Wood sawdust from an invasive arboreal species, Parkinsonia aculeata, and seeds from a tropical fruit of massive consumption, Pouteria sapota, were used as precursors for the development of activated carbons (ACs) directed to CO2 adsorption. Chemical activation employing KOH as activating agent and pre-established experimental conditions was applied. Main physicochemical properties of the ACs in relation to their CO2 adsorption performance were examined. The ACs developed from the wood sawdust and the seeds presented specific surfaces areas of 770 and 1000 m2 g−1, respectively, with their porosity development resulting essentially microporous (< 2 nm). They also showed a similar content of acidic surface groups, but basic functionalities of the former duplicated those of the latter. Maximum CO2 adsorbed at equilibrium (273 K and 100 kPa) was 5.0 mmol g−1 and 4.4 mmol g−1 for the samples derived from the sawdust and the seeds, respectively. On the other hand, CO2 adsorption capacities mimicking post-combustion conditions, as evaluated from thermogravimetric assays and breakthrough curves obtained in a packed-bed column, were approximately 1 mmol g−1, indicating a good CO2 adsorption performance for both ACs. Nevertheless, those derived from the wood sawdust with a notorious preeminence of micropores (~ 93%), narrower pore size distribution centered around 1 nm, and a higher content of basic functionalities than the ACs obtained from the seeds showed a relatively better performance. The CO2 removal capacity of the activated carbons was not noticeably affected after five CO2 adsorption–desorption cycles, with both samples almost keeping their initial CO2 adsorption capacity.

본 논문에서는 이산화탄소 친화적인 PBEM-POEM (PBE) 공중합체를 기반으로 고분자 블렌드 분리막을 제조하 는 방법을 제시한다. PBE 공중합체는 자유 라디칼 중합 반응을 통해 손쉽게 합성이 가능하며, 이를 상용 고분자인 PEG와 다 양한 비율로 혼합하여 이산화탄소/질소 분리막을 제조하였다. 이산화탄소/질소 분리 성능을 테스트한 결과, PEG의 함량이 높을수록 이산화탄소 투과도는 감소하는 반면 이산화탄소/질소 선택도는 크게 증가하는 상충(trade-off) 관계가 나타났다. 그러 나 PBE/PEG (9 : 1)과 PBE/PEG (7 : 3)을 비교하면 이산화탄소 투과도는 단지 8.3% 감소한 반면에 질소 투과도는 69.1%나 감소하였다. 따라서 이산화탄소/질소 선택도가 33.8에서 100.3으로 크게 증가하였다. 이것은 PBE 공중합체의 80%를 차지하 는 POEM 사슬이 PEG와 상호작용하여 더욱 조밀한 구조가 되었기 때문이며, 이를 FT-IR, XRD, SEM 분석으로 확인하였다. PBE/PEG (7 : 3) 블렌드 막이 가장 최적의 기체 분리 성능을 가졌고, 이산화탄소투과도는 170.5 GPU, 이산화탄소/질소 선택 도는 100.3이었다.

The growing demand for nano-structured composite materials and sustainable processes for next generation CO2 capture technologies has necessitated the need to develop novel and cost-effective synthetic routes for solid CO2 adsorbents based on hypercross-linked polymers (HCPs) and reduced graphene oxide (RGO) microporous sorbent materials with improved physico-chemical properties. The most important selection is modification of the synthesized microporous sorbent materials by the incorporation of RGO, giving rise to composite materials that combine the properties of both. These hybrid materials will be of great potential for carbon capture and storage (CCS) applications, especially for post-combustion CO2 capture, owing to the increase in CO2 capturing efficiency and selectivity to CO2 compared to other flue gases. Herein, we report a facile and effective approach for fabrication of HCPs-supported reduced graphene oxide composites. The microporous HCPs was synthesized using 4,4′-bis(chloromethyl)-1,1′-biphenyl monomer by Friedel–Crafts alkylation. The RGO was prepared by modified Hammers method. The as-synthesized composites were characterized by TEM, SEM, FTIR, TGA and N2 adsorption–desorption isotherm. The HCP/RGO composite showed maximum CO2 adsorption of 5.1 wt% than the HCPs alone at 40 °C and 1 atm.

