An Effect of pH on Radiation Assisted Modification of Oxygen-Rich Activated Carbon by Urea

Activated carbons (ACs) are a versatile group of adsorbents for water pollution control, especially organic dyes. Harsh chemicals and high temperatures are required for the activation process of ACs, which becomes a significant concern due to their toxicity and harmful effects on human health and the environment. Gamma irradiation, an alternative green technique, is a promising strategy for pretreatment and escalates the nitrogen or oxygen functional group of ACs. The current study provides the modification of ACs by the gamma irradiation in the various pH (5-11) of urea solution. The modified ACs were characterized by scanning electron microscopy (SEM), nitrogen gas adsorption-desorption analysts (BET), temperature program desorption (TPD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray diffraction spectroscopy (XRD). The point of zero charges and dye adsorption capacities were determined. This finding demonstrates that the ACs can be modified by gamma irradiation at 25 kGy in the urea solution media. The degree of graphitization enhanced significantly at pH 11(AC-pH11). The oxygen-rich functional groups created by radiation assists could enhance the electrostatic attraction between acid gases or cationic dyes. AC-pH11 also was able to adsorb methylene blue (160.73 ± 1.70 mg/g) greater than methyl orange (127.57 ± 2.22 mg/g).

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Characterization and comparison of walnut shells-based activated carbons and their adsorptive properties

Adsorption Science & Technology ◽

10.1177/0263617420946524 ◽

2020 ◽

Vol 38 (9-10) ◽

pp. 450-463

Author(s):

Xiya Li ◽

Jieqiong Qiu ◽

Yiqi Hu ◽

Xiaoyuan Ren ◽

Lu He ◽

...

Keyword(s):

Adsorption Capacity ◽

Activated Carbons ◽

Low Cost ◽

Total Pore Volume ◽

Textural Properties ◽

Hydrothermal Carbonization ◽

Bet Surface Area ◽

Activation Process ◽

Walnut Shells ◽

Adsorption Desorption

The production of low-cost biologically activated carbons (BACs) is urgent need of environmental protection and ecological sustainability. Hence, walnut shells were treated by traditional pyrolysis, direct KOH impregnation and combined activation composed of hydrothermal carbonization and two-step H3PO4- and pyrolysis-activation process to obtain porous carbon with high adsorption capacity. It was found that the best adsorption capacity for iodine and organic dye methylene blue (MB) can be obtained using the KOH impregnation at impregnation ratio of 1:1 or combined activation comprising of 2 h H3PO4 activation and 1 h pyrolysis activation at 1000°C. The produced KOH, H3PO4/pyrolysis activated BACs at the optimum conditions are superior to that of commercial ACs, 9.4 and 1.3 times for MB removal, 4 and 4.5 times for iodine number respectively. Characterization results demonstrated their porous structure with very good textural properties such as high BET surface area (1689.1 m2/g, 1545.3 m2/g) and high total pore volume (0.94 cm3/g, 0.96 cm3/g). The N2 adsorption-desorption isotherm of H3PO4/pyrolysis activated hydrochar suggested the co-existence of micro and meso-pores. Moreover, they are more effective for the removal of Fe(III) and Cr(VI) from aqueous solution than the commercial AC, suggesting a promising application in the field of water treatment.

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Effect of Activating Agent on the Properties of TiO2/Activated Carbon Heterostructures for Solar Photocatalytic Degradation of Acetaminophen

Materials ◽

10.3390/ma12030378 ◽

2019 ◽

Vol 12 (3) ◽

pp. 378 ◽

Cited By ~ 13

Author(s):

Manuel Peñas-Garzón ◽

Almudena Gómez-Avilés ◽

Jorge Bedia ◽

Juan Rodriguez ◽

Carolina Belver

Keyword(s):

Activated Carbon ◽

Activated Carbons ◽

Anatase Phase ◽

Chemical Activation ◽

Reaction Medium ◽

X Ray Diffraction ◽

X Ray ◽

Porous Texture ◽

Adsorption Desorption ◽

Synthesized Materials

Several activated carbons (ACs) were prepared by chemical activation of lignin with different activating agents (FeCl3, ZnCl2, H3PO4 and KOH) and used for synthesizing TiO2/activated carbon heterostructures. These heterostructures were obtained by the combination of the activated carbons with a titania precursor using a solvothermal treatment. The synthesized materials were fully characterized (Wavelength-dispersive X-ray fluorescence (WDXRF), X-ray diffraction (XRD), Scanning electron microscopy (SEM), N2 adsorption-desorption, Fourier transform infrared (FTIR) and UV-visible diffuse reflectance spectra (UV-Vis DRS) and further used in the photodegradation of a target pharmaceutical compound (acetaminophen). All heterostructures were composed of anatase phase regardless of the activated carbon used, while the porous texture and surface chemistry depended on the chemical compound used to activate the lignin. Among all heterostructures studied, that obtained by FeCl3-activation yielded complete conversion of acetaminophen after 6 h of reaction under solar-simulated irradiation, also showing high conversion after successive cycles. Although the reaction rate was lower than the observed with bare TiO2, the heterostructure showed higher settling velocity, thus being considerably easier to recover from the reaction medium.

