scholarly journals Development and Characterization of Composite Carbon Adsorbents with Photocatalytic Regeneration Ability: Application to Diclofenac Removal from Water

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 173
Author(s):  
Velma Beri Kimbi Yaah ◽  
Satu Ojala ◽  
Hamza Khallok ◽  
Tiina Laitinen ◽  
Marcin Selent ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
Palm Kernel ◽  
Hydrothermal Carbonization ◽  
Carbon Composite ◽  
Carbon Adsorbents ◽  
Regeneration Ability ◽  
Activation Temperature

This paper presents results related to the development of a carbon composite intended for water purification. The aim was to develop an adsorbent that could be regenerated using light leading to complete degradation of pollutants and avoiding the secondary pollution caused by regeneration. The composites were prepared by hydrothermal carbonization of palm kernel shells, TiO2, and W followed by activation at 400 °C under N2 flow. To evaluate the regeneration using light, photocatalytic experiments were carried out under UV-A, UV-B, and visible lights. The materials were thoroughly characterized, and their performance was evaluated for diclofenac removal. A maximum of 74% removal was observed with the composite containing TiO2, carbon, and W (HCP25W) under UV-B irradiation and non-adjusted pH (~5). Almost similar results were observed for the material that did not contain tungsten. The best results using visible light were achieved with HCP25W providing 24% removal of diclofenac, demonstrating the effect of W in the composite. Both the composites had significant amounts of oxygen-containing functional groups. The specific surface area of HCP25W was about 3 m2g−1, while for HCP25, it was 160 m2g−1. Increasing the specific surface area using a higher activation temperature (600 °C) adversely affected diclofenac removal due to the loss of the surface functional groups. Regeneration of the composite under UV-B light led to a complete recovery of the adsorption capacity. These results show that TiO2- and W-containing carbon composites are interesting materials for water treatment and they could be regenerated using photocatalysis.

scholarly journals New Electrodes Prepared from Mineral and Plant Raw Materials of Kazakhstan

2016 ◽  
Vol 18 (2) ◽  
pp. 141 ◽  
Author(s):  
A.A. Atchabarova ◽  
R.R. Tokpayev ◽  
A.T. Kabulov ◽  
S.V. Nechipurenko ◽  
R.A. Nurmanova ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrode Materials ◽  
Raw Materials ◽  
Hydrothermal Carbonization ◽  
Walnut Shell ◽  
High Background ◽  
Plant Raw Materials ◽  
Developed Surface

<p>Electrode materials were prepared from activated carbonizates of walnut shell, apricot pits and shungite rock from “Bakyrchik” deposit, East Kazakhstan. Physicochemical characteristics of the obtained samples were studied by the Brunauer-Emett-Taylor method, scanning electron microscopy, Raman spectroscopy and other methods. Electrochemical properties of the obtained materials were studied by the method of cyclic voltammetry. It was found that the samples have an amorphous structure. Samples based on plant raw materials after hydrothermal carbonization at 240 °С during 24 h, have more homogeneous and developed surface. Specific surface area of carbon containing materials based on apricot pits is 1300 m<sup>2</sup>/g, for those on the based on mineral raw material, it is 153 m<sup>2</sup>/g. It was shown that materials after hydrothermal carbonization can be used for catalytic purposes and electrodes after thermal carbonization for analytical and electrocatalytic purposes. Electrode obtained by HTC have electrocatalytic activity. CSC 240 has high background current (slope i/Е is 43 mА V<sup>–1</sup> cm<sup>–2</sup>), low potential of the hydrogen electroreduction (more positive by ~ 0.5 V than samples based on plant raw materials). The reaction of DA determination is more pronounced on the electrodes obtained by HTC 240 °C, 24 h, due to the nature, carbon structure and high specific surface area of obtained samples.</p>

scholarly journals Adsorption of pharmaceuticals from aqueous solutions using biochar derived from cotton gin waste and guayule bagasse

