scholarly journals CHARACTERISTICS OF NEW PROMISING BENTONITE COAL SORBENTS MODIFIED BY DIFFERENT COMPOUNDS

2021 ◽  
Vol 17 (3) ◽  
pp. 87-95
Author(s):  
Ilkhom Tagaev ◽  
Manzura Muratova ◽  
Lyudmila Andriyko ◽  
Mohigul Yusuf Kizi Boykhonova

Introduction. Bentonite clays are traditional inexpensive and effective adsorbents that have a high potential for removing heavy metals from wastewater due to their abundance, chemical and mechanical stability, high exchange ability, and unique structural properties.Problem Statement. To obtain activated carbon, high-temperature muffle furnaces are used with the consumption of a large amount of electricity, which is economically unprofitable. In addition, the resulting sorbents must be in the form of granules or tablets, have high strength and the ability to be repeatedly used in technological processes.Purpose. Development of a method for the production of low-cost granular sorbents based on bentonite as amineral component, activated carbon, as well as natural production waste (sunflower husk, straw, sawdust, etc. as modifiers), which can be removed from the activation process to increase porosity of these materials.Materials and Methods. Angren brown coal; bentonite of the Navbakhor deposit was used as a sorbent and a basic substance for the granules formation; modifiers were sodium chloride, potassium, chopped straw, sawdust. Methods of thermal decarbonization and activation of the obtained granules under the optimal conditions (950 °С, 45 min) were applied; the bulk density, the specific surface area, pore types and their total volume was determined by optical microscopy and nitrogen adsorption methods.Results. Inexpensive hybrid bentonite-carbon sorbents in the form of high-strength granules were synthesized.The optimal ratio of the main components is Bentonite:Coal = 1 : 2, size (2.5 mm) and strength of granules (83—99%), total pore volume 0.863—1.01 cm3/g, confirmed the presence of macro-, meso- and micropores. The most promising sample has a specific surface area (Langmuir) 184 m2/g.Conclusions. The method for obtaining new effective granular carbon sorbents of low cost, having high sorption capacity relative to organic and inorganic pollutants for purification of industrial process waters has been proposed.

RSC Advances ◽  
2018 ◽  
Vol 8 (74) ◽  
pp. 42280-42291 ◽  
Author(s):  
Ling Zhang ◽  
Ling-yu Tu ◽  
Yan Liang ◽  
Qi Chen ◽  
Ze-sheng Li ◽  
...  

Activated carbon fibers with high micropore volume and large specific surface area were prepared from abundant and low-cost coconut fibers, which show excellent adsorption performances towards various dyes.


2010 ◽  
Vol 62 (11) ◽  
pp. 2637-2646 ◽  
Author(s):  
A. B. Namazi ◽  
C. Q. Jia ◽  
D. G. Allen

The goal of this work is to establish the technical feasibility of producing activated carbon from pulp mill sludges. KOH chemical activation of four lignocellulosic biomass materials, two sludges from pulp mills, one sludge for a linerboard mill, and cow manure, were investigated experimentally, with a focus on the effects of KOH/biomass ratio (1/1, 1.5/1 and 2/1), activation temperature (400–600°C) and activation time (1 to 2 h) on the development of porosity. The activation products were characterized for their physical and chemical properties using a surface area analyzer, scanning electron microscopy and Fourier transform infrared spectroscopy. Experiments were carried out to establish the effectiveness of the lignocellulosic biomass-derived activated carbon in removing methylene blue (MB), a surrogate of large organic molecules. The results show that the activated carbon are highly porous with specific surface area greater than 500 m2/g. The yield of activated carbon was greater than the percent of fixed carbon in the dry sludge, suggesting that the activation process was able to capture a substantial amount of carbon from the organic matter in the sludge. While 400°C was too low, 600°C was high enough to sustain a substantial rate of activation for linerboard sludge. The KOH/biomass ratio, activation temperature and time all play important roles in pore development and yield control, allowing optimization of the activation process. MB adsorption followed a Langmuir isotherm for all four activated carbon, although the adsorption capacity of NK-primary sludge-derived activated carbon was considerably lower than the rest, consistent with its lower specific surface area.


Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3429
Author(s):  
Lei Zhao ◽  
Ziwei Lan ◽  
Wenhao Mo ◽  
Junyu Su ◽  
Huazhu Liang ◽  
...  

