• Advances in materials Research
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• 제11권4호
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• pp.299-330
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• 2022

This review article highlights the physical, mechanical, and chemical properties of coconut shells, and the fresh and hardened properties of the coconut shell concrete are summarized and were compared with other types of aggregates. Furthermore, the structural behavior in terms of flexural, shear, and torsion was also highlighted, with other properties including shrinkage, elastic modulus, and permeability of the coconut shell concrete. Based on the reviewed literature, concrete containing coconut shell as coarse aggregate with normal sand as fine showed the 28-day compressive strength between 2 and 36 MPa with the dried density range of 1865 to 2300 kg/m³. Coconut shell concretes showed a 28-day modulus of rupture and splitting tensile strength values in the ranges of 2.59 to 8.45 MPa and 0.8 to 3.70 MPa, respectively, and these values were in the range of 5-20% of the compressive strength. The flexural behavior of CSC was found similar to other types of lightweight concrete. There were no horizontal cracks on beams which indicate no bond failure. Whereas, the diagonal shear failure was prominent in beams with no shear reinforcements while flexural failure mode was seen in beams having shear reinforcement. Under torsion, CSC beams behave like conventional concrete. Finally, future recommendations are also suggested in this study to investigate the innovative lightweight aggregate concrete based on the environmental and financial design factors.

• 공업화학
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• 제35권1호
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• pp.37-41
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• 2024

열대성 과일로 널리 재배되고 있는 코코넛(coconut)의 독특한 껍질(shell)은 과육 섭취 후 얻어지는 부산물로 활용 가치가 클 것으로 기대된다. 이 코코넛 껍질을 전도성 고분자와 혼합하여 복합소재를 간단한 방식으로 제조하고 섭씨 600도 정도의 상대적 저온에서 탄화하여 수득되는 소재의 전기화학적 특성 및 활용 가능성을 고찰하였다. 먼저, 외형적 요소를 주사전자현미경(scanning electron microscope, SEM)으로 관찰하였다. 탄소의 미세구조를 라만(Raman) 분광 분석을 통하여 추론하였다. 전기전도 가능성을 간단한 옴의 관계(Ohmic relation)를 통하여 확인하였다. 나아가, 탄화된 재료가 리튬 이차 전지의 음극(anode) 소재로 활용될 수 있는지 여부를 반쪽 전지(half-cell) 충방전(charge/discharge) 테스트를 통해 살펴보았으며, 최대 충전 용량은 약 750 mAh로 높게 나타났으나, 충전이 진행됨에 따라 빠른 감소를 보였다. 본 연구는 향후 목질계 폐기물의 활용에 대한 중요한 정보를 제공할 것이다.

• 대한환경공학회지
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• 제37권6호
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• pp.357-362
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• 2015

새로운 형태의 $TiO_2$가 합성된 코코넛 껍질 분말 복합체를 제조하기 위해 솔-젤 합성법과 열처리를 사용하였고, 제조된 TCSPC는 MB를 대상으로 제거효율을 평가하였다. TCSPC를 제조하기 위한 최적의 조건은 반응표면분석법의 중심합성설계법을 사용하여 조사하였다. 소성온도가 $400^{\circ}C$에서 $600^{\circ}C$ 증가함에 따라 BET 비표면적은 $254m^2/g$에서 $398m^2/g$로 증가하고 기공용적, 기공률 또한 증가하며, 그 이유는 소성공정 시 발생한 열분해(pyrolysis)에 의해 코코넛 껍질 분말이 가지고 있는 헤미셀룰로우스, 셀룰로우스, 그리고 리그닌과 같은 물질들의 polymerization 반응 때문인 것으로 판단된다. 코코넛 껍질 분말의 양이 10 g에서 20 g으로 증가 할수록 BET 비표면적은 $303m^2/g$에서 $398m^2/g$로 증가하였으며, 30 g으로 증가 시에는 BET 비표면적은 $345m^2/g$으로 감소하는 경향을 나타내었다. Response optimization을 사용하여 얻은 최적의 합성조건은 소성온도 $642^{\circ}C$, 코코넛 껍질 분말 주입량이 22.7 g으로 나타났다.