Biochar ◽  
2020 ◽  
Author(s):  
Marlene C. Ndoun ◽  
Herschel A. Elliott ◽  
Heather E. Preisendanz ◽  
Clinton F. Williams ◽  
Allan Knopf ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
High Surface ◽  
Strong Interactions ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Cotton Gin Waste ◽  
Cotton Gin

Abstract Biochars produced from cotton gin waste (CG) and guayule bagasse (GB) were characterized and explored as potential adsorbents for the removal of pharmaceuticals (sulfapyridine-SPY, docusate-DCT and erythromycin-ETM) from aqueous solution. An increase in biochar pyrolysis temperature from 350 οC to 700 οC led to an increase in pH, specific surface area, and surface hydrophobicity. The electronegative surface of all tested biochars indicated that non-Coulombic mechanisms were involved in adsorption of the anionic or uncharged pharmaceuticals under experimental conditions. The adsorption capacities of Sulfapyridine (SPY), Docusate (DCT) and Erythromycin (ETM) on biochar were influenced by the contact time and solution pH, as well as biochar specific surface area and functional groups. Adsorption of these pharmaceutical compounds was dominated by a complex interplay of three mechanisms: hydrophobic partitioning, hydrogen bonding and π–π electron donor–acceptor (EDA) interactions. Despite weaker π–π EDA interactions, reduced hydrophobicity of SPY− and increased electrostatic repulsion between anionic SPY− and the electronegative CG biochar surface at higher pH, the adsorption of SPY unexpectedly increased from 40% to 70% with an increase in pH from 7 to 10. Under alkaline conditions, adsorption was dominated by the formation of strong negative charge-assisted H-bonding between the sulfonamide moiety of SPY and surface carboxylic groups. There seemed to be no appreciable and consistent differences in the extent of DCT and ETM adsorption as the pH changed. Results suggest the CG and GB biochars could act as effective adsorbents for the removal of pharmaceuticals from reclaimed water prior to irrigation. High surface area biochars with physico-chemical properties (e.g., presence of functional groups, high cation and anion exchange capacities) conducive to strong interactions with polar-nonpolar functionality of pharmaceuticals could be used to achieve significant contaminant removal from water. Graphic Abstract

scholarly journals Effects of Wet Oxidation Process on Biochar Surface in Acid and Alkaline Soil Environments

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2362 ◽  
Author(s):  
Qinya Fan ◽  
Liqiang Cui ◽  
Guixiang Quan ◽  
Sanfei Wang ◽  
Jianxiong Sun ◽  
...  
Keyword(s):  
Specific Surface ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
Contaminated Soils ◽  
Soil Conditions ◽  
Acid Oxidation ◽  
Wet Oxidation ◽  
Alkaline Soil

Biochar has been studied for remediation of heavy metal-contaminated soils by many researchers. When in external conditions, biochar in soils ages, which can transform its structural properties and adsorption capacity. This study was conducted with two oxidation processes, HNO3/H2SO4 and NaOH/H2O2, to simulate the effects of biochar in acid and alkaline soil conditions. The results show that the oxygen-containing functional groups increased in aged biochar, which led to improve the ratio of oxygen and carbon (O/C). Nitro functional groups were found in the acid-oxidation treated biochar. Destroyed ditches and scars were observed on the surface of aged biochar and resulted in growth in their specific surface area and porosity. Specific surface area increased by 21.1%, 164.9%, and 63.0% for reed-derived biochar treated with water washing, acid oxidation, and basic oxidation, respectively. Greater peaks in the Fourier Transform Infrared Spectroscopy (FTIR) results were found in C–O and O–H on the surface of field-aged biochar. Meanwhile, mappings of energy-dispersive spectroscopy showed that biochar aged in soil was abundant in minerals such as silicon, iron, aluminum, and magnesium. In summary, biochar subjected to wet oxidation aging had an increased capacity to immobilize Cd compared to unaged biochar, and the adsorption capacity of oxidized biochar increased by 28.4% and 13.15% compared to unaged biochar due to improvements in porosity and an increase in functional groups.

scholarly journals Low-Temperature Synthesis of Monolithic Titanium Carbide/Carbon Composite Aerogel

