• Journal of the Korea Organic Resources Recycling Association
• /
• v.23 no.1
• /
• pp.45-51
• /
• 2015

In this study, continuous microbial fuel cells (MFCs) were operated using non-precious metal catalysts such as iron(II) phthalocyanine (FePc) and cobalt tetramethoxyphenylporphyrin (CoTMPP)) as alternative cathode catalysts for platinum. To evaluate MFCs performance, operational conditions of organic loading rate (OLR) (0.5~3 g COD/L/d) and hydraulic retention rate (HRT) (0.25~1 day) were changed. Power density of MFCs were determined by cathode electrode performance. The maximum power density was $3.3W/m^3$ with platinum at OLR 3 g COD/L/d. Given each HRTs at 1 g COD/L/d, FePc showed to be a better alternative for platinum than CoTMPP because the power density of MFC with FePc was similar to that of MFC with platinum. CoTMPP catalyst, however, showed the lowest power density due to increase of internal resistance during continuous operation.

• Applied Chemistry for Engineering
• /
• v.24 no.1
• /
• pp.87-92
• /
• 2013

Nonthermal plasma hybridized with photocatalysts is proven to be an effective tool to degrade toxic organics in wastewater. In this study, a specially designed dielectric barrier discharge (DBD) plasma system combined with photocatalysts was applied to decompose pestiticides such as dichlorovos, carbofuran and methidathon, which are frequently used in the golf courses and the orange plantations. The degradations of the pesticides in single and coupled systems were evaluated. The single system was used with ozone plasma which consisted of electrons, radicals, ions produced by oxygen gas and air, with and without ultra-violet (UV) irradiation, respectively. The coupled systems utilized the air-derived ozone plasma combined with zinc oxide, titanium dioxide and graphite oxide photocatalyst activated by UV. The graphite oxide was synthesized by a modified Hummer's method and characterized using FTIR spectrometer. It was elucidated that the plasma reaction with graphite oxide (0.01 g/L) brought about almost 100% of degradation degrees for dichlorovos and carbofuran in 60 min, as compared with the performances showed by no catalyst condition. The photocatalyst-hybridized plasma in the presence of UV irradiation was proven to be an effective alternative for degrading pesticides.

• Journal of the Korea Convergence Society
• /
• v.12 no.2
• /
• pp.193-200
• /
• 2021

As the degree of environmental pollution caused by the use of fossil fuels intensifies, many countries continue to invest in the development of alternative energy. PEMFC, one of the alternative energies, consists of four main components: bipolor plate, electrolyte, gas diffusion layer, and electrode. Among them, bipolor plate, the gas diffusion layer, and electrode are generally manufactured using carbon materials such as carbon black and carbon fiber. These carbon materials are expensive in manufacturing process or have disadvantages such as corrosion, and research is being conducted in many fields to improve this. This paper collects several research results conducted to improve the shortcomings of these three components and examines the trends of PEMFC by grasping what problems have been and how they have improved.

• Applied Chemistry for Engineering
• /
• v.33 no.5
• /
• pp.538-544
• /
• 2022

One of the most exciting areas for the development of alternative fuels is the production of biodiesel. To reduce the cost of biodiesel production, in situ trans-esterification has been introduced to simplify the production process by enabling extraction and trans-esterification to occur at a single stage in the presence of a catalyst. In this study, we investigated the feasibility of using non-corrosive and environmentally receptive flying jet plasma as an alternative catalytic route for in situ tran-sesterification of castor bean seeds (CBS). Upon optimizing the reaction conditions, it is elucidated that applying a low ratio of methanol to seeds (≤6:1) has resulted in hindering the in situ trans-esterification and leading to insignificant conversion. The yield of esters has increased from 80.5% to 91.7% as the molar ratio rose from 9:1 to 12:1. Excess alcohol beyond the ratio of 15:1 was shown to have a negative impact on the yield of the produced esters, attributed to an increase in the biodiesel portion prone to dissolving in the co-product (glycerol). An increase in the reaction bulk temperature from 40 to 55 ℃ led to a higher ester content by 50%. Further increases in the bulk temperature beyond 55 ℃ did not affect yields. Regarding the reaction period, the results have shown that 3 h of reaction is adequate for a higher biodiesel yield. The quality of the biodiesel obtained has demonstrated that all physicochemical properties meet the ASTM D6751 specifications.

• KSBB Journal
• /
• v.23 no.4
• /
• pp.335-339
• /
• 2008

Biodiesel is an alternative and renewable energy source, which is hoped to reduce global dependence on petroleum and environmental problem. Biodiesel produced from a variety of oil sources such as vegetable oil, animal fat and waste oils, and has properties similar to those associated with petro-diesel, including cetane number, volumetric heating value, flash point, viscosity and so on. In this study, we investigate the effect of quality of raw materials on alkali-catalyzed transesterification for producing of biodiesel. The increase of content of free fatty acid and water in oil were caused the sharp decrease of conversion yield. Also, the low purity of methanol in reactant was inhibited the reaction rate. In the case of addition of sodium sulfate as absorbent to prepare catalyst solution, the content of fatty acid methyl ester in product was increased more about 1.6% than that of control. However, the addition of zeolite, sodium chloride and sodium sulfate as absorbent in reactant to remove water generated from reaction did not show any enhancement in the reaction yield. This result may provide useful information with regard to the choice and preparation of raw materials for more economic and efficient biodiesel production.

