열수가압탄화를 이용한 커피찌꺼기 Biochar의 최적 생성 및 Toluene 흡착 평가

김장영 ( Jang Yeong Kim ),조우리 ( Woori Cho ),이재영 ( Jai-young Lee ) 한국폐기물자원순환학회(구 한국폐기물학회) 2021 한국폐기물자원순환학회지 Vol.38 No.2

In this study, biochar was created from coffee wastes with a high moisture content by applying a hydrothermal carbonization (HTC) method. Environmental problems during the treatment and optimal conditions were derived based on the adsorption performance of biochar. In addition, we compared biochar and activated biochar to evaluate their potential as adsorbents for VOCs by chemical activation using KOH to activate micro-secessions of biochar. The highest yield was obtained at 260 ℃ for 1 h and the iodine adsorption performance at approximately 687.11 mg/L. Therefore, the HTC optimal reaction conditions using coffee wastes increased its potential for use as an adsorbent. KOH was used as a chemical activator to activate the biochar under optimal generative conditions. A second batch test was conducted and analyzed for yield and iodine adsorption performance. The second batch test showed that the optimal activation temperature was about 700℃, the optimal mixing ratio of biochar and KOH was 1 : 0.5, and the optimal activation time was 1 h for 1,105.33 mg/g iodine adsorption performance. Toluene adsorption experiments were conducted to evaluate the VOC adsorption potential of coffee wastes, biochar, activated biochar, and GAC (Granular Activated Charcoal, Untreated). As a result, activated biochar, which was adsorbed at 240 minutes, was considered a more efficient adsorbent than coffee wastes, biochar, and GAC. Therefore, this study conducted an adsorbent evaluation of activated biochar produced from the HTC process. The resultant biochar showed higher efficiency in a shorter period and was sufficient to be used as an adsorbent.

Biochar와 ZnCl2-activated Biochar의 질소 및 인 흡착능력 비교

조규랑 ( Gyu-rang Jo ),김혜영 ( Hye-yeong Kim ),박종환 ( Jong-hwan Park ),김성헌 ( Seong-heon Kim ),서동철 ( Dong-cheol Seo ) 한국환경농학회 2016 한국환경농학회 학술대회집 Vol.2016 No.-

최근 들어 biochar를 수처리로 활용하는 연구가 이루어지고 있지만 biochar 자체에서 질소와 인이가 용출되어 수처리제로 활용하는데 많은 제약이 따르고 있다. 이에 본 연구에서는 biochar의 NH4-N과 PO4-P의 용출특성을 파악하고, 활성화 되지 않은 biochar와 ZnCl2로 활성한 biochar를 이용하여 NH4-N 및 PO4-P의 흡착특성을 조사하였다. 실험에 사용한 biochar는 볏짚을 600℃ 4시간 열분해 하였으며 ZnCl2로 활성화 된 biochar를 이용하여 질소 및 인 흡착능력을 비교하였다. 질소와 인의 용출량은 시간에 따른 NH4-N 및 PO4-P의 용출농도로부터 산출하였으며, 질소 및 인의 흡착실험은 동일량의 biochar에 NH4-N 및 PO4-P 용액의 농도를 달리하여 단위 g당 흡착량을 조사하고, 그 결과를 Langmuir 및 Freundlich 등온흡착식에 적용하여 NH4-N 및 PO4-P의 흡착능력을 조사하였다. NH4-N은 대부분이 반응 1시간 이내에 용출되었으며, PO4-P도 NH4-N과 유사하게 반응 1 시간 이내에서 대부분이 용출되었다. 이상의 결과에서 biochar의 경우는 영양염류(특히 P)의 용출 활성화 과정 없이는 질소와 인의 흡착제로 활용이 힘들 것으로 판단되었다. Biochar의 활성화 유무에 따른 NH4-N 및 PO4-P의 흡착결과를 Freundlich 및 Langmuir 등온흡착식에 적용한 결과 NH4-N의 경우 biochar에서는 적은량(26.5 mg/g)의 NH4-N가 흡착되었으나, ZnCl2-activated biochar에서는 NH4-N이 거의 흡착되지 않았다. 반면에 PO4-P는 활성화 되지 않은 biochar에서는 흡착보다 용출이 많았으나, ZnCl2-activated biochar에서는 최대흡착능이 12.7 mg/g 정도로 매우 높은 흡착능력을 보였다.

