scholarly journals Synthesis of Au-decorated three-phase-mixed TiO2/phosphate modified active carbon nanocomposites as easily-recycled efficient photocatalysts for degrading high-concentration 2,4-DCP

RSC Advances ◽  
2019 ◽  
Vol 9 (66) ◽  
pp. 38414-38421 ◽  
Author(s):  
Sharafat Ali ◽  
Zhijun Li ◽  
Wajid Ali ◽  
Ziqing Zhang ◽  
Mingzhuo Wei ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Carbon ◽  
Charge Separation ◽  
High Concentration ◽  
Carbon Nanocomposites ◽  
Three Phase

Au decorated three-phase-mixed nanosized TiO2 coupled with phosphate-treated AC as recyclable nanocomposite photocatalysts exhibit excellent photoactivity for degrading high-concentration 2, 4-DCP, mainly due to the improved charge separation and specific surface area.

Facile synthesis of novel Roe-like TiO2 hollow nanospheres with mesoporous cavity for improved photocatalytic activity

2017 ◽  
Vol 10 (03) ◽  
pp. 1750028 ◽  
Author(s):  
Yan Zhu ◽  
Xiaoxia Yan ◽  
Yuanxin Ge ◽  
Shumin Wang ◽  
Dongmei Deng ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Self Assembly ◽  
Charge Separation ◽  
Synergistic Effects ◽  
Assembly Process ◽  
Hollow Nanospheres ◽  
Facile Synthesis

A facile approach was developed to synthesize novel Roe-like TiO2 hollow nanospheres via a template-assisted self-assembly process. These TiO2 nanospheres possessing mesoporous cavity manifest significantly improved photocatalytic activity owing to the synergistic effects of increased charge separation, more efficient use of the light and specific surface area.

Co-Producing Active Carbons and Sodium Silicate from Pyrolyzed Rice Husk by CO2 Activation Coupled with NaOH Solution Boiling

2014 ◽  
Vol 595 ◽  
pp. 30-35
Author(s):  
Da Wei Li ◽  
Xi Feng Zhu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Sodium Silicate ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Active Carbon ◽  
Desirability Function ◽  
Active Carbons ◽  
Solid Ratio ◽  
Naoh Solution

Active carbon and sodium silicate were produced simultaneously from pyrolyzed rice husk (PRH) by CO2 activation coupled with NaOH solution boiling. Doehlert matrix and Derringer's desirability function were applied to optimizing the boiling conditions to achieve a large specific surface area, a high silica extraction and low alkali consumption. In terms of this purpose, the optimum condition was determined as boiling CO2-activated char with 1mol/L NaOH solution at a liquid/solid ratio of 9.7 mL/g. Under this condition, the modulus of the sodium silicate and the specific surface area (SSA) of the active carbon were 2.62 and 897 m2/g, respectively. The values both reached their respective commercial levels. The pretreatment of the PRH with CO2 activation can markedly increase the SSA of active carbons.

Fabrication of Activated Carbon Fibers from Stabilized PAN-Based Fibers by KOH

2004 ◽  
Vol 449-452 ◽  
pp. 217-220 ◽  
Author(s):  
Young Jae Lee ◽  
Jae Hyung Kim ◽  
Jang Soon Kim ◽  
Dong Bok Lee ◽  
Jae Chun Lee ◽  
...  
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Potassium Hydroxide ◽  
Chemical Activation ◽  
Activated Carbon Fibers ◽  
High Concentration

Activated carbon fibers were prepared from stabilized PAN-based fibers by chemical activation using potassium hydroxide at different concentration. The experimental data showed variations in specific surface area, microstructure by the activated carbon fibers. Specific surface area of about 2545 m2/g was obtained in the KOH/stabilized PAN-based fiber ratio of 1:1 at 800°. An abrupt reduction of specific surface area was observed in the experiments with the ratio of 3:1 of OH/stabilized PAN-based fiber, being dissimilar with the result of KOH/fiber ratios of 1:1 and 2:1 in the similar experiments. The high concentration of KOH led to the destruction of micropore walls instead of forming mesopores.

Facile one-pot synthesis of MoS2 quantum dots–graphene–TiO2 composites for highly enhanced photocatalytic properties

2015 ◽  
Vol 51 (9) ◽  
pp. 1709-1712 ◽  
Author(s):  
Weiyin Gao ◽  
Minqiang Wang ◽  
Chenxin Ran ◽  
Le Li
Keyword(s):  
Quantum Dots ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Charge Separation ◽  
One Pot ◽  
Composite Photocatalyst ◽  
One Pot Synthesis ◽  
Light Absorbance

We reported a simple one-pot solvothermal approach to fabricate MoS2 quantum dots (QDs)–graphene–TiO2 (MGT) composite photocatalyst with significant improved photocatalysis property, which is caused by the increased charge separation, visible-light absorbance, specific surface area and reaction sites upon the introduction of MoS2 QDs.

