• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.114-121
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• 2020

BACKGROUND: Biochar-based fertilizers delay the nutrient release and feature a slow release effect for agricultural and environmental advantages. This experiment was conducted to evaluate agro-environmental effects of different application ratios of modified biochar pellets supplemented. METHODS AND RESULTS: The treatments consisted of the control, 40% N, 60% N and 60% N (0.07M MgO) of modified supplemented biochar pellets (MSBP), which were based on recommended ratio of nitrogen for rice cultivation. For the paddy water, the NH₄-N and NO₃-N concentrations in whole treatments rapidly increased at 84 days and 40 days after transplanting, respectively. The PO4-P concentrations in the MSBP were generally lower than those of the control. For the paddy soil, NH₄-N concentrations in the MSBP were higher than those of the control at 5 days after transplanting, while NO₃-N concentrations were not significantly different in the treatments through rice cultivation. P₂O₅ concentrations in the control were higher than those of the MSBP until 40 days after transplanting while K₂O concentrations were not significantly different among the treatment. The highest carbon sequestration was 970 kg ha^-1 in the 60% N (0.07M MgO), and the potential carbon storage in the 60% N (0.07M MgO) was higher at 222 kg ha^-1 than the control during rice cultivation. It shown that the rice yield in the control was not significantly different from the 40% N and 60% N (0.07M MgO) application plots. CONCLUSION: Application of MSBP for rice cultivation was effective for carbon sequestration and agro-environmental effects even though nitrogen application ratio was reduced at 40% based on recommended application ratio of fertilizer.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.529-533
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• 2017

In this work, a new type of biosorbent was prepared from the biochar of Liriodendron tulipifera L. by adding an activation process using water vapor. By using the biosorbent, the removal characteristics of nikel ions in the water phase were investigated. When the equilibrium experiments to remove both 5 and 10 mg/L of nikel ions were performed, the adsorption amount of nickel ions was 4.2 and 5.4 mg/g, respectively. Also, the optimal initial pH was 6 to increase the removal efficiency with respect to two different nickel concentrations of 5 and 10 mg/L. To enhance the removal efficiency of 10 mg/L of nikel ions, a chemical treatment using critic acid was applied for the biosorbent. In addition, 100% removal efficiency was observed for 10 mg/L of nikel ions when the experiment was conducted for 2 h using the modified biosorbent treated by 4 M of critic acid. The results of desorption experiment to recover nikel ions indicated that 0.1 M of nitrilotriacetic acid (NTA) was selected as the optimal desorption agent. Consequently, these experimental results could be employed as an economical and environmentally friendly technology for the development of nickel removal processes.

• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.275-282
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• 2020

As pesticide safety was extended to agricultural environments and Positive List System was carried out, Pesticide safety management in soils has become even more important. To improve pesticide safety in soils needs the degradation technology of the residues in soils and reduce plant uptake of pesticides. In this study, biochars and quicklime as the degradation methods of pesticides (azoxystrboin, procymidone and tricyclazole) were used to identify the reduction effects. The experimental methods were putting biochars and quicklimes (0, 0.5, 1.0, 2.0% per 15 cm soil weight) in soils and analyzing the pesticide residues at 0, 10, 20, 35, 50 day. To identify the reduction effects of uptake from soil to korean cabbages (roots, leave, stems) by biochar treatment, the residues in samples were analyzed. As a results, azoxystrobin (36-96%), procymidone (40-117%) and tricyclazole (26-83%) were reduced in soils when treated with 2.0% quicklime (p<0.05). There were no reduction effect in soils when treated with 1.0% or less biochar. However, the amounts of residues translocated to roots (0.11-1.62 mg/kg), leave (0.05-0.29 mg/kg), stems (0.06-0.1 mg/kg) were reduced treated with 2.0% biochar treatments. The biochar and quicklime can be applicable to agricultural field to improve pesticide safety in soils.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.332-339
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• 2015