• 대한화학회지
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• 제51권2호
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• pp.154-159
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• 2007

유리 및 고정화된 Bacillus brevis에 의한 큐놀린의 분해를 조사하였다. 코코넛 껍질 탄소에 고정화된 Bacillus brevis에 의한 큐놀린 분해 속도는 폼조각에 고정화되었거나 유리된 미생물에 의한 속도보다 빠르다. 시료에 존재하는 큐놀린 100 ppm을 완전히 제거하기 위해서는 코코넛 껍질 탄소에 고정화된 Bacillus brevis로 만든 생촉매를 물속에서 20시간 유지시키면 되었다. 이 생촉매는 꽤 긴 보존기간과 적절한 재생력을 가지고 있었다.

• 한국연초학회지
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• 제16권2호
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• pp.181-190
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• 1994

Various active carbons were made from plant sources of coconut shell, pine tree, oak tree and lignite coal. Pore characteristics of these adsorbents were investigated. 1, With increasing activation time, specific surface area and pore volume increased, but the development of micropores was limited at a certain level. The average pore diameter, by BET, of coconut active carbon was 15.5-21.8$\AA$ and that of lignite carbon was 15.6-31.3$\AA$. The pore diameters of silica-gel, sepiolite and zeolite was 30.9$\AA$, 58.6$\AA$ and 55.7$\AA$, respectively. 2. The Horvath - Kawazoe micropore diameter of coconut shell active carbon was under 10.5$\AA$ and that of the other active carbon was under 20.9$\AA$ but silica-gel 33$\AA$, sepiolite 103 $\AA$ and zeolite was unexpectedly large to be 175$\AA$. From the difference between BET micropore diameter and Howath - Kawazoe diameter, it could be said that silica - gel has comparatively uniform pore diameter but sepiolite and zeolite have very uneven diameter. 3. Total pore volume of coconut shell active carbon was 0.27-1.04 cm3/g but that of the other active carbon, 0.23-0.62 cm3/g, was much lower than that of coconut shell active carbon. Hydrophilic adsorbent silica - gel and sepiolite showed big difference in specific surface area, but pore volumes of these were 0.47 and 0.56 cm3/g showing similar value and micropore volumes of these were, respectively, 0.06 cm3/g and 0.04 cm3/g. Total pore volume of zeolite was 0.1 cm3/g and that of micropore was only 0.02 cm3/g.

• 한국환경보건학회지
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• 제19권4호
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• pp.25-32
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• 1993

Granular activated carbon is commonly used in fixed-bed adsorbers to remove organic chemicals. In this experiment organic chemical solutions were prepared by adding the reagent grade organic chemical to distilled water. Isotherm adsorption tests of volatile organic chemicals were conducted using bottle-point technique and column test. Organic chemicals after passing through the column were extracted with hexane and analyzed with gas chromatography (Hewlett-Packard 5890) to check the adsorption capacity and breakthrough curve. The result were as follows: 1. The BET surface area of coconut activated carbon was 658~1,010 m$^2$/g where as coconut shell carbon was 6.6 m$^2$/g. Coconut activated carbon increased the BET surface area and adsorption capacity in bottle-point isotherm. 2. The adsorption capacity of coconut activated carbon for trichloroethylene (TCE) was reduced in the presence of humic substance. 3. A decrease in particle size of activated carbon resulted in higher adsorption capacity and lower intraparticle diffusion coefficient. It is reflected not only as a decrease in Freudlich adsorption capacity value (K) but also as an increase in Freudlich exponenent value (1/n).

