• Environmental Engineering Research
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• 제21권1호
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• pp.36-44
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• 2016

Constructed wetlands are established efficient technologies and provide sustainable solution for wastewater treatment. Similarly, biochar, which is an organic material, produced by means of pyrolysis, offers simple and low cost techniques to treat water and reduce carbon footprint. Combining both of these technologies can greatly augment the efficiency of the system. The objective of this study was to evaluate the efficiency of constructed wetlands by using biochar as media. Horizontal wetland beds with dimension ($1m{\times}0.33m{\times}0.3m$) were prepared using gravels and biochar, and cultivated with the Canna species. Synthetic wastewater was passed through these beds with average flow rate of $1.2{\times}10^{-7}m^3/sec$ achieving a retention time of three days. Pollutant removal performance was compared between the controlled and experimental wetland beds. This study reveals that the wetland with biochar were more efficient as compared to the wetland with gravels alone with average removal rate of 91.3% COD, 58.3% TN, 58.3% $NH_3$, 92% $NO_3-N$, 79.5% TP, and 67.7% $PO_4$.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.694-704
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• 2018

Novel $SnO_2$ mixed biochar composite was prepared from banana peel developed as electrode material for supercapacitor using simple chemical co-precipitation method. The physiochemical and morphological properties of activated composite $SnO_2$ mixed biochar were investigated with XRD, FTIR, UV-vis, FESEM and HRTEM. The composite accounts for outstanding electrochemical behavior such as high specific capacitance, significant rate capability and leading to good cycle retention up to 3500 cycles when used as electrode material for supercapacitors. Highly permeable $SnO_2$ mixed biochar derived from banana peel exhibited maximum specific capacitance of $465F\;g^{-1}$ at a scan rate of $10mV\;s^{-1}$ by cyclic voltammetry (CV) and $476Fg^{-1}$ at current density of $0.15Ag^{-1}$ by charge discharge studies significantly higher about 47% than previously reported identical work on banana peel biochar.

• Environmental Engineering Research
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• 제24권3호
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• pp.434-442
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• 2019

The present study investigated a novel calcium hydroxide-coated dairy manure-derived biochar (Ca-BC) for adsorption of phosphate from water and dairy wastewater. The Ca-BC showed much higher adsorption of phosphate than that of dairy manure-derived biochar. The Ca-BC possessed mainly the calcium hydroxide and various functional groups resulting in high reactivity between phosphate and calcium hydroxide in the Ca-BC. The adsorption of phosphate onto Ca-BC followed pseudo-second order kinetic and Freundlich isotherm models indicating chemisorptive interaction occurred on energetically heterogeneous surface of Ca-BC. The maximum adsorption capacity of the Ca-BC was higher than those of iron oxide and zinc oxide-coated biochars, but lower than those of CaO- and MgO-coated biochars. However, the Ca-BC showed high reactivity per surface area for adsorption of phosphate indicating importance of surface functionalization of biochar. On the other hand, the adsorption of phosphate in dairy wastewater on Ca-BC was lower than that in water owing to competition between other anions in wastewater and phosphate. Overall, the Ca-BC would be a low cost and effective adsorbent for recovery of phosphate from water and wastewater.

• Korean Chemical Engineering Research
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• 제60권3호
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• pp.423-432
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• 2022

Magnetic biochar produced from pyrolysis of dairy cattle manure was used to develop an effective sorbent for arsenic purification from aqueous solution. Biomass and magnetized biomass were pyrolyzed in a tube furnace with 10 ℃/min heating rate at 450 ℃ under nitrogen flow of 100 cm³/min for 2 h. Biochars were characterized by SEM-EDX, BET, XDR, FTIR, TGA, zeta potential analysis. The resultant biochar and magnetic biochar were opposed to 50-100-500 ppm As(V) laden aqueous solution. Adsorption experiments were performed by using ASTM 4646-03 batch method. The effects of concentration, pH, temperature and stirring rate on adsorption were evaluated. As(V) was successfully removed from aqueous solution by magnetic biochar due to its highly porous structure, high aromaticity and polarity. The results suggest dairy cattle manure pyrolysis is a promising route for managing animal manure and producing a cost effective biosorbent for efficient immobilization of arsenic in aqueous solutions.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권1호
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• pp.31-38
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• 2022

The common algae and industrial waste, chlorella and red mud, were co-pyrolyzed in carbon dioxide condition to fabricate iron-biochar composite. In order to investigate the direct effect of chlorella and red mud in the syngas generation and the property of biochar, experiments were performed using mixture samples of chlorella and red mud. The evolution of flammable gasses (H₂, CH₄, CO) was monitored during pyrolysis. The produced biochar composite was employed as a catalyst for persulfate activation for methylene blue removal. BET analysis indicated that the iron-biochar composite mainly possessed meso- and macropores. The XRD analysis revealed that hematite (Fe₂O₃) contained in red mud was transformed to Fe₃O₄ during co-pyrolysis. The composite effectively activated persulfate and removed methylene blue. Among the composite samples, the composite fabricated from the mixture composed of 1:2 chlorella:red mud showed the best performance in syngas generation and methylene blue removal.