KOH 농도 및 탄화온도가 왕겨 활성 바이오차의 NH₄-N 흡착능 향상에 미치는 영향

김희선 ( Huiseon Kim ),윤석인 ( Seok-in Yun ),안난희 ( Nanhee An ),신중두 ( Joungdu Shin ) 한국환경농학회 2020 한국환경농학회지 Vol.39 No.3

BACKGROUND: Recently, biomass conversion from agricultural wastes to carbon-rich materials such as biochar has been recognized as a promising option to maintain or increase soil productivity, reduce nutrient losses, and mitigate greenhouse gas emissions from the agro-ecosystem. This experiment was conducted to select an optimum conditions for enhancing the NH₄-N adsorption capacity of rice hull activated biochar. METHODS AND RESULTS: For deciding the proper molarity of KOH for enhancing its porosity, biochars treated with different molarity of KOH (0, 1, 2, 4, 6, 8) were carbonized at 600℃ in the reactor. The maximum adsorption capacity was 1.464 mg g^-1, and an optimum molarity was selected to be 6 M KOH. For the effect of adsorption capacity to different carbonized temperatures, 6 M KOH-treated biochar was carbonized at 600℃ and 800℃ under the pyrolysis system. The result has shown that the maximum adsorption capacity was 1.76 mg g^-1 in the rice hull activated biochar treated with 6 M KOH at 600℃ of pyrolysis temperature, while its non-treated biochar was 1.17 mg g^-1. The adsorption rate in the rice hull activated biochar treated with 6 M KOH at 600℃ was increased at 62.18% compared to that of the control. Adsorption of NH₄-N in the rice hull activated biochar was well suited for the Langmuir model because it was observed that dimensionless constant (R_L) was 0.97 and 0.66 at 600℃ and 800℃ of pyrolysis temperatures, respectively. The maximum adsorption amount (q_m) and the bond strength constants (b) were 0.092 mg g^-1 and 0.001 mg L^-1, respectively, for the rice hull activated biochar treated with 6 M KOH at 600℃ of pyrolysis. CONCLUSION: Optimum condition of rice hull activated biochar was 6M KOH at 600℃ of pyrolysis temperature.

