scholarly journals Activated carbons from common nettle as potential adsorbents for CO2 capture

2019 ◽  
Vol 21 (1) ◽  
pp. 59-66
Author(s):  
Alicja Szymańska ◽  
Amelia Skoczek ◽  
Jacek Przepiórski

Abstract Activated carbons (ACs) prepared from common nettle (Urtica Dioica L.) were studied in terms of carbon dioxide adsorption. ACs were prepared by KOH chemical activation in a nitrogen atmosphere at temperatures (ranging from 500 to 850°C). The pore structure and the surface characterization of the ACs were specified based on adsorption-desorption isotherms of nitrogen measured at –196°C and carbon dioxide at 0°C. The specific surface area was calculated according to the BET equation. The pore volume was estimated using the DFT method. The highest values of the specific surface area (SSA) showed activated carbons produced at higher carbonization temperatures. All samples revealed presence of micropores and mesopores with a diameter range of 0.3–10 nm. The highest value of the CO2 adsorption, 4.22 mmol/g, was found for the material activated at 700°C.

2012 ◽  
Vol 36 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Gabriela Martucci Couto ◽  
Anelise Lima de Abreu Dessimoni ◽  
Maria Lúcia Bianchi ◽  
Deise Morone Perígolo ◽  
Paulo Fernando Trugilho

Wood sawdust is a solid residue, generated in the timber industry, which is of no profitable use and can cause serious environmental problems if disposed inadequately. The aim of this study was to use the eucalyptus sawdust in the preparation of activated carbons AC) and test them as adsorbents of methylene blue (MB) and phenol, representative pollutants from aqueous effluents of various industries. The eucalyptus sawdust was characterized by instrumental analysis such as elementary analysis (CHNS-O), thermogravimetric analysis (TGA), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The activated carbons were prepared by physical activation with carbon dioxide AC_CO2, (10º C min-1, 850º C, 1h) and by chemical activation with potassium carbonate AC_K2CO3 (10º C min-1, 850º C, 3h). The AC_CO2 and AC_K2CO3 were characterized by CHN-O, TGA, FTIR, N2 adsorption/desorption (BET) to evaluate the specific surface area and SEM. The resulting activated carbons were tested for their ability to adsorb MB and phenol in water. The activated carbons produced in this work were predominantly microporous and showed specific surface area of about 535 m² g-1. The AC_K2CO3 was more effective in the adsorption of MB (81 mg g-1) and phenol (330 mg g-1) than AC_CO2 (32 mg g-1 and 172 mg g-1, respectively, for MB and phenol).


Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 405 ◽  
Author(s):  
Chaozheng Liu ◽  
Weimin Chen ◽  
Shu Hong ◽  
Mingzhu Pan ◽  
Min Jiang ◽  
...  

The synthesis of biomass-derived porous carbons (PCs) for supercapacitors by conventional two-steps method (chemical activation after carbonization) is complicated and time-consuming. In this study, we present a one-step microwave activation strategy to prepare hierarchically PCs from waste palm boosted by activated carbons (ACs). ACs with various specific surface areas (14, 642, and 1344 m2·g−1) were used for the first time to fast absorb microwave energy for converting waste palm into hierarchically PCs, that is, PC1, PC2, and PC3, respectively. The morphological and structural characterizations of PCs were studied. Also, the electrochemical performances of supercapacitors based on PCs as electrodes were further investigated. The results showed that the PC (PC1) boosted by AC with the lowest specific surface area possessed a porous structure (containing micro-, meso-, and macro- pores) with the largest specific surface area (1573 m2·g−1) and the highest micropore volume (0.573 cm3·g−1), as well as the suitable mesoporosity (29.69%). The as-prepared PC1 supercapacitor even in a gel electrolyte (PVA/LiCl) exhibited a high specific capacitance of 226.0 F·g−1 at 0.5 A·g−1 and presented excellent charge-discharge performance with an energy density of 72.3 Wh·kg−1 at a power density of 1.4 kW·kg−1 and 50.0 Wh·kg−1 at 28.8 kW·kg−1. Moreover, this promising method exhibited a simple, rapid, and cost-effective preparation of carbon materials from renewable biomass for energy storage applications.


Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1004 ◽  
Author(s):  
João Nogueira ◽  
Maria António ◽  
Sergey Mikhalev ◽  
Sara Fateixa ◽  
Tito Trindade ◽  
...  

