2-Steps KOH activation of rice straw: an efficient method for preparing high-performance activated carbons.
Effects of both pre-treatment and number of steps in KOH activation of raw rice straw (RS) on textural and adsorption properties of RS-derived activated carbons (ACs) were investigated. Three pre-treatment protocols were tested: mechanical, chemical by NaOH pulping, and a combination of both. Activation of RS-based materials was investigated, at a constant temperature of 800 degrees C, according to two ways: a 1-step simultaneous carbonisation-activation with KOH, and a 2-steps process: carbonisation followed by activation by KOH. 2-Steps KOH activation was more efficient in producing activated carbons with high surface areas and high methylene blue adsorption than 1-step KOH activation. Additionally, 2-steps KOH activation increased the yield of activated carbons having moderate ash content (8-14%). Surface areas as high as 1917 m(2)/g were obtained when the combined mechanical-chemical pre-treatment method and a 2-steps activation process were carried out.
Cellulose and Paper Dept, National Research Centre, Dokki, Cairo, Egypt.
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Basta
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Fierro
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El-Saied
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Celzard
D000327:Adsorption; D002606:Charcoal / Q000138:chemical synthesis* / Q000737:chemistry; D002625:Chemistry, Organic / Q000379:methods*; D006878:Hydroxides / Q000737