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Pore characterization of marine-continental transitional shale in Permian Shanxi Formation of The Southern North China Basin

Energy Exploration & Exploitation ◽

10.1177/0144598720912346 ◽

2020 ◽

Vol 38 (6) ◽

pp. 2199-2216 ◽

Cited By ~ 1

Author(s):

Xiaoguang Yang ◽

Shaobin Guo

Keyword(s):

Negative Correlation ◽

North China ◽

Gas Adsorption ◽

Relative Content ◽

X Ray Diffraction ◽

Mesopore Volume ◽

Positive Correlation ◽

Pore Types ◽

North China Basin ◽

Adsorption Desorption

Organic-rich marine-continental transitional shale is widely developed in the Permian Shanxi Formation in the Southern North China Basin. In this study, shale samples from the southern and northern wells of the basin were characterized by X-ray diffraction, high-pressure mercury intrusion porosimetry, low-pressure gas adsorption (N2 and CO2) and argon ion polishing-field emissions scanning electron microscopy. The pore types and structures of shale micropores, mesopores and macropores are qualitatively described; their pore size distribution and volume are quantitatively characterized; and the influencing factors of the pore volume are analyzed. The results show that the marine-continental transitional shale pores exhibit an unbalanced multimodal distribution with four peaks at 0.4–0.8 nm, 2–4 nm, 10–50 nm, and >10 µm. The mesopore volume is dominant, accounting for 40–70% of pores. The mesopores of the samples are slit-shaped pores and ink bottle-shaped pores. Since there is a desorption hysteresis loop on the N2 adsorption-desorption curve, most of them belong to the H4 type, and ye23-8 belongs to the mixed H2 and H4 type according to the IUPAC classification scheme. The slit-shaped pores are mainly interlayer pores and interparticle pores in clays, and the ink bottle-shaped pores are tiny dissolved pores and organic matter pores. Ro has negative correlation with the volumes of the mesopores and macropores, but it does not affect the volume of micropores. TOC has a positive correlation with the macropore and micropore volumes, and it has a negative correlation with mesopore volume. The relative contents of kaolinite and I/S have a positive correlation with the mesopore and macropore volumes. The relative content of illite has a negative correlation with the mesopore and macropore volumes. The relative content of chlorite has a negative correlation with the mesopore volume.

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Synthesis and Characterization of Iron Oxide Nanostructured Particles in Na–Y Zeolite Matrix

Journal of Materials Research ◽

10.1557/jmr.2004.19.3.930 ◽

2004 ◽

Vol 19 (3) ◽

pp. 930-936 ◽

Cited By ~ 7

Author(s):

Maxine Yee ◽

Iskandar I. Yaacob

Keyword(s):

Iron Oxide ◽

Fine Particles ◽

Gas Adsorption ◽

Morphological Changes ◽

X Ray Diffraction ◽

Oxide Systems ◽

Nanostructured Particles ◽

Transmission Electron ◽

Xrd Patterns ◽

Adsorption Desorption

Formation of iron oxide nanoparticles within the internal cages of Na–Y zeolites was investigated. Sodium ions within the zeolites were replaced with iron(II) ions. Elemental composition studies showed a significant amount of iron in the exchanged sample. NaOH and dropwise additions of H2O2 at 60 °C triggered formation of zeolite–iron oxide systems. X-ray diffraction (XRD) patterns showed diminishing zeolite peaks along with evolution of peaks corresponding to γ-Fe2O3 and α-Fe2O3 with increasing NaOH concentration. Morphological changes from hexagonal-shaped zeolite to clusters of fine particles were observed under scanning electron microscope. Particles with about 15-nm diameter were detected by transmission electron microscopy. γ-Fe2O3 crystallites of 13.4 nm were determined from the broadening of XRD peaks. The magnetization curves of samples (precipitated using NaOH with concentrations of 2.0 M and above) showed absence of hysteresis and passed through the origin, indicating the particles are superparamagnetic. Gas adsorption–desorption measurement of the system precipitated with 2.0 M NaOH revealed a 26% increase in its specific surface area, indicating the presence of nanometer-sized particles within the zeolites.

