scholarly journals Reactivation Process of Activated Carbons: Effect on the Mechanical and Adsorptive Properties

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1681 ◽  
Author(s):  
Rita B. Cevallos Toledo ◽  
Carlos F. Aragón-Tobar ◽  
Sebastián Gámez ◽  
Ernesto de la Torre

Carbon reactivation is a strategy to reduce waste and cost in many industrial processes, for example, effluent treatment, food industry, and hydrometallurgy. In this work, the effect of physical and chemical reactivation of granular activated carbon (AC) was studied. Spent activated carbon (SAC) was obtained from a carbon in pulp (CIP) leaching process for gold extraction. Chemical and physical reactivations were evaluated using several acid-wash procedures (HCl, HNO3, H2SO4) and thermal treatment (650–950 °C) methods, respectively. The effect of the reactivation processes on the mechanical properties was evaluated determining ball pan hardness and normal abrasion in pulp resistance. The effect on the adsorptive properties was evaluated via the iodine number, the gold adsorption value (k expressed in mg Au/g AC), and Brunauer–Emmett–Teller (BET) surface area. Initial characterization of the SAC showed an iodine number of 734 mg I2/g AC, a k value of 1.37 mg Au/g AC, and a BET surface area of 869 m2/g. The best reactivation results of the SAC were achieved via acid washing with HNO3 at 20% v/v and 50 °C over 30 min, and a subsequent thermal reactivation at 850 °C over 1 h. The final reactivated carbon had an iodine number of 1199 mg I2/g AC, a k value of 14.9 mg Au/g AC, and a BET surface area of 1079 m²/g. Acid wash prior to thermal treatment was critical to reactivate the SAC. The reactivation process had a minor impact (<1% change) on the mechanical properties of the AC.

TAPPI Journal ◽  
2018 ◽  
Vol 17 (02) ◽  
pp. 63-69 ◽  
Author(s):  
Mamon Sarkar ◽  
Chao Tian ◽  
M. Sarwar Jahan

Activated carbon was prepared by phosphoric acid (H3PO4) activation of potassium hydroxide (KOH) pulping spent liquor lignin from rice straw and compared with KOH hydroxide activation. The process parameters, such as impregnation ratio, activation temperature, and activation time were varied and their effects on the yield of activated carbon and iodine number were studied. The activated carbon prepared by H3PO4 at 800°C for 60 min at an impregnation ratio of 2.5 reached a Brunauer-Emmett-Teller (BET) surface area of 1063 m2/g, including pore diameter of 14.4 nm, iodine number of 525 mg/g, and yield of 49.2%. Yield and BET surface area in KOH activation was much lower than that of H3PO4.


2011 ◽  
Vol 704-705 ◽  
pp. 517-522 ◽  
Author(s):  
Xiao Juan Jin ◽  
Zhi Ming Yu ◽  
Gao Jiang Yan ◽  
Wu Yu

Activated carbons were prepared through chemical activation of lignin from straw pulping precursor using potassium carbonate as the chemical agent. Effects of activated temperature, K2CO3/lignin ratio and the activated time on the yield, Iodine number of activated carbon were investigated. Experimental results indicated that the optimum conditions were as follow: activated temperature 800°C, K3CO3(40% concentration) /lignin ratio 5: l, activated time 50min. These conditions allowed us to obtain a BET surface area of 1104 m2/g, including the external or non-microporous surface of 417 m2/g,Amount of methylene blue adsorption, Iodine number and the yield of activated carbon prepared under optimum conditions were 10.6mL/0.lg,1310 mg/g and 19.75%, respectively.


Author(s):  
Mustafa Kaya ◽  
Ömer Şahin ◽  
Cafer Saka

AbstractIn this study, low cost activated carbon was prepared from the pistachio shell by chemical activation with zinc chloride (ZnCl2). The prepared activated carbon was characterized by thermogravimetry (TG) and differential thermal gravimetry (DTG), infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) surface area analyses. Results showed that the activation temperature and impregnation ratio have significant effect on the iodine number of the prepared activated carbon. The optimum conditions for preparing the activated carbon having the highest surface area were found to be an activation temperature of 700 °C, soaking time of 24 h and ZnCl2/ pistachio shell ratio of 50 %. The results showed that the BET surface area, total pore volume, iodine number and methylene blue (MB) number of activated carbon prepared under the optimum conditions were 1108 m2/g, 0.39 cm3/g, 1051 mg/g, 98.48 mg/g, respectively.


2018 ◽  
Vol 16 (5) ◽  
pp. 814-826
Author(s):  
Xiaowei Liu ◽  
Lihui Huang ◽  
Lisha Wang ◽  
Chuang Wang ◽  
Xueyuan Wu ◽  
...  

