• 한국지하수토양환경학회지:지하수토양환경
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• 제18권3호
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• pp.58-64
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• 2013

This study proposed a low temperature hydrothermal carbonization to treat and recycle sewage sludge and determined the optimal conditions for the biochar production. The physical and chemical properties of biochar were analyzed and its sorption capacity for heavy metals was evaluated. To produce biochar, 50 g of sewage sludge was heated at 220, 230, and $240^{\circ}C$ for 1, 2, 3, 5, 8, and 10 hours in a reactor. The optimal conditions to produce biochar was $230^{\circ}C$ and 8 hours. Sorption capacity tests were conducted for arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn) and nickel (Ni). Among them, lead was shown the highest heavy metal adsorption efficiency of biochar, followed by copper, cadmium, zinc, and nickel, but arsenic was hardly adsorbed overall.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권2호
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• pp.47-53
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• 2012

In this study, the adsorption of $Cu^{2+}$ and $Cd^{2+}$ from aqueous solution on the biochar derived from used coffee grounds at different pyrolysis temperatures has been investigated as a potential low-cost treatment method for heavy metal-containing waters. Three biochar samples prepared by heating coffee sludge at temperature of $300^{\circ}C$ (B300), $500^{\circ}C$ (B500), and $700^{\circ}C$ (B700) were tested for the adsorption capacity and kinetics of Cd and Cu. Also the influencing factor of heavy metal removal by ion exchange in terms of cation exchange capacity (CEC) of each biochar was measured. Adsorption of Ca and Cu by biochar produced at higher pyrolysis temperature showed higher adsorption capacity but the optimal pyrolysis temperature based on performance and economy was known as $500^{\circ}C$. Sorption of Cu and Cd by biochar followed a Langmuir model at pH 6~6.5, attributing mainly to surface sorption. The biochar was more effective in Cu and Cd sorption than activated carbon (AC), with BC 500 being the most effective, which indicates that sorption of Cd and Cu by coffee sludge biochar is partly influenced by chemical sorption on surface functional group as well as physical sorption.

• 한국기후변화학회지
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• 제5권4호
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• pp.277-284
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• 2014

Biochar application to soil is widely known to have effects of climate change mitigation and soil quality improvement. However, effects of biochar on soil ecosystem are not always positive and some biochars are reported to contain toxic materials which might influence soil ecosystem. In this context, this study aims to investigate behavioral changes of earthworms(Eisenia fetida, Eisenia andrei) in response to different application rates of biochar to artificial soil. Treatment included two types of biochars made from rice husk (RH_Char) and wastewater sludge (SL_Char) with 1% and 10% application rates, respectively. Avoidance test revealed that earthworms did not avoid SL_Char treatments at 1% and 10%, while they rather moved to the RH_Char treatments probably due to higher labile carbon content(Hot water extractable carbon) of the RH_Char. The HWC content of RH_Char was 4 times higher than that of the SL_Char. Results of reproduction test showed that the survival rates, number of juveniles and number of cocoons were not influenced by biochar application except for the treatment of SL_Char at 10% rate. In the SL_Char 10% treatment, fatality was approximately 3.3 times as high as the control and the number of cocoons was 1.3 times higher in the same treatment than the control, indicating that earthworms were under environmental stress. The possible explanation for the stress condition was related to higher Cd, Ni, Cr, and As contents in the SL_Char. Overall results imply that biochar application at low rate might not change earthworms' behavior for the short term, while the reproduction behavior might be negatively influenced under the high application rate.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2019년도 정기학술대회 발표논문집
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• pp.134-134
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• 2019