CO2 separation technology for carbon capture, which is one of the hot issues to reduce greenhouse gases from industrial flue gas, has been intensively investigated so far. Despite of several benefits, the membrane technology has some obstacles like large-scale module fabrication, membrane durability, need of pre-treatment or high pressure drive for its industrial application. Also, the power plant flue gas with normally 10~20% of CO2 content should be concentrated upto 99% for being compressed and liquefied to transportable CO2 by pipeline, indicating the need of high selective membrane process as well as high recovery. In this work, the possibility of membrane process for post-combustion treatment in terms of recent technology will be announced. The practically applicable process for CO2 capture also be suggested briefly.

The stereotype of flexible MOFs(Amino-MIL-53) and carbonized porous carbon prepared from renewable resources is successfully synthesized for CO2 reduction application. The textural properties of these microporous materials are investigated, and their CO2 storage capacity and separation performance are evaluated. Owing to the combined effects of CO2-Amino interaction and its flexibility, a CO2 uptake of 2.5 mmol g−1 is observed in Amino-MIL-53 at 20 bar 298 K. In contrast, CH4 uptake in Amino-MIL-53 is very low up to 20 bar, implying potential sorbent for CO2/CH4 separation. Carbonized samples contain a small quantity of metal residues(K, Ca, Mg, S), resulting in naturally doped porous carbon. Due to the trace metal, even higher CO2 uptake of 4.7 mmol g−1 is also observed at 20 bar 298 K. Furthermore, the CH4 storage capacity is 2.9 mmol g−1 at 298 K and 20 bar. To evaluate the CO2 separation performance, the selectivity based on ideal adsorption solution theory for CO2/CH4 binary mixtures on the presented porous materials is investigated.

본 연구에서는 이산화탄소 포집 및 물 재이용을 위한 통합 시스템으로서 정삼투 공정의 적용 가능성에 대한 평가를 수행하였다. 해당 통합 공정은 이산화탄소 배출 저감을 위해 화력발전소에 적용되고 있는 습식 이산화탄소 포집설비에 정삼투 기반 공정을 추가함으로써 이산화탄소 포집뿐만 아니라 물 재이용 및 냉각수 생산을 동시에 달성할 수 있다. CO2를 흡수한 5M의 모노에탄올아민(습식용매)을 유도용액으로 적용한 결과 40 LMH (FO mode) 및 85 LMH (PRO mode)라는 매우 높은 수투과도를 얻을 수 있었다.

지구온난화 문제 해결을 위하여 효율적인 CO2 포집 기술 개발이 활발히 이루어지고 있으며, 최근 분리막, 흡수 공정의 하이브리드 기술인 접촉막 공정이 주목받고 있다. 본 연구진은 2014년부터 열적, 화학적 안정성이 뛰어난 세라믹 소재의 중공사막을 적용한 접촉막 공정을 개발해오고 있다. 대규모 공정 실증을 위하여 세라믹 중공사막 기공 구조 제어 기술부터 소수성 코팅, 모듈 디자인 및 배치, 공정 구성 최적화 등을 연구하였다.

Membrane-based gas separation process is one of the next generations’ gas separation processes for carbon capture and storage (CCS). Membrane process has the advantages of i) low energy consumption without a phase change during the separation, ii) small footprint and easy scale-up of membrane modules, and iii) clean process without any emission of harmful byproducts. The hollow fiber membranes used in this study shows CO2 permeance over 900 GPU (1 GPU = 10-6 cm³/cm²⋅sec⋅cmHg). Using the hollow fiber membranes and modules, we established a moveable CO2 separation system including pretreatment of flue gas and 3-stages of membrane cascade. The system was installed at the several on-site flue gas sources, and the performance of pilot plant operation will be presented in the presentation.