Abstract Activated carbon (AC) was prepared from Platanus orientalis leaves by H3PO4 activation using a microwave heating method and characterized by SEM (scanning electron microscopy), Brunauer-Emmett-Teller (BET) surface area analysis and FTIR (Fourier transform infrared spectroscopy) techniques. AC exhibited a surface area of 1089.67 m2/g and a relatively high pore volume of 1.468 cm3/g. Utilization of AC for the removal of Cr(VI) from aqueous solution was researched. The adsorption efficiency was highly pH dependent and adsorption capacity of AC for Cr(VI) could reach up to 135.24 mg/g. Adsorption equilibrium could be quickly reached within 2 h. A kinetic study indicated that the adsorption of Cr(VI) conformed to the pseudo-second-order model (R2 &gt; 0.99). An intraparticle diffusion model was applied to describe the adsorption kinetics, and the results showed that there are other factors that affect the rate. Chemical regeneration for AC saturated with Cr(VI) was performed and HNO3 displayed the best regeneration performance among the four chemical regeneration agents (HNO3, H2SO4, NaOH, NaCl). The regeneration performance increased at first and then decreased with the rise of HNO3 concentration, and regeneration reaction could reach equilibrium within 4 h in the first cycle. The FTIR spectra revealed that HNO3 successfully introduced N-H bonds onto the AC surface in the regeneration process.


Author(s):  
Batkhishig Damdin ◽  
Purevsuren Barnasan ◽  
Chung-Jun Lin ◽  
Batbileg Sanjaa ◽  
Ariunaa Alyeksandr

Initial coal was purified in heavy liquid with a density 1.3 cm3 of ZnCl2 solution and purified coal was carbonized and the initial coal samples of each deposits were purified by pyrolysis. Thus, the yield of pyrolysis hard residue in the enriched sample was slightly higher than in the hard residue of initial coal. Therefore, pyrolysis hard residue of purified coal (carbonized sample) was activated at 800°C for 2 hours by preheated water steam. Activated carbons (ACs) and non-activated and non-carbonized coal from Baganuur, Ereen and Nariin Sukhait deposits were technically analyzed and their iodine number, BET surface area, pore volume and adsorption of methylene blue (MB) were determined. When these results were compared, these indicators increased 5-17 times in the Baganuur activated carbon (BN-AC), Ereen activated carbon (E-AC) and Nariin Sukhait activated carbon (NS-AC) as compared to inactivated coal.


2019 ◽  
Vol 69 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Arjun Singh ◽  
Sanjeevan Aggrawal ◽  
Darshan Lal

Phenolic beads (PBs) prepared from different formaldehyde to phenol (F/P) molar ratios were used as polymeric precursor for activated carbon. Activated carbon spheres (ACSs) have been produced from PBs via the physical activation process using carbon dioxide (CO2) as activating agent at 950 °C for different burn-off. The prepared ACSs were investigated for nitrogen adsorption, surface morphology and compressive strength by means of BET surface area analyser, scanning electron microscopy (SEM) and carbon and sphere tester techniques. The results indicated that the effects of F/P ratio observed, especially variation in the adsorption and mechanical properties. It was found that ACSs obtained from F/P ratio one showed the superior adsorption properties, possessed a high BET surface area in a range of 836 m2 g-1 to 3694 m2 g-1 with high pore volume (0.47 cm3 g-1 - 2.47 cm3 g-1) and 73-97 per cent microporosity. The BET surface area and pore volume increased, while the microporosity gradually decreased, with increasing the extent of burn-off. Compressive strength decreased with increasing F/P ratio as well as the extent of burn-off. ACSs upheld improved compressive strength (from 160 N mm-2 to 9 N mm-2) than those obtained from F/P ratio 2 and 3 in PBs. SEM studies of ACSs demonstrated well developed pore structure.


2021 ◽  
Author(s):  
Emmanuel Ayodele ◽  
Victoria Ezeagwula ◽  
Precious Igbokwubiri

Abstract Bamboo trees are one of the fastest growing trees in tropical rainforests around the world, they have various uses ranging from construction to fly ash generation used in oil and gas cementing, to development of activated carbon which is one of the latest uses of bamboo trees. This paper focuses on development of activated carbon from bamboo trees for carbon capture and sequestration. The need for improved air quality becomes imperative as the SDG Goal 12 and SDG Goal13 implies. One of the major greenhouse gases is CO2 which accounts for over 80% of greenhouse gases in the environment. Eliminating the greenhouse gases without adding another pollutant to the environment is highly sought after in the 21st century. Bamboo trees are mostly seen as agricultural waste with the advent of scaffolding and other support systems being in the construction industry. Instead of burning bamboo trees or using them for cooking in the local communities which in turn generates CO2 and fly ash, an alternative was considered in this research work, which is the usage of bamboo trees to generate activated, moderately porous and high surface area carbon for extracting CO2 from various CO2 discharge sources atmosphere and for water purification. This paper focuses on the quality testing of activated carbon that can effectively absorb CO2. The porosity, pore volume, bulk volume, and BET surface area were measured. The porosity of the activated carbon is 27%, BET surface area as 1260m²/g. Fixed carbon was 11.7%, Volatility 73%, ash content 1.7%.


