The addition of fiber sto concrete matrix has been a norm to enhance the mechanical strength of concrete. However, the use ot synthetic fibers (artificial fibers) is rampant compared to natural fibers due to a low mechanical strength of some natural fibers. The study added cellulose fiber made from jute at 0.2%, 0.25, and 0.3% of cement weight to concrete matrix to determine their influence on the early strength development. It was observed that compressive strength and flexural strength increases as the proportion of fiber added to the concrete increased. Further observation showed that the compressive strength had its optimum point at 0.3% fiber addition. However, the optimum point of the flexural strength lied at 0.25% fiber addition. It was concluded that cellulose fiber is capable of enhancing the mechanical strengths of concrete matrix.

음이온 교환막은 수전해 시스템에서 매우 중요한 역할을 하며, 생성된 수소와 산소 기체를 물리적으로 분리할 뿐 만 아니라 전극 사이에서 수산화 이온의 선택적인 전달을 용이하게 한다. 음이온 교환막에 요구되는 특성은 수산화 이온에 대한 높은 전도도와 알칼리 환경에서의 화학적/기계적 안정성 등이 있다. 본 연구에서는 셀룰로오스 나노 크리스탈이 포함된 poly(terphenyl piperidinium) (qPTP/CNC) 복합매질분리막을 제조하였다. 고분자 매질로 사용된 poly(terphenyl piperidinium) 은 super-acid 중합법을 통해 제조되었으며 이온전도성과 알칼라인 내구성이 뛰어난 소재로 알려져 있다. qPTP/CNC 분리막 의 구조는 고분자와 나노 입자 계면의 공극이나 큰 응집체가 없는 조밀하고 균일한 형태를 나타냈다. CNC 나노 입자가 2 wt% 첨가된 qPTP/CNC 분리막은 높은 이온교환용량(1.90 mmol/g)과 낮은 함수율(9.09%) 및 팽윤도(5.56%)를 보였다. 또한, 복합막은 수전해 작동 환경인 50°C 1 M KOH에서 상용 FAA-3-50 분리막에 비해 월등히 낮은 저항과 우수한 알칼라인 내구 성(384시간)을 달성했다. 이러한 결과는 친수성 첨가제인 CNC가 음이온 교환막의 이온 전도 특성과 알칼라인 내구성 향상에 기여할 수 있음을 보고하였다.

The significance of this study lies in addressing critical issues prevalent in the worldwide construction sector, particularly concerning the durability and sustainability of cement-based materials. Plain cement composites commonly suffer from deficiencies in tensile strength and strain capacity, resulting in the formation of nano-cracks under relatively low tensile loads. These nano- cracks pose a significant challenge to the longevity and resilience of cement matrices, contributing to structural degradation and reduced service life of infrastructure. To mitigate these challenges, the integration of cellulose nanofibers (CNF) as reinforcements in cement composites presents a promising solution. CNF, renowned for their exceptional material properties including high stiffness, tensile strength, and corrosion resistance, offer the potential to significantly enhance the mechanical performance and durability of cement-based materials. Through systematic experimentation, this study investigates the effects of CNF reinforcement on the mechanical properties of cement composites. By leveraging ultrasonically dispersion techniques, CNF extracted from bamboo, broad leaf, and kenaf are uniformly dispersed within the cement matrix at varying concentrations. Compressive and flexural tests are subsequently conducted to evaluate the impact of CNF on the strength characteristics of the cement composites. By elucidating the efficacy of CNF reinforcement through rigorous experimentation, this study aims to provide valuable insights into the development of construction materials with improved durability and sustainability. Ultimately, this research contributes to addressing critical challenges in the construction industry, offering potential solutions to enhance the performance and longevity of cement-based infrastructure.

To raise the physical strength of alginate beads, this study manufactured alginate-cellulose bead by adding cellulose to alginate, and wanted to identify whether falginate-cellulose beads were sufficiently efficient in removing heavy metals. To find out optimal amounts of alginate and cellulose injection, this study conducted a pilot study, and repeated experiments proved that alginate 2 w/v% + cellulose 1 w/v% were the optimal amounts in manufacturing beads. Using micro materials tester, this study compared strengths of alginate beads and alginate-cellulose beads. Choosing Cd2+, Pb2+, and Ni2+ as materials to be removed, this study analyzed concentrations of them before and after the treatment. Experiments showed that, compared with alginate beads, the strength of alginate-cellulose beads was 2.26 times stronger, and that the latter could remove 98.22%, 99.99%, and 92.57% of Cd2+, Pb2+, Ni2+, respectively. While addition of cellulose to alginate made the absorption rate drop by about 1%, the beads were still highly efficient in removing heavy metals. Accordingly, it seems that alginate-cellulose beads can be used in removing heavy metals.

PURPOSES : This study describes the experimental findings on the mechanical properties of calcium aluminate cement (CAC)-based repair mortars with or without natural cellulose fiber (NCF). Additionally, the effect of adding NCF to the reduction of fugitive dust in the CAC powder was examined. METHODS : To produce mortar, four different levels of NCF (0.0.5, 1.0, and 2.0% by binder weight) were adopted, and the water-binder ratio was fixed at 0.485. The flow, strength characteristics, absorption, and surface electrical resistivity of the mortars were measured at predetermined periods. Additionally, SEM observations were performed to examine the microstructural changes and hydrates formed on the 28 day-mortar samples. RESULTS : The addition of NCF led to a decrease in fugitive dust. Regarding the mechanical properties of the mortars, that with 0.5% NCF exhibited a better performance in terms of strength development and surface electric resistivity compared to those of other mortars. However, the addition of NCF was less effective in the enhancement of the absorption of mortars. Further, we discovered that the microstructures of the mortars with additional NCF were comparatively dense compared to those without NCF. CONCLUSIONS : The appropriate addition of NCF can enhance the performance of CAC-based repair materials. However, further studies on the durability of CAC with the addition of NCF are needed to determine the optimal mixture.