Role of Acetaldehyde on Synthesizing Large Surface Area Porous g-C3N4 Nanosheets with Enhanced Photocatalytic Performance by Using Acetaldehyde–Melamine

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050066
Author(s):  
Xiangxiang Cheng ◽  
Xiaojuan Xu ◽  
Hongliang Wang ◽  
He Cai ◽  
Lan Jia ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Photocatalytic Performance ◽  
Low Cost ◽  
High Concentration ◽  
Air Atmosphere ◽  
Oxidative Etching

Large specific surface area porous g-C3N4 nanosheets were prepared by utilizing acetaldehyde-mediated melamine. The synthetic processes adopted two-step thermal treatments which are in N2 and then in an air atmosphere. The introduced acetaldehyde made melamine condensation incompletely and generated body defects in g-C3N4 when heated in N2. Further heating in air realized pores formation at sites of body defects, thus increase the specific surface area of g-C3N4. Notably, the introduction of acetaldehyde is beneficial to generate high concentration defects, which are active sites for thermal oxidative etching, and increase the yield of g-C3N4 by inhibiting the sublimation of melamine. The photocatalytic performance of obtained g-C3N4 was evaluated by the degradation of 2-propanol under visible light irradiation ([Formula: see text][Formula: see text]nm). The porous g-C3N4 exhibits excellent photocatalytic performance than bulk g-C3N4. The addition of trace acetaldehyde significantly increased the specific surface area and enhanced photocatalytic activity, providing a new idea for the development of simple, low-cost and high active g-C3N4 photocatalyst.

scholarly journals Fabrication of carbon nanospheres by the pyrolysis of polyacrylonitrile–poly(methyl methacrylate) core–shell composite nanoparticles

2017 ◽  
Vol 8 ◽  
pp. 1897-1908 ◽  
Author(s):  
Dafu Wei ◽  
Youwei Zhang ◽  
Jinping Fu
Keyword(s):  
Heat Treatment ◽  
Methyl Methacrylate ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Core Shell ◽  
Carbon Nanospheres ◽  
High Concentration ◽  
Poly Methyl Methacrylate ◽  
Bet Specific Surface Area

Carbon nanospheres with a high Brunauer–Emmett–Teller (BET) specific surface area were fabricated via the pyrolysis of polyacrylonitrile–poly(methyl methacrylate) (PAN–PMMA) core–shell nanoparticles. Firstly, PAN–PMMA nanoparticles at high concentration and low surfactant content were controllably synthesized by a two-stage azobisisobutyronitrile (AIBN)-initiated semicontinuous emulsion polymerization. The carbon nanospheres were obtained after the PAN core domain was converted into carbon and the PMMA shell was sacrificed via the subsequent heat treatment steps. The thickness of the PMMA shell can be easily adjusted by changing the feeding volume ratio (FVR) of methyl methacrylate (MMA) to acrylonitrile (AN). At an FVR of 1.6, the coarse PAN cores were completely buried in the PMMA shells, and the surface of the obtained PAN–PMMA nanoparticles became smooth. The thick PMMA shell can inhibit the adhesion between carbon nanospheres caused by cyclization reactions during heat treatment. The carbon nanospheres with a diameter of 35–65 nm and a high BET specific surface area of 612.8 m2/g were obtained from the PAN–PMMA nanoparticles synthesized at an FVR of 1.6. The carbon nanospheres exhibited a large adsorption capacity of 190.0 mg/g for methylene blue, thus making them excellent adsorbents for the removal of organic pollutants from water.

scholarly journals Limitation of K2CO3 as a Chemical Agent for Upgrading Activated Carbon

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1000
Author(s):  
Ji-Hyun Kim ◽  
Gibbum Lee ◽  
Jung-Eun Park ◽  
Seok-Hwi Kim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Alkali Metals ◽  
Chemical Activation ◽  
Molar Ratio ◽  
Chemical Agent ◽  
Carbon Precursor ◽  
High Concentration

The chemical activation of a carbon precursor with KOH generally results in an activated carbon (AC) with a high specific surface area. However, this process generates a large volume of wastewater that includes dissolved alkali metals, existing mainly as K2CO3. Thus, wastewaters with a high concentration of dissolved K2CO3 can potentially be used in place of KOH as a chemical agent. In the present study, to reduce the thermal stability of K2CO3, which decomposes at temperatures greater than 891 °C, K2CO3 was chemically impregnated into carbon precursors prior to activation of the precursors. The thermochemical properties and activation efficiency of the carbon precursors treated with K2CO3 were compared with those of carbon precursors treated with KOH. Analysis by XPS indicated that C–O–K complexes formed on the surface of the carbon precursors; in addition, their peak intensities were approximately the same irrespective of the chemical agent used. However, the specific surface area of the K2CO3-impregnated AC was 2162 m2/g, which was ~70% of that of the KOH-impregnated AC (3047 m2/g) prepared using the same K/C molar ratio of 0.5. XRD results confirmed that both K2CO3 and KOH transformed into KHCO3 and K4H2(CO3)3·1.5H2O during the impregnation. The peak intensities of these compounds in the XRD pattern of the K2CO3-impregnated carbon precursors were two times greater than those in the pattern of the KOH-impregnated carbon precursors. These compounds eventually transformed into K2CO3, which hardly participated as a chemical agent at the temperature used in the present study (850 °C). Therefore, recrystallisation of K2CO3, even during the impregnation, appeared to adversely affect the degree of activation. Nevertheless, the specific surface area of the K2CO3-activated AC was still ~1.6 times greater than that of the untreated carbon precursor (1378 m2/g), suggesting that the use of wastewater as a chemical agent is feasible for resource recycling.

Sign in / Sign up

Export Citation Format

Share Document