scholarly journals Nanoporous Activated Carbon Derived via Pyrolysis Process of Spent Coffee: Structural Characterization. Investigation of Its Use for Hexavalent Chromium Removal

2020 ◽  
Vol 10 (24) ◽  
pp. 8812
Author(s):  
Georgios Asimakopoulos ◽  
Maria Baikousi ◽  
Vasilis Kostas ◽  
Marios Papantoniou ◽  
Athanasios B. Bourlinos ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Hexavalent Chromium ◽  
Chemical Activation ◽  
Micropore Volume ◽  
Industrial Applications ◽  
Nitrogen Atmosphere ◽  
Pyrolysis Process ◽  
Initial Adsorption ◽  
Initial Adsorption Rate

Hexavalent chromium (Cr(VI)) is a heavy metal that is highly soluble and exhibits toxic effects on biological systems. Nevertheless, it is used in many industrial applications. The adsorption process of Cr(VI), using activated carbon (AC), is under investigation globally. On the other hand, around six million tons of spent coffee is sent to landfill annually. In the spirit of cyclic economy, this research investigated the production of AC from spent coffee for the removal of Cr(VI) from wastewater. The AC was produced via pyrolysis process under a nitrogen atmosphere. Chemical activation using potassium hydroxide (KOH) occurred simultaneously with the pyrolysis process. The produced AC was tested as an absorber of Cr(VI). The best fitted kinetic model was the diffusion–chemisorption model. A 24-h adsorption experiment was carried out using a solution with a pH of 3 and an initial Cr(VI) concentration of 54.14 ppm. This resulted in an experimental maximum capacity of 109 mg/g, while the theoretical prediction was 137 mg/g. It also resulted in an initial adsorption rate (ri) of 110 (mg/(g h)). The Brunauer–Emmett–Teller surface area (SgBET) was 1372 m2/g, the Langmuir surface area (SgLang.) was 1875 m2/g, and the corrugated pore structure model surface area (SgCPSM) was 1869 m2/g. The micropore volume was 84.6%, exhibiting micropores at Dmicro1 = 1.28 and Dmicro2 = 1.6 nm. The tortuosity factor (τ) was 4.65.

scholarly journals Preparation of Activated Carbon from Desiccated Coconut Residue by Chemical Activation with NaOH

2015 ◽  
Vol 5 (1) ◽  
pp. 24 ◽  
Author(s):  
Mohd Adib Yahya ◽  
C. W. Zanariah C. W. Ngah ◽  
M. A. Hashim ◽  
Z. Al-Qodah
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Agricultural Waste ◽  
Chemical Activation ◽  
Nitrogen Atmosphere ◽  
Effect Of Temperature ◽  
Impregnation Ratio ◽  
Different Temperatures

<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>

Increase the Microporosity and CO2 Adsorption of a Commercial Activated Carbon

2015 ◽  
Vol 749 ◽  
pp. 17-21 ◽  
Author(s):  
Joanna Sreńscek Nazzal ◽  
Karolina Glonek ◽  
Jacek Młodzik ◽  
Urszula Narkiewicz ◽  
Antoni W. Morawski ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Materials ◽  
Micropore Volume ◽  
Microporous Carbon ◽  
Microporous Carbons ◽  
Adsorption Capacities

Microporous carbons prepared from commercial activated carbon WG12 by KOH and/or ZnCl2 treatment were examined as adsorbents for CO2 capture. The micropore volume and specific surface area of the resulting carbons varied from 0.52 cm3/g (1374 m2/g) to 0.70 cm3/g (1800 m2/g), respectively. The obtained microporous carbon materials showed high CO2 adsorption capacities at 40 bar pressure reaching 16.4 mmol/g.

scholarly journals Development of Activated Carbon Using One Step Carbonization and Activation Reaction by Polymer Blend Method

2015 ◽  
Vol 57 ◽  
pp. 156-162 ◽  
Author(s):  
S. Manocha ◽  
Parth Joshi ◽  
Amit Brahmbhatt ◽  
Amiya Banerjee ◽  
Snehasis Sahoo ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Surface Characteristics ◽  
Nitrogen Atmosphere ◽  
Activation Process ◽  
Average Pore ◽  
Activation Temperature ◽  
Optimum Synthesis ◽  
Different Temperatures ◽  
One Step

