Mesoporous Activated Carbon Prepared from Bamboo by One-Step CO2 Activation Used for Puerarin Separation

2012 ◽  
Vol 232 ◽  
pp. 33-38
Author(s):  
Jia Guo ◽  
Yu Qiong Guan ◽  
Xing Wang ◽  
Chao Sun ◽  
Ye Luo

The feasibility of preparing mesoporous activated carbons from bamboo, a fast growing plant in some Asian countries, particularly in China, was investigated. The effects of activation conditions, namely, activation temperature and retention time, on the characteristics of the activated carbons, i.e., specific surface area, pore size distribution and surface chemistry, were studied. The separation performance for Puerarin using the prepared bamboo activated carbon was compared to other adsorbents which included a commercial activated carbon and a macroporous resin. The experimental results showed that it was feasible to prepare mesoporous activated carbon from bamboo and to use it instead of the expensive resins presently used for Puerarin separation.

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2951
Author(s):  
Mirosław Kwiatkowski ◽  
Jarosław Serafin ◽  
Andy M. Booth ◽  
Beata Michalkiewicz

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.


Author(s):  
S. Manocha ◽  
Parth Joshi ◽  
Amit Brahmbhatt ◽  
Amiya Banerjee ◽  
Snehasis Sahoo ◽  
...  

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Daouda Kouotou ◽  
Horace Ngomo Manga ◽  
Abdelaziz Baçaoui ◽  
Abdelrani Yaacoubi ◽  
Joseph Ketcha Mbadcam

In this study, activated carbons were prepared from oil palm shells by physicochemical activation. The methodology of experimental design was used to optimize the preparation conditions. The influences of the impregnation ratio (0.6–3.4) and the activation temperature between 601°C and 799°C on the following three responses: activated carbon yield (R/AC-H3PO4), the iodine adsorption (I2/AC-H3PO4), and the methylene blue adsorption (MB/AC-H3PO4) results were investigated using analysis of variance (ANOVA) to identify the significant parameters. Under the experimental conditions investigated, the activation temperature of 770°C and impregnation ratio of 2/1 leading to the R/AC-H3PO4of 52.10%, theI2/AC-H3PO4of 697.86 mg/g, and the MB/AC-H3PO4of 346.25 mg/g were found to be optimum conditions for producing activated carbon with well compromise of desirability. The two factors had both synergetic and antagonistic effects on the three responses studied. The micrographs of activated carbons examined with scanning electron microscopy revealed that the activated carbons were found to be mainly microporous and mesoporous.


2009 ◽  
Vol 59 (12) ◽  
pp. 2387-2394 ◽  
Author(s):  
X. Wang ◽  
N. Zhu ◽  
J. Xu ◽  
B. Yin

An improved method for preparing activated carbons from wet waste activated sludge (WAS) by direct chemical activation was studied in this paper. The effects of processing parameters on iodine adsorption capacity of the product were investigated. Results show that sludge-based activated carbon prepared with KOH had a larger iodine value than those activated with ZnCl2 and KCl. The maximum iodine value was observed at the KOH concentration of 0.50 M. Increasing the impregnation time from 10 to 20 h resulted in a 20% increase in the iodine value. The highest iodine value was obtained at the activation temperature of 600°C and holding time of 1 h. Sludge water content had insignificant effects on the iodine value of products. Raw WAS with a water content of 93.2% can be converted into an activated carbon with a high specific surface area of 737.6 m2 g−1 and iodine value of 864.8 mgg−1 under optimum experimental conditions. Other physical properties such as total pore volume, micropore volume and mean pore diameter of the product were also reported and compared with those of commercial activated carbon.


2019 ◽  
Vol 26 (01) ◽  
pp. 1830006 ◽  
Author(s):  
MATHEUS PEGO ◽  
JANAÍNA CARVALHO ◽  
DAVID GUEDES

The main and new surface modification methods of activated carbon (AC) and their influence on application (adsorption capacity) were reviewed. Adsorption capacity is an important issue, contributing to hazardous substances environment management. According to literature, it is true that surface chemistry strongly affects adsorption capacity. Surface chemistry can be modified by several methods that lead to different activated carbon properties. Furthermore, adsorbate properties, and their relationships with surface structure, can impact adsorption properties. Surface modifications can be conducted by adding some atoms to the surface structure, making the surface more acidic or basic. Introduction of oxygen and ammonia atoms (chemical modification) are the main processes to make the surface more acidic and basic, respectively, although may bring chemical wastes to environment. Surface modification is done by chemical and physical modifications that lead activated carbons to present different properties. The main and new methods of chemical and physical modifications are compared and presented in this paper. Some new physical methods, like corona treatment, plasma discharge and microwave radiation, can be applied to cause surface modifications. Corona treatment can be a practical and new way to cause surface modification on an activated carbon surface.


