The present work is aimed at evaluating the kinetics and dynamic adsorption of methylene blue by CO2- activated carbon gels. The carbon gels were characterized by textural properties, thermal degradation and surface chemistry. The result shows that the carbon gels are highly microporous with surface area of 514 m2/g and 745 m2/g for resorcinol-to-catalyst ratios of 1000 (AC1) and 2000 (AC2), respectively. The kinetics data could be described by pseudo-first-order model, with a longer duration to attain equilibrium due to restricted pore diffusion as concentration increases. Also, AC1 exhibits insignificant kinetics with fluctuating adsorption with time at concentrations of 20 and 25 mg/L. However, AC1 reveals a better performance than AC2 in dynamic adsorption due to concentration gradient for molecules diffusion to active sites. The applicability of Yoon–Nelson and Thomas models indicates that the dynamic adsorption is controlled by external and internal diffusion.

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.

In this paper, nitrogen (N)-doped ultra-porous carbon derived from lignin is synthesized through hydrothermal carbonization, KOH activation, and post-doping process for CO2 adsorption. The specific surface areas of obtained N-doped porous carbons range from 247 to 3064 m2/g due to a successful KOH activation. N-containing groups of 0.62–1.17 wt% including pyridinic N, pyridone N, pyridine-N-oxide are found on the surface of porous carbon. N-doped porous carbon achieves the maximum CO2 adsorption capacity of 13.6 mmol/g at 25 °C up to 10 atm and high stability over 10 adsorption/desorption cycles. As confirmed by enthalpy calculation with the Clausius–Clapeyron equation, an adsorption heat of N-doped porous carbon is higher than non-doped porous carbon, indicating a role of N functionalities for enhanced CO2 adsorption capability. The overall results suggest that this carbon has high CO2 capture capacity and can be easily regenerated and reused without any clear loss of CO2 adsorption capacity.

In order to industrialization of the entomopathogenic nematode (EPN) isolated in Korea, it is necessary to switch to infective juveniles. Since the conversion to infective juveniles in the end of solid culture is important against the outside environment, it has a great influence on insecticidal efficacy and shelf life. We investigated whether the concentration of CO2 and NH3 at the end of the solid culture was artificially increased to affect the infective juvenile induction rate. Optimal exposure time for conversion to infective juveniles was 5 minutes for CO2 and 3 minutes for NH3. Optimal treatment time was 9 days after EPN inoculation for both CO2 and NH3. And optimum concentration was 80~90% for both CO2 and NH3 for EPN infective juveniles stage conversion.

Photosynthetic characteristics and growth responses of Phalaenopsis Queen Beer ‘Mantefon’ orchid were determined in plants exposed to variable carbon dioxide (CO2) concentrations at 2-, 24-, and 36-weeks age (i.e., corresponding to juvenile, young, and mature vegetative growth stages, respectively). Plants were grown at 400 (control), 800, or 1,600 μmol･mol-1 CO2 for 6 hours during the nighttime for 32 weeks. Phalaenopsis ‘Mantefon’ in 2- and 24-week-old plants grown at 1,600 μmol･mol-1 CO2 had increased leaf number and net CO2 uptake compared with the plants grown at 400 μmol･mol-1 CO2. In 36-week-old of Phalaenopsis ‘Mantefon’, leaf number was significantly greater in plant grown at 800 and 1,600 μmol･mol-1 conditions compared with plants grown at 400 μmol･mol-1 CO2. Leaves that emerged after the start of the CO2 treatment were initially longer in the plants grown at 1,600 μmol･mol-1 CO2 than at 400 μmol·mol-1 C O2, but the final leaf length was shortest in the plants grown at 1,600 μmol･mol-1 CO2 condition. Plants showed crassulancean acid metabolism characteristic of nighttime CO2 uptake regardless plant growth stages. We found that growers may be able to promote leaf growth with increasing leaf number and reducing time to leaf initiation in the 36-week-old (i.e., mature stage) plants with 800 – 1,600 μmol·mol-1 CO2 and 2- and 24-week-old (i.e., juvenile and young stages) plants with 1,600 μmol·mol-1 C O2 for Phalaenopsis ‘Mantefon’.

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.

Nitrogen-doped carbons have attracted much attention due to their novel application in relation to gas storage. In this study, nitrogen-doped porous carbons were synthesized using SBA-15 as a template, polypyrrole as the carbon and nitrogen precursor, and KOH as an activating agent. The effect of the activation temperature (600–850°C) on the CO2 adsorption capacity of the obtained porous carbons was studied. Characterization of the resulting carbons showed that they were micro-/meso-porous carbon materials with a well-developed pore structure that varied with the activation temperature. The highest surface area of 1488 m2 g–1 was achieved at an activation temperature of 800°C (AC-800). The nitrogen content of the activated carbon decreased from 4.74 to 1.39 wt% with an increase in the activation temperature from 600 to 850°C. This shows that nitrogen is oxidized and more easily removed than carbon during the activation process, which indicates that C-N bonds are more easily ruptured at higher temperatures. Furthermore, CO2 adsorption isotherms showed that AC-800 exhibited the best CO2 adsorption capacity of 110 mg g–1 at 298 K and 1 bar.