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Efficiency of TiO2 catalyst supported by modified waste fly ash during photodegradation of RR45 dye

Science and Engineering of Composite Materials ◽

10.1515/secm-2019-0017 ◽

2019 ◽

Vol 26 (1) ◽

pp. 292-300 ◽

Cited By ~ 3

Author(s):

Vanja Gilja ◽

Zvonimir Katančić ◽

Ljerka Kratofil Krehula ◽

Vilko Mandić ◽

Zlata Hrnjak-Murgić

Keyword(s):

Fly Ash ◽

Gas Adsorption ◽

Sol Gel ◽

Efficiency Evaluation ◽

X Ray Diffraction ◽

X Ray ◽

Sol Gel Synthesis ◽

Adsorption Desorption

AbstractThe waste fly ash (FA) material was subjected to chemical treatment with HCl at elevated temperature for a different time to modify its porosity. Modified FA particles with highest surface area and pore volume were further used as a support for TiO2 catalyst during FA/TiO2 nanocomposite preparation. The nanocomposite photocatalysts were obtained by in situ sol–gel synthesis of titanium dioxide in the presence of FA particles. To perform accurate characterization of modified FA and FA/TiO2 nanocomposite photocatalysts, gas adsorption-desorption analysis, X-ray diffraction, scanning electron microscopy, UV/Vis and Infrared spectroscopy were used. Efficiency evaluation of the synthesized FA/TiO2 nanocomposites was performed by following the removal of Reactive Red 45 (RR45) azo dye during photocatalytic treatment under the UV-A irradiation. Photocatalysis has been carried out up to five cycles with the same catalysts to investigate their stability and the possible reuse. The FA/TiO2 photocatalyst showed very good photocatalytic activity and stability even after the fifth cycles. The obtained results show that successfully modified waste fly ash can be used as very good TiO2 support.

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Synthesis and Characterization of Nanocrystalline CeO2

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.306-308.1103 ◽

2006 ◽

Vol 306-308 ◽

pp. 1103-1108

Author(s):

Abdul Hadi ◽

Iskandar Idris Yaacob

Keyword(s):

Fine Particles ◽

Gas Adsorption ◽

Mesoporous Structure ◽

Face Centered Cubic ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Face Centered ◽

Adsorption Desorption

Nanocrystalline CeO2 has been synthesized at room temperature using water-in-oil (w/o) microemulsion technique. The structure and properties of the nanocrystalline CeO2 were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and gas adsorption desorption measurement. XRD results showed the synthesized CeO2 has a face centered cubic structure with crystallite size of about 5.2 nm. TEM observation also indicated the presence of nanometer sized particles of CeO2. Coarser particles were also observed due to agglomeration. Gas adsorption desorption isotherms showed the behavior of fine particles with mesoporous structure.

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Mechanochemical Synthesis of Nanocrystalline CeO2: The Effect of Annealing Temperatures on the Particle Size

Materials Science Forum ◽

10.4028/www.scientific.net/msf.517.252 ◽

2006 ◽

Vol 517 ◽

pp. 252-256 ◽

Cited By ~ 3

Author(s):

Abdul Hadi ◽

Iskandar Idris Yaacob ◽

Lee Seok Ling

Keyword(s):

Annealing Temperature ◽

Gas Adsorption ◽

Weight Ratio ◽

X Ray Diffraction ◽

Treatment Results ◽

Scanning Calorimetry ◽

Characterization Methods ◽

X Ray ◽

Annealing Temperatures ◽

Adsorption Desorption

Cerium dioxide (CeO2) nanoparticles were synthesized by a novel mechanochemical process. The precursors of Ce2(CO3)3.xH2O and NaOH were mixed at a weight ratio of 4 to 1. The mixtures were milled using a planetary ball mill with ball to powder ratio of 10:1. The products were then characterized using a battery of characterization methods, including X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and gas adsorption-desorption measurement. The as-prepared particles were largely amorphous with an average specific surface area of about 119.94 m2/g. Nanocrystalline CeO2 with crystallite size of 4.5 nm was obtained when the sample was annealed in air at 350 oC. The heat treatment results showed that the crystallinity of nanocrystalline CeO2 increased with increasing annealing temperature.