The objective of this study was to evaluate the effectiveness of different biochars on the removal of heavy metals from aqueous media. The experiment was carried out in aqueous solutions containing $200mg\;CdL^{-1}$ or $200mg\;PbL^{-1}$ using two different biochars derived from soybean stover and orange peel (20 mg Cd or $Pbg^{-1}$ biochar). After shaking for 24 hours, biochars were filtered out, and Cd and Pb in the filtrate were analyzed by flame atomic absorption spectrophotometer (FAAS). In order to provide information regarding metal binding strength on biochars, sequential extraction was performed by modified SM&T (formerly BCR). The results showed that 70~100% of initially added Cd and Pb was adsorbed on biochars and removed from aqueous solution. The removal rate of Pb (95%, 100%) was higher than that of Cd (70%, 91%). In the case of Cd, orange peel derived biochar (91%) showed higher adsorption rate than soybean stover derived biochar (70%). Cd was adsorbed on the biochar mainly in exchangeable and carbonates fraction (1st phase). In contrast, Pb was adsorbed on it mainly in the form of Fe-Mn oxides and residual fraction (2nd and 4th phase). The existence of Cd and Pb as a form of surface-precipitated complex was also observed on the surfaces of biochars detected by field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectrometer (EDAX).

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.49-56
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• 2019

This experiment was conducted to select an optimum application rate of blended biochar pellet as slow release fertilizer during cabbage cultivation. The blended biochar pellet made with a combination(4:6) of biochar and pig manure compost with unloading N, P, K solutions for adjusting about 9% of total nitrogen(TN). The treatments were consisted of the control as recommended application rates for cabbage cultivation in National Institute of Agricultural Sciences, N 40%, N 40% and 0.07M MgO and N 60 % of the blended biochar pellet, respectively, based on nitrogen application of recommended rates to cabbage cultivation. Changes of $NH_4-N$, $NO_3-N$, $P_2O_5$ and $K_2O$ concentrations in the soil and growth characteristic and yield components were investigated and observed during the cabbage cultivation. The experimental result shown that contents of $NH_4-N$, $NO_3-N$ and $K_2O$ of soil in the N 40% were significantly difference(p<0.01) with the control. $P_2O_5$ concentrations of soil in the N 40% were highest among the treatments. The fresh weight per cabbage in the N 40% was not significantly different(p>0.05) from the control, but in the N 40% and 0.07M MgO and N 60% was lower than that of the control. It was considered that an optimum blended biochar application rate for cabbage cultivation was 40% of recommended nitrogen application.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.67-77
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• 2011

Heavy metal remediation in shooting range soil is a challenge over the world. The excessive Pb accumulation in the soil can deteriorate soil quality and fertility. The objectives of this research were to evaluate the efficiency of biochar (BC) in improving the physicochemical and biological properties of the soil and to evaluate its effect on Pb availability in a military shooting range soil. Sandy loam soil was collected from shooting range of Gyeonggi Province, South Korea and was incubated for 30 days with different application rates (0-30% w $w^{-1}$) of BC. The results showed that the addition of BC increased aggregate stability, nitrogen (N) and phosphorus (P) contents, and enzyme activities in soil. Sequential extraction showed that residual and organic bound fractions in the soil amended with BC increased by 33.1 and 16.7%, respectively, and the exchangeable fraction decreased by 93.7% in the soil amended with BC, compared to the unamended soil. We concluded that the application of BC could not only improve physicochemical and biological soil qualities but also stabilize Pb in a shooting range soil.

• Environmental Engineering Research
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• v.25 no.4
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• pp.536-544
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• 2020

To address organic dye wastewater, economic and effective adsorbents are required. Here, magnetic biochar from alkali-activated rice straw (AMBC) was successfully synthesized using one-step magnetization and carbonization method. The alkaline activation caused the large specific surface area, high pore volume and abundant oxygen-containing groups of the AMBC, and the magnetization gave the AMBC a certain degree of electropositivity and fast equilibrium characteristics. These characteristics collectively contributed to a relative high adsorption capacity of 53.66 mg g^-1 for this adsorbent towards rhodamine B (RhB). In brief, RhB can spontaneously adsorb onto the heterogeneous surface of the AMBC and reach the equilibrium in 60 min. Although the initial pH, ionic strength and other substances of the solution affected the adsorption performance of the AMBC, it could be easily regenerated and reused with considerable adsorption content. Based on the results, H-bonds, π-π stacking and electrostatic interactions were speculated as the primary mechanisms for RhB adsorption onto the AMBC, which was also demonstrated by the FTIR analysis. With the advantageous features of low cost, easy separation, considerable adsorption capacity and favorable stability and reusability, the AMBC would be a potential adsorbent for removing organic dyes from wastewater.

