scholarly journals The Analysis of Pore Development and Formation of Surface Functional Groups in Bamboo-Based Activated Carbon during CO2 Activation

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5641
Author(s):  
Krittamet Phothong ◽  
Chaiyot Tangsathitkulchai ◽  
Panuwat Lawtae
Keyword(s):  
Activated Carbon ◽  
Functional Groups ◽  
Active Sites ◽  
Activated Carbons ◽  
Carbonization Temperature ◽  
Activation Process ◽  
Activation Time ◽  
Oxygen Functional Groups ◽  
Porous Properties ◽  
Activation Conditions

Pore development and the formation of oxygen functional groups were studied for activated carbon prepared from bamboo (Bambusa bambos) using a two-step activation with CO2, as functions of carbonization temperature and activation conditions (time and temperature). Results show that activated carbon produced from bamboo contains mostly micropores in the pore size range of 0.65 to 1.4 nm. All porous properties of activated carbons increased with the increase in the activation temperature over the range from 850 to 950 °C, but decreased in the temperature range of 950 to 1000 °C, due principally to the merging of neighboring pores. The increase in the activation time also increased the porous properties linearly from 60 to 90 min, which then dropped from 90 to 120 min. It was found that the carbonization temperature played an important role in determining the number and distribution of active sites for CO2 gasification during the activation process. Empirical equations were proposed to conveniently predict all important porous properties of the prepared activated carbons in terms of carbonization temperature and activation conditions. Oxygen functional groups formed during the carbonization and activation steps of activated carbon synthesis and their contents were dependent on the preparation conditions employed. Using Boehm’s titration technique, only phenolic and carboxylic groups were detected for the acid functional groups in both the chars and activated carbons in varying amounts. Empirical correlations were also developed to estimate the total contents of the acid and basic groups in activated carbons in terms of the carbonization temperature, activation time and temperature.

scholarly journals Role of Activated Carbon Precursor for Mercury Oxidation and Removal: Oxidized Surface and Carbene Site Interaction

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1190
Author(s):  
Regina Rodriguez ◽  
Domenic Contrino ◽  
David Mazyck
Keyword(s):  
Activated Carbon ◽  
Nitric Acid ◽  
Gas Phase ◽  
Functional Groups ◽  
Bituminous Coal ◽  
Activated Carbons ◽  
Elemental Mercury ◽  
Coconut Shell ◽  
Mercury Removal ◽  
Oxygen Functional Groups

Activated carbon (AC) is widely accepted for the removal of inorganic contaminants like mercury; however, the raw material used in the production of activated carbon is not always taken into consideration when evaluating its efficacy. Mercury oxidation and adsorption mechanisms governed by carbene sites are more likely to occur when graphitic-like activated carbons (such as those produced from high-ranking coals) are employed versus lignocellulosic-based ACs; this is likely due to the differences in carbon structures where lignocellulosic materials are less aromatic. In this research, the team studied bituminous coal-based ACs in comparison to coconut shell and wood-based (both less aromatic) ACs for elemental mercury removal. Nitric acid of 0.5 M, 1 M, and 5 M concentrations along with 10 M hydrogen peroxide were used to oxidize the surface of the ACs. Boehm titrations and FTIR analysis were used to quantify the addition of functional groups on the activated carbons. A trend was observed herein, resulting in increasing nitric acid molarity and an increased quantity of oxygen-containing functional groups. Gas-phase mercury removal mechanisms including physisorption, oxygen functional groups, and carbene sites were evaluated. The results showed significantly better elemental mercury removal in the gas phase with a bituminous coal-based AC embodying similar physical and chemical characteristics to that of its coconut shell-based counterpart. The ACs treated with various oxidizing agents to populate oxygen functional groups on the surface showed increased mercury removal. It is hypothesized that nitric acid treatment creates oxygen functional groups and carbene sites, with carbene sites being more responsible for mercury removal. Heat treatments post-oxidation with nitric acid showed remarkable results in mercury removal. This process created free carbene sites on the surface and shows that carbene sites are more reactive to mercury adsorption than oxygen. Overall, physisorption and oxygen functional groups were also dismissed as mercury removal mechanisms, leaving carbene-free sites as the most compelling mechanism.

