Adsorption properties and microstructure of activated carbons produced from agricultural by-products by steam pyrolysis

Gergova, K.; Petrov, N.; Eser, Semih

doi:10.1016/0008-6223(94)90091-4

Cited by 199 publications

(99 citation statements)

References 11 publications

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“…Previous studies about the preparation of activated carbon from grape seeds reported S BET values around 400-500 m 2 /g with a burn-off of 75% by one-step pyrolysis/activation at 800°C with steam [23]. Savova et al [24] obtained a granular activated carbon from grape seeds with heterogeneous pore size distribution with macropore, mesopore and micropore volumes of 0.28, 0.18 and 0.12 cm 3 /g, respectively.…”

Section: Influence Of Activation Conditionsmentioning

confidence: 99%

Development of porosity upon physical activation of grape seeds char by gas phase oxygen chemisorption–desorption cycles

Jiménez-Cordero

Heras

Alonso-Morales

et al. 2013

Chemical Engineering Journal

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h i g h l i g h t sNovel method of activation by cycles permits good control of porosity development. S BET values above 1000 m 2 /g can be obtained with burn-off values lower than 40%. The low burn-off helps to maintain granular morphology of the activated carbons.Carbons with unique hollow core structure and wall thickness of 250 lm are produced.The activated carbons showed a good mechanical strength during attrition test. a r t i c l e i n f o t r a c tActivation of grape seeds char upon cyclic oxygen chemisorption-desorption permits a controlled development of porosity versus burn-off using air as a cheap activation agent. In this work the influence of chemisorption and desorption temperature and the number of cycles is investigated. A fast increase of BET surface area (S BET ) is obtained in the two first cycles; that increase becomes then lower although the S BET continues increasing upon the successive cycles. Regarding the Dubinin-Astakhov surface area (S DA ) a slow increase was observed from cycle to cycle. The activation process led to the development of both micro and mesoporosity. Under the optimum conditions for surface area development, i.e. an oxidation temperature of 275°C and desorption temperatures between 850 and 950°C, values of 1129-1256 and 1339-1219 m 2 /g were obtained for S BET and S DA , respectively. Porosity was found to increase mainly during the desorption stage, although chemisorption also led to some surface area development. SEM characterization showed that the activated carbon maintained the granular morphology of the seeds even after 10 cycles showing the egg-shell structure of the precursor with longer and deeper cracks at the outer surface. The activated carbons showed a good mechanical strength during attrition tests.

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Section: Influence Of Activation Conditionsmentioning

confidence: 99%

Development of porosity upon physical activation of grape seeds char by gas phase oxygen chemisorption–desorption cycles

Jiménez-Cordero

Heras

Alonso-Morales

et al. 2013

Chemical Engineering Journal

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“…Iodine number is defined as the number of milligrams of iodine that is adsorbed by 1 g of adsorbent when the iodine concentration of the residual filtrate is 0.02 N (McKay, 1996). The residual iodine concentration was determined by titration with sodium thiosulfate solution (Gergova et al, 1994). Three measurements were taken for each sample, and the average values are shown; the relative CV for each mean value is shown as an error bar.…”

Section: Iodine Numbermentioning

confidence: 99%

“…The burnoff value for walnut shells was slightly (2%) higher than that of jujube seeds at the same temperature. Gergova et al (1994) reported that the surface structures of carbon and iodine numbers changed by soak time. Table 1 shows the burnoff and iodine number as a function of temperature for the raw materials (jujube seeds and walnut shells).…”

Section: Effect Of Activation Time and Temperaturementioning

confidence: 99%

Production of granular activated carbon from food-processing wastes (walnut shells and jujube seeds) and its adsorptive properties

Bae

Kim

Chung

2014

Journal of the Air & Waste Management Association

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Commercial activated carbon is a highly effective absorbent that can be used to remove micropollutants from water. As a result, the demand for activated carbon is increasing. In this study, we investigated the optimum manufacturing conditions for producing activated carbon from ligneous wastes generated from food processing. Jujube seeds and walnut shells were selected as raw materials. Carbonization and steam activation were performed in a fixed-bed laboratory electric furnace. To obtain the highest iodine number, the optimum conditions for producing activated carbon from jujube seeds and walnut shells were 2 hr and 1.5 hr (carbonization at 700 C) followed by 1 hr and 0.5 hr (activation at 1000 C), respectively. The surface area and iodine number of activated carbon made from jujube seeds and walnut shells were 1,477 and 1,184 m 2 /g and 1,450 and 1,200 mg/g, respectively. A pore-distribution analysis revealed that most pores had a pore diameter within or around 30-40 Å, and adsorption capacity for surfactants was about 2 times larger than the commercial activated carbon, indicating that waste-based activated carbon can be used as alternative.Implications: Wastes discharged from agricultural and food industries results in a serious environmental problem. A method is proposed to convert food-processing wastes such as jujube seeds and walnut shells into high-grade granular activated carbon. Especially, the performance of jujube seeds as activated carbon is worthy of close attention. There is little research about the application of jujube seeds. Also, when compared to two commercial carbons (Samchully and Calgon samples), the results show that it is possible to produce high-quality carbon, particularly from jujube seed, using a one-stage, 1,000 C, steam pyrolysis. The preparation of activated carbon from food-processing wastes could increase economic return and reduce pollution.

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“…Many researchers have prepared activated carbon from various carbonaceous precursors (Gergova 1994) such as various grain sorghum (Diao 2002), fruits stones, rice and peanut husk , wood (Anuar 2002, Anuar 2001, wheat straw , coconut and oil palm shell (Collin 2005, etc. Activated carbon is also the most commonly used support in first aid process of detoxification, owing mainly to its highly porous structure and high surface area.…”

Section: Introductionmentioning

confidence: 99%

Three Dimensional Finite Element Analysis of Radial-flow Impeller Temperature Field

Zhong¹,

Ni²,

He³

2008

MAS

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The technique of three dimensional solid element model and assembly was used to determine the temperature field of radial-flow impeller. The FEM software Cosmos was applied to analyze model system, and the precise analytic results were obtained. The results show that the analytic model can reflect the stead-state and transient temperature field characteristics of impeller directly, and thus can be worthy reference to analyze and calculate the temperature field of impeller in engineering design.

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Adsorption properties and microstructure of activated carbons produced from agricultural by-products by steam pyrolysis

Cited by 199 publications

References 11 publications

Development of porosity upon physical activation of grape seeds char by gas phase oxygen chemisorption–desorption cycles

Development of porosity upon physical activation of grape seeds char by gas phase oxygen chemisorption–desorption cycles

Production of granular activated carbon from food-processing wastes (walnut shells and jujube seeds) and its adsorptive properties

Three Dimensional Finite Element Analysis of Radial-flow Impeller Temperature Field

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