Utilization of organic waste as a renewable energy source is promising for sustainability and mitigation of climate change. Pyrolysis converts organic waste to gas, oil, and biochar by incomplete biomass combustion. Biochar is widely used as a soil conditioner and adsorbent. Biochar adsorbs/desorbs metals and ions depending on the soil environment and condition to act as a nutrient buffer in soils. Biochar is also regarded as a carbon storage by fixation of organic carbon. Phosphorus (P) and nitrogen (N) are strictly controlled in many wastewater treatment plants because it causes eutrophication in water bodies. P and N is removed by biological and chemical methods in wastewater treatment plants and transferred to sludge for disposal. On the other hand, P is an irreplaceable essential element for all living organisms and its resource (phosphate rock) is estimated about 100 years of economical mining. Therefore, P and N recovery from waste and wastewater is a critical issue for sustainable human society. For the purpose, intensive researches have been carried out to remove and recover P and N from waste and wastewater. Previous studies have shown that biochars can adsorb and desorbed phosphates implying that biochars could be a complementary fertilizer. However, most of the conventional biochar have limited capacity to adsorb phosphates and nitrate. Recent studies have focused on biochar impregnated with metal salts to improve phosphates and nitrate adsorption by synthesizing biochars with novel structures and surface properties. Metal salts and metal oxides have been used for the surface modification of biochars. If P removal is the only concern, P adsorption kinetics and capacity are the only important factors. If both of P and N removal and the application of recovery are concerned, however, P and N desorption characteristics and bioavailability are also critical factors to be considered. Most of the researches on impregnated biochars have focused on P removal efficiency and kinetics. In this study, coffee waste is thermally treated to produce biochar and it was impregnated with Mg/Al to enhance phosphates and nitrate adsorption/desorption and P bioavailability to increase its value as a fertilizer. Kinetics of phosphates and nitrate adsorption/desorption and bioavailability analysis were carried out to estimate its potential as a P and N removal adsorbent in wasewater and a fertilizer in soil.

• 농업과학연구
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• 제45권2호
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• pp.197-203
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• 2018

Biochar is the carbon solid produced through the pyrolysis of a biomass from organic sources such as agricultural waste, animal manure, and sludge under limited or anaerobic conditions. Biochar has the effect of reducing greenhouse gases through the carbon sequestration method; additionally, biochar is known to function as a soil amendment. This experiment was conducted to evaluate the application of biochar on the growth characteristics of Chinese cabbage at Chungnam National University in Daejeon, Korea. The Chinese cabbage was grown for 50 days in a glasshouse in pots. A pruning branch was used to produce the bead and pellet forms of biochar through pyrolysis. The biochar was added to the soil at 0, 2, and 5% by weight. The Chinese cabbage with the 2% treatment of the bead form of biochar had the highest fresh weight ($149.43{\pm}15.92g\;plant^{-1}$) which was increased by 10% compared to the control ($136.91{\pm}31.46g\;plant^{-1}$). Moreover, for the 5% treatment of the bead form of biochar ($60.91{\pm}9.82g\;plant^{-1}$), the growth decreased by 57% compared to the control. As the content of the bead form of biochar increased, the shoot dry weight, leaf number, leaf length and lead width that appeared decreased. An increase in the total organic matter, Avail. $P_2O_5$, Ex. cation and EC was observed when the biochar content was increased. Our results support the application of 2% biochar in the bead form for increased growth of Chinese cabbage.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권1호
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• pp.17-24
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• 2022

This work examined the effect of mixing transition metal-based additives [FeCl₃, Fe-containing paper mill sludge (PMS), CoCl₂·H₂O, ZrO₂, and α-Fe₂O₃] on the thermochemical conversion of coffee waste (CW) in carbon dioxide-assisted pyrolysis process. Compared to the generation amounts of syngas (0.7 mole% H₂ & 3.0 mole% CO) at 700℃ from single pyrolysis of CW, co-pyrolysis in the presence of Fe- or Zr-based additives resulted in the enhanced production of syngas, with the measured concentrations of H₂ and CO ranging 1.1-3.4 mole% and 4.6-13.2 mole% at the same temperature, respectively. In addition, α-Fe₂O₃ biochar possessed the adsorption capacity of As(V) (19.3 mg g^-1) comparable to that of ZrO₂-biochar (21.2 mg g^-1). In conclusion, solid-type Fe-based additive can be highly considered as an efficient catalyst to simultaneously produce syngas (H₂ & CO) as fuel energy resource and metal-biochar as sorbent.

• 유기물자원화
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• 제27권2호
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• pp.19-30
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• 2019