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2527
Author(s):  
Tingting Niu ◽  
Bin Zhou ◽  
Zehui Zhang ◽  
Xiujie Ji ◽  
Jianming Yang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Electron Microscope ◽  
Low Temperature ◽  
Titanium Carbide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Composite ◽  
Composite Aerogel ◽  
X Ray

Resorcinol-formaldehyde/titanium dioxide composite (RF/TiO2) gel was prepared simultaneously by acid catalysis and then dried to aerogel with supercritical fluid CO2. The carbon/titanium dioxide aerogel was obtained by carbonization and then converted to nanoporous titanium carbide/carbon composite aerogel via 800 °C magnesiothermic catalysis. Meanwhile, the evolution of the samples in different stages was characterized by X-ray diffraction (XRD), an energy-dispersive X-ray (EDX) spectrometer, a scanning electron microscope (SEM), a transmission electron microscope (TEM) and specific surface area analysis (BET). The results showed that the final product was nanoporous TiC/C composite aerogel with a low apparent density of 339.5 mg/cm3 and a high specific surface area of 459.5 m2/g. Comparing to C aerogel, it could also be considered as one type of highly potential material with efficient photothermal conversion. The idea of converting oxide–carbon composite into titanium carbide via the confining template and low-temperature magnesiothermic catalysis may provide new sight to the synthesis of novel nanoscale carbide materials.

Activated carbon powder derived from cashmere guard hair

2019 ◽  
Vol 50 (5) ◽  
pp. 599-615
Author(s):  
Zhuanyong Zou ◽  
Xin Liu ◽  
Jiahui Ding ◽  
Tanqi Chen ◽  
Xungai Wang
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Powder ◽  
Guard Hair ◽  
Carbon Yield ◽  
Activation Temperature ◽  
Impregnation Ratio ◽  
Study Results

Converting waste fiber to high value-added carbonaceous materials has been considered as an effective and affordable route in response to the increasing volume of waste fiber in recent year. In this study, we are the first to prepare activated carbon powder derived from cashmere guard hair as a renewable waste protein fiber, using a chemical activation method at different impregnation ratios of K2CO3/cashmere guard hair char and activation temperatures ranging from 400℃ to 600℃. Characterization of the activated carbon powder was carried out by morphology study, specific surface area study, and adsorption study. Results have shown that the increase of the impregnation ratio and the activation temperature created more microporous structure in the activated carbon powder, and then increased the specific surface area of the activated carbon powder as well as the amount of methylene blue adsorbed. However, the carbon yield increases with the increase in the impregnation ratio of K2CO3/cashmere guard hair char and decreases with the increase in the activation temperature. The activated carbon powder, activated by the condition of 1:2 K2CO3/cashmere guard hair char impregnation ratio and 600℃ activation temperature, has a specific surface area of 764.86 m2g−1 and a carbon yield of 14.07 wt%. Compared to the activated carbon powder derived from fine merino wool fibers, the activated carbon powder derived from cashmere guard hair has higher carbon yield, surface area, and total pore volume, showing a superior adsorption performance.

Effects of activation temperature on the deoxygenation, specific surface area and supercapacitor performance of graphene

Carbon ◽  
2016 ◽  
Vol 109 ◽  
pp. 558-565 ◽  
Author(s):  
Chuanming Yin ◽  
Cheng-an Tao ◽  
Fenglian Cai ◽  
Chenchao Song ◽  
Hang Gong ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Activation Temperature ◽  
Supercapacitor Performance

scholarly journals Bio-polishing sludge adsorbents for dye removal

2016 ◽  
Vol 18 (4) ◽  
pp. 15-21 ◽  
Author(s):  
Muhammad Abbas Ahmad Zaini ◽  
Norulaina Alias ◽  
Mohd. Azizi Che Yunus
Keyword(s):  
Methylene Blue ◽  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
Treatment Strategies ◽  
Blue Dye ◽  
Surface Functional Groups ◽  
Adsorption Capacities ◽  
Maximum Removal

