• Carbon letters
• /
• v.19
• /
• pp.66-71
• /
• 2016

The development of nanostructured functional materials derived from biomass and/or waste is of growing importance for creating sustainable energy-storage systems. In this study, nanoporous carbonaceous materials containing numerous heteroatoms were fabricated from waste coffee grounds using a top-down process via simple heating with KOH. The nanoporous carbon nanosheets exhibited notable material properties such as high specific surface area (1960.1 m² g⁻¹), numerous redox-active heteroatoms (16.1 at% oxygen, 2.7 at% nitrogen, and 1.6 at% sulfur), and high aspect ratios (>100). These unique properties led to good electrochemical performance as supercapacitor electrodes. A specific capacitance of ~438.5 F g⁻¹ was achieved at a scan rate of 2 mV s⁻¹, and a capacitance of 176 F g⁻¹ was maintained at a fast scan rate of 100 mV s⁻¹. Furthermore, cyclic stability was achieved for over 2000 cycles.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.3
• /
• pp.371-377
• /
• 2012

The present study describes medium-chain-length polyhydroxyalkanoates (mcl-PHAs) production by the Pseudomonas Gl01 strain isolated from mixed microbial communities utilized for PHAs synthesis. A two-step fed-batch fermentation was conducted with glucose and waste rapeseed oil as the main carbon source for obtaining cell growth and mcl-PHAs accumulation, respectively. The results show that the Pseudomonas Gl01 strain is capable of growing and accumulating mcl-PHAs using a waste oily carbon source. The biomass value reached 3.0 g/l of CDW with 20% of PHAs content within 48 h of cultivation. The polymer was purified from lyophilized cells and analyzed by gas chromatography (GC). The results revealed that the monomeric composition of the obtained polyesters depended on the available substrate. When glucose was used in the growth phase, 3-hydroxyundecanoate and 3-hydroxydodecanoate were found in the polymer composition, whereas in the PHAs-accumulating stage, the Pseudomonas Gl01 strain synthesized mcl-PHAs consisting mainly of 3-hydroxyoctanoate and 3-hydroxydecanoate. The transcriptional analysis using reverse-transcription real-time PCR reaction revealed that the phaC1 gene could be transcribed simultaneously to the phaZ gene.

• Environmental Engineering Research
• /
• v.23 no.4
• /
• pp.456-461
• /
• 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 the Korea Organic Resources Recycling Association
• /
• v.12 no.2
• /
• pp.91-100
• /
• 2004

This study was on a recyling system of food waste using poultry and earthworms. Food waste was fed to the egg-raising hens(Gallus gallus) or ducks(Anas platyrynchos). And the excrement of poultry after ingestion of food waste was mixed with other organic waste such as paper mill sludge or night soil sludge, aged and then provided to the earthworms(Eisenia andrei). An egg-raising hen and a duck ate up 0.40kg and 0.79kg of food waste per day, respectively. And the percental rate of exctretion(the amount of excrement/the amount of food waste eaten up) of an egg-raising hen and a duck was 71.0% and 53.7%, respectively. The excrement of poultry that had been mixed with paper mill sludge and aged was vermicomposted more easily than the excrement that had been mixed with night soil sludge and aged. The excrement of poultry aged for more than 21 days was more suitable to vermicompost than the excrement of poultry aged for less than 21 days. Even though, the earthworm lost its biomass on the mixed feeds regardless of their aging periods, which was supposed to be caused by high salinity in poulty's excrements.

• Clean Technology
• /
• v.29 no.4
• /
• pp.272-278
• /
• 2023

There is a lot of interest in methods for pollutants using adsorption, and recent research is being conducted to show that biochar can be used to remove organic and inorganic pollutants. In particular, wood waste as waste biomass requires a biomass recycling method, and a method to increase the adsorption capacity of biochar produced using wood waste is needed. Biochar is created by Hydrothermal carbonization (HTC) using, which uses low temperature and high pressure, has low energy consumption and does not require moisture removal pretreatment, and biochar is created through chemical activation using KOH, NaOH, and ZnCl₂ chemicals. The adsorption characteristics of biochar were determined by analyzing iodine adsorptivity, specific surface area, pore diameter, pore volume, pore distribution, and SEM according to the activation. The results of analyzing the selecting biochar by activating the biochar produced at HTC 300℃, 4 hr by KOH, NaOH, and ZnCl₂ chemicals, the specific surface area was 774~1.387 m²/g, showing a high specific surface area similar to activated carbon, and it was confirmed that micropores with an average pore diameter in the range of 21~24 Å were formed. As a result of SEM observation, the surface was uniform with a certain shape depending on activation. It was confirmed that one pore was developed and the number of pores increased.

• Korean Journal of Environmental Biology
• /
• v.37 no.4
• /
• pp.741-748
• /
• 2019

As the occurrence of harmful algal blooms (HABs) have become severe in precious water resources, the development of efficient harmful algae treatment methods is considering as an important environmental issue for sustainable conservation of water resources. To treat HABs in water resources, various conventional physical and chemical methods have been utilized and showed treatment efficiency, However, these methods can lead to discharging of cyanotoxins into the water bodies by chemical or physical algal cell lysis or destruction. Thus, to overcome this limitation, the development of safe HABs treatment methods is required. In the present study, adsorption technology was investigated for the removal of harmful algal species, Microcystis aeruginosa from aqueous phases. Industrial waste biomass, Corynebacterium glutamicum biomass was valorized as biosorbent (PEI-modified alginate/biomass composite fiber; PEI-AlgBF) for M. aeruginosa through immobilization with alginate matrix and cationic polymer (polyethylenimine; PEI) coating. The functional groups characteristic of PEI-Alg was determined using FT-IR analysis. By adsorption process used PEI-AlgBF, 52 and 67% of M. aeruginosa could be removed under the initial density of M. aeruginosa 200×10⁴ cells mL^-1 and 50×10⁴ cells mL^-1, respectively. As the increasing surface area of PEI-AlgBF, the removal efficiency was increased. In addition, we could find that adsorptive removal of M. aeruginosa has occurred without any M. aeruginosa cell lysis and destruction.

