Reversible Absorption of CO₂ Triggered by Phase Transition of Amine-Containing Micro- and Nanogel Particles

Abstract

Herein we report that an aqueous solution of temperature-responsive micro- and nanogel particles (GPs) consisting of N-isopropylacrylamide (NIPAm) and N-[3-(dimethylamino)propyl]methacrylamide (DMAPM) reversibly absorbs and desorbs CO(2) via a phase transition induced by cooling and heating cycles (30-75 °C). Below the phase-transition temperature, most of the amines in the swollen GPs are capable of forming ion pairs with absorbed bicarbonate ions. However, above the phase-transition temperature, shrinkage of the GPs lowers the pK(a) and the number of amine groups exposed to water, thereby resulting in almost complete desorption of CO(2). The GPs can reversibly absorb more than the DMAPM monomer and polymer without NIPAm, which indicates the importance of the temperature-responsive phase transition of polymers in determining the degree of absorption. The results show the potential of temperature-responsive polymer solutions as absorbents to sequester CO(2) at a low energy cost.

Synthesis and characterization of ammonia-responsive polymer microgels

“…25,41,42 The deteriorative polymer-solvent affinity favors the gel shrinking. [6][7][8][9][10][11][12][13][14][15][16] Since the reaction is reversible, the microgels should be able to return to the initial status if ammonia is removed. Indeed, recycling experiments of adding/removing ammonia revealed the robustness of the ARM microgels.…”

“…[6][7][8][9] Considering the importance of a chemical system to distinguish between molecules and regulate behaviors accordingly, the development of microgels that is responsive to the changes of a molecule concentration in the milieu is currently a major area of interest. [10][11][12][13][14][15][16] In this work, we aim to develop a type of polymer microgels that can respond to changes in the concentration of ammonia (Fig. 1), a simple compound but with high toxicity for human being and wildlife produced in fertilizer and chemical factories.…”

Preparation and characterization of CO2-responsive poly(amino acid) derivatives with guanidine group

“…Recently, several reports have been published on the CO 2 -responsive hydrogel and particle [20][21][22]. Since the influence of gas on polymer assemblies has rarely been investigated, considering the construction of a CO 2 -responsive polymer system is quite a challenge.…”

Versatile particles from water-soluble chitosan and sodium alginate for loading toxic or bioactive substance

“…Adsorption is usually adopted to deal with these problems due to its effectiveness and economy [1][2][3][4][5]. Therefore, the development of adsorbent becomes primary and attractive [6,7].…”