본 연구는 국내산 우각이 혼합된 유기질비료를 개발하여 가장 많은 유기재배 면적을 차지하고 있는 벼를 포함하여 가지에 대한 시용효과를 조사하고 수입 유박을 대체할 유기자원으로 우각의 활용가능성을 구명하고자 실시하였다. 질소함량이 높은 국내산 유기자원 선발을 위하여 계분, 어분, 콩깻묵, 참깻묵, 들깻묵, 혈분, 우각, 맥주오니 등 8종을 분석하여 질소함량이 높은 유기자원을 선발하였고 보조제로 왕겨 바이오차, 미강 등을 원료별, 혼합비율별로 혼합하고 성분을 분석하여 유기농업에 사용 가능한 유기질비료 제조조건을 확립하였다. 우각은 전질소(T-N) 함량이 12.0 %로 높아 혈분 13.5 % 다음으로 높았으며 어분 및 깻묵은 전질소 함량이 5.9~7.9 % 수준이었다. 계분은 유기농업에 사용가능한 무항생제 산란계 계분을 사용하였으며, 맥주오니는 질소함량이 3.4 %로 나타났다. 무항생제 계분, 우각, 맥주오니 등을 주재료로 바이오차, 미강 등을 보조제로 사용하여 유기질비료를 제조한 결과. 수입유박의 질소함량(4.0~4.2 %) 대비 개발한 유기질비료의 질소함량은 7.5 %로 높고 중금속함량은 Zn 400 mg/kg, Cu 120 mg/kg 이하 등으로 나타나 질소 함량이 높고 유기농업자재 품질기준에 적합한 유기질비료를 개발하였다. 우각이 포함된 유기질비료를 사용하여 벼와 가지를 재배하면서 시용효과를 조사한 결과 토양검정질소시비량 기준 100 % 시용시 혼합유박 대비 시용량을 40 % 감소하였음에도 벼 생육 및 수량이 대등하였으며, 가지 재배시에도 동일한 결과를 나타내었다. 우각 등 국산 유기자원을 이용한 새로운 고농도 질소원 선발 및 이를 이용한 유기재배 적합 유기질비료 개발은 친환경농업 확대 보급의 중요성이 높아지고 있는 현 시점에서 지역자원을 이용한 기존 수입 혼합유박 대체 연구의 출발점이자 폐기되고 있는 국내 유기자원의 활용 방안 모색에서 큰 의미를 가지며 향후 확대 보급된다면 친환경농산물의 안정적 생산에 기여할 수 있을 것으로 기대된다.

• 자원환경지질
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• 제54권1호
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• pp.21-33
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• 2021

국내 오염시나리오별 안정화 효율과 경제성이 뛰어난 안정화제를 선택하여 적용할 수 있도록, 국내외에서 연구된 대표적인 안정화제를 대상으로 국내 중금속 오염 현장 부지 특성별 중금속 안정화 효율이 높은 안정화제 순위를 결정하였다. 총 5종류의 오염시나리오를 가정하여 각각 해당되는 국내 오염부지 토양을 확보하였다. 국내외 활용도와 안정화 효율 연구 결과, 오염특성별 부지 시나리오에 적용 가능성 등을 고려하여 기존에 연구되었던 안정화제 13가지를 선정하였다. 선정한 오염 토양과 안정화제의 오염 가능성과 현장 적용 가능성을 평가하기 위하여 XRD/XRF 분석, 독성용출시험과 인공강우용출시험 등을 실시하였다. 부지 오염시나리오를 대표하는 5종류 오염 토양에 대하여 선정된 13종의 안정화제에 의한 비소, 수은, 납, 6가 크롬, 아연, 니켈, 구리 등 총 8종의 중금속(반금속인 비소 포함) 용출 저감 효과를 규명하는 용출 배치실험을 수행하였다. 총 5개 오염 토양에 대하여 13개 안정화제 주입 비율 3%, 5%, 7% 적용 시, 각 중금속(비소 포함)에 대한 중금속 용출 저감 효율이 안정화제를 주입하지 않은 토양 대비 20% 이상을 나타내는 안정화제 중에서 저감 효율이 높은 순위부터 5개 안정화제(Top 5)를 선택하였다. 각 안정화제에 대하여 안정화제 주입비율, 중금속 종류, 부지별 조건에 따라 수행된 배치실험 결과에 대하여 Top 5에 해당하는 총 횟수를 합산하여, 다양한 국내 부지 오염시나리오에 적용할 수 있는 안정화제의 순위를 결정하였다. 5개 오염 토양에 대하여 8개 중금속 항목별 용출 저감 효율이 20% 이상인 경우, 가장 안정화 효율이 높은 순위는 광산배수처리 슬러지(mine drainage treatment sludge), 산화철, 생석회, 소석회-석회석, 황화철, 바이오차 순으로 나타났다. 위 안정화제들에 대하여 안정화제의 효율대비 단가를 산정한 결과, 광산배수처리 슬러지, 석회석, 제강슬래그(비소의 경우), 생석회, 소석회 순으로 경제성이 높게 나타나 현장 적용성이 뛰어난 것으로 밝혀졌다.