아민 흡수제를 이용한 CO2 포집용 충전탑 기술의 문제점으로 제기되고 있는 범람, 거품, 과다한 재생 에너지 등을 해결하기 위하여 최근 접촉막 기술이 주목받고 있다. 연구자들 대부분은 고분자 분리막을 이용하여 접촉막 기술을 개발 하고 있으며, 장기 운전 시 팽윤 현상에 의한 성능저하 문제가 제기되고 있다. 세라믹은 고분자 소재에 비해 화학적, 열적안정성이 뛰어나기 때문에 아민 흡수 제에 대한 팽윤 현상을 방지할 수 있다. 본 연구에서는 세라믹 중공사 접촉막의 기공구조 제어 기술을 개발하고, CO2 포집 특성을 분석하였다.

The gas separation through membrane is considered as a promising solution for the stabilization of greenhouse gas level of atmosphere attributed from CO2. The separation process of membrane allows low energy requirement, low cost, and ease of operation. However, conventional polymeric membranes generally suffer from the trade-off between permeability and selectivity, which remains as one of the most important challenges for commercialization. Mixed matrix membranes (MMMs), consisting of a polymer matrix and porous nano-filler, are considered to be a promising solution to overcome the trade-offs in polymeric membranes. Herein the porous nano-structures were fabricated to enhance the permselectity of CO2 separation membranes. The MMM which were fabricated with prepared porous nano-filler showed permeability improvement without significant selectivity loss.

Membrane-based CO2 capture is an energy-saving way to separate CO2 from N2 in post-combustion. Chabazite (Si-CHA) zeolites with a pore size of 0.37 nm × 0.42 nm are expected to separate CO2 from larger N2 (0.364 nm) by recognizing minute size differences. The pore mouth size on the Si-CHA zeolites outer surface was reduced via the chemical vapor deposition (CVD) to increase the molecular sieving effect by disfavoring the penetration of N2. The CVD process was conducted on CHA membranes to improve their CO2/N2 separation performance. Compared to the intact CHA membranes, the CO2/N2 max separation factor for CVD-treated CHA membranes increased by ~2.5 fold under dry conditions and by ~6.4 fold under wet conditions. It is noteworthy that the membrane kept its separation performance without degradation in the presence of H2O.

본 연구에서는 높은 이산화탄소 분리성능을 가지는 폴리이미드 제조를 위해 3가지 모노머를 이용하여 합성하였다. 합성된 고분자를 비용매 상전이법으로 비대칭 분리막을 제조하기 위하여 고분자의 용해도 지수 추정 값과 비용매 상전이 계수 측정을 통해 용매를 선정하였고, 고분자 용액 점도 측정을 통해 분리막제조를 위한 도프용액 중의 고분자의 함량을 결정하여 질산리튬을 첨가제로 사용하여 최종적으로 분리막을 제조하였다. 제조된 비대칭 분리막은 전자주사현미경(SEM)을 통해 질산리튬과 휘발성 용매 함량에 변화에 따른 모폴로지의 변화를 확인하였으며, 이의 변화에 따른 기체 투과도 변화를 확인하였다. 휘발성 용매 함량이 작을수록 선택도는 유지되면서 이산화탄소 투과도가 증가하는 것을 확인하였다.

In this study, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT-PSS) was introduced into polymer gas separation membrane. The composite membrane consisted of poly(2-[3-(2H-benzotriazol –2-yl)-4-hydroxyphenyl] ethyl methacrylate)-poly(oxyethylene methacryalate) (PBEMPOEM) comb copolymer matrix and PEDOT-PSS filler. PEDOT-PSS has strong ionic bonding interaction between PEDOT and PSS, and sulfonic acid groups in PSS interact with water molecules with hydrogen-bond. Because of these specific properties, the incorporation of PEDOT-PSS could form CO2 pathway for gas transport through the membrane. PEDOT-PSS chains were homogeneously dispersed in the PBEM-POEM matrix as a network. The best performance of prepared PEDOT-PSS/PBEM-POEM composite membranes was CO2 permeability of 59.6 Barrer with a CO2/N2 selectivity of 77.4, being close to the 2008 Robeson upper boundlines.