• Environmental Engineering Research
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• v.23 no.4
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• pp.456-461
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• 2018

The solid-state anaerobic digestion (SS-AD) has promoted the development and application for biogas production from biomass which operate a high solid content feedstock, as higher than 15% of total solids. However, the digested byproduct of SS-AD can be used as a fertilizer or as solid fuel, but it has serious problems: high moisture content and poor dewaterability. The organic residue from SS-AD has to be improved to address these problems and to make it a useful alternative energy source. Hydrothermal carbonization was investigated for conversion of the organic residue from the SS-AD of livestock waste to solid fuels. The effects of hydrothermal carbonization were evaluated by varying the reaction temperatures within the range of $180-240^{\circ}C$. Hydrothermal carbonization increased the calorific value through the reduction of the hydrogen and oxygen contents of the solid fuel, in addition to its drying performance. Therefore, after the hydrothermal carbonization, the H/C and O/C atomic ratios decreased through the chemical conversion. Thermogravimatric analysis provided the changed combustion characteristics due to the improvement of the fuel properties. As a result, the hydrothermal carbonization process can be said to be an advantageous technology in terms of improving the properties of organic waste as a solid-recovered fuel product.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.297-301
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• 2009

Hydrogen peroxide, which is used in various crops as an oxidizer to improve high temperature adaptation, was evaluated on the effects on productivity and disease incidence in paprika (Capsicum annuum L.) by periodic leaf spray at summer. Hydrogen peroxide treatment not only increased the leaf thickness and SPAD (chlorophyll content) but also the fruit set numbers per plant by 2. Hydrogen peroxide content increase in leaf resulted in increase of catalase and peroxidase activities, and the powdery mildew disease (Leveillula taurica) was also suppressed by the treatment. Transpiration was improved by the reduced leaf stomata resistance in the hydrogen peroxide treatment. Therefore, hydrogen peroxide leaf spray is recommended for improvement of summer productivity in paprika.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.6
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• pp.609-628
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• 2015

Thie study presents the biomass-derived jet (bio-jet) fuel production technologies for greenhouse gas (GHG) reduction in aviation sector. The aviation sector is responsible for the 2% of the world anthropogenic $CO_2$ emissions and the 10% of the fuel consumption: airlines' costs for fuel reach 30% of operating costs. In addition, the aviation traffic is expected to double within 15 years from 2012, while fuel consumption and $CO_2$ emissions should double in 25 years. Biojet fuels have been claimed to be one of the most promising and strategic solutions to mitigate aviation emissions. This jet fuel, additionally, must meet ASTM International specifications and potentially be a100% drop-in replacement for current petroleum jet fuel. In this study, the current technologies for producing renewable jet fuels, categorized by alcohols-to-jet, oil-to-jet, syngas-to-jet, and sugar-to-jet pathways are reviewed for process, economic analysis and life cycle assessment (LCA) on conversion pathways to bio-jet fuel.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.66-73
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• 2012

Plant growth promoting traits like production of indoleacetic acid (IAA), ammonia, hydrogen cyanide (HCN), siderophore, and like the enzyme activities of catalase, ACC deaminase, cellulase, chitinase and protease were assayed in vitro for twenty one phosphorus solubilizing bacteria isolated from soil isolates. Except SPP-5 and SPP-15 strains, all the other isolated strains produced IAA in various amounts of 10 to $23{\mu}g\;ml^{-1}$. All strains showed positive response for ammonia production and ACC deaminase activity implying that they are capable of growing in a N-free basal medium. Catalase activity was found to be superior in SPP-2, SPP-7, SPP-12 and SPP-17 compared to the other strains tested. HCN production was detected by 15 strains and among them SPP-9, SPP-15, SAph-11, and SAph-24 were found to be strong HCN producers. Except the isolates SPP-10, SPP-12, SPP-13 and SPP-14, all the other isolates produced more than 80% siderophore units. None of the strains showed cellulose and chitinase activity. SAph-8, SAPh-11, SAPh-24 and SPP-15 strains showed 35.84, 50.33, 56.64 and 34.78 U/ml protease activities, respectively. SPP-1, SPP-2, SPP-3, SPP-11, SPP-17, SPP-18, SAph-11 and SAph-24 strains showed positive response for all the tested plant growth promotion traits except cell wall degrading enzyme activities. According to the results, all the tested phosphorus solubilizing isolates could exhibit more than three or four plant growth promoting traits, which may promote plant growth directly or indirectly or synergistically. Therefore, these phosphorus solubilizing strains could be employed as bio-inoculants for agriculture soils.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2787-2790
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• 2014

Quercetin is a major dietary flavonoid found in onions, apples, tea, and red wine, and potentially has beneficial effects on disease prevention. We carried out this study to investigate the effect of quercetin on UVB-induced matrix metalloproteinase-1 (MMP-1) expression in human keratinocyte HaCaT cells and to further understand the mechanisms of its action. The anti-inflammatory activity of quercetin was investigated and quercetin significantly suppressed the NO production in LPS-stimulated RAW264.7 mouse macrophages. Post treatment of quercetin decreased UV irradiation-induced phosphorylation of JNK, p38 MAPK, and ERK by 91%, 21%, and 17%, respectively. MMP-1 is mainly responsible for the degradation of dermal collagen during the aging process of human skin and quercetin suppressed the UVB-induced MMP-1 by 94%. Binding studies revealed that quercetin binds to p38 with high binding affinity ($1.85{\times}10^6M^{-1}$). The binding model showed that the 4'-hydroxy groups of the B-ring of quercetin participated in hydrogen bonding interactions with the side chains of Lys53, Glu71, and Asp168 and the 5-hydroxy group of the A-ring formed a hydrogen bond with the backbone amide of Met109. The major finding of this study shows that quercetin inhibits phosphorylation of JNK, p38 MAPK, and ERK pathway leading to the prevention of MMP-1 expression in human keratinocyte HaCaT cells. Therefore, our findings suggested the potentials of quercetin as a skin anti-photoaging agent.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1654-1658
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• 2014

