…”