• 농업과학연구
• /
• 제49권2호
• /
• pp.357-366
• /
• 2022

Biochar can be obtained by using various types of biomass under an oxygen-limited condition. Biochar can be utilized for various applications such as soil improvement, waste management, growth promotion, and adsorption. Wood vinegar is produced by the process of pyrolysis wood biomass and is used as a growth promoter, for soil improvement, and as a feed additive. When wood vinegar is treated on soil, it acts to control soil pH, improve nutrient availability, and alleviate N₂O and NH₃ volatilization. The objective of this study was to evaluate the effect of biochar and wood vinegar on the growth of perilla and soil quality. The experiment was conducted by using a Wagner pot (1·5,000 a^-1) in a glass greenhouse. The biochar was produced by pyrolysis at 450℃ for 30 minutes using rice husk and rice straw. Wood vinegar was diluted to 1 : 500 (v·v^-1) and used in this experiement. In the results of a cultivation experiment, co-application of biochar and wood vinegar enhanced the growth of perilla. In particular, rice husk biochar affected the leaves of the perilla, and rice straw biochar influenced the stems of the perilla. In addition, soil quality after treatment with biochar and wood vinegar applied together was highest compared to other units. Therefore, it is anticipated that co-application of biochar and wood vinegar will be more productive and improve soil quality compared to individual utilization of biochar and wood vinegar.

• 농업과학연구
• /
• 제25권1호
• /
• pp.89-96
• /
• 1998

이 연구는 폴리머를 결합재로 사용하고 시멘트와 왕겨재를 충전재로 혼입한 투수용 폴리머 콘크리트의 공학적 성질을 구명한 것으로서, 이 연구를 통해 얻어진 결과를 요약하면 다음과 같다. 1. 각 강도는 시멘트와 왕겨재를 중량비로 반반씩 충전재로 사용한 투수용 폴리머 콘크리트에서 가장 크게 나타났고, 보통 시멘트 콘크리트보다 압축강도에서는 24%, 인장강도에서는 123%, 휨강도에서는 90%가 증가되었다. 2. 정탄성계수는 $1.27{\times}10^5{\sim}1.75{\times}10^5kgf/cm^2$으로 보통 시멘트 콘크리트의 58~70%정도로서 변형성이 크게 나타났으며, 충전재로는 시멘트와 왕겨재를 중량비로 반반씩 사용한 투수용 폴리머 콘크리트에서 가장 높은 값을 보였고 왕겨재의 혼입량이 많을수록 높은 값을 보였으며, 포아손수는 3.140~5.314로 보통 시멘트 콘크리트보다 작게 나타났다. 3. 초음파진동속도는 2,503~3,083m/sec로서 보통 시멘트 콘크리트와 거의 비슷하게 나타났으며, 시멘트와 왕겨재를 반반씩 충전재로 사용한 투수용 폴리머 콘크리트에서 비교적 높은 값을 보였다. 4. 투수량은 $4.612{\sim}5.913{\ell}/cm^2/hr$로서 배합설계에 따라 크게 좌우되었으며, 이러한 콘크리트는 투수를 요하는 구조물에 유용하게 이용할 수 있을 것이다.

• Carbon letters
• /
• 제13권2호
• /
• pp.61-72
• /
• 2012

Dye removal from waste water via adsorption by activated carbons (ACs) developed from agricultural wastes represents an ideal alternative to other expensive treatment options. Physical and chemical ACs were prepared from rice husks. The textural properties of the ACs were characterized by Brunauer-Emmett-Teller-$N_2$ adsorption and scanning electron microscopy. The chemistry of the carbon surface was investigated by Fourier transform infrared spectroscopy, base and acid neutralization capacities, pH of the active carbon slurry, and $pH_{pzc}$. The adsorption capacities of the ACs for the basic dye (methylene blue) and acid dye (acid green 25) were determined using parameters such as contact time, pH, and temperature. NaOH-ACs showed the highest surface area and total pore volume, whereas steam-ACs showed the lowest ones.

• 펄프종이기술
• /
• 제44권3호
• /
• pp.79-85
• /
• 2012

In this study, purified cellulose was prepared from rice husk which is one of the major agricultural residues in Korea. The various bleaching processes such as ozone bleaching, $ClO_2$ bleaching and $H_2O_2$ bleaching were applied to remove residual lignin and impurities. In order to increase the contents of ${\alpha}$-cellulose contents, the effects of acid and alkali treatments were evaluated. Although the multi stages of the bleaching processes resulted in less than 0.5 % residual lignin contents, the application of ozone leaded to the decrease in DP(degree in Polymerization) and ${\alpha}$-cellulose contents. The alkali treatment after bleaching processes resulted in pure cellulose which showed more than 98% of ${\alpha}$-cellulose contents.

• 한국재료학회지
• /
• 제22권6호
• /
• pp.321-327
• /
• 2012

The production of functional activated carbon materials starting from inexpensive natural precursors using environmentally friendly and economically effective processes has attracted much attention in the areas of material science and technology. In particular, the use of plant biomass to produce functional carbonaceous materials has attracted a great deal of attention in various aspects. In this study the preparation of activated carbon has been attempted from rice husks via a chemical activation-assisted microwave system. The rice husks were milled via attrition milling with aluminum balls, and then carbonized under purified $N_2$. The operational parameters including the activation agents, chemical impregnation weight ratio of the calcined rice husk to KOH (1:1, 1:2 and 1:4), microwave power heating within irradiation time (3-5 min), and the second activation process on the adsorption capability were investigated. Experimental results were investigated using XRD, FT-IR, and SEM. It was found that the BET surface area of activated carbons irrespective of the activation agent resulted in surface area. The activated carbons prepared by microwave heating with an activation process have higher surface area and larger average pore size than those prepared by activation without microwave heating when the ratio with KOH solution was the same. The activation time using microwave heating and the chemical impregnation ratio with KOH solution were varied to determine the optimal method for obtaining high surface area activated carbon (1505 $m^2$/g).