Abstract The objective of this work is to evaluate the removal of methylene blue dye by bio-polishing sludge-based adsorbents. The adsorbents were characterized according to the specific surface area, pH upon the treatment and surface functional groups. The adsorption of dye was carried out at room temperature, and the adsorption data were analyzed using the isotherm and kinetics models. The bio-polishing sludge is rich in ash content, and the presence of surface functional groups varied with the treatment strategies. The specific surface area of adsorbents is between 7.25 and 20.8 m2/g. Results show that the maximum removal of methylene blue by sludge adsorbents was observed to have the following order: untreated sludge (SR) > zinc chloride-treated (SZ) > microwave-dried (SW) = potassium carbonate-treated (SK) > acid-washed (SH). The maximum adsorption capacities for SR and SZ as predicted by the Langmuir model are 170 and 135 mg/g, respectively. Although SR demonstrates a higher maximum removal than SZ, the latter exhibits greater removal intensity and rate constant even at high dye concentration. The bio-polishing sludge is a promising adsorbent for dye wastewater treatment.

Low Temperature Synthesis of Mesoporous SiC in Dual-Confined Spaces via Magnesiothermic Reduction

NANO ◽  
2019 ◽  
Vol 14 (09) ◽  
pp. 1950115 ◽  
Author(s):  
Zeng-Rong Wang ◽  
Long Liu ◽  
Xue Zhang ◽  
Jia-Lin Xu ◽  
Qiang Sun
Keyword(s):  
Low Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Catalyst Support ◽  
Reduction Process ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Magnesiothermic Reduction ◽  
Confined Spaces

Silicon carbide (SiC), especially mesoporous SiC has been in immense vogue for more than a decade because of its intriguing properties and wide applications. However, it is still challenging to synthesize mesoporous SiC with good structural integrality, large specific surface area and desirable porosity at a low temperature. In this study, we reported a “dual-confined spaces”-assisted synthesis of mesoporous SiC using well-assembled SiO2/carbon composite as precursor via a magnesiothermic reduction process. The well-crystallinity mesoporous SiC presented a mesopore structure with high specific surface area of 267.3 m2 g[Formula: see text] and large mesopore size of ca. 10[Formula: see text]nm can be directly fabricated at a temperature of at least 550∘C and the optimum synthesis temperature is 650∘C. During the synthesis, mesoporous carbon matrix and a pressure-tight stainless steel reactor were served as “dual-confined spaces” to avoid the aggregation of silica and the silicon residue left in the final SiC sample. Furthermore, the as-prepared mesoporous SiC showed prominent performance as catalyst support for the reduction of 4-nitrophenol to 4-aminophenol.

Synthesis of Se/chitosan-derived hierarchical porous carbon composite as Li–Se battery cathode

2017 ◽  
Vol 10 (02) ◽  
pp. 1650074 ◽  
Author(s):  
Cheng Chen ◽  
Chenhao Zhao ◽  
Zhibiao Hu ◽  
Kaiyu Liu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Discharge Capacity ◽  
Porous Carbon ◽  
Carbon Composite ◽  
High Rate ◽  
Electrochemical Performances ◽  
Hierarchical Porous Carbon ◽  
Hierarchical Porous

The hierarchical porous carbon with overall macropores and surface micropores has been prepared from carbonization of chitosan/[Formula: see text][Formula: see text] gel-like composite. The specific surface area and pore volume of this carbon can come to 2358.9[Formula: see text][Formula: see text] g[Formula: see text] and 1.14[Formula: see text]cm3 g[Formula: see text], respectively, and the active component Se with amorphous structure is uniformly encapsulated into the microporous structure to form Se/carbon composite. As Li–Se battery cathode, the composite delivers a second discharge capacity of 537.6[Formula: see text]mAh g[Formula: see text] at 0.2[Formula: see text]C, and a discharge capacity of 517.9[Formula: see text]mA h g[Formula: see text] can be retained after 100 cycles. Even at a high rate of 5[Formula: see text]C, the composite still reveals a stable discharge capacity of 325.2[Formula: see text]mAh g[Formula: see text]. The excellent electrochemical performances of Se/carbon composite may attribute to high specific surface area and hierarchical porous feature.

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