염화아연 전처리를 통해 제조된 커피잔재물 바이오차와 분말활성탄의 의약품 흡착능 비교

신재관,하금률,전강민 대한환경공학회 2019 대한환경공학회지 Vol.41 No.10

Objectives : The main objective of this study was to identify the feasibility of ZnCl2 pre-treated biochar derived from coffee residues (C-biochar) as a potential adsorbent for the removal of the pharmaceuticals (i.e., ibuprofen (IBF), atenolol (ATE), and carbamazepine (CBZ)) from wastewater. Methods : The removal efficiencies of IBF, ATE, and CBZ by C-biochar and powdered activated carbon (PAC) were compared under different pH (3 ~ 9), temperature (15 ~ 45℃), and ionic strength (0 ~ 0.5 M) conditions and directly correlated to their physicochemical properties to provide deeper insights into the removal mechanisms of the pharmaceuticals by the adsorption processes. Results and Discussion : C-biochar was more effective for the removal of IBF and CBZ compared to PAC since it showed the greater surface area (C-biochar = 1048.2 m2/g; PAC = 957.6 m2/g) and pore volume (C-biochar = 1.044 cm3/g; PAC = 0.676 cm3/g). However, the removal efficiency of ATE by PAC was higher than that of ATE by C-biochar due to the differences in their function group composition. The Freundlich isotherm model was well fitted to the adsorption of the selected pharmaceuticals by C-biochar and PAC compared with the Langmuir isotherm model. The removal of IBF and ATE by C-biochar and PAC varied substantially depending on the pH of the solutions as their adsorption phenomena were mainly governed by the electrostatic interaction whereas the effects of pH on the removal of CBZ were not significant because of its high pKa value (14). Furthermore, the adsorption of all the selected pharmaceuticals by C-biochar and PAC was found to be independent of the solution ionic strength. Conclusions : This study demonstrated that C-biochar may be utilized as a potential adsorbent for the effective removal of the pharmaceuticals from wastewater due to the greater surface area and pore volume compared to PAC. The removal of IBF, ATE, and CBZ by C-biochar and PAC was strongly influenced by the physicochemical properties of the pharmaceuticals and adsorbents. 목적 : 본 연구에서는 커피잔재물을 염화아연으로 활성화하여 제조한 Biochar (C-biochar)를 의약품(i.e., Ibuprofen (IBF), Atenolol (ATE), Carbamazepine (CBZ)) 제거를 위한 흡착제로서 적용 가능성을 상용화된 분말활성탄(PAC: Powdered Activated Carbon)과의 비교를 통해 평가하였다. 방법 : 본 연구에서는 2가지 흡착등온식 모델을 이용하여 C-biochar와 PAC에 의한 미량오염물질의 제거기작을 조사하였다. 또한, 다양한 변수들이 미량오염물질 흡착에 미치는 영향을 알아보기 위하여 pH (3 ~ 9), 온도(15 ~ 45℃) 및 이온강도(0 ~ 0.5 M) 조건들을 변화시키면서 흡착실험을 수행하였다. 결과 및 토의: C-biochar는 PAC보다 더 넓은 비표면적(C-biochar = 1048.2 m2/g; PAC = 957.6 m2/g)과 공극(C-biochar = 1.044 cm3/g; PAC = 0.676 cm3/g)이 잘 발달되어 IBF와 CBZ의 제거율이 높았지만, PAC보다 표면작용기가 다양하지 않아 ATE의 제거율은 낮았다. 이를 통해 흡착제와 흡착질의 물리화학적 속성과 수용액 조건에따라 제거율이 좌우된다는 것을 확인할 수 있었다. 등온흡착실험 결과를 통해 C-biochar와 PAC에 의한 대상 의약품의 제거는 Langmuir 등온흡착모델보다 Freundlich 등온흡착모델에 적합한 것으로 보아 다층흡착에 대한 특성을나타내었다. C-biochar에 의한 IBF와 ATE의 제거는 정전기적 상호작용에 의해 이루어졌기 때문에 pH의 변화에따라 크게 달라졌지만, CBZ는 pKa가 높아 pH의 영향을 받지 않았다. C-biochar에 의한 대상 의약품 제거에 온도가 미치는 영향은 IBF는 온도에 영향을 받지 않았으며, ATE과 CBZ은 흡열반응으로 온도가 증가함에 따라 제거율이 증가하였다. pH와 온도와 달리, 이온강도 경우 C-biochar와 PAC에 의한 대상 의약품 제거에 일관된 영향을미치지 않는 것으로 나타났다. C-biochar는 PAC와 비교하였을 때 대상 의약품 제거에 대해 현저한 차이가 없는 것을 확인할 수 있었다. 결론 : 본 연구는 ZnCl2 전처리를 통한 커피잔재물로부터 우수한 표면특성을 갖는 Biochar를 제조할 수 있다는 것을 입증하였다. 또한 C-biochar와 PAC의 의약품 제거 메커니즘을 다양한 조건에서 알아본 결과 의약품의 물리화학적 속성들과 흡착제의 특징에 따라 달라진다는 것을 확인할 수 있었다.

Engineered biochar from pine wood: Characterization and potential application for removal of sulfamethoxazole in water

Hyun Min Jang,Seunghyun Yoo,Sunkyu Park,Eunsung Kan 대한환경공학회 2019 Environmental Engineering Research Vol.24 No.4

The adsorption of sulfamethoxazole (SMX) onto a NaOH-activated pine wood-derived biochar was investigated via batch experiments and models. Surprisingly, the maximum adsorption capacity of activated biochar for SMX (397.29 ㎎/g) was superior than those of pristine biochars from various feedstock, but comparable to those of commercially available activated carbons. Elovich kinetic and Freundlich isotherm models revealed the best fitted ones for the adsorption of SMX onto the activated biochar indicating chemisorptive interaction occurred on surface of the activated biochar. In addition, the intraparticle diffusion limitation was thought to be the major barrier for the adsorption of SMX on the activated biochar. The main mechanisms for the activated biochar would include hydrophobic, π-π interactions and hydrogen bonding. This was consistent with the changes in physicochemical properties of the activated biochar (e.g., increase in sp2 and surface area, but decrease in the ratios of O/C and H/C).