High value-added aromatic aldehydes (e.g. vanillin and syringaldehyde) were produced from heavy fraction of bio-oil (HFBO) via catalytic oxidation. The concept is based on the use of metalloporphyin as catalyst and hydrogen peroxide ($H_2O_2$) as oxidant under alkaline condition. The biomimetic catalyst cobalt(II)-sulfonated tetraphenylporphyrin ($Co(TPPS_4)$) was prepared and characterized. It exhibited relative high activity in the catalytic oxidation of HFBO. 4.57 wt % vanillin and 1.58 wt % syringaldehyde were obtained from catalytic oxidation of HFBO, compared to 2.6 wt % vanillin and 0.86 wt % syringaldehyde without $Co(TPPS_4)$. Moreover, a possible mechanism of HFBO oxidation using $Co(TPPS_4)/H_2O_2$ was proposed by the research of model compounds. The results showed that this is a promising and environmentally friendly method for production of aromatic aldehydes from HFBO under $Co(TPPS_4)/H_2O_2$ system.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.4
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• pp.43-49
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• 2008

Objective of this study was to monitor the hydrogen sulfide production rate and concentration in anaerobic co-digestion of swine manure and food waste for biogas production in order to alternate the petroleum based energy. Anaerobic co-digestion for biogas production was performed in serum bottles at 2% volatile solids (VS) concentration and various mixing ratios of two substrates(swine manure: food waste = 100:0 ~ 0:100). Although hydrogen sulfide production rates were varied with digestion periods at different treatments, it was observed that hydrogen sulfide produced in the swine manure alone was lower at 2.4 fold than that of food waste. For effects of hydrogen sulfide concentration in the different mixing ratios of swine manure to food waste, the higher food waste ratio the higher hydrogen sulfide concentration. Also its average concentrations were varied from 0.1452% in the swine waste only to 0.3420% in the food waste alone. For the composition ratio of bio-gas in their anaerobic co-digestion, it appeared that there was 53.2% of $CH_4$, 23.9% of $CO_2$, 0.3% of $H_2S$ and 22.7% of miscellaneous gases including moisture.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.1
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• pp.52-64
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• 2002

유기성 폐기물을 이용하여 생물학적 수소생산 통합화 시스템 연구를 수행하였다. 통합화 시스템은 유기성폐기물의 전처리, 2단계 혐기발효 및 광합성 배양으로 구성된 생물학적 수소생산 공정, 초임계수 가스화 공정, 생산된 가스의 저장, 분리 및 연료전지를 이용한 전력 생산으로 구성되었다. 실험에 사용된 유기성 폐자원은 식품공장 폐수, 과일폐기물, 하수슬러지이며, 전처리는 폐기물에 따라 열처리 및 물리적 처리를 하였으며, 전처리된 시료는 생물학적 수소생산 공정에 직접 적용되었다. Clostridium butyricum 및 메탄 생성조에서 발생하는 하수슬러지중의 미생물 복합체는 수소생산 혐기 발효공정에 사용되었으며, 광합성 수소생산 미생물인 홍색 비유황 세균은 광합성 배양에 사용되었다. 생물학적 공정에서 발생하는 미생물 슬러지는 초임계수 가스화 공정으로 수소를 발생하였으며, 슬러지 중의 COD를 저하시켰다. 생물학적 공정 및 초임계수 가스화 공정에서 발생하는 수소는 가스탱크에 가입상태로 저장한 후, 95%순도로 분리하였으며, 정제된 수소는 연료전지에 연결하여 전력 생산을 하였다.

• Carbon letters
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• v.13 no.1
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• pp.48-50
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• 2012

Mass production of graphene-based materials, which have high specific surface area, is of importance for industrial applications. Herein, we report on a facile approach to produce thermally modified graphene oxide (TMG) in large quantities. We performed this experiment with a hot plate under environments that have relatively low temperature and no using inert gas. TMG materials showed a high specific surface area (430 $m^2g^{-1}$). Successful reduction was confirmed by elemental analysis, X-ray photoelectron spectroscopy, thermogravimetic analysis, and X-ray diffraction. The resulting materials might be useful for various applications such as in rechargeable batteries, as hydrogen storage materials, as nano-fillers in composites, in ultracapacitors, and in chemical/bio sensors.

• New & Renewable Energy
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• v.9 no.1
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• pp.51-59
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• 2013

Tantalum carbide crystallites which is to be used for $H_2$ fuel cell has been synthesized via a temperature-programmed reduction of $Ta_2O_5$ with pure $CH_4$. The resultant Ta carbide crystallites prepared using two different heating rates and space velocity exhibit the different surface areas. The $O_2$ uptake has a linear relation with surface area, corresponding to an oxygen capacity of $1.36{\times}10^{13}\;O\;cm^{-2}$. Tantalum carbide crystallites are very active for hydrogen production form ammonia decomposition reaction. Tantalum carbides are as much as two orders of magnitude more active than Pt/C catalyst (Engelhard). The highest activity has been observed at a ratio of $C_1/Ta^{{\delta}+}=0.85$, suggesting the presence of electron transfer between metals and carbon in metal carbides.