scholarly journals Characterization of High-Temperature Hierarchical Porous Mullite Washcoat Synthesized Using Aluminum Dross and Coal Fly Ash

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 178 ◽  
Author(s):  
Thye Foo Choo ◽  
Mohamad Amran Mohd Salleh ◽  
Kuan Ying Kok ◽  
Khamirul Amin Matori ◽  
Suraya Abdul Rashid
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Coal Fly Ash ◽  
Waste Product ◽  
Aluminum Dross ◽  
Hierarchical Porous ◽  
Porous Mullite

Mixture of aluminum dross (AD) and coal fly ash (CFA) was used to produce high-temperature porous mullite for washcoat application. CFA is the combustion by-product of pulverized coal in a coal-fired power plant, while AD is a waste product produced in secondary aluminum refining. In this study, 80 wt% of AD and 20 wt% of CFA was used to prepare a mullite precursor (MP) via acid leaching and dry-milling. The precursor was coated on a substrate and subsequently fired at 1500 °C. The results showed that the precursor transformed to a hierarchical porous microstructure assembled by large interlocked acicular mullite crystals. The pore structures consisted of large interconnected open pores and small pores. The specific surface area of the mullite washcoat was 4.85 m2g−1 after heating at 1500 °C for 4 h. The specific surface area was compatible with the specific surface area of other high-temperature washcoats.

scholarly journals Zeolite Synthesis from Brazilian Coal Fly Ash for Removal of Zn2+ and Cd2+ from Water

2011 ◽  
Vol 356-360 ◽  
pp. 1900-1908 ◽  
Author(s):  
Juliana De Carvalho Izidoro ◽  
Denise Alves Fungaro ◽  
Shao Bin Wang
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Metal Ion ◽  
Raw Materials ◽  
Coal Fly Ash ◽  
Mineralogical Composition ◽  
Batch Process ◽  
Metal Ion Removal

A Brazilian fly ash sample (CM1) was used to synthesize zeolites by hydrothermal treatment. Products and raw materials were characterized in terms of real density (Helium Pycnometry), specific surface area (BET method), morphological analysis (SEM), chemical composition (XRF) and mineralogical composition (XRD). The zeolites (ZM1) from fly ash were used for metal ion removal from water. Results indicated that hydroxy-sodalite zeolite could be synthesized from fly ash sample. The zeolite presented higher specific surface area and lower SiO2/Al2O3ratio than the ash precursor. The adsorption showed that cadmium is more preferentially adsorbed on ZM1 than zinc. The adsorption equilibrium time for both Zn2+and Cd2+was 20 hours in a batch process. The adsorption isotherms were better fitted by the Langmuir model and the highest percentages of removal using ZM1 were obtained at pH 6 and 5 and doses of 15 and 18 g L-1for Zn2+and Cd2+, respectively. Thermodynamic studies indicated that adsorption of Zn2+and Cd2+by ZM1 was a spontaneous, endothermic process and presented an increase of disorder at the interface solid/solution.

Study of Solid Amine CO2 Sorbents Based on the Modified Fly Ash

2013 ◽  
Vol 448-453 ◽  
pp. 174-177
Author(s):  
Ying Lu Ji ◽  
Hui Ping Song ◽  
Fang Qin Cheng ◽  
Nan Zheng ◽  
Xu Ming Wang
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sodium Hydroxide Solution ◽  
Coal Fly Ash ◽  
Synthesis Method ◽  
Bet Analysis ◽  
Ft Ir ◽  
Modified Fly Ash

In this paper, coal fly ash was modified by the hydrothermal synthesis method based on sodium hydroxide solution, and then was macerated by ethanol amine. Then we obtained the solid amine adsorbents used to absorb CO2. The modified fly ash was investigated by scanning electron microscope (SEM) and the specific surface area analyzer (BET) for the microstructure and specific surface area. Then, the solid CO2 adsorbent was analyzed by fourier transform infrared spectrometer (FT-IR) and thermal analyzer (TGA) in CO2 atmosphere. Results showed that modified fly ash generated many kinds of zeolite material by the SEM and the BET analysis, greatly increasing the specific surface area, improved the adsorption capacity. FT-IR analysis that the surface of solid amine CO2 adsorbent with amine groups; TGA analysis that compared with the original fly ash, CO2 adsorbent by this paper made has the capability of adsorption of CO2.

scholarly journals Nanoporous Quasi-High-Entropy Alloy Microspheres

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 345 ◽  
Author(s):  
Lianzan Yang ◽  
Yongyan Li ◽  
Zhifeng Wang ◽  
Weimin Zhao ◽  
Chunling Qin
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Specific Surface Area ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Hierarchical Porous

High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.

Preparation of Fe/N co-doped hierarchical porous carbon nanosheets derived from chitosan nanofibers for high-performance supercapacitors

2021 ◽  
pp. 1-16
Author(s):  
Yaqi Yang ◽  
Ziqiang Shao ◽  
Feijun Wang
Keyword(s):  
Specific Surface ◽  
Specific Capacitance ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Porous Carbon ◽  
Active Sites ◽  
Transport Pathway ◽  
Carbon Nanosheets ◽  
Hierarchical Porous

