• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.250.1-250.1
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• 2010

최근 석유공급 불안정성과 이산화탄소 배출 규제 움직임에 대응하기 위한 수단으로 바이오연료의 공급이 전세계적으로 증가하고 있다. 이와 같은 바이오디젤의 보급 활성화는 식물성 기름의 가격 상승과 수급 불안정 문제, 그리고 식량자원과의 충돌 문제를 야기하고 있다. 국내 바이오디젤 생산 원료로 사용되는 대두, 유채, 해바라기, 팜 등은 모두 식용시장과 수급 균형을 형성하고 있어 바이오디젤의 생산이 증가하게 되면 식용 오일 시장의 수급균형이 깨져 오일곡물 가격의 변동을 초래하게 될 것이다. 과거에는 수거비용을 들여 폐기하던 폐식용유 마저 이제는 돈을 주고 구입해야하는 실정에 다다랐다. 바이오디젤 생산비의 70~80%를 차지하는 원료유의 부족 현상에 따라 바이오디젤 업계에서는 soapstock, trapped grease, 폐식용유 등의 저급유지 활용 방안을 강구하고 있으며 자트로파와 같은 비식용 작물의 해외플랜테이션도 진행하고 있다. 본 연구에서는 커피찌거기에 남아 있는 오일을 속슬렛추출장치를 이용해 추출하고 전이에스테르화 반응을 수행하여 반응 특성과 커피오일 바이오디젤의 지방산 조성을 알아보고 바이오디젤 원료유로서의 사용가능성에 대해 알아보았다. 석유에테르를 용매로 속슬렛 추출장치를 이용해 추출시 원료대비 약 17%(w/w)의 오일을 추출할 수 있었다. 추출된 오일의 산가는 18.79mgKOH/g으로 매우 높아 직접 전이에스테르화 반응이 불가능하다. 고체 산 촉매 하에서 전처리 반응을 실시하여 유리지방산을 전환 제거한 후 염기촉매를 이용해 전이에스테르화 반응을 진행한 결과 약 80%의 바이오디젤(FAME) 함량을 얻을 수 있었다. 지방산 조성 분석 결과 리놀레익산(Linoleic acid, C18:2), 올레익산(Oleic acid, C18:1), 팔미틱산(Palmitic acid, C16:0)이 대부분을 차지하며 이 중에서도 리놀레익산이 44.17%로 가장 많은 함량을 보였다. 이는 커피찌꺼기 추출 오일이 바이오디젤 원료유로 활용 가능성을 나타내는 결과로, 색소성분 등의 불순물을 효율적으로 제거하여 증류정제 전단계에서의 바이오디젤 순도와 생산 수율을 증대시키기 위한 추가 연구가 필요한 것으로 판단된다.

• Magazine of RCR
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• v.16 no.4
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• pp.65-69
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• 2021

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.63-64
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• 2023

In order to reduce the high absorption ratio of spent coffee grounds, this study examined the compressive strength and absorption ratio of mortar replacing coated spent coffee grounds according to the type of water repellent. In order to examine this, as the water repellent used, a silane-based water repellent (fluorine-based water repellent) and an acrylic-based water repellent, which are film-type water repellents, and a silane/siloxane-based water repellent, which are penetration-type water repellents, were used. The spent coffee grounds were coated with each of three water repellents, and mortar was prepared by mixing cement and fine aggregate. As a result of the experiment, the compressive strength and absorption ratio of the mortar replaced with coated spent coffee grounds coated with the film-type water repellent were superior to the penetration-type water repellent. Therefore, in order to reduce the high absorption ratio of spent coffee grounds, a suitable water repellent is a film-type water repellent. Among them, it is judged that the acrylic type has excellent water repellency and is suitable.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.2
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• pp.45-49
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• 2019

Relatively fine silicon carbide (SiC) crystalline aggregates have been synthesized with the carbonized rice husks, paper sludge, coffee grounds as the carbon sources and the silica powder. The main reaction source to obtain silicon carbide (SiC) aggregates from the mixture of carbon sources and silica was inferred as the gaseous silicon monoxide (SiO) phase, being created from this mixture through the carbothermal reduction reaction. The silicon carbide (SiC) crystalline aggregates, fabricated from the carbonized rice husks and paper sludge, coffee grounds and silica ($SiO_2$) powder, were investigated by XRD patterns, FE-SEM and FE-TEM images. In these specimens, obtained from the carbonized rice husks, paper sludge and silica, XRD patterns showed rather high strong peak of (111) plane near $35^{\circ}$. The FE-TEM images and patterns of specimens, synthesized from carbonized rice husks, paper sludge, coffee grounds and silica under Ar atmosphere, showed relatively fine particles under $1{\mu}m$ and crystalline peak (110) of silicon carbide (SiC) diffraction pattern.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.529-533
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• 2023

The fundamental electrochemical properties and adsorption capabilities of the carbonized product derived from coffee grounds, a prevalent form of lignocellulose abundantly generated in our daily lives, have been extensively investigated. The structure and morphology of the resultant carbonized product, obtained through a carbonization process conducted at a relatively low temperature of 600 ℃, were meticulously examined using a scanning electron microscope. Raman spectroscopy measurements yielded a relative crystallinity (D/G ratio) of the carbon product of 0.64. Electrical measurements revealed a linear ohmic relationship within the carbonized product. Furthermore, the viability of utilizing this carbonized material as an anode in lithium-ion batteries was evaluated through half-cell charge/discharge experiments, demonstrating an initial specific capacity of 520 mAh/g. Additionally, the adsorption performance of the carbon material towards a representative dye molecule was assessed via UV spectroscopy analyses. Supplementary experiments corroborated the material's ability to adsorb a distinct model molecule characterized by differing surface polarity, achieved through surface modification. This article presents pivotal findings that hold substantial implications for forthcoming research endeavors centered around the recycling of lignocellulose waste.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.571-580
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• 2018

