JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2024
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IF 5.8
Xiao Cheng,Yuchen Jiang,Kai Sun,Chao Li,Shu Zhang,Yi Wang,Hengda Han,Xun Hu
Mixing feedstocks of varied aromatic/aliphatic content is a simple method for tailoring pore structures of activated carbon (AC) in activation. Herein, willow wood and homogenous biochar produced at 300 or 500°C, which have distinct content of aliphatic component, were co-activated with K 2 C 2 O 4 , at 800°C for changing pore characteristics of resulting AC. The results indicated that co-activation of willow and biochar diminished production of AC and impacted evolution of organics and gases through intensive volatiles-char interactions. The AC from the co-activation of willow with either biochar-300 or biochar-500 exhibited higher specific surface area than that from direct activation of willow (1409.7 or 1297.0 m 2 g −1 versus 1243.6 m 2 g −1 ), which was also higher than calculated average of that from feedstock (ca. 1160 m 2 g −1 ). This resulted from intensified gasification of the biochar with H 2 O/CO 2 derived from willow, creating additional macropores and micropores of enlarged pore sizes. The enhanced gasification also reduced crystallinity of graphitic carbon, lowered O content via accelerated deoxygenation and diminished C O on nascent AC. Volatiles-char interactions also minimized pore filling from carbonaceous deposit generated from secondary condensation of primary volatiles. Additionally, direct activation of aliphatic-rich willow tended to form more micropores, while more mesopores were formed from aromatic-rich biochar.
研究领域:
能源与环境科学
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材料科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
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2022
·Vol. 23
·期 23
·14618
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IF 6.208
Yingjie Su,Yuqing Shi,Meiyi Jiang,Siji Chen
In this work, birch bark (BB) was used for the first time to prepare porous biochars via different one-step methods including direct activation (BBB) and N-doping co-activation (N-BBB). The specific surface area and total pore volume of BBB and N-BBB were 2502.3 and 2292.7 m2/g, and 1.1389 and 1.0356 cm3/g, respectively. When removing synthetic methyl orange (MO) dye and heavy metal Cr6+, both BBB and N-BBB showed excellent treatment ability. The maximum adsorption capacities of BBB and N-BBB were 836.9 and 858.3 mg/g for MO, and 141.1 and 169.1 mg/g for Cr6+, respectively, which were higher than most previously reported biochar adsorbents. The probable adsorption mechanisms, including pore filling, π–π interaction, H-bond interaction, and electrostatic attraction, supported the biochars’ demonstrated high performance. In addition, after five recycles, the removal rates remained above 80%, which showed the high stability of the biochars. This work verified the feasibility of the one-step N-doping co-activation method to prepare high-performance biochars, and two kinds of biochars with excellent performance (BBB and N-BBB) were prepared. More importantly, this method provides new directions and ideas for the development and utilization of other biomasses.Keywords:one-step synthesis;N-doping co-activation;biochar;water pollutants;adsorption performance
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
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2022
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IF 11.889
Shaojuan Yan,Jianhua Qu,Fuxuan Bi,Shuqi Wei,Siqi Wang,Zhao Jiang,Lei Wang,Hongwen Yu,Ying Zhang
KOH-activated N -doped hydrochar (KHCN) was synthesized via co-activation method to eliminate atrazine (AT) in water efficiently. Compared to primitive HC, KHCN had advantages of splendid specific surface area (1205.82 m 2 /g) and developed microsphere structures on the surface. Specially for KHCN, the extra melamine added strengthened and preserved partial structure of polar oxygen-containing groups that were decomposed in the process of pore making. Besides, the estimated uptake amount of AT onto KHCN (216.50 mg/g) was remarkably superior to KHC (114.25 mg/g). KHCN exhibited the pH-dependence for AT removal, and presented excellent uptake capacity at a relatively neutral environment. Notably, the proposed mechanisms for AT removal by KHCN included electrostatic attraction, pore filling, π-π EDA, H-bond as well as hydrophilic effect. Hence, the porous N -doped hydrochar was a kind of adsorbent which was easy to prepare and had the application prospect for AT removal in natural water.
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2019
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IF 4.175
Dewei Wang,Lang Xu,Jiawang Nai,Tao Sun
Two-dimensional (2D) nanocarbons have attracted considerable researching interest in electrochemical energy storage owing to their large surface area and shortened ion-diffusion distance. Herein, we propose a versatile co-activation strategy for preparing porous carbon nanosheets by employing easily available petroleum asphalt as the precursor. Besides KOH, introducing of NaOH as the co-activating reagent not only realized the morphological change from microparticles to nanosheets , but also altered the textural properties of the products, which is totally different from the traditional template route, offers a new possibility towards 2D nanocarbons. The large specific surface area and highly-developed micropores combined with its unique structural advantages, make it a very promising electrode material for high-rate supercapacitor in ionic liquid electrolyte. For instance, the porous carbon nanosheets deliver a large specific capacitance (169 F/g 1 A/g), superior rate capability (72.8% capacitance retention at 50 A/g), and good cycling stability after 5000 cycles. Moreover, the energy density can reach to 52.3 Wh/kg even at an ultrahigh power density of 43.75 kW/kg, which have shown great potential for applications in electrochemical energy storage devices such as supercapacitors.
研究领域:
材料科学
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能源存储
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DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2023
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IF 8.9
Tao Pei,Feng Shi,Can Liu,Yi Lu,Xu Lin,Defa Hou,Shunxiong Yang,Jirong Li,Zhifeng Zheng,Yunwu Zheng
In this study, a novel nitrogen-doped magnetic Fe–Ca codoped biochar for phenol removal was successfully fabricated via a hydrothermal and coactivation pyrolysis method. A series of adsorption process parameters (K 2 FeO 4 to CaCO 3 ratio, initial phenol concentration, pH value, adsorption time, adsorbent dosage and ion strength) and adsorption models (kinetic models, isotherms and thermodynamic models) were determined using batch experiments and various analysis techniques (XRD, BET, SEM-EDX, Raman spectroscopy , VSM, FTIR and XPS) to investigate the adsorption mechanism and metal-nitrogen-carbon interaction. The biochar with a ratio of Biochar: K 2 FeO 4 : CaCO 3 = 3:1:1 exhibited superior properties for adsorption of phenol and had a maximum adsorption capacity of 211.73 mg/g at 298 K, C 0 = 200 mg/L, pH = 6.0 and t = 480 min. These excellent adsorption properties were due to superior physicomechanical properties (a large specific surface area (610.53 m 2 /g) and pore volume (0.3950 cm 3 /g), a well-developed pore structure (hierarchical), a high graphitization degree (I D /I G = 2.02), the presence of O/N-rich functional groups and Fe-Ox,Ca-Ox, N-doping, as well as synergistic activation by K 2 FeO 4 and CaCO 3 ). The Freundlich and pseudo-second-order models effectively fit the adsorption data, indicating multilayer physicochemical adsorption. Pore filling and π-π interactions were the predominant mechanisms for phenol removal, and H-bonding interactions, Lewis-acid-base interactions, and metal complexation played an important role in enhancing phenol removal. A simple, feasible approach with application potential to organic contaminant/pollutant removal was developed in this study.
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
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