Cost-effective and sustainable high-performance supercapacitor material was successfully prepared from cellulosic waste (Sapindus trifoliatus nut shells) biomass-derived activated carbon (CBAC) by physical activation method. The CBAC displays nanofiber morphology, high specific surface area (786 m2/ g), large pore volume (0.212 cm3 g− 1) which are evaluated using FESEM, BET and possessed excellent electrochemical behavior analyzed through various electrochemical methods. Moreover, the assembled symmetric CBAC//CBAC device exhibits high specific capacitance of 240.8 F g− 1 with current density of 0.2 A g− 1 and it is maintained to 65.6 F g− 1 at high current density of 2.0 A g− 1. In addition, the symmetric device delivers an excellent specific energy maximum of over 30 Wh kg− 1 at 400 W kg− 1 of specific power and excellent cycling stability in long term over 5000 cycles. The operation of the device was tested by light-emitting diode. Hence, CBAC-based materials pave way for developing large-scale, low-cost materials for energy storage device applications.

In this study, composite PAN-based ACNFs embedded with MgO and MnO2 were prepared by the electrospinning method. The resultant pristine ACNFs, ACNF/MgO and ACNF/MnO2 were characterized in terms of their morphological changes, SSA, crystallinity and functional group with FESEM-EDX, the BET method, XRD and FTIR analysis, respectively. Results from this study showed that the SSA of the ACNF/MgO composite (1893 m2 g–1) is significantly higher than that of the pristine ACNFs and ACNF/MnO2 which is 478 and 430 m2 g–1, respectively. FTIR analysis showed peaks of 476 and 547 cm–1, indicating the presence of MgO and MnO2, respectively. The FESEM micrographs analysis showed a smooth but coarser structure in all the ACNFs. Meanwhile, the ACNF/MgO has the smallest fiber diameter (314.38±62.42 nm) compared to other ACNFs. The presence of MgO and MnO2 inside the ACNFs was also confirmed with EDX analysis as well as XRD. The adsorption capacities of each ACNF toward CH4 were tested with the volumetric adsorption method in which the ACNF/MgO exhibited the highest CH4 adsorption up to 2.39 mmol g–1. Meanwhile, all the ACNF samples followed the pseudo-second order kinetic model with a R2 up to 0.9996.

고강도, 내약품성, 무독성, 내연소성의 장점을 가지고 있는 PVdF (polyvinylidene fluoride) 나노섬유로 기공이 0.4 μm 평막을 제조한 후, 부직포와 평막으로 나권형 모듈을 제작하였다. 용존유기물의 흡착 제거를 위한 입상 활성탄(GAC, granular activated carbon) 흡착 컬럼과 자체 제작한 나권형 모듈로 혼성 수처리 공정을 구성하였다. 카올린과 휴믹산으로 조 제한 모사 용액을 대상으로, 처리수를 재순환하는 경우와 배출하는 경우 각각 GAC 충진량의 영향을 알아보았다. 여과실험 후 물 역세를 하여 회복률과 여과저항을 계산하였다. 또한, 탁도와 UV254 흡광도를 측정하여 GAC의 흡착 효과를 고찰하였 다. 그 결과, 처리수를 재순환하는 경우와 배출하는 경우 모두 탁도 처리율에는 GAC 충진량의 영향이 없었다, 하지만 GAC 의 UV254 흡광도 처리율이 처리수를 순환하는 경우 0.7~3.6%이었는데, 처리수를 배출하는 경우 3.2-5.7%로 증가하였다. 처리 수를 순환하는 경우 GAC의 충진량이 증가함에 따라, 가역적 여과저항(Rr)과 비가역적 여과저항(Rir)은 감소하는 경향을 보였 다. 그러나 총여과저항(Rt)은 거의 일정하였고, 물 역세 회복률(Rb)은 다소 증가하는 경향을 보였다.

기공 0.4 μm PVDF 나노섬유 정밀여과 나권형 모듈과 GAC 컬럼의 혼성공정에서 모사용액을 순환 없이 선형유속 0.013 m/s, TMP를 0.5 bar 조건으로 GAC 충진량을 변화시키면서 실험하였다. 또한 동일한 혼성공정에서 모사용액을 순환시키면서 선형유속 0.026 m/s, TMP 1.5 bar의 조건으로 GAC 충진량의 영향을 고찰하였다. 탁도와 UV254 흡광도(DOM) 처리율을 비교하였는데, 탁도 처리율에는 영향이 없었으나, GAC의 충진량이 많을수록 DOM 이 증가하였다. 하지만 TMP와 유속이 높은 조건인 순환이 있는 실험에서 GAC에 의한 DOM 처리율이 더 낮은 이유는 순환으로 인해 모사용액 농도가 낮아졌기 때문인 것으로 판단된다.