2014 ◽  
Vol 699 ◽  
pp. 1006-1011
Author(s):  
Nurul’ Ain binti Jamion ◽  
Siti Mazleena binti Mohamed

Interface adsorption of gases and liquid on a clean solid surface could be due to the physical or chemical adsorption. In this study, the activated carbon was prepared from sugar cane husk (powder and granular form) using phosphoric acid (H3PO4) as activating agent. Sample was activated at 500°C for two hours in the furnace and washed using vacuum method. Besides, surface area of activated carbon was defined using Single Point Brunauer-Emmett-Teller (BET) Nitrogen Gas. The physico-chemical characteristics of the prepared activated carbon were characterized by Fourier-Transformed Infrared Spectroscopy (FTIR), gravimetric method, and Field Emission Scanning Electron Microscopy (FESEM). The adsorption study by surfactants, namely CTAB (cationic) and TX-100 (non-ionic) were investigated. The experimental results showed that a good activated carbon was prepared from sugar cane husk granular (SCH-G) gave the highest BET surface area of 860.18 m2/g and the adsorption capacity of SCH-G activated carbon at 25°C using TX-100 (205.81 mg g-1) was greater compared to the CTAB (108.20 mg g-1). This study has shown that the sugar cane husk was a good activated carbon and has potential to be used as adsorbent for the removal of surfactants from aqueous solutions.


2019 ◽  
Vol 8 (1) ◽  
pp. 408-415 ◽  
Author(s):  
Wenhai Hu ◽  
Song Cheng ◽  
Hongying Xia ◽  
Libo Zhang ◽  
Xin Jiang ◽  
...  

Abstract The waste phenolic resin was utilized as the raw material to prepare activated carbon (AC) used KOH as the activating agent via microwave heating. The phenolic resin was carbonized at 500°C and then performed with a KOH/Char ratio of 4 and microwave power of 700 W for a duration of 15 min. The physic-chemical characteristics of the AC were characterized by N2 adsorption instrument, FTIR, SEM and TEM. The BET surface area and pore volume of AC were found to be 4269 m2/g and 2.396 ml/g, respectively. The activation process to generate such a phenomenally high surface area of the AC has little reported in open literatures and could pave way for preparation adsorbents that are far superior to the currently marketed adsorbents. The methylene blue (MB) was used as the model to assess its suitability to dye wastewater treatment. Towards this, the MB adsorption isotherms were conducted at three different temperatures and tested with different adsorption isotherm models. The adsorption isotherms could be modeled using Langmuir isotherm. While the kinetics could be used the pseudo-second order kinetics to describe. Thermodynamic results demonstrated that the adsorption process was a spontaneous, as well as an endothermic.


Holzforschung ◽  
2018 ◽  
Vol 72 (5) ◽  
pp. 367-374 ◽  
Author(s):  
Yuxiang Huang ◽  
Wenji Yu ◽  
Guangjie Zhao

AbstractA novel way to prepare mesoporous activated carbon fibers (ACFs-P) has been developed, while the ACFs-P with high surface area were obtained from liquefied wood by combining polyvinyl butyral (PVB) blending and steam activation. The porosity properties of the new material was investigated by N2adsorption and the Brunauer–Emmett–Teller (BET) surface area was found to be 2710 m2g−1and a pore volume of 1.540 cm3g−1, of which 58.2% was mesoporous with diameters between 3 and 6 nm. ACFs-P had a higher methylene blue (MB) adsorption capacity (962 mg/g) than the PVB-added carbon fibers (CFs-P) and ACFs-P without PVB (ACFs-C). Flexible all-carbon yarn supercapacitors can be produced from ACFs-P as powder or fiber. The fiber approach led to yarn supercapacitors with a less favorable electrochemical performance than the powder based production owing to the poor strength of the fibers. A 10 cm long yarn supercapacitor from the powdered ACFs exhibited a high specific length capacitance of 43 mF cm−1at 2 mV s−1. Yarn supercapacitors showed an excellent mechanical flexibility and its capacitor properties were not diminished after bending or crumpling.


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