In this study, hybrid adsorbents (SS) were prepared by mixing spent coffee grounds (SCG) and sericite, a kind of clay minerals, to adsorb Pb(II) from an aqueous solution. In FT-IR analyses, the main functional groups of SS adsorbents were O-H, C=O and C-N groups. The specific surface area, cation exchange capacity and the pore diameter of SS were larger than those of using SCG and sericite. Formation conditions of the SS adsorbent were the optimum pyrolysis temperature of $300^{\circ}C$, SCG : sericite ratio of 8 : 2, and particle size of 0.3 mm. Langmuir adsorption isotherm was more suitable than Freundlich one, and the maximum adsorption capacity was reached 44.42 mg/g. As a result of the adsorption thermodynamic analysis, the adsorption of Pb(II) onto SS was the physical adsorption and exothermic process in nature. The regeneration of SS adsorbent using distilled water showed 88~92% recovery and the active site of SS adsorbent decreased with increasing the reuse cycle time. As a result, SS adsorbent showed that it can be used to remove Pb(II) easily, inexpensively and efficiently without any pre-treatment from aqueous solutions.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1678-1686
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• 2020

This study attempted to derive the possibility of using wood pellet using rice husk, which is an agricultural byproduct, and tried to improve the lower calorific value of rice hulls thorough expansion technology and combustion additives. In the physical and chemical analysis of rice husk, the result was obtained that the chlorine content was 0.09%, which did not meet the wood pellet quality standard of Korea. When making rice hulls into expanded rice husk through the expansion technology, the chlorine content decreased, resulting in a product of 0.02%, which is equivalent to the wood pellet standard of Korea, and the calorific value was also increased to 4,280 kcal/kg compared to the existing 3,780 kcal/kg. To obtain a product of 5,000 kcal/kg or more, borax, hydrogen peroxide, and sodium hydroxide was used as combustion improver. However the improvement in calorific value was insufficient. After conversion to coffee oil path using coffee grounds, which is a waste resource biomass, it is mixed into an expanded rice husk, and when the product is analyzed, the coffee oil 15 wt% mixed product shows an excess of 4,949 kcal/kg. When using rice husk, an agricultural byproduct, as wood pellets, it is considered desirable to use waste resources to improve the calorific value, and according to the results of this study, when mixing coffee oil, rice husk can be sufficiently used as wooden pellets.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.21-28
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• 1995

The removal of heavy metals from synthetic wastewater containing Pb, Cr, Cd using previously washed and dried exhausted coffee was studied varying cohcentration, pH and temperature. All the heavy metals were removed in 3.0 minutes and the removal efficiency was maximum 80~90% with different pH and temperature conditions. The differences in removal efficiency between exhausted coffee and activated carbon under the same conditions were not seen. The removal efficiency was slightly increased with increasing pH in Cd and increasing temperature in Cr, respectively. The batch adsorption kinetics and adsorption equilibrium were examined and described by a first order reversible reaction and Freundlich isotherm, respectively. And the removal of Pb was found to have the best removal efficiency.

• Journal of the Korean Wood Science and Technology
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• v.41 no.4
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• pp.293-301
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• 2013

This study discusses the feasibility of coffee bean residue as a raw material of medium-density fiberboard (MDF). In this relation, the effect of coffee bean residue known as an absorbent material on the physical and mechanical properties of MDF manufactured at its different addition level. Coffee bean residue which is a by-product of coffee mill and large amount of waste left over after processing for instant coffee was added at the level of 3, 6, and 9% on dry basis and urea formaldehyde resin was used as the adhesive. The MDF made with mixture of wood fiber and coffee bean residue was tested for physical and mechanical properties as well as formaldehyde emission. The bending strength and internal bonding strength of the MDF made with mixture of wood fiber-coffee bean residue were higher than that of the KS standard in randomized mat structure type, but not in layered mat structure type. Also, the physical properties of MDF made with mixture of wood fiber-coffee bean residue showed a considerable improvement in thickness swelling over the commercial MDF. More importantly, the formaldehyde emission rate of MDF made with mixture of wood fiber-coffee bean residue met the KS standard and was close to that of commercial MDF. These results showed the feasibility of coffee bean residue as a raw material for the production of environmentally-friendly MDF. Additional works on adhesive-coffee bean compatibility, improvement of moisture absorption effect and reduction the formaldehyde emission rate by carbonization of coffee bean residue may be required.

• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.20-31
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• 1998

There is a need for waste recycling. This study was carried out to investigate removal efficiency of TCE in water treatment with adsorbent made from coffee grounds which obtained after extraction of coffee through hot water. The removal of TCE in synthetic Waste water using adsorbents was examined varying dose, concentration and temperature on a laboratory scale. The results were as followed 1. As much as 95% TCE remogal was possible with adsorbent made from coffee grounds at an adsorbent dose over 2.5 g/l under the test conditions. 2. The removal rate of TCE was propotional to weight of adsorbent made from coffee grounds (0.025, 0.1, 0.3, 0.5 g). 3. In the effect of temperature, as temperature of wastewater was high, the rate of removal was increased. 4. Iodine number (865 mg/g) of adsorbent made from coffee grounds was not higher than that (1123 mg/g) of adsorbent made from coconut. But, in considering adsorption capacity, Iodine number was inapplicable to adsorbent made from coffee grounds. 5. Generally, Freundlich's equation applies to adsorption in wastewater. In case of TCE, slope (1/n) was 0.83, 1.06 and intercept (k) was 456.18, 405.19 at 150, 300 ppb respectively (average r=0.904, 0.933).