Abstract Due to the low specific capacitance and small specific surface area of conventional carbon materials used as electrode materials for double-layer capacitors, the search for more ideal materials and ingenious preparation methods remains a major challenge. In this study, fractional porous carbon nanosheets were prepared by co-doping Fe and N with chitosan as nitrogen source. The advantage of this method is that the carbon nanosheets can have a large number of pore structures and produce a large specific surface area. The presence of Fe catalyzes the graphitization of carbon in the carbon layer during carbonization process, and further increases the specific surface area of the electrode material. This structure provides an efficient ion and electron transport pathway, which enables more active sites to participate in the REDOX reaction, thus significantly enhancing the electrochemical performance of SCs. The specific surface area of CS-800 is up to 1587 m2 g−1. When the current density is 0.5 A g−1, the specific capacitance of CS-800 reaches 308.84 F g−1, and remains 84.61 % of the initial value after 10,000 cycles. The Coulomb efficiency of CS-800 is almost 100 % after a long cycle, which indicates that CS-800 has more ideal double-layer capacitance and pseudo capacitance.

scholarly journals Study on Adsorption Mechanism and Failure Characteristics of CO2 Adsorption by Potassium-Based Adsorbents with Different Supports

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2424 ◽  
Author(s):  
Bao-guo Fan ◽  
Li Jia ◽  
Yan-lin Wang ◽  
Rui Zhao ◽  
Xue-song Mei ◽  
...  
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Reaction Temperature ◽  
Adsorption Mechanism ◽  
Co2 Adsorption ◽  
Carbonation Reaction ◽  
Failure Characteristics ◽  
Boiler Fly Ash

In order to obtain the adsorption mechanism and failure characteristics of CO2 adsorption by potassium-based adsorbents with different supports, five types of supports (circulating fluidized bed boiler fly ash, pulverized coal boiler fly ash, activated carbon, molecular sieve, and alumina) and three kinds of adsorbents under the modified conditions of K2CO3 theoretical loading (10%, 30%, and 50%) were studied. The effect of the reaction temperature (50 °C, 60 °C, 70 °C, 80 °C, and 90 °C) and CO2 concentration (5%, 7.5%, 10%, 12.5%, and 15%) on the adsorption of CO2 by the adsorbent after loading and the effect of flue gas composition on the failure characteristics of adsorbents were obtained. At the same time, the microscopic characteristics of the adsorbents before and after loading and the reaction were studied by using a specific surface area and porosity analyzer as well as a scanning electron microscope and X-ray diffractometer. Combining its reaction and adsorption kinetics process, the mechanism of influence was explored. The results show that the optimal theoretical loading of the five adsorbents is 30% and the reaction temperature of 70 °C and the concentration of 12.5% CO2 are the best reaction conditions. The actual loading and CO2 adsorption performance of the K2CO3/AC adsorbent are the best while the K2CO3/Al2O3 adsorbent is the worst. During the carbonation reaction of the adsorbent, the cumulative pore volume plays a more important role in the adsorption process than the specific surface area. As the reaction temperature increases, the internal diffusion resistance increases remarkably. K2CO3/AC has the lowest activation energy and the carbonation reaction is the easiest to carry out. SO2 and HCl react with K2CO3 to produce new substances, which leads to the gradual failure of the adsorbents and K2CO3/AC has the best cycle failure performance.

scholarly journals Ionothermally synthesized hierarchical porous Schiff-base-type polymeric networks with ultrahigh specific surface area for supercapacitors

RSC Advances ◽  
2017 ◽  
Vol 7 (32) ◽  
pp. 19934-19939 ◽  
Author(s):  
Yuhang Zhao ◽  
Ping Liu ◽  
Xiaodong Zhuang ◽  
Dongqing Wu ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Schiff Base ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Synthesis Method ◽  
Ionothermal Synthesis ◽  
Polymeric Network ◽  
Polymeric Networks ◽  
Hierarchical Porous ◽  
One Step

A hierarchical porous polymeric network (HPPN) with ultrahigh specific surface area up to 2870 m2 g−1 was synthesized via a one-step ionothermal synthesis method without using templates.

3D hierarchical porous amidoxime fibers speed up uranium extraction from seawater

2019 ◽  
Vol 12 (6) ◽  
pp. 1979-1988 ◽  
Author(s):  
Xiao Xu ◽  
Hongjun Zhang ◽  
Junxuan Ao ◽  
Lu Xu ◽  
Xiyan Liu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Nuclear Fuel ◽  
Specific Surface Area ◽  
New Technology ◽  
High Specific Surface Area ◽  
Fuel Production ◽  
Uranium Extraction ◽  
Hierarchical Porous ◽  
Speed Up

The development of high specific surface area amidoxime-based polymeric (H-ABP) fibers presents a new technology for the synthesis of highly efficient adsorbents for uranium extraction from seawater (UES), thus opening a whole new means of nuclear fuel production from the ocean.

scholarly journals Silkworm cocoon derived N, O-codoped hierarchical porous carbon with ultrahigh specific surface area for efficient capture of methylene blue with exceptionally high uptake: kinetics, isotherm, and thermodynamics

RSC Advances ◽  
2019 ◽  
Vol 9 (58) ◽  
pp. 33872-33882
Author(s):  
Genxing Zhu ◽  
Qi Liu ◽  
Fengyi Cao ◽  
Qi Qin ◽  
Mingli Jiao
Keyword(s):  
Methylene Blue ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Porous Carbon ◽  
Uptake Kinetics ◽  
High Uptake ◽  
Hierarchical Porous Carbon ◽  
Hierarchical Porous ◽  
Silkworm Cocoon

Silkworm cocoon derived N, O-HPC (SBET = 2270.19 m2 g−1) was synthesized, and demonstrated exceptionally high uptake of MB (2104.29 mg g−1).

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