In the present work, a one step carbon activation process was developed by stabilized poly-blend. It is carbonized in nitrogen atmosphere and activated in steam in one step for known interval of times to enhance the surface area and develop interconnected porosity. The weight-loss behavior during steam activation of stabilized poly-blend at different temperatures, surface area and pore size distribution were studied to identify the optimum synthesis parameters. The results of surface characteristics were compared with those of activated carbon prepared by carbonization and activation in two steps. It was found that activation temperature has profound effect on surface characteristics. As activation temperature was raised from 800 °C to 1150 °C, surface area of activated carbon increased about three times. In addition to surface area, average pore diameter also increases with increasing activation temperature. Thus, activated carbon with high percentage of porosity and surface area can be developed by controlling the activation temperature during activation process.

scholarly journals Microporosity Development of Herringbone Carbon Nanofibers by RbOH Chemical Activation

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Vicente Jiménez ◽  
Paula Sánchez ◽  
Fernando Dorado ◽  
José Luís Valverde ◽  
Amaya Romero
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Carbon Nanofibers ◽  
Flow Rate ◽  
Chemical Activation ◽  
Micropore Volume ◽  
Structure Development ◽  
Activation Temperature ◽  
Activating Agent ◽  
Activation Conditions

The influence of different activation conditions, including activating agent/CNFs ratio, activation temperature, and He flow rate, on the pore structure development of herringbone carbon nanofibers (CNFs) was studied. The best results of activated CNFs with larger specific surface area can be achieved using the following optimized factors: RbOH/CNFs ratio = 4/1, activation temperature = ,and a He flow rate = 850 ml/min. The optimization of these three factors leads to high CNFs micropore volume, being the surface area increased by a factor of 3 compared to the raw CNFs. It is important to note that only the creation of micropores (ultramicropores principally) took place, and mesopores were not generated if compared with raw CNFs.

scholarly journals Adsorption of hexavalent chromium by activated carbon obtained from a waste lignocellulosic material (Ziziphus jujuba cores): Kinetic, equilibrium, and thermodynamic study

2018 ◽  
Vol 36 (3-4) ◽  
pp. 1066-1099 ◽  
Author(s):  
Radia Labied ◽  
Oumessaad Benturki ◽  
Adh’ Ya Eddine Hamitouche ◽  
André Donnot
Keyword(s):  
Fourier Transform ◽  
Activated Carbon ◽  
Hexavalent Chromium ◽  
Chemical Activation ◽  
Fourier Transform Infrared ◽  
Infrared Analysis ◽  
Order Kinetic ◽  
Lignocellulosic Material ◽  
Ziziphus Jujuba ◽  
Key Functional Groups

In aqueous solutions, hexavalent chromium Cr(VI) was successfully removed by activated carbon “ Z. jujuba rubidium carbonate-activated carbon” obtained from waste lignocellulosic material ( Ziziphus jujuba cores). Rubidium carbonate was used to prepare Z. jujuba rubidium carbonate-activated carbon by chemical activation using a 1:1 w/w ratio. Our results indicate that the obtained surface area of the activated carbon was equal to 608.31 m2/g. The adsorption study of Cr(VI) was investigated under batch conditions at constant stirring speed (220 r/min). Factors such as pH (1–6), temperature (20–40°C), adsorbent concentration (0.5–3 g/l), and initial Cr(VI) concentration (50–500 mg/l) were all studied to attain the maximum removal efficiency. Prior to the adsorption process, the morphology, elementary composition, and loss mass of activated carbon were characterized using scanning electron microscopy, X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Fourier transform infrared analysis of the adsorbent demonstrated the presence of key functional groups associated with the adsorption phenomenon such as those of hydroxyl and aromatic groups. The obtained results showed that the optimal conditions for a maximum adsorption efficiency are 2 for pH, 1 g/l for activated carbon dosage and 100 mg/l for Cr(VI) concentration. The removal percentage increased from 27.2 to 62.08%. The kinetic sorption was described by a pseudo-second-order kinetic equation ( R2 ≈ 0.995). The Tóth ( R2 = 0.997) and Elovich models were best to explain the sorption phenomenon. Thermodynamic studies showed that the adsorption of Cr(VI) onto activated carbon was feasible, spontaneous, and endothermic at 20–40°C. This novel Z. jujuba rubidium carbonate-activated carbon derived from Z. jujuba core has been found to be effective for the removal of Cr(VI) and not harmful to the ecosystem.