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1998년도 동계 학술대회 논문집
• /
• pp.250-258
• /
• 1998

• Journal of Biosystems Engineering
• /
• 제9권1호
• /
• pp.22-33
• /
• 1984

Husk separator is an indispensable equipment in rice milling plants. However, any basic research on the designing and operating criteria of the husk separator have rarely been conducted in Korea. According to the survey results reported recently, grain loss occurs in the process of rice husk separation at custom rice milling plants in Korea and the performance of husk separator has also not been identified. With this regard this study was conducted with a typical commercial husk separator to investigate the effect of the operational factors such as feed rate, blower speed and opening ratio on the velocity distribution in the air duct and the performance of the separator. The results are summerized as follows: 1. The average wind velocity in the primary air duct increased linearly with the blower rpm and the size of air inlet port in both cases of double type and single type operations. 2. The coefficient of variation in the horizontal wind velocities in the primary air duct was the minimum when the opening ratio was 0.22 ($0.052m^2$ of air inlet port) in both cases of single type and double type operations regardless of the blower speeds used in this test. The average wind velocity at the upper part of air duct was greater by 2-5 m/s than the velocity at the bottom part in double type operation. In case of single type operation, however, the average velocity in the middle part was greater than the upper or bottom part when the opening ratio was greater than 0.74. 3. The relationship between the overall effectiveness of separation(Ed for double type and Es for single type) and the average wind velocity (Va) in the primary air duct was expressed in the following quadratic functions. $$Ed=-190.84+106.18Va-10.052Va^2$$ ($r^2$ = 0.97782) $$Es=-223.76+106.23Va-9.1935Va^2$$ ($r^2$ = 0.97029) The average wind velocity required to obtain the overall effectiveness of separation more than 80% ranged from 4.04 m/sec to 5.84 m/sec in case of double type operation, and from 4.70 m/sec to 6.20 m/sec in case of single type. 4. An optimum wind velocity can be obtained with an increase in the blower speed or the size of air inlet port as presented in Figure 8. There was a tendency that the faster the blower speed, the narrower the control range of the air inlet port. 5. The feed rates (1850kg/hr and 2100kg/hr) adopted in this experiment did not bring about a significant difference in both the overall effectiveness of separation and the power consumption. 6. The energy consumption increased cubically with the blower speed but linearly with the size of the air inlet port. On the basis of the results described in items 1, 3, and 6, it would be more economic to adjust the size of the air inlet port larger with a relatively low blower speed than to adjust the size smaller with a relatively high speed.

• 펄프종이기술
• /
• 제46권5호
• /
• pp.43-50
• /
• 2014

The cultivation of agricultural crops results in the generation of agricultural byproducts. Researchers have reported that these materials can be useful in a variety of applications. However, over 50% of them are currently discarded because of the lack of specific technologies in industrial applications. Therefore, effective and specific applications must be developed in order to manufacture high-quality materials using discarded lignocellulosic resources. In this study, we determined the possibility of using kraft pulp from major agricultural byproducts as a raw material for the manufacture of paperboard. Rice husks, peanut husks, and garlic stems were obtained and used to prepare many kinds of kraft pulps by controlling the active alkali, sulfidity, reaction time, and liquor ratio. After the production of these kraft pulps, handsheets were manufactured by mixing them with KOCC. After preconditioning, the physical properties and strengths of the handsheets were measured according to the TAPPI test methods. The shapes, lengths, and widths of the pulp fibers varied according to the type of agricultural byproduct and the kraft pulping conditions. Rice husk and garlic stem pulps manufactured under mild pulping conditions resulted in handsheets of higher bulk than other pulps. Garlic stem pulps manufactured under mild pulping conditions were stronger than rice husk pulps and peanut husk pulps.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2020년도 봄 학술논문 발표대회
• /
• pp.187-188
• /
• 2020

Recently, some researchers have found, as a part of the development of new materials, the rice straw ash can also be used as a pozzolanic material for concrete considering similar chemical properties of rice straw ash to that of rice husk ash. Therefore, the purpose of this study was to improve compressive strength of concrete adding agriculture by-product. Compressive strength were tested on rice straw ashes at 600℃ to identify improving strength effect.

• 한국재료학회지
• /
• 제23권11호
• /
• pp.643-648
• /
• 2013

Activated carbon (AC) was synthesized from rice husks using the chemical activation method with KOH, NaOH, a combination of (NaOH + $Na_2CO_3$), and a combination of (KOH + $K_2CO_3$) as the chemical activating reagents. The activated carbon with the highest surface area (around $2000m^2/g$) and high porosity, which allows the absorption of a large number of ions, was applied as electrode material in electric double layer capacitors (EDLCs). The AC for EDLC electrodes is required to have a high surface area and an optimal pore size distribution; these are important to attain high specific capacitance of the EDLC electrodes. The electrodes were fabricated by compounding the rice husk activated carbons with super-P and mixed with polyvinylidene difluoride (PVDF) at a weight ratio of 83:10:7. AC electrodes and nickel foams were assembled with potassium hydroxide (KOH) solution as the electrolyte. Electrochemical measurements were carried out with a three electrode cell using 6 M KOH as electrolyte and Hg/HgO as the reference electrode. The specific capacitance strongly depends on the pore structure; the highest specific capacitance was 179 F/g, obtained for the AC with the highest specific surface area. Additionally, different activation times, levels of heating, and chemical reagents were used to compare and determine the optimal parameters for obtaining high surface area of the activated carbon.