Effects of Pre-Carbonization on Structure and Electrochemical Performances of Amphiphilic Carbonaceous Material-Based Activated Carbons

2012 ◽  
Vol 549 ◽  
pp. 96-100
Author(s):  
Cui Zhang ◽  
Cheng Yang Wang ◽  
Ming Ming Chen ◽  
Jia Ming Zheng ◽  
Jiu Zhou Wang
Keyword(s):  
Functional Groups ◽  
Active Sites ◽  
Activated Carbons ◽  
Carbonaceous Material ◽  
Alkaline Solutions ◽  
Electrochemical Performances ◽  
Activation Process ◽  
Xps Spectra ◽  
Electrochemical Double Layer ◽  
Two Parameters

Activated carbons to be used as electrode in electrochemical double-layer capacitors were fabricated using amphiphilic carbonaceous material (ACM) as precursor. To study the significance of functional groups and microcrystalline of the precursor in preparing AC, we applied pre-carbonization upon the ACM under different conditions to control these two parameters in this paper. FTIR and XPS spectra showed functional groups on the precursors decreased as the increase of pre-carbonization temperature. After carbonization at 800 °C, the growth of graphitic microcrystallites was noticeable. Porous structure parameters of final ACs inferred that the functional groups on the precursors have a more significant effect than microcrystalline size on formation of mesopores during activation process not only for its role as active sites but also the homogeneous activation profited from the solubility of samples in alkaline solutions. The sample AC0 with almost half mesopores showed the best electrochemical behavior with a specific gravimetric capacitance of 255 F/g at current density of 1000mA/g and kept rectangular shape cyclic voltammetry curve even at scan rate high as 400 mV/s.

scholarly journals Catalytic Effect of NaCl on the Improvement of the Physicochemical Structure of Coal-Based Activated Carbons for SO2 Adsorption

Processes ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 338 ◽  
Author(s):  
Dongdong Liu ◽  
Rui Su ◽  
Zhengkai Hao ◽  
Xiaoman Zhao ◽  
Boyin Jia ◽  
...  
Keyword(s):  
Functional Groups ◽  
Active Sites ◽  
Catalytic Effect ◽  
High Efficiency ◽  
Activated Carbons ◽  
Rapid Development ◽  
Adsorptive Capacity ◽  
Oxygen Functional Groups ◽  
So2 Adsorption ◽  
Physicochemical Structure

The utilization of coal-based activated carbons focuses on improving the physicochemical structure for achieving high-capacity. Herein, the catalytic effect of NaCl (1 and 3 wt%) in the presence of oxygen functional groups on the improvement of the physicochemical structure of coal-based activated carbons is studied in this work. A large quantity of Na can be retained in 1NaJXO and 3NaJXO with the presence of oxygen functional groups to promote further its catalytic characteristics during pyrolysis, resulting in the disordered transformation of the carbon structure. In addition, the development of micropores is mainly affected by the distribution and movement of Na catalyst, whereas the growth of mesopores is mainly influenced by the evolution of oxygen functional groups. Then, the active sites of 3NaJXO-800 can no longer be consumed preferentially in the presence of Na catalyst during subsequent CO2 activation to facilitate the sustained disordered conversion of the microstructure and the rapid development of the micropores, resulting in the obvious high SBET value as activation proceeds. And the high SBET/burn-off ratio value (41.48 m2∙g−1/%) of 3NaJXO-800 with a high value of SBET (1995.35 m2∙g−1) at a low burn-off value (48.1%) can be obtained, presenting the high efficiency of pore formation. Finally, the SO2 adsorption efficiency of 3NaJXO-800-48.1 maintains at 100% within 90 min. After 180 min, 3NaJXO-800-48.1 still presents a high adsorptive capacity (140.2 mg/g). It is observed that a large micropore volume in the case of hierarchical pore structure necessarily assures optimal adsorption of SO2.