1986 ◽  
Vol 18 (1) ◽  
pp. 55-66 ◽  
Author(s):  
H. Keirsse ◽  
F. Van Hoof ◽  
J. Janssens ◽  
A. Buekens

Man's natural water supplies are threatened by a large number of nonbiodegradable and toxic organic compounds. Proper environmental standards often can only be attained using tertiary treatment processes, such as adsorption on activated carbon. The latter is an expensive process, owing to the initial cost of activated carbon and the losses occurring during regeneration. Methods are being investigated at the Free University of Brussels for producing and activating carbon, using various types of waste as a raw material. Following materials have already been used : cacao hulls, sawdust, fruit stones, bark, and waste tyres. Both carbonization and activation have been conducted under the carefully controlled conditions of a fluidized bed reactor. The influence of the following process parameters has been investigated : pyrolysis temperature and time, activation temperature and time, and composition of the furnace atmosphere. The resulting activated carbons should exhibit the following qualities : high adsorption capacity and rate, good resistance to attrition, and possibility of regenerating the carbon. The properties of the carbon obtained have been evaluated by means of a number of standard tests (Iodine-index, BET-surface, Tannin-index, Methylene blue-index, and Phenol-index), and adsorption isotherms of phenol, pentachlorophenol, p. toluene sulphonate and dodecyl benzenesulphonate. In general the properties of the carbons obtained were comparable to those of commercial qualities. Some of the activated carbons tested will soon be evaluated using synthetic and real phenolic industrial wastewaters (1.5 % of phenol).


2016 ◽  
Vol 75 (5) ◽  
pp. 1158-1168 ◽  
Author(s):  
Agha Arslan Wasim ◽  
Muhammad Nasiruddin Khan

Activated carbons produced from a variety of raw materials are normally selective towards a narrow range of pollutants present in wastewater. This study focuses on shifting the selectivity of activated carbon from inorganic to organic pollutants using activation temperature as a variable. The material produced from carbonization of pine shells substrate was activated at 250°C and 850°C. Both adsorbents were compared with commercial activated carbon for the sorption of lead, cadmium, methylene blue, methyl blue, xylenol orange, and crystal violet. It was observed that carbon activated at 250°C was selective for lead and cadmium whereas the one activated at 850°C was selective for the organic dyes. The Fourier transform infrared spectroscopy study revealed that AC850 had less surface functional groups as compared to AC250. Point of zero charge and point of zero salt effect showed that AC250 had acidic groups at its surface. Scanning electron microscopy depicted that increase in activation temperature resulted in an increase in pore size of activated carbon. Both AC250 and AC850 followed pseudo-second-order kinetics. Temkin isotherm model was a best fit for empirical data obtained at equilibrium. The model also showed that sorption process for both AC250 and AC850 was physisorption.


2018 ◽  
Vol 42 (17) ◽  
pp. 14612-14619 ◽  
Author(s):  
Cínthia Soares de Castro ◽  
Luísa Nagyidai Viau ◽  
Júlia Teixeira Andrade ◽  
Thais A. Prado Mendonça ◽  
Maraísa Gonçalves

Activated carbons of high mesoporosity were prepared from PET wastes and presented high adsorption capacity, including relatively large-molecule dyes.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
S. G. Herawan ◽  
M. A. Ahmad ◽  
A. Putra ◽  
A. A. Yusof

Activated carbons are regularly used the treatment of dye wastewater. They can be produced from various organics materials having high level of carbon content. In this study, a novel Pinang frond activated carbon (PFAC) was produced at various CO2flow rates in the range of 150–600 mL/min at activation temperature of 800°C for 3 hours. The optimum PFAC sample is found on CO2flow rate of 300 mL/min which gives the highest BET surface area and pore volume of 958 m2/g and 0.5469 mL/g, respectively. This sample shows well-developed pore structure with high fixed carbon content of 79.74%. The removal of methylene blue (MB) by 95.8% for initial MB concentration of 50 mg/L and 72.6% for 500 mg/L is achieved via this sample. The PFAC is thus identified to be a suitable adsorbent for removing MB from aqueous solution.


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