• Environmental Analysis Health and Toxicology
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• 제4권3_4호
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• pp.29-59
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• 1989

For the purpose of electrolytic treatment of wastewater containing various heavy metals, the BPBE Cell of batch and continuous type was considered and experimented. Some results from this study were summarized as follows: 1. When the artificial wastewater containing 500 mg/l of the concentration of various heavy metallic ion was electrolyzed in BPBE Cell of batch type, the removal efficicency was over 95% in cadmiun (II), lead (II), chromium (Ⅵ) and over 85% in copper (II), chromium (III). 2, As granular activated carbon packed in BPBE Cell, coconut shell was superior to lignite and the removal efficiency was the highest when the activated carbon was 4/6 mesh, the voltage was 20V. 3. When the heavy metallic ion in wastewater was electrolyzed in BPBE Cell of continuous type, about 1,000mg of heavy metal per 1kg of coconut sell could be removed. 4. The treatment method of heavy metallic ion in wastewater by BPBE Cell cost less than in the former chemical treatment method and the coconut shell packed in BPBE Cell could be regenerated by chemical method.

• 한국응용과학기술학회지
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• 제30권2호
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• pp.362-370
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• 2013

Coconut shell 계 상용 활성탄을 후처리하여 EDLC 전극재로 적용하였다. Coconut shell계 활성탄을 별도의 처리없이 EDLC 전극재로 사용하였을 때, 초기 무게용량 및 부피용량은 66 F/g 및 39 F/cc이었고, 100 사이클 충 방전을 반복한 후, 각각 54 F/g 및 32 F/cc로 감소하여 82%의 충 방전효율을 나타내었다. 충 방전 반복에 따른 용량의 감소폭이 크며, CV 특성에서 부반응에 의한 분극현상이 발생하여 전극재로 적합하지 않았다. 상업용 활성탄에 포함된 불순물을 효율적으로 제거하기 위하여 알칼리 및 산 처리를 하였고, 그 후 세공 분포와 표면의 산성 관능기 함량을 제어하기 위하여 질소 분위기에서 열처리하였다. 알칼리 및 질산처리 한 후 $800^{\circ}C$에서 열처리한 전극재의 경우, 초기부피용량 44 F/cc, 100사이클 후 42 F/cc로서 실용화 가능한 수준의 높은 부피용량 및 95% 이상의 높은 충 방전 효율을 나타내었다.

• Carbon letters
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• 제20권
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• pp.1-9
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• 2016

Activated carbon was synthesized from coconut shells. The Brunauer, Emmett and Teller surface area of the synthesized activated carbon was found to be 1640 m²/g with a pore volume of 1.032 cm³/g. The average pore diameter of the activated carbon was found to be 2.52 nm. By applying the size-strain plot method to the X-ray diffraction data, the crystallite size and the crystal strain was determined to be 42.46 nm and 0.000489897, respectively, which indicate a perfect crystallite structure. The field emission scanning electron microscopy image showed the presence of well-developed pores on the surface of the activated carbon. The presence of important functional groups was shown by the Fourier transform infrared spectroscopy spectrum. The adsorption of methyl orange onto the activated carbon reached 100% after 12 min. Kinetic analysis indicated that the adsorption of methyl orange solution by the activated carbon followed a pseudo-second-order kinetic mechanism (R² > 0.995). Therefore, the results show that the produced activated carbon can be used as a proper adsorbent for dye containing effluents.

• 환경위생공학
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• 제14권2호
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• pp.18-24
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• 1999

The purpose of this study was carried out to estimate removal possibility of IBMP and IPMP causing odor in raw water. As a result of Freundlich isotherm. IBMP was superior to IPMP in adsorptive capacity. Adsorptive capacities of activated carbon were found to be in order of Lignite, Coconut shell, and Charcoal. These were well fitted with Freundlich isotherm. According to adsorption breakthrough tests for Lignite GAC, breakthrough time of IPMP and IBMP were 5.7hr and 5.5hr, respectively. Because adsorptive capacities of target material were very different with pore size distribution, it seemed that Lignite and Coconut shell based activated carbons were recommended in order to remove door compounds.