강도가 강하고 내약품성, 무독성, 내연소성의 장점을 가지고 있는 PVdF (polyvinylidene fluoride) 나노섬유로 기공이 0.4 μm 평막을 제조한 후, 그 평막으로 부직포를 첨가하여 나권형 모듈을 제작하였다. 카올린과 휴믹산으로 조제한 모사용액과 순수를 대상으로 나권형 모듈의 투과선속과 처리율을 비교하여 pH의 영향을 알아보았고, 여과실험 후 물 역세척을 하여 회복률과 여과저항을 계산하였다. 또한, 나권형 모듈을 통과한 처리수를 입상 활성탄(GAC, granular activated carbon)으로 채워진 컬럼에 통과시킨 후, 탁도와 UV254 흡광도를 측정하여 GAC의 흡착 효과를 고찰하였다.

In this work, activated carbon nanofiber(ACNF) electrodes with high double-layer capaci-tance and good rate capability were prepared from polyacrylonitrile nanofibersby optimiz-ing the carbonization temperature prior to H2O activation. The morphology of the ACNFs was observed by scanning electron microscopy. The elemental composition was determined by analysis of X-ray photoelectron spectroscopy. N2-adsorption-isotherm characteristics at 77 K were confirmedby Brunauer-Emmett-Teller and Dubinin-Radushkevich equations. ACNFs processed at different carbonization temperatures were applied as electrodes for electrical double-layer capacitors. The experimental results showed that the surface mor-phology of the CNFs was not significantlychanged after the carbonization process, although their diameters gradually decreased with increasing carbonization temperature. It was found that the carbon content in the CNFs could easily be tailored by controlling the carbonization temperature. The specificcapacitance of the prepared ACNFs was enhanced by increasing the carbonization temperature.

Activated carbon nanofibers(ACNF) were prepared from polyacrylonitrile (PAN)-based nanofibersusing CO2 activation methods with varying activation process times. The surface and structural characteristics of the ACNF were observed by scanning electron microscopy and X-ray diffraction, respectively. N2 adsorption isotherm characteristics at 77 K were con-firmedby Brunauer-Emmett-Teller and Dubinin-Radushkevich equations. As experimental results, many holes or cavernous structures were found on the fibersurfaces after the CO2 activation as confirmedby scanning electron microscopy analysis. Specificsurface areas and pore volumes of the prepared ACNFs were enhanced within a range of 10 to 30 min of acti-vation times. Performance of the porous PAN-based nanofibersas an electrode for electrical double layer capacitors was evaluated in terms of the activation conditions.

The oxyfluorination effects of activated carbon nanofibers (OFACFs) were investigated for CO2 storage. Electrospun CFs were prepared from a polyacrylonitrile/N,N-dimethylformamide solution via electrospinning and heat treatment. The electrospun CFs were chemically activated in order to generate the pore structure, and then oxyfluorination was used to modify the surface. The samples were labeled CF (electrospun CF), ACF (activated CF), OFACF-1 (O2:F2 = 7:3), OFACF-2 (O2:F2 = 5:5) and OFACF-3 (O2:F2 = 3:7). The functional group of OFACFs was investigated using X-ray photoelectron spectroscopy analysis. The C-F bonds formed on surface of ACFs. The intensities of the C-O peaks increased after oxyfluorination and increased the oxygen content in the reaction gas. The specific surface area, pore volume and pore size of OFACFs were calculated by the Brunauer-Emmett-Teller and density functional theory equation. Through the N2 adsorption isotherm, the specific surface area and pore volume slightly decreased as a result of oxyfluorination treatment. Nevertheless, the CO2 adsorption efficiency of oxyfluorinated ACF improved around 16 wt% due to the semi-ionic interaction effect of surface modificated oxygen functional groups and CO2 molecules.

Carbon nanofiber (CNF) grown catalytically was chemically activated with KOH to attain structural change of CNF. The structural changes of CNF through KOH activation were investigated by using BET and SEM. From the results of BET, it was found that KOH activation was effective to develop particular sizes of pores on the CNF surface, increasing the surface area of CNF. Activated CNF was applied as an anode catalyst support of fuel cell. The effects of different activation conditions including the activation temperature and the activation time on the specific surface area of the CNF activated with KOH were investigated to obtain appropriate structure as a catalyst support. The 60 wt% Pt-Ru catalyst prepared was observed by using TEM and XRD.