왕겨 바이오차 적용이 상추 성장 및 토양 효소 활성에 미치는 영향

아쿠문트아타나시 ( Athanasie Akumuntu ),조은혜 ( Eun Hea Jho ) 한국환경농학회 2022 한국환경농학회 학술대회집 Vol.2022 No.-

Despite a large number of studies on biochar, few studies have investigated the effect of biochar on lettuce growth. Here, the effects of rice husk biochar on lettuce growth (Lactuca sativa) and soil enzyme (alkaline phosphatase, beta-glucosidase, and dehydrogenase) activities were studied using pot experiments with different biochar concentrations (0-1.5%). After 28 d-growth period, no significant effects were recorded on total height, root length, and root weight of lettuce among the different biochar concentrations. However, total fresh weight, shoot height, and leaf number significantly increased in the presence of higher biochar concentrations. Significant changes in soil pH were observed in the soil without lettuce at higher biochar concentrations (1% and 1.5%) whereas no significant changes were observed in the soil with lettuce at all biochar concentrations. The average alkaline phosphatase activity (in p-nitrophenol (pNP) content) of the control soil on Day 0 was 145 μg pNP mL^-1, and this is was reduced to 69.5 μg pNP mL^-1 on Day 28. Compared to the Day 28 control soil activity, the average alkaline phosphatase activity of the soil with 1.5% biochar was greater (212 μg pNP mL^-1) suggesting the positive effects of biochar on the soil enzyme activities. Similar patterns were observed with beta-glucosidase and dehydrogenase activities. The results demonstrated that the application of rice husk biochar could promote lettuce growth and enhance soil enzyme activities.

Effects on Growth Characteristics of Chinese Cabbage to Application of Formulated Granular Fertilizer Contained Activated Biochar

In-Ho Jung,Hong-Sik Na,김민수,Hong-Shik Nam,JoungDu Shin 한국토양비료학회 2020 한국토양비료학회지 Vol.53 No.3

This study was conducted to develop an eco-friendly slow-release fertilizer by utilizing activated biochar through black carbonization of rice hull biochar and activated palm biochar. To manufacturing these fertilizers, the raw materials were ground into powder form, mixed with the binder, granulated, and then screened and dried. The best six types were selected by considering the hardness and coupling degree with activated biochar and binder. The nutrient contents of the granular fertilizer contained within the activated biochar were 30-0-13 (N-P2O5-K2O, %). Results did not show a significant effect on cabbage’s leaf color, length, and width among the different treatments except for the control. However, it showed that the highest yield among the treatments was 3.5 kg plant-1 in the treatment of 5% of rice hull activated biochar. In this treatment, the yield was increased by 20% relative to that of the control. Therefore, it was decided that the optimum mixing ratio was 5% of activated rice hull biochar.

Phosphoric acid-activated wood biochar for catalytic conversion of starch-rich food waste into glucose and 5-hydroxymethylfurfural

Cao, Leichang,Yu, Iris K.M.,Tsang, Daniel C.W.,Zhang, Shicheng,Ok, Yong Sik,Kwon, Eilhann E.,Song, Hocheol,Poon, Chi Sun Elsevier 2018 Bioresource technology Vol.267 No.-

<P><B>Abstract</B></P> <P>The catalytic activity of engineered biochar was scrutinized for generation of glucose and hydroxymethylfurfural (HMF) from starch-rich food waste (bread, rice, and spaghetti). The biochar catalysts were synthesized by chemical activation of pinewood sawdust with phosphoric acid at 400–600 °C. Higher activation temperatures enhanced the development of porosity and acidity (characterized by COPO<SUB>3</SUB> and CPO<SUB>3</SUB> surface groups), which imparted higher catalytic activity of H<SUB>3</SUB>PO<SUB>4</SUB>-activated biochar towards starch hydrolysis and fructose dehydration. Positive correlations were observed between HMF selectivity and ratio of mesopore to micropore volume, and between fructose conversion and total acid density. High yields of glucose (86.5 Cmol% at 150 °C, 20 min) and HMF (30.2 Cmol% at 180 °C, 20 min) were produced from rice starch and bread waste, respectively, over H<SUB>3</SUB>PO<SUB>4</SUB>-activated biochar. These results highlighted the potential of biochar catalyst in biorefinery as an emerging application of engineered biochar.</P> <P><B>Highlights</B></P> <P> <UL> <LI> H<SUB>3</SUB>PO<SUB>4</SUB>-activated biochar catalyzed production of HMF (30.2%) and glucose (86.5%). </LI> <LI> HMF selectivity depended on ratio of mesopore to micropore volume of biochar. </LI> <LI> Biomass conversion was positively correlated to total acid density of biochar. </LI> <LI> Acidity originated from COPO<SUB>3</SUB> and CPO<SUB>3</SUB> surface groups of H<SUB>3</SUB>PO<SUB>4</SUB>-modified biochar. </LI> <LI> Engineered biochars are potential catalysts for biorefinery reactions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

The potential of biochar as sorptive media for removal of hazardous benzene in air

Khan, Azmatullah,Szulejko, Jan E.,Samaddar, Pallabi,Kim, Ki-Hyun,Liu, Botao,Maitlo, Hubdar Ali,Yang, Xiao,Ok, Yong Sik Elsevier 2019 Chemical Engineering Journal Vol. No.