Non-platinum carbon-based catalysts have attracted much more attention in recent years because of their low cost and outstanding performance, and are regarded as one of the most promising alternatives to precious metal catalysts. Activated carbon (AC), which has a large specific surface area (SSA), can be used as a carrier or carbon source at the same time. In this work, stable pine peel bio-based materials were used to prepare large-surface-area activated carbon and then compound with cobalt phthalocyanine (CoPc) to obtain a high-performance cobalt/nitrogen/carbon (Co-N-C) catalyst. High catalytic activity is related to increasing the number of Co particles on the large-specific-area activated carbon, which are related with the immersing effect of CoPc into the AC and the rational decomposed temperature of the CoPc ring. The synergy with N promoting the exposure of CoNx active sites is also important. The Eonset of the catalyst treated with a composite proportion of AC and CoPc of 1 to 2 at 800 °C (AC@CoPc-800-1-2) is 1.006 V, higher than the Pt/C (20 wt%) catalyst. Apart from this, compared with other AC/CoPc series catalysts and Pt/C (20 wt%) catalyst, the stability of AC/CoPc-800-1-2 is 87.8% in 0.1 M KOH after 20,000 s testing. Considering the performance and price of the catalyst in a practical application, these composite catalysts combining biomass carbon materials with phthalocyanine series could be widely used in the area of catalysts and energy storage.


2006 ◽  
Vol 510-511 ◽  
pp. 750-753 ◽  
Author(s):  
Sook Young Moon ◽  
Myung Soo Kim ◽  
Hyun Sik Hahm ◽  
Yun Soo Lim

Activated carbon fibers were prepared from stabilized PAN-based fibers by chemical activation using hydroxides at different concentrations. The experimental data showed variations in specific surface area, microstructure, pore size distribution, and amounts of iodine adsorbed by the activated carbon fibers. Specific surface area of about 2244m2/g and iodine adsorption of 1202mg/g were obtained in the KOH 1.5M. However, the use of NaOH in the activation process rather than KOH and using the same time/ temperature profiles resulted in a carbon with a much lower surface area. KOH is a more developed pore structure than NaOH, which means that KOH is a better activation agent in producing ACF than NaOH.


2018 ◽  
Vol 53 ◽  
pp. 01025
Author(s):  
Qiao Yang ◽  
Chao Gao ◽  
Zhen-Xing Wu ◽  
Sheng-Na Liang ◽  
Min-Hui Liu

Constructed wetland (CW) is a low cost and easy operation process for wastewater treatment, while filler clogging is one of the disadvantages for this technology. Using activated carbon as the filler, a regular CW and an integration of constructed wetland with microbial fuel cell (CW-MFC) were constructed. After continuous operation of four months, specific surface area and pore size distribution of the activated carbon were analyzed. The specific surface area of the fresh activated carbon was 133.8 m2/g, while the filler in the CW and CW-MFC systems had specific surface area of 38.1 m2/g and 58.2 m2/g. The surface decrease of the CW-MFC filler was 21% lower than that of CW filler. Comparing with the regular CW, the filler in the CW-MFC was more clogging resistant. The alleviation of the filler clogging in CW-MFC may be caused by the micro-electric field as the function of MFC. CW-MFC is a promising microbial electrochemical technology for wastewater treatment and filler clogging resistant, there are some detailed issues deserve to be further researched.


2011 ◽  
Vol 480-481 ◽  
pp. 6-10
Author(s):  
Yan Feng Yang ◽  
Xue Jun Zhang ◽  
Hai Yan Li

General purpose pitch-based carbon fiber (PCF) was pretreated with steam to develop pores on the surface of fiber. After immersed in cobalt salt solution, PCF was used as raw materials to prepare activated carbon fiber (ACF) through steam activation process. The effect of pretreatment of carbon fiber on specific surface area, mesopore volume and pore size distribution was investigated by N2 adsorption, and morphology of the resultant ACF was observed with scanning electron microscope(SEM). The results show that pretreatment of PCF enlarges specific surface area and mesopore ratio of ACF remarkably. The best ACF obtained in experiment is the one with specific surface area of 2670 m2/g and mesoporosity of 61.8%. Cobalt has evident catalysis in preparing ACF from activation of PCF, while specific surface area and pore size of ACF get smaller with cobalt salt immersion when pretreatment is too strong.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3811
Author(s):  
Zhongbao Liu ◽  
Jiayang Gao ◽  
Xin Qi ◽  
Zhi Zhao ◽  
Han Sun

