(22g) Development of Poly(amidoamine) (PAMAM) Dendrimer Composite Membrane Module for CO2 Separation

Carbon dioxide Capture and Storage (CCS) has been widely accepted as a promising way of mitigating global warming. The first step of CCS is capturing CO₂ from a large stationary CO₂ source such as a power station, where capturing CO₂ accounts for more than 70 % of the total CCS cost. The cost reduction of CO₂ capture is critically important for spreading CCS technology. CO₂ membrane separation is a powerful candidate technology for reducing CO₂ capture costs. Poly(amidoamine) (PAMAM) dendrimer was reported to have excellent CO₂/N₂ selectivity as an immobilized liquid membrane for the isobaric test condition of atmospheric pressure [Kovvali and Sirkar, Ind. Eng. Chem. Res. 40 (2001) 2502]. However, this immobilized liquid membrane had insufficient pressure tolerance for practical use. In previous papers [Kouketsu, Duan, Kai, Kazama and Yamada, J. Memr. Sc. 287 (2007) 51; Kazama, Kai, Kouketsu, Matsui, Yamada, Hoffman and Pennline, Session 30, Proceedings of Pittsburgh Coal Conference, Pittsburgh, USA (2006)], we have prepared stable PAMAM dendrimer composite membranes using chitosan (CTS) as a gutter layer by the In-situ Modification (IM) method. The PAMAM dendrimer composite membrane had high CO₂/N₂ selectivity and can afford a practical tolerance of the pressure difference of 100 kPa. CO₂ permeance of the PAMAM dendrimer composite membrane was reasonably high. However, further improvement for CO₂ permeance was still required. In this presentation, we investigated the effect of the addition of hyaluronic acid (HA) to the CTS gutter layer to improve the CO₂ performance of the composite membrane. The influences of HA addition on the swelling degree in water, the content of PAMAM dendrimer in the gutter layer, and CO₂ separation performance of the composite membrane are discussed. In addition, a novel hydroxyl PAMAM dendrimer was applied to improve the composite membrane performance. The HA addition increased the PAMAM dendrimer content in the gutter layer. A composite membrane prepared with a novel hydroxyl PAMAM dendrimer in the CTS-HA gutter layer exhibited an excellent CO₂/N₂ selectivity of 1,100 and CO₂ permeance of 8.8 x 10^-10 m³ (STP) m^-2 s^-1 Pa^-1.