• Applied Chemistry for Engineering
• /
• v.21 no.6
• /
• pp.653-658
• /
• 2010

Biodiesel is well known for an eco-friendly alternative fuel for petrodiesel. But biodiesel has a disadvantage since it is derived from expensive food resource. In this study, we synthesized the biodiesel from duck's oil which was food trash via transesterification under base catalyst. After analytic result of density, kinematic viscosity, cold temperature characteristics, lubricity and cetane number which were main fuel characteristics, this duck's biodiesel has enough potential to use as fuel except only domestic winter season.

• Journal of the korean Society of Automotive Engineers
• /
• v.14 no.6
• /
• pp.67-73
• /
• 1992

This paper describes Hyundai's research and development work on a flexible fuel vehicle (FFV). The work on FFV has been conducted to evaluate its potential as an alternative to the conventional gasoline vehicle. Hyundai FFV described here can be operated on M85, gasoline, or any of their combinations, in which the methanol concentration is measured by an electrostatic type fuel sensor. For that operation, a special FFV ECU(Eletronic Control Unit) has been developed and incorporated in the FFV. The characteristics affecting FFV operation, such as FFV ECU control strategy and injector flow rate, have been investigated and optimized through the experiment. And various development tests have been performed in view of engine performance, durability, cold startability, and exhaust emissions reduction. The exhaust gas aftertreatment system consisting of manifold type catalyst and secondary air injection system shows good emission reduction performance including formaldehyde, and finally, the possibility of the FFVs as the low emission vehicles is evaluated by presenting NMOG(Non-Methane Organic Gases) levels with respect to M0 and M85. With these results, it is concluded that FFV can be a candidate for the low emission vehicles, but more works on its durability improvement is required.

• Asian Journal of Atmospheric Environment
• /
• v.4 no.2
• /
• pp.63-71
• /
• 2010

The removal characteristics for aromatic and aliphatic VOCs by electron beam (EB) were discussed in terms of several removal variables such as initial VOC concentration, absorbed dose, background gas, moisture content, reactor material and inlet temperature. It was reviewed that only reactor material was an independent variable among the potential control factors concerned. It was also suggested that main mechanism by EB should be radical reaction for the VOC removal rather than that by primary electrons. It was discussed that the removal efficiency of benzene was lower than that of hexane due to a closed benzene ring. In the case of aromatic VOCs, it was observed that the decomposition of the VOCs with more functional groups attached on the benzene ring was much easier than those with less ones. As for aliphatic VOCs, it was also implied that the longer carbon chain was, the higher the removal efficiency became. An EB-catalyst hybrid system was discussed as an alternative way to remove VOCs more effectively than EB-only system due to much less by-products. This hybrid included supporting materials such as cordierite, Y-zeolite, and $\gamma$-alumina.

• Journal of Electrochemical Science and Technology
• /
• v.10 no.3
• /
• pp.313-320
• /
• 2019

In this study, cobalt diselenide ($CoSe_2$) and the composites ($CoSe_2@RGO$) of $CoSe_2$ and reduced graphene oxide (RGO) were synthesized by a facile hydrothermal reaction using cobalt ions and selenide source with or without graphene oxide (GO). The formation of $CoSe_2@RGO$ composites was identified by analysis with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and scanning electron microscopy (SEM). Electrochemical analyses demonstrated that the $CoSe_2@RGO$ composites have excellent catalytic activity for the reduction of $I_3{^-}$, possibly indicating a synergetic effect of $CoSe_2$ and RGO. As a consequence, the $CoSe_2@RGO$ composites were applied as a counter electrode in DSSC for the reduction of redox couple electrolyte, and exhibiting the comparable power conversion efficiency (7.01%) to the rare metal platinum (Pt) based photovoltaic device (6.77%).

• Journal of Hydrogen and New Energy
• /
• v.30 no.2
• /
• pp.111-118
• /
• 2019

Greenhouse gas emissions have a profound effect on global warming. Various environmental regulations have been introduced to reduce the emissions. The largest amount of greenhouse gases, including carbon dioxide, is produced in the steel industry. To decrease carbon dioxide emission, hydrogen-based iron oxide reduction, which can replace carbon-based reduction has received a great attention. Iron production generates various by-product gases, such as cokes oven gas (COG), blast furnace gas (BFG), and Linz-Donawitz gas (LDG). In particular, COG, due to its high concentrations of hydrogen and methane, can be reformed to become a major source of hydrogen for reducing iron oxide. Nevertheless, continuous COG cannot be supplied under actual operation condition of steel industry. To solve this problem, this study proposed to use two alternative COG-based fuel mixtures; one with natural gas and the other with biogas. Reforming study on two types of mixed gas were carried out to evaluate catalyst performance under a variety of operating conditions. In addition, methane conversion and product composition were investigated both theoretically and experimentally.