scholarly journals Pinecone-Derived Activated Carbons as an Effective Medium for Hydrogen Storage

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2237
Author(s):  
Sara Stelitano ◽  
Giuseppe Conte ◽  
Alfonso Policicchio ◽  
Alfredo Aloise ◽  
Giovanni Desiderio ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Hydrogen Storage ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Hydrogen Adsorption ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Textural Properties ◽  
Biomass Waste ◽  
Wavelength Dispersive Spectrometry

Pinecones, a common biomass waste, has an interesting composition in terms of cellulose and lignine content that makes them excellent precursors in various activated carbon production processes. The synthesized, nanostructured, activated carbon materials show textural properties, a high specific surface area, and a large volume of micropores, which are all features that make them suitable for various applications ranging from the purification of water to energy storage. Amongst them, a very interesting application is hydrogen storage. For this purpose, activated carbon from pinecones were prepared using chemical activation with different KOH/precursor ratios, and their hydrogen adsorption capacity was evaluated at liquid nitrogen temperatures (77 K) at pressures of up to 80 bar using a Sievert’s type volumetric apparatus. Regarding the comprehensive characterization of the samples’ textural properties, the measurement of the surface area was carried out using the Brunauer–Emmett–Teller method, the chemical composition was investigated using wavelength-dispersive spectrometry, and the topography and long-range order was estimated using scanning electron microscopy and X-ray diffraction, respectively. The hydrogen adsorption properties of the activated carbon samples were measured and then fitted using the Langmuir/ Töth isotherm model to estimate the adsorption capacity at higher pressures. The results showed that chemical activation induced the formation of an optimal pore size distribution for hydrogen adsorption centered at about 0.5 nm and the proportion of micropore volume was higher than 50%, which resulted in an adsorption capacity of 5.5 wt% at 77 K and 80 bar; this was an increase of as much as 150% relative to the one predicted by the Chahine rule.

scholarly journals Pre-Treatment Methods for Regeneration of Spent Activated Carbon

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4561
Author(s):  
Sang Youp Hwang ◽  
Gi Bbum Lee ◽  
Ji Hyun Kim ◽  
Bum Ui Hong ◽  
Jung Eun Park
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Acid Treatment ◽  
Chemical Activation ◽  
Fixed Carbon ◽  
Treatment Methods ◽  
Positive Effects ◽  
Area Increase ◽  
Pre Treatment ◽  
Surface Area Increase

Spent activated carbon (SAC) usually exhibits a low specific surface area due to its high ash contents. In this study, pre-treatments, such as heat and acid treatments, were optimized to improve this feature. The heat pre-treatment did not reduce the ash content, nor did it increase the surface area. Because metallic ions adsorbed in SACs turn into ash upon the heat treatment. In the acid pre-treatment, the volatiles and fixed carbon were increased with decreasing ash contents. In this study, it was found that the surface area increase was correlated with the ratio between fixed carbon and ash. Among the pre-treatment methods, the combined heat and acid pre-treatment method highly increased the ratio, and therefore led to the surface area increase. Additionally, the acid pre-treatment was carried out using different types of acid (organic and inorganic acids) solutions to further improve the surface areas. The organic acid treatment caused a significant structural collapse compared to the inorganic acid treatment, decreasing the surface area. In particular, H3PO4 effectively removed ashes adsorbed on the activated carbon surface and regenerated the exhausted activated carbon. Both the heat and acid pre-treatments before chemical activation resulted in the positive effects such as strong desorption of pollutants and ashes within the internal structure of the activated carbon. Therefore, the regeneration introduced in this study is methodically the best method to regenerate SAC and maintain a stable structure.