• Clean Technology
• /
• v.17 no.4
• /
• pp.336-345
• /
• 2011

The total area of forest land in Korea is 64.2%, and significant forest resources can continuously be produced. However our country didn't separate the recyclable waste wood and was illegal landfill or incinerated. In this study, waste-wood and rice husk of biomass and low-grade-anthracite made refuse derived fuel by mixing and compressing. In addition, the binding effect of binders and additives were analyzed. Physical and chemical characteristics of manufactured refuse derived fuel were analyzed and evaluated suitability by compared with quality standards. A result of change with compressed and relaxed density, added 20% anthracite and 10% rice husk is optimal density change and average density increased large range when 20 wt.% P.V.A., guargum, molasses and 10 wt.% starch were added. All fuel samples be distributed over 3,500 kcal/kg LHV and grade of No. 3~4 fuels appeared. A result of the characteristics of physical and chemical compressed biomass refuse derived fuel with addictive, 12.9% of durability improvement appeared when is mixing asphalt and 5.8% of durability improvement appeared when is mixing rice bran by pretreatment of NaOH 5%.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.3
• /
• pp.123-129
• /
• 1999

The utilization methods of algae biomass have been studied constantly in whole world. These are $\circled1$the wastewater treatment if waste stabilization pond and oxidation ditch etc. and $\circled2$the biosorption of heavy metals and recovery of strategic' precious metals and $\circled3$the single-celled protein production and the production of chemicals like coloring agent and $\circled4$the production of electric energy through methane gasification. The culture system also has been developed constantly in relation with such utilization method developments. In the result of experimental operation under continuous and cyclic irradiation of light, using high rate algae biomass culture pond(HRABCP), which had been made so as to be an association system with the various items which had been managed to have high efficiency for algae culture, the algae production of the 12 hours-irradiance pond was 41.48 Chlorophyll-a ${\mu}g/L$ only in spite of having the more chance of $CO_2$ synthesis to algae cell than the 24 hours-irradiance pond. This means that the energy supply required for dark-reaction of photosynthesis is very important like this. The difference of algae production between continuous and cyclc irradiation explains that the dark-reaction of photosynthesis acts on algae production as the biggest primary factor. The continuous irradiance on HRABCP made the good algae-production($1403.97{\;}{\mu}g$ Chlorophyll-a/mg) and the good oxygen-production(5.8 mg $O_2/L$) and the good solid-liquid seperation. especially, DO concentration through the oxygen-production was enough to fishes' survival.

• Journal of Korean Society for Atmospheric Environment
• /
• v.30 no.1
• /
• pp.48-58
• /
• 2014

It is very important to investigate air pollutants emissions emitted from open burning in order to control nonpoint sources effectively. In this study, we utilized incineration simulator proposed by U.S EPA and investigated emissions of CO, OC/EC, from household waste and biomass burning to estimate pollutant emissions by illegal incineration of biomass wastes. Emission factor of OC was estimated as 17.1 g/kg for rice strew, 23.5 g/kg for barley, 10.3 g/kg for corn stover, 4.3 g/kg for unseasoned wood, respectively. In case of EC, it was calculated as 1.6 g/kg for rice strew, 4.3 g/kg for barley, 1.4 g/kg for corn stover, 0.6 g/kg for unseasoned wood, respectively. Most of the pollutants emissions were emitted at the stage 1 and 2. In the stage 3, the pollutants concentration decreased gradually. To estimate emissions and build inventory for biomass burning, we need to know accurate activity data. We, therefore, used activity data of both survey results of previous study and statistical data of National Statistical Office. However, we need to perform additional experiments in the future to obtain more accurate activity data for various cases.

• Asian Journal of Atmospheric Environment
• /
• v.11 no.3
• /
• pp.165-175
• /
• 2017

In Japan, the primary carbonaceous particles emitted from motor vehicles and waste incinerators have been reduced due to strict regulations against exhaust gas. However, the relative contribution of carbonaceous particles derived from plants and biomass has been increasing. Accordingly, compositional analysis of carbonaceous particles has become increasingly important to determine the sources and types of particles produced. To reveal the sources of the organic particles contained in particulate matter with diameters of ${\leq}2.5{\mu}m$ ($PM_{2.5}$) and the processes involved in their generation, we analyzed molecular marker compounds (2-methyltetrols, cis-pinonic acid, and levoglucosan) derived from the plants and biomass in the $PM_{2.5}$ collected during daytime- and nighttime-sampling periods in summer (July and August) and autumn (November) in Kazo, which is in the northern area of Saitama prefecture, Japan. We also measured $^{14}C$ carbonaceous concentrations in the same $PM_{2.5}$ samples. The concentrations of 2-methyltetrols were higher in the summer than in the autumn. Because the deciduous period overlaps with this decrease in the levels of 2-methyltetrols, we considered the emission source to broad-leaved trees. In contrast, the emission source of the cis-pinonic acid precursor was considered to be conifers, because its concentration remained almost constant throughout the year. The concentration of levoglucosan was considerably increased in the autumn due to frequent biomass open burning. The ratio of plant-derived carbon to total carbon, obtained by measuring of $^{14}C$, in summer $PM_{2.5}$ sample was higher in the nighttime, and could be influenced by anthropogenic sources during the daytime.