Development and Characterization of Activated Carbons Derived from Lignocellulosic Material

2020 ◽  
Vol 988 ◽  
pp. 80-86
Author(s):  
Dewa Ngakan Ketut Putra Negara ◽  
Tjokorda Gde Tirta Nindhia ◽  
Lusiana ◽  
I. Made Astika ◽  
Cokorda Istri Putri Kusuma Kencanawati
Keyword(s):  
Activated Carbon ◽  
Pore Size ◽  
Surface Area ◽  
Pore Volume ◽  
Activated Carbons ◽  
High Surface ◽  
Carbonization Temperature ◽  
Lignocellulosic Material ◽  
Activation Time ◽  
Average Pore

Activated carbon is a multipurpose material due to its unique properties such as high surface area and pore volume. The reduced carbon source from coal has led to the development of activated carbon from lignocellulosic material. However, there is limited literature reported the use of swat bamboo (Gigantocholoa verticillata) as an activated carbon precursor. In this research, swat bamboo has been converted to activated carbons under different carbonization temperatures of 550, 650, and 750OC and activation durations of 1.5 and 2 h. The results show that at activation time of 1.5 h, increasing carbonization temperature affecting the higher pore volume and surface area gained. The optimal characteristics of activated carbon were obtained at a carbonization temperature of 750OC and activation time of 1.5 h. This due to the activated carbon produced in this condition has the highest pore volume, surface area, and adsorption capacity of 0.138 cm3/g, 135.30 m2/g, and 95.776 cm3/g, respectively. Its average pore diameter was 2.053 nm with fix carbon of 75.26% and C of 76.79%. It has a monomodal pore size distribution with the highest adsorption of 0.056 cm3/g/nm occurred at a pore size of 1.516 nm.

scholarly journals Computer Analysis of the Effect of Activation Temperature on the Microporous Structure Development of Activated Carbon Derived from Common Polypody

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2951
Author(s):  
Mirosław Kwiatkowski ◽  
Jarosław Serafin ◽  
Andy M. Booth ◽  
Beata Michalkiewicz
Keyword(s):  
Activated Carbon ◽  
Porous Structure ◽  
Computer Analysis ◽  
Density Functional ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Geometrical Parameters ◽  
Activation Process ◽  
Microporous Structure ◽  
Activation Temperature

This paper presents the results of a computer analysis of the effect of activation process temperature on the development of the microporous structure of activated carbon derived from the leaves of common polypody (Polypodium vulgare) via chemical activation with phosphoric acid (H3PO4) at activation temperatures of 700, 800, and 900 °C. An unconventional approach to porous structure analysis, using the new numerical clustering-based adsorption analysis (LBET) method together with the implemented unique gas state equation, was used in this study. The LBET method is based on unique mathematical models that take into account, in addition to surface heterogeneity, the possibility of molecule clusters branching and the geometric and energy limitations of adsorbate cluster formation. It enabled us to determine a set of parameters comprehensively and reliably describing the porous structure of carbon material on the basis of the determined adsorption isotherm. Porous structure analyses using the LBET method were based on nitrogen (N2), carbon dioxide (CO2), and methane (CH4) adsorption isotherms determined for individual activated carbon. The analyses carried out showed the highest CO2 adsorption capacity for activated carbon obtained was at an activation temperature of 900 °C, a value only slightly higher than that obtained for activated carbon prepared at 700 °C, but the values of geometrical parameters determined for these activated carbons showed significant differences. The results of the analyses obtained with the LBET method were also compared with the results of iodine number analysis and the results obtained with the Brunauer–Emmett–Teller (BET), Dubinin–Radushkevich (DR), and quenched solid density functional theory (QSDFT) methods, demonstrating their complementarity.

