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Synthesis of Hydrophobic Silica Aerogel from Rice Husk Biomass
반가람,김희택,박성수 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
Silica aerogel has received attention in various fields due to its properties such as large specific surface area, high porosity, low density, and low thermal conductivity. However, general procedure for the synthesis of silica aerogel, which includes expensive precursors and supercritical drying, limits mass production of the aerogel. One way to solve these issues that uses inexpensive starting materials has been developed. For this reason, this study proposes the method for synthesis of silica aerogel from rice husk. Rice husk, which contains high content of silica, is considered as a cheap natural source of silica-based materials. Rice husk ash (RHA) was obtained after thermal decomposition of organic matter in rice husk. Silica was extracted from RHA with sodium hydroxide. The prepared solution was converted into hydrogel via sol-gel process, then the silica gel was experienced solvent exchange and surface modification. After drying at ambient pressure, silica aerogel was attained.
반가람,박인수,홍혜진 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1
Spinel Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> (LTO) is one of promising anode materials for lithium ion batteries (LIBs) due to their high levels of electrochemical reversibility stability, and safety. Moreover spherical morphology of LTO can provide large specific surface area and high packing density. In this study, spinel LTO microspheres were synthesized by microwaveassisted hydrothermal (M-H) method. The M-H process requires lower temperature and shorter time for reaction than normal hydrothermal method. LTO microsphere was synthesized by two-step M-H method. First, spherical TiO<sub>2</sub> with particle size of 0.5 - 1.0 μm was prepared by first hydrothermal reaction. Subsequently, the spinel LTO was obtained in second hydrothermal reaction using the as-prepared TiO<sub>2</sub> and LiOH·H<sub>2</sub>O. The uniform shaped and highly pure spinel structured LTO microsphere was obtained by M-H method within 2 h of reaction time. This result indicates that M-H process is highly effective and simple method for preparation of LTO microsphere.
Synthesis of rice husk-based silica aerogel at ambient pressure
반가람,전순정,( Shao Godlisten Namwel ),박성수,김희택 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
Silica aerogel was synthesized from rice husk by sol-gel process followed by ambient pressure drying (APD). The conventional ways to produce silica aerogel have used costly silicon alkoxides and energy-intensive supercritical drying (SCD). The organic silicon sources and SCD hinder the large-scale production of the aerogel in terms of expenses and safety. Therefore utilizing inexpensive starting material and APD are needed. In experiments rice husk ash was obtained simply by calcination of rice husk and was extracted with sodium hydroxide solution. The mixed solution was neutralized using acid to form silica hydrosol. After gelation and aging, the prepared gel experienced solvent exchange and surface modification. The wet gel was dried at ambient pressure and then silica aerogel was attained. Our aim is to enhance the textural properties of the aerogel, such as specific surface area, pore size, and pore volume. This study proposes eco-friendly and cost-effective method to synthesize silica aerogel with excellent properties from rice husk via APD.
Preparation and Characterization of Silicon composite from Rice Husk Ash
송시내,반가람,김희택 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
Rice as the main grain in Asia, including Republic of Korea, has been produced about 424 ton in 2014(National Statistical Office, 2014). The Rice Husk, by-product generated after milling of rice, typically contains approximately 20% of rice in weight ratio and Rice Husk would be supplied about 85 ton as by-product through milling process in domestic. It could be resource of Biomass to utilize for practical use. Silica is relatively included in Rice Husk comparing with other crops. In case of Silica included Rice Husk, high purity Silica is obtained because of `Natural selectivity` process from roots of rice. In this study, we purpose to produce high purity Silica through Rice Husk separation process in by optimized experimental factors and then compound Silicon composite by using certain polymer.
2P-442 저온 소성 공정을 이용한 리튬 이온 전지용 Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> 음극 소재 제조 및 특성 평가
박인수,반가람,홍혜진 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1
Spinel Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub>(LTO) 소재는 고전력 이차전지의 음극 소재로 적용이 가능하여 주목을 받고 있는데 일반적으로 사용되는 카본 소재와 다르게 LTO는 안정하고 높은 작동 전압(1.55-1.56 V vs. Li/Li+)을 갖기 때문에 전해질의 환원 반응이 억제되고 리튬 금속(덴드라이트)가 증착되지 않아서 안전하다. 일반적으로 LTO는 Ti과 Li 원료 물질을 균일하게 혼합한 다음에 고온 하소 온도(800-1000 °C)에서 고상 합성(solid-state synthesis)에 의해서 제조되는데 이 방법에서 이용된 고온 열처리로 인해 LTO 결정이 크기가 크고 불균일하게 서로 성장하여 분말들이 뭉쳐지기 때문에 전기화학적 특성이 크게 제한을 받는다. 본 연구에서 수행된 600 °C 이하의 저온 공정을 이용한 LTO 제조 공정 및 전기화학적 결과를 발표하고자 한다.
Synthesis of Hydrophobic Silica Aerogel from Biomass at an Ambient pressure
노영아,박성수,반가람,김희택 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
The expensive precursor and drying process were main issue of synthesis of silica aerogel process. Therefore, we attempt to develop an economical and an eco-friendly synthesis process of hydrophobic silica aerogel according to rice husk amount, pH, and aging time. In this study, rice husk ash was extracted by sodium hydroxide solution to obtain sodium silicate solution. The sodium silicate solution was neutralized using hydrochloric acid to form silica hydrosol. After aging and gelation, the surface of silica hydrogel was modified by solvent exchange using TMCS/n-Hexane solution. Finally drying step was performed at ambient pressure. The synthesized silica aerogel was characterized by SEM, BET, FTIR, and contact angle analysis.