• 환경생물
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• 제32권4호
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• pp.327-334
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• 2014

Emission reduction of $CH_4$ (methane gas) from rice paddy soil is a very important measure for climate change mitigation in agricultural sector. In this study, we investigated the changes in crop yield and $CH_4$ emissions in response to application of biochar and fertilizers. The experimental site is located in Hwasung, Kyunggido and experimental design is the split-plot method with three replicates. Treatments included rice straw (RS) and biochar (BC) amendments nested with the conventional NPK fertilizer (NPK) and slow release fertilizer (SRF). Control was also prepared with the soil with the conventional NPK fertilization with no amendment. Measurement of $CH_4$ emission was conducted during the growing season of 2014 using a dynamic chamber method. The results showed that application of rice straw increased daily $CH_4$ emission rate by 15%, while application of biochar reduced daily $CH_4$ emission rate by 38%. When we combined biochar application with slow release fertilizer, $CH_4$ emission was reduced by 45%. Further, the crop yield was also increased in all treatments compared with the control except for the treatment of rice straw application with slow release fertilizer. Overall results imply that biochar amendment to agricultural soil can be an effective strategy to decrease annual $CH_4$ emission with no reduction in crop yield.

• 한국환경농학회지
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• 제39권4호
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• pp.289-296
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• 2020

BACKGROUND: There is a need for a revolutionary method to overcome the problem of biochar, which has relatively low adsorption capacity for existing anion pollutants, along with collectively recycling fallen leaves, a kind of forest by-product. Therefore, the objective of this study was to prepare iron-decorated biochar derived from fallen leaves (Fe-FLB), and to evaluate their adsorption properties to Congo red (CR) as anionic dye. METHODS AND RESULTS: The adsorption properties of CR by fallen leaves biochar (FLB) and Fe-FLB were performed under various conditions such as initial CR concentration, reaction time, pH and dosage with isotherm and kinetic models. In this study, Fe-FLB prepared through iron impregnation and pyrolysis of fallen leaves contained 56.9% carbon and 6.3% iron. Congo red adsorption by FLB and Fe-FLB was well described by Langmuir model and pseudo second order model and the maximum adsorption capacities of FLB and Fe-FLB were 1.1 mg/g and 25.6 mg/g, respectively. In particular, it was found that the adsorption of CR was occurred by chemical adsorption process by the outer boundary layer of Fe-FLB. CONCLUSION: Overall, the production of Fe-FLB using fallen leaves and using it as an anion adsorbent is considered to be a way to overcome the problem of biochar with relatively low anion adsorption in addition to the reduction effect of waste.

• 한국물환경학회지
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• 제37권6호
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• pp.483-492
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• 2021

This study evaluated the removal efficiencies of methylene blue (MB) and humic acids (HA) using a rice husk (RH) biochar and powdered activated carbon (PAC). The pseudo-second-order model better presented the adsorption of MB and HA onto a RH biochar than the pseudo-first-order model. Furthermore, better description of the adsorption behavior of MB and HA by the Langmuir isotherm model (R² of the RH biochar: MB = 0.986 and HA = 0.984; R² of PAC: MB = 0.997 and HA = 0.989) than the Freundlich isotherm model (R² of the RH biochar: MB = 0.955 and HA = 0.965; R² of PAC: MB = 0.982 and HA = 0.973) supports the assumption that monolayer adsorption played key roles in the removal of MB and HA using the RH biochar and PAC. Batch experiments were performed on the effects of dosage, temperature, and pH. For all experiments, PAC showed higher efficiencies than RH biochar and MB adsorption efficiencies were higher than those of HA. Adsorption efficiencies increased with increasing amounts of adsorbents and temperature. As the pH increased, adsorption efficiencies of MB were increased while adsorption efficiencies of HA were decreased.

• 공업화학
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• 제34권2호
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• pp.153-160
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• 2023

본 논문에서는 미이용 바이오매스로부터 바이오차를 생산하고 메틸렌블루 흡착 특성을 평가하였다. 바이오매스는 주로 셀룰로오스, 헤미셀룰로오스, 리그닌으로 구성되어 있으며 회분의 함량은 벌채부산물에서 가장 높았다. 탄화 온도가 증가할수록 탄화 수율은 감소하였으며, 수소와 산소 함량도 감소하였다. 반면, 탄소 함량은 증가하였다. 탄화 온도가 증가할수록 바이오차의 비표면적과 미세기공은 증가하였다. 바이오차 비표면적은 탄화 온도 600 ℃에서 가장 높았다(216.15~301.80 m² /g). 600 ℃에서 탄화한 바이오차를 이용하여 메틸렌블루 흡착 실험을 수행한 결과, 참나무, 벌채부산물, 사과 전정가지의 흡착 거동은 Freundlich model, 복숭아 전정가지는 Langmuir model에 적합하였다. 흡착 동역학에서 참나무와 복숭아 전정가지는 pseudo-first-order model, 벌채부산물과 사과 전정가지는 pseudo-second-order model에 적합하였다.

• 농업과학연구
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• 제48권4호
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• pp.787-796
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• 2021

Nitrogen (N) is the most important element during the process of plant growth, and the quality of crops varies depending on the amount of nitrogen present. Most of the nitrogen is used for plant growth, but approximately 10 - 20% of Nitrogen is carried away by the wind in the form of NH₃. This volatilized NH₃ reacts with various oxides in the atmosphere to generate secondary particulate matter. To address this, the present study attempts to reduce NH₃ occurring in the soil using biochar at a specific pH. Biochar was used as a treatment with 1% (w·w^-1) of the soil, and urea was applied at different levels of 160, 320, and 640 kg·N·ha^-1. NH₃ generated in the soil was collected using a dynamic column and analyzed using the indophenol blue method. NH₃ showed the maximum emission within 4 - 7 days after the fertilizer treatment, decreasing sharply afterward. NH₃ emission levels were reduced with the biochar treatment in all cases. Among them, the best reduction efficiency was found to be approximately 25% for the 320 kg·ha^-1 + pH 6.7 biochar treatment. Consequently, in order to reduce the amount of NH₃ generated in the soil, it is most effective to use pH 6.7 biochar and a standard amount (320 kg·N·ha^-1) of urea.