<P><B>Abstract</B></P> <P>Airborne benzene is hazardous even at sub-ppm levels. Therefore, an effective strategy is required for its removal, such as the use of a sorbent with large adsorption capacity or high breakthrough volume. To meet the goal, the performance for the removal of benzene was assessed by loading benzene at 5 Pa inlet partial pressure against seven types of biowaste-derived biochar: (1) paper mill sludge, (2) conventional biochar with magnetic properties, (3) biochar composites with carbon nanotubes (CNTs), (4) gasification biochar from mixed feedstock, (5) gasification biochar from a single feedstock, (6) modified gasification biochar, and (7) activated carbon (AC) as a reference. The 298 K maximum adsorption capacities (mg g<SUP>−1</SUP>), when measured at a benzene inlet pressure of 5 Pa (or 50 ppm in ultrapure nitrogen) and flow rate of 50 mL atm min<SUP>−1</SUP>, varied widely for different biochars, from 0.35 (MS: Swine manure + plastic mulch film waste) to 144 mg g<SUP>−1</SUP> (XC-1: biochar from mixed feedstock); their 10% breakthrough volumes (BTV) were in the range of 0.22–492 L g<SUP>−1</SUP>, respectively. The experimental data (capacity vs. benzene outlet partial pressure) could be fitted to either two or three linearized Langmuir isotherms with distinctive sorption mechanisms ((1) a retrograde region (Type III isotherm: 0 to ∼0.2 Pa), (2) an intermediate pressure region (0.2 and 2.0 Pa), and (3) a higher pressure region (>2 Pa)) which was also confirmed similarly by Freundlich, Dubinin–Radushkevich, and Elovich fitting. About 65% of the maximum capacity was achieved in the retrograde region. The strongest biochar sorbent, XC-1, showed similar performance as activated carbon to prove its feasibility toward air quality management (AQM) applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Performance of biochars for gaseous benzene removal was assessed. </LI> <LI> The adsorption isotherms were assessed by maximum capacity, partition coefficient, and BTV. </LI> <LI> Retrograde was found for activated carbon and gasified/modified biochars. </LI> <LI> The strong sorbents of multiple sorption sites fitted best with Elovich and Langmuir models. </LI> </UL> </P>

Mechanistic insights of 2,4-D sorption onto biochar: Influence of feedstock materials and biochar properties

Mandal, Sanchita,Sarkar, Binoy,Igalavithana, Avanthi Deshani,Ok, Yong Sik,Yang, Xiao,Lombi, Enzo,Bolan, Nanthi Elsevier Applied Science 2017 Bioresource technology Vol.246 No.-

<P><B>Abstract</B></P> <P>Objective of this study was to investigate the mechanisms of 2,4-Dichlorophynoxy acetic acid (2,4-D) sorption on biochar in aqueous solutions. Sorption isotherm, kinetics, and desorption experiments were performed to identify the role of biochars’ feedstock and production conditions on 2,4-D sorption. Biochars were prepared from various green wastes (tea, burcucumber, and hardwood) at two pyrolytic temperatures (400 and 700°C). The tea waste biochar produced at 700°C was further activated with steam under a controlled flow. The sorption of 2,4-D was strongly dependent on the biochar properties such as specific surface area, surface functional groups, and microporosity. The steam activated biochar produced from tea waste showed the highest (58.8mgg<SUP>−1</SUP>) 2,4-D sorption capacity, which was attributed to the high specific surface area (576m<SUP>2</SUP> g<SUP>−1</SUP>). The mechanism of 2,4-D removal from aqueous solution by biochar is mainly attributed to the formation of heterogeneous sorption sites due to the steam activation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Steam activated tea waste biochar sorbed the highest amount of 2,4-D. </LI> <LI> Steam activation increased biochar surface area and conserved oxygen-containing functional groups. </LI> <LI> 2,4-D desorption was lowest in steam activated biochar. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>