Retransformed graphitic activated carbon from ionic liquid-derived carbon containing nitrogen

2015 ◽  
Vol 3 (6) ◽  
pp. 2564-2567 ◽  
Author(s):  
Mok-Hwa Kim ◽  
Sol Yun ◽  
Ho Seok Park ◽  
Joong Tark Han ◽  
Kwang-Bum Kim ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Activated Carbon ◽  
Surface Area ◽  
Chemical Activation ◽  
High Surface ◽  
High Surface Area ◽  
Graphitic Structure

Carbonization and chemical activation of an ionic liquid are demonstrated to produce an outstanding structural combination of an unexpectedly high surface area and a graphitic structure.

AKTIVASI KIMIA-FISIK LIMBAH SERUTAN ROTAN MENJADI KARBON AKTIF

2014 ◽  
Vol 14 (1) ◽  
pp. 82-98
Author(s):  
Andy Mizwar
Keyword(s):  
Activated Carbon ◽  
Water Content ◽  
Iodine Number ◽  
Surface Area ◽  
Chemical Activation ◽  
Raw Material ◽  
Physical Activation ◽  
Fixed Carbon ◽  
Impregnation Time ◽  
Physical And Chemical

Limbah rotan dari industri kerajinan dan mebel berpotensi untuk dijadikan sebagai bahan baku pembuatan karbon aktif karena memiliki kandungan holoselulosa dan kadar karbon yang tinggi. Penelitian ini bertujuan untuk menganalisis efektifitas dari aktivasi kimia menggunakan larutan natrium klorida (NaCl) yang dilanjutkan dengan aktivasi fisik dalam pembuatan karbon aktif berbahan dasar  limbah serutan rotan. Pembuatan karbon aktif diawali dengan proses karbonisasi pada suhu 250°C selama 1 jam. Selanjutnya aktivasi kimia menggunakan larutan NaCl dengan variasi konsentrasi 10%, 15% dan 20% serta waktu perendaman selama 10, 15 dan 20 jam. Aktivasi fisik dilakukan dengan pembakaran pada suhu 700°C selama 30 menit. Analisis karakteristik fisik-kimia karbon aktif mengacu pada SNI 06-3730-95, meliputi kadar air, fixed carbon, dan iodine number, sedangkan perhitungan luas permukaan spesifik karbon aktif dilakukan dengan Metode Sears. Hasil penelitian ini menunjukkan bahwa kondisi optimum aktivasi kimia terjadi pada konsentrasi NaCl 10% dan lama perendaman 10 jam dengan hasil analisis kadar air 2.90%, fixed carbon 72.70%, iodine number 994.59 mg/g dan luas permukaan 1587.67 m²/g. Peningkatan fixed carbon, iodine number dan luas permukaan karbon aktif berbanding terbalik dengan peningkatan konsentrasi NaCl dan lama waktu perendaman, sedangkan peningkatan kadar air pada karbon aktif berlaku sebaliknya. Rattan waste from handicraft and furniture industry could potentially be used as raw material of activated carbon due to high content of holoselulosa and carbon. This paper investigates the effectiveness of chemical activation using sodium chloride (NaCl) followed by physical activation in the making of activated carbon-based on rattan shavings waste. Preparation of the activated carbon began with the carbonization process at 250°C for 1 hour. Furthermore chemical activation using a variation of NaCl concentrations 10%, 15% and 20% as well as the time of immersion 10, 15 and 20 hours. Physical activation was done by burning at 700°C for 30 minutes. Analysis of the physical and chemical characteristics of the activated carbon was referred to the SNI 06-3730-95, including of moisture content, fixed carbon and iodine number, while the calculation of the specific surface area was done by the Sears’s method. The results of this study showed that the optimum conditions of chemical activation occurred in impregnation by NaCl 10% for 10 hours. The water content, fixed carbon, iodine number and surface area of activated carbon was 2.90%, 72.70%, 994.59 mg/g and 1587.67 m²/g  respectively. The increase values of fixed carbon, iodine number, and surface area was inversely proportional to the increase of NaCl concentration and the length of impregnation time, while the increase of water content applied vice versa.

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