바이오산업의 발전으로 의약품, 식품 등의 생산 과정의 분리/정제 공정에 사용되어 왔던 기존의 컬럼 크로마토그 래피를 대체하여 더 높은 처리효율을 갖는 막 크로마토그래피가 부상하고 있다. 본 연구에서는 서로 다른 기공 크기의 두 가 지 상용 셀룰로오스 아세테이트(Cellulose acetate, CA) 분리막을 탈아세틸화 과정을 통해, 리간드의 개질이 용이한 다공성 재 생 셀룰로오스 지지체를(Regenerated cellulose, RC) 제조하였다. 음이온 교환능을 부여하고자 grafting을 수행하였으며, 구체 적으로는 UV 중합법을 통해 4차 암모늄을 포함하는 음이온 교환 리간드(MAPTAC)를 부착하여 음이온 교환용 흡착막을 제 조하였다. 단백질 흡착 용량은 정적 흡착 용량(Static binding capacity, SBC)시험을 통해 총 단백질 흡착 용량을 측정했고, 동 적 흡착 용량(Dynamic binding capacity, DBC)을 측정하여 상용막과 비교 평가하였다. 성능 평가 결과 단백질 흡착량은 넓은 표면적에 의해 리간드 밀도가 높은, 기공 크기가 작은 순서로 높게 측정되었고, 상용 CA분리막을 탈아세틸화하고 리간드를 부착시킨 분리막(RC 0.8 + MAPTAC 43.69 mg/ml, RC 3.0 + MAPTAC 36.33 mg/ml)이 상용 막 크로마토그래피 제품(28.38 mg/ml) 대비 높은 흡착 용량을 보였다.

This study was carried out to examine the physical characteristics of bacterial cellulose (BC) and its optimal culture condition using coffee by-products. Recently, recycling resources and employing eco-friendly materials have been raised as significant issues in the food industry. As the coffee industry develops, interests and efforts for recycling coffee wastes are also growing. This study attempted to confirm the production of BC by utilizing spent coffee grounds filtrate as a medium. In order to confirm the optimal culture conditions for BC production, different culture methods, initial pH, culture temperature, and culture period were examined. The optimal pH and temperature were 6.0 and 30oC, and the optimal culture period was 14 days. The cultivated BC was dried by hot air drying, freezedrying, and mold drying, respectively. Then, the properties of the BC films, such as tensile strength, elongation, water-solubility, thickness, and chromaticity were compared. The drying method affected the shape and structure of the final BC films. The production of BC film is expected to expand opportunities for recycling coffee by-products and contribute to solving environmental problems caused by food waste.

현재 우리 산업의 가속화된 발전으로 인해 다양하고 많은 양의 오염이 만들어지기 시작하고 있다. 특히 폐수의 경우 석유, 금속 및 유기물로 오염되는 강과 바다가 늘고 있으며, 빠른 조치가 필요해 보인다. 이러한 오염에 대응하기 위해 폐수에서 분리막을 이용한 깨끗한 물의 여과가 비용적으로 유리하고 친환경적인 기술로 떠오르고 있다. 재생 자원으로 만들 어진 막여과 기법들이 환경오염의 원인 중 하나인 합성고분자 분리막들을 대체하기 위해 많이 사용되고 있다. 박테리아 셀룰 로오스(Bacterial Cellulose / BC)는 순수하고 뚜렷한 형태의 셀룰로오스 나노섬유(Cellulose nanofibrils / CNF)이다. CNF에서 제조된 나노페이퍼는 각기 다른 용도로 한외여과막과 나노여과막으로 사용된다. BC의 높은 결정성으로 인해 폐수 처리 막의 필수 기준인 우수한 기계적 성질을 가질 수 있다. 본 리뷰 논문에서는 염료, 오일 및 중금속 등 폐수의 오염물질들을 걸러내기 위해 사용될 수 있는 BC 기반 분리막들에 대해 논의한다.

An enthalpy exchange element (EEE) is frequently made of papers, and a concern exists on growth of fungus or bacteria. This concern may be eliminated if polymer membrane is used instead of paper. Furthermore, most existing enthalpy exchangers have cross-flow configuration, which yields lower performance than counter-flow one. In this study, a counter-flow enthalpy exchange element was made using PVDF and cellulose composite. Heat and moisture transfer tests were conducted changing the frontal air flow rate from 150 m 3 /h to 350 m 3 /h at both the heating and the cooling condition. Results showed that the temperature efficiencies were approximately the same independent of the weather condition. Humidity efficiencies at the heating condition, however, were higher than those at the cooling condition. Furthermore, the heat transfer coefficients approached the theoretical value as the flow rate increased. In addition, the vapor transmission rates at the heating condition were higher than those at the cooling condition, probably due to the higher humidity efficiency at the heating condition. Future research will be focused on moisture diffusion characteristics of the composite membrane, which requires further measurements of water holdup, equilibrium adsorption curve, etc.