PREPARATION AND CHARACTERIZATION OF ACTIVATED CARBON FROM OIL PALM EMPTY FRUIT BUNCH WASTES USING ZINC CHLORIDE

2015 ◽  
Vol 74 (11) ◽  
Author(s):  
Riry Wirasnita ◽  
Tony Hadibarata ◽  
Abdull Rahim Mohd Yusoff ◽  
Zainab Mat Lazim
Keyword(s):  
Activated Carbon ◽  
Zinc Chloride ◽  
Oil Palm ◽  
Active Sites ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Proximate Analysis ◽  
Infrared Spectrometry ◽  
Empty Fruit Bunch

An oil palm empty fruit bunch-derived activated carbon has been successfully produced by chemical activation with zinc chloride and without chemical activation. The preparation was conducted in the tube furnace at 500oC for 1 h. The surface structure and active sites of activated carbons were characterized by means of Fourier transform infrared spectrometry and field emission scanning electron microscopy. The proximate analysis including moisture content, ash content, bulk density, pH, and pH at zero charge was conducted to identify the psychochemical properties of the adsorbent. The results showed that the zinc chloride-activated carbon has better characteristics compared to the carbon without chemical activation.  

scholarly journals Performance of Sweet Potato’s Leaf-Derived Activated Carbon for Hydrogen Sulphide Removal from Biogas

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Geni Juma ◽  
Revocatus Machunda ◽  
Tatiana Pogrebnaya
Keyword(s):  
Activated Carbon ◽  
Adsorption Process ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Carbonization Temperature ◽  
Optimal Test ◽  
Potato Leaf ◽  
Bet Analysis ◽  
S 100 ◽  
Activation Ratio

In this study, sweet potato leaf activated carbon (SpLAC) was prepared by the chemical activation method using KOH and applied as an adsorbent for H2S removal from biogas. The study focused on the understanding of the effect of carbonization temperature (Tc), varying KOH : C activation ratio, flow rate (FR) of biogas, and mass of SpLAC on sample adsorption capacity. The BET analysis was performed for both fresh and spent activated carbons as well as for carbonized samples, which were not activated; also, the activated carbon was characterized by XRF and CHNS techniques. The results showed that removal efficiency (RE) of the SpLAC increased with increase carbonization temperature from 600 to 800°C and the mass of sorbent from 0.4 g to 1.0 g. The optimal test conditions were determined: 1.0 g of sorbent with a KOH : C ratio of 1 : 1, Tc=800°C, and FR=0.02 m3/h which resulted in a sorption capacity of about 3.7 g S/100 g of the SpLAC. Our findings corroborated that H2S removal was contributed not only by the adsorption process with the pore available but also by the presence of iron in the sample that reacted with H2S. Therefore, upon successful H2S sorption, SpLAC is suggested as a viable adsorbent for H2S removal from biogas.

Modification of Activated Carbon and its Application on Adsorption of UDMH Gas

2013 ◽  
Vol 634-638 ◽  
pp. 1026-1030 ◽  
Author(s):  
Huan Chun Wang ◽  
Xiao Li Gou ◽  
Xiao Meng Lv
Keyword(s):  
Activated Carbon ◽  
High Temperature ◽  
Transition Metal ◽  
Surface Structure ◽  
Functional Groups ◽  
Room Temperature ◽  
Activated Carbons ◽  
Metal Solution ◽  
Modified Activated Carbons

Two kinds of modified activated carbons were prepared by dipping with Zn(NO3)2 solution and by reducing in the atmosphere of N2 at high temperature respectively, which were characterized by FTIR,DSC,SEM and EDS. The surface structure was strongly changed in the process, along with the changes of chemical functional groups. The results of adsorption experiments revealed that the adsorbent capacities of UDMH gas at room temperature were enhanced obviously by modification compared with the raw activated carbon, especially dipped by transition metal solution. The mechanism probably involved was also discussed.

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