• Environmental Engineering Research
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• v.25 no.3
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• pp.384-392
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• 2020

The presence of high fluoride concentration (> 1.5 mg/L) in water causes serious health problems such as fluorosis, infertility, brain damage, etc., which are endemic to many places in the world. This study has investigated the fluoride removal capacity of the novel activated biochar (BTS) and hydrochar (HTS) using Teff (Eragrostis tef) straw as a precursor. Activated biochar with mesoporous structures and large specific surface area of 627.7 ㎡/g were prepared via pyrolysis process. Low-cost carbonaceous hydrochar were also synthesized by an acid assisted hydrothermal carbonization process. Results obtained from both adsorbents show that the best local maximum fluoride removal was achieved at pH 2, contact time 120 min and agitation speed 200 rpm. The thermodynamic studies proved that the adsorption process was spontaneous and exothermic in nature. Both adsorbents equilibrium data fitted to Langmuir isotherm. However, Freundlich isotherm fitted best for BTS. The maximum fluoride loading capacity of BTS and HTS was found to be 212 and 88.7 mg/g, respectively. The variation could primarily be attributed to a relatively larger Surface area for BTS. Hence, to treat fluoride contaminated water, BTS can be promising as an effective adsorbent.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.452-461
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• 2017

This study was conducted to select an optimal approach to corn waste biochar (BC) application, and to evaluate the effects of combined application of BC and inorganic fertilizer (IF) on corn growth and soil chemical properties in a pot experiment. Corn growth differed with BC application timing and BC application levels. Based on the characteristics of corn growth in pot-based experiments, the selected optimal application conditions of BC were application of $500kg\;10a^{-1}$ at 20 days before sowing. Also, the chemical properties of the tested soil with BC after corn harvesting were significantly improved than those in the other treatments. In particular, soil pH and CEC regardless of application conditions were markedly increased by 0.04~0.19 units and $0.08{\sim}2.58coml_c\;kg^{-1}$ in BC treatments than without BC treatments. Additionally, combined application of BC and IF had greater effects on corn growth than single application of BC. Therefore, the results suggest using properly BC application conditions and a combination of BC and IF for effective corn cultivation in an upland field.

• Korean Journal of Environmental Agriculture
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• v.41 no.3
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• pp.185-190
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• 2022

BACKGROUND: Most of the bottom ash(BA) from wood pellet-based thermal power plants that is not recycled is placed into landfill. BA has a function and structure similar to biochar. Hence, BA is classified as waste, but, it is predicted that BA can be used agricultural utilization. METHODS AND RESULTS: To investigate the effect of BA application on lettuce, growth characteristics and Pb contents were examined with BA application levels(0, 1, 2, 3 and 4 g/L), respectively, in hydroponic cultivation with Pb solution. Irrespective with BA application levels, the length, leaf number and fresh weight of lettuce in BA treatments were increased by 84.3~120, 36.2~39.0, and 215~322%, respectively, compared to the BA-0 treatment. The groups with BA treatments, Pb in the nutrient solution was adsorbed to the BA due to the surface area and functional groups of the BA, and the lettuce growth was maintained more smoothly than in the BA-0 treatment. BA application is considered to have created a favorable environment for lettuce growth in hydroponic cultivation with Pb solution. CONCLUSION(S): Although direct comparing the removal effect of heavy metal between BA and biochar is not present, the BA application in contaminated area suggested a significant meaning on the recycling waste, and increasing potential crop productivity by immobilizing heavy metal.