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Hybrid carbon in the form of the area ratio of the samples produced at different treatment conditions.
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The SO2 adsorption efficiency of activated carbons (ACs) is clearly dependent on its physicochemical structure. Related to this, the effect of physical and mechanical activation on the physicochemical structure of coal-based ACs has been investigated in this work. In the stage of CO2 activation, the rapid decrease of the defective structure and the...
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Context 1
... the D1 peak is represented as the defective sp 2 bonding carbon atoms; the D3 peak is represented as the amorphous sp 2 bonding carbon atoms; the D4 peak is represented as the sp 2 -sp 3 bonding carbon atoms; the G peak is represented as the crystalline sp 2 bonding carbon atoms; furthermore, the relative quantities of different hybridized structures is as follows: (1) AD1/AG represents the relative quantity of the big aromatic rings, including C-C between aromatic rings and aromatics with no fewer than 6 rings with a defective structure; (2) AD3/AG represents the relative quantity of the small aromatic rings including aromatics with 3-5 rings and the semi-circle breathing of aromatic rings; and (3) AD4/AG represents the relative quantity of the cross-linking structure, including Caromatic-Calkyl, aromatic (aliphatic) ethers and C-C on hydroaromatic rings [42]. The results of the different hybrid carbons in the form of area ratios of the samples are shown in Table 3. ...Similar publications
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Citations
... Liu et al. [10] studied the effect of physical and mechanical activation on the physicochemical structure of coal-based activated carbons (ACs). In the stage of CO 2 activation, a rapid decrease of the defective structure and the growth of aromatic layers accompanied by the dehydrogenation of aromatic rings resulted in the ordered conversion of the microstructure and severe carbon losses on the surfaces of Char-PA, while the oxygen content of Char-PA, including C=O (39.6%), ...
The increasing trends in gas emissions have had direct adverse impacts on human health and ecological habitats in the world. A variety of technologies have been deployed to mitigate the release of such gases, including CO2, CO, SO2, H2S, NOx and H2. This special issue on gas-capture processes collects 25 review and research papers on the applications of novel techniques, processes, and theories in gas capture and removal.
... Physical activation can increase the surface area and improve the pore structure of biochar. Likewise, chemical activation can enrich the functional types of biochar and provide more binding sites for pollutant removal [13][14][15][16]. The preparation of highly effective adsorbents can provide a new option for the utilization of corn residues. ...
Improperly treated or directly discharged into the environment, wastewater containing dyes can destroy the quality of water bodies and pollute the ecological environment. The removal of dye wastewater is urgent and essential. In this study, corn stalk was pyrolyzed to pristine biochar (CSBC) in a limited oxygen atmosphere and modified using KOH and H3PO4 (KOH-CSBC, H3PO4-CSBC, respectively). The biochars were characterized by surface area and pore size, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), as well as their behavior in adsorbing methylene blue (MB). Results indicated that the pore structure of CSBC became more developed after modification by KOH. Meanwhile, H3PO4-CSBC contained more functional groups after activation treatment. The pseudo-second-order kinetic and the Langmuir adsorption isotherm represented the adsorption process well. The maximum MB adsorption capacity of CSBC, KOH-CSBC, and H3PO4-CSBC was 43.14 mg g−1, 406.43 mg g−1 and 230.39 mg g−1, respectively. Chemical modification significantly enhanced the adsorption of MB onto biochar, especially for KOH-CSBC. The adsorption mechanism between MB and biochar involved physical interaction, electrostatic interaction, hydrogen bonding and π–π interaction. Hence, modified CSBC (especially KOH-CSBC) has the potential for use as an adsorbent to remove dye from textile wastewater.
Coal-based activated carbon (CBAC) is widely used in several industrial processes and daily life, however, it is susceptible to spontaneous combustion during storage and transportation. Therefore, it is essential to probe the spontaneous combustion risk of CBAC. The oxidation process of briquetting material sample (BM), carbonized material sample (CM), and activated material sample (AM) was studied via thermogravimetric (TG–DTG) analysis. The oxidation mechanism of the samples was investigated via the proximate and ultimate analyses, Fourier transform Infrared (FTIR) spectroscopy, and nitrogen adsorption. Kinetic characteristics of the samples during the combustion were determined using the Kissinger–Akahira–Sunose (KAS) method. Five characteristic temperature points and the five stages of the samples during oxidation were obtained. With an increase in the heating rate, the hysteresis phenomenon was observed during thermal decomposition and combustion of AM in TG–DTG curves. The heating value of BM, CM, and AM were 6678, 6705, and 6776 cal g–1, respectively. AM has a developed pore structure that leads to enhanced oxygen adsorption and limited heat transfer, easy to induce spontaneous combustion. The main functional groups of AM were hydroxyl groups and aromatic hydrocarbons, especially hydroxyl groups that played a key role in the spontaneous combustion of AM. The apparent activation energy (Ea) during the combustion of BM, CM, and AM were 110.70, 85.90, and 111.80 kJ mol–1 from the KAS method, respectively. These results are expected to facilitate a better understanding of CBAC spontaneous combustion.
In this study, limestone samples were investigated in terms of grinding product particle size distribution (PSD) differentiations after microwave treatment. Initially, collected limestone samples (a total of 58 sample) were crushed and prepared for microwave treatment. In order to observe the effect of microwave treatment, 58 of these samples were ground directly while the other 58 samples were objected to microwave treatment (5 min, 180 W) prior to the grinding. In this paper, size parameters (D10, D50, D90, D32, and D43) and their corresponding differentiations after microwave treatment were evaluated. As regards to the finding of this study, microwave treatment prior to grinding can be claimed to ease the grinding, and finer size distribution can be obtained especially for lower Fe2O3 content samples. It was also found out the fact that MgO and CaO content of samples have influenced the abovementioned PSD differentiation to some extent.