In this study, the hydrothermal method was used to synthesize MIL-101(Cr), and activated carbon (AC) with different content was incorporated in to MIL-101(Cr), thereby obtaining AC-MIL-101(Cr) composite material with a huge specific surface area. The physical properties of MIL-101(Cr) and AC-MIL-101(Cr) were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), nitrogen adsorption and desorption and specific surface area testing, and ethanol vapor adsorption performance testing. The results show that with the increase of activated carbon content, the thermal stability of AC-MIL-101(Cr) is improved. Compared with the pure sample, the BET specific surface area and pore volume of AC-MIL-101(Cr) have increased; In the relative pressure range of 0–0.4, the saturated adsorption capacity of AC-MIL-101(Cr) to ethanol vapor decreases slightly. It is lower than MIL-101(Cr), but its adsorption rate is improved. Therefore, AC-MIL-101(Cr)/ethanol vapor has a good application prospect in adsorption refrigeration systems. The exploration of AC-MIL-101(Cr) composite materials in this paper provides a reference for the future application of carbon-based/MOFS composite adsorbent/ethanol vapor working fluid in adsorption refrigeration.


Chemosensors ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 149
Author(s):  
André Olean-Oliveira ◽  
Gilberto A. Oliveira Brito ◽  
Celso Xavier Cardoso ◽  
Marcos F. S. Teixeira

The use of graphene and its derivatives in the development of electrochemical sensors has been growing in recent decades. Part of this success is due to the excellent characteristics of such materials, such as good electrical and mechanical properties and a large specific surface area. The formation of composites and nanocomposites with these two materials leads to better sensing performance compared to pure graphene and conductive polymers. The increased large specific surface area of the nanocomposites and the synergistic effect between graphene and conducting polymers is responsible for this interesting result. The most widely used methodologies for the synthesis of these materials are still based on chemical routes. However, electrochemical routes have emerged and are gaining space, affording advantages such as low cost and the promising possibility of modulation of the structural characteristics of composites. As a result, application in sensor devices can lead to increased sensitivity and decreased analysis cost. Thus, this review presents the main aspects for the construction of nanomaterials based on graphene oxide and conducting polymers, as well as the recent efforts made to apply this methodology in the development of sensors and biosensors.


2015 ◽  
Vol 749 ◽  
pp. 17-21 ◽  
Author(s):  
Joanna Sreńscek Nazzal ◽  
Karolina Glonek ◽  
Jacek Młodzik ◽  
Urszula Narkiewicz ◽  
Antoni W. Morawski ◽  
...  

Microporous carbons prepared from commercial activated carbon WG12 by KOH and/or ZnCl2 treatment were examined as adsorbents for CO2 capture. The micropore volume and specific surface area of the resulting carbons varied from 0.52 cm3/g (1374 m2/g) to 0.70 cm3/g (1800 m2/g), respectively. The obtained microporous carbon materials showed high CO2 adsorption capacities at 40 bar pressure reaching 16.4 mmol/g.


2021 ◽  
Vol 15 (2) ◽  
pp. 131-144
Author(s):  
Chunjiang Jin ◽  
Huimin Chen ◽  
Luyuan Wang ◽  
Xingxing Cheng ◽  
Donghai An ◽  
...  

In this study, aspen wood sawdust was used as the raw material, and Fe(NO3)3 and CO2 were used as activators. Activated carbon powder (ACP) was produced by the one-step physicochemical activation method in an open vacuum tube furnace. The effects of different mass ratios of Fe(NO3)3 and aspen wood sawdust on the pore structure of ACP were examined under single-variable experimental conditions. The mass ratio was 0–0.4. The detailed characteristics of ACP were examined by nitrogen adsorption, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The adsorption capacity of ACP was established by simulating volatile organic compounds (VOCs) using ethyl acetate. The results showed that ACP has a good nanostructure with a large pore volume, specific surface area, and surface functional groups. The pore volume and specific surface area of Fe-AC-0.3 were 0.26 cm3/g and 455.36 m2/g, respectively. The activator played an important role in the formation of the pore structure and morphology of ACP. When the mass ratio was 0–0.3, the porosity increased linearly, but when it was higher than 0.3, the porosity decreased. For example, the pore volume and specific surface area of Fe-AC-0.4 reached 0.24 cm3/g and 430.87 m2/g, respectively. ACP presented good VOC adsorption performance. The Fe-AC-0.3 sample, which contained the most micropore structures, presented the best adsorption capacity for ethyl acetate at 712.58 mg/g. Under the action of the specific reaction products nitrogen dioxide (NO2) and oxygen, the surface of modified ACP samples showed different rich C/O/N surface functional groups, including C-H, C=C, C=O, C-O-C, and C-N.


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