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Efficient toluene adsorption/desorption on biochar derived from in situ acid-treated sugarcane bagasse

10.21203/rs.3.rs-354810/v1 ◽

2021 ◽

Author(s):

Yuan Qu ◽

Li Xu ◽

Yi Chen ◽

Shikuan Sun ◽

Yu Wang ◽

...

Keyword(s):

Sugarcane Bagasse ◽

High Performance ◽

Gas Adsorption ◽

Activated Carbons ◽

Hydrothermal Carbonization ◽

Modified Biochar ◽

Micropore Surface Area ◽

Practical Engineering ◽

Adsorption Desorption

Abstract Carbon-based materials with great adsorption performance are of importance to meet the needs of industrial gas adsorption. Being massive agricultural wastes of sugarcane bagasse, China could use this waste into wealth. However, the comprehensive utilization of sugarcane bagasse as precursors for biochar that can be used as adsorbent has not been extensively explored. In this study, a series of in-situ sulfuric acid modified biochar were prepared by hydrothermal carbonization process. The prepared biochar (SBAC-7) is combined of two main advantages that are high microporosity (micropore surface area = 1106 m 2 /g) and rich in S-containing functional groups on the surface. In particular, SBAC-7 showed an excellent adsorption capacity of toluene (771.1 mg/g) at 30 o C, which is nearly 3 times as high as the commercial activated carbons. Meanwhile, it showed great stability and cyclic regeneration performance with five toluene adsorption-desorption test cycles. This study provides a high-performance biochar for adsorption-desorption cycle in practical engineering applications, and would contribute to the sustainable “sugarcane production - bagasse utilization” circular economy.

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The Effect of Caramelization and Carbonization Temperatures toward Structural Properties of Mesoporous Carbon from Fructose with Zinc Borosilicate Activator

Indonesian Journal of Chemistry ◽

10.22146/ijc.21236 ◽

2014 ◽

Vol 14 (3) ◽

pp. 253-261

Author(s):

Tutik Setianingsih ◽

Indriana Kartini ◽

Yateman Arryanto

Keyword(s):

Mesoporous Carbon ◽

Gas Adsorption ◽

Carbon Surface ◽

X Ray Diffraction ◽

Nitrogen Gas ◽

Transmission Electron ◽

Ftir Spectrophotometry ◽

Adsorption Desorption ◽

Degree Of Graphitization ◽

Zinc Borosilicate

Mesoporous carbon was prepared from fructose using zinc borosilicate (ZBS) activator. The synthesis involves caramelization and carbonization processes. The effect of both process temperature toward porosity and functional group of carbon surface are investigated in this research. The caramelization was conducted hydrothermally at 85 and 100 °C, followed by thermally 130 °C. The carbonization was conducted at various temperatures (450–750 °C). The carbon-ZBS composite were washed by using HF 48% solution, 1M HCl solution, and aquadest respectively to remove ZBS from the carbon. The carbon products were characterized with nitrogen gas adsorption-desorption method, FTIR spectrophotometry, X-ray diffraction, and Transmission Electron Microscopy. The highest mesopore characteristics is achieved at 100 °C (caramelization) and 450 °C (carbonization), including Vmeso about 2.21 cm3/g (pore cage) and 2.32 cm3/g (pore window) with pore uniformity centered at 300 Å (pore cage) and 200 Å (pore window), containing the surface functional groups of C=O and OH, degree of graphitization about 57% and aromaticity fraction about 0.68.

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An Ecofriendly Synthesis of 2-oxazolidinone From 2-aminoethanol and Urea Under Solvent-free Condition Using CeO2 Nanoparticles

10.21203/rs.3.rs-535619/v1 ◽

2021 ◽

Author(s):

ALI NEMATI KHARAT ◽

Mehrnaz Aliahmadi

Keyword(s):

Gas Adsorption ◽

Sol Gel ◽

Solvent Free ◽

X Ray Diffraction ◽

Nitrogen Gas ◽

X Ray ◽

Solvent Free Condition ◽

Solvent Free Conditions ◽

Adsorption Desorption ◽

Desorption Method

Abstract Cerium dioxide nanoparticles were prepared by the sol-gel method using cellulose as a template and used in the synthesis of 2-oxazolidinone from urea and 2-aminoethanol under solvent-free conditions. All the reaction parameters were optimized to obtain the best selectivity and conversion. The selectivity of 100 % to 2-oxazolidinone with a pretty complete conversion of about 98.4 % was achieved. The prepared catalyst was characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and volumetric isothermal nitrogen gas adsorption-desorption method (BET).

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