Porous carbon materials derived from biopolymers are attractive sorbents for the removal of emerging pollutants from water, due to their high specific surface area, high porosity, tunable surface chemistry, and reasonable cost. However, carrageenan biopolymers were scarcely investigated as a carbon source to prepare porous carbon materials. Herein, hydrochars (HCs) and porous activated carbons (ACs) derived from natural occurring polysaccharides with variable sulfate content (κ-, ι- and λ-carrageenan) were prepared and investigated in the uptake of ciprofloxacin, which is an antibiotic detected in water sources and that poses serious hazards to public health. The materials were prepared using hydrothermal carbonization and subsequent chemical activation with KOH to increase the available surface area. The activated carbons were markedly microporous, presenting high specific surface area, up to 2800 m2/g. Activated carbons derived from κ- and λ-carrageenan showed high adsorption capacity (422 and 459 mg/g, respectively) for ciprofloxacin and fast adsorption kinetics, reaching the sorption equilibrium in approximately 5 min. These features place the ACs investigated here among the best systems reported in the literature for the removal of ciprofloxacin from water.


2015 ◽  
Vol 5 (1) ◽  
pp. 24 ◽  
Author(s):  
Mohd Adib Yahya ◽  
C. W. Zanariah C. W. Ngah ◽  
M. A. Hashim ◽  
Z. Al-Qodah

<p class="1Body">This study investigates the effect of temperature and impregnation ratio on the physicochemical properties of activated carbon prepared from agricultural waste; desiccated coconut residue (DCR) by chemical activation using sodium hydroxide (NaOH). DCR sample was first carbonized at three different temperatures for 1 hour at 400°C, 500°C, and 600°C respectively. The resulting chars were impregnated with NaOH at three different impregnation ratio; 1:1, 1:2, and 1:3 respectively and activated under nitrogen atmosphere for 1 hour at three different temperatures based on its carbonization temperature. The specific surface area was strongly affected by impregnation ratio in which increased with impregnation ratio. The specific surface area also increased with temperature but then decreased at highest desired temperature.</p>


2010 ◽  
Vol 146-147 ◽  
pp. 18-21 ◽  
Author(s):  
Rui Rui Zhao ◽  
Dong Shu ◽  
Hong Yu Chen

N2 adsorption-desorption method, scanning electron microscope and transmission electron microscopy were employed to test changes of the specific surface area, average pore diameter and appearances of activated carbons treated with different concentration of sulfuric acid. It can be concluded that these performances altered with sulfuric acid concentration. Activated carbon can be oxidized when the acid concentration increase to a certain value and this process takes time that sulfuric acid molecules first insert in the pore of the carbon which represented by reduction of the specific surface area of carbon and then oxidization occurred. This study is very significant in the development of carbon which is suitable for lead acid battery.


2012 ◽  
Vol 463-464 ◽  
pp. 543-547 ◽  
Author(s):  
Cheng Feng Li ◽  
Xiao Lu Ge ◽  
Shu Guang Liu ◽  
Fei Yu Liu

Core-shell structured hydroxyapatite (HA)/meso-silica was prepared and used as absorbance of methylene blue (MB). HA/meso-silica was synthesized in three steps: preparation of nano-sized HA by wet precipitation method, coating of dense silica and deposition of meso-silica shell on HA. As-received samples were characterized by Fourier transformed infare spectra, small angle X-ray diffraction, nitrogen adsorption-desorption isotherm and transmission electron microscopy. A wormhole framework mesostructure was found for HA/meso-silica. The specific surface area and pore volume were 128 m2•g-1 and 0.36 cm3•g-1, respectively. From the adsorption isotherm, HA/meso-silica with the great specific surface area exhibited a prominent adsorption capacity of MB (134.0 mg/g) in comparison with bare HA (0 mg/g). This study might shed light on surface modification of conventional low-cost adsorbents for removal of organic pollutants from aqueous solutions.


2020 ◽  
Vol 860 ◽  
pp. 173-177
Author(s):  
Otong Nurhilal ◽  
Renaldy Sharin Lesmana ◽  
Karina Ramadayanti ◽  
Sholihatul Habibah ◽  
Sahrul Hidayat ◽  
...  

Water Hyacinth (WH) is a plant that can absorb various pollutants in water. However, this plant is categorized as an invasive plant that can become a weed in the waters. To improve the functionality of WH, processing of WH is needed to be used for various applications. One of modifications of WH is as porous carbon for battery cathode composite. In this paper, we reported a synthesis of a porous carbon from WH. WH is processed into carbon by carbonization at various temperatures of 400, 500 and 600 °C with various activators of KOH, H3PO4 and ZnCl2 to obtain high quality porous carbon which has high electrical conductivity, large specific surface area and large porous volume. All synthesized carbons were characterized by proximate analysis measurements, scanning electron microscopy (SEM), and N2 adsorption-desorption measurements. The highest carbon fixed content of 37.79% is obtained from charcoal with a carbonization temperature of 400 °C. The largest specific surface area of 264.77 m2/g was obtained from activated carbon with H3PO4 as activator. The values of pore volume and pore radius were 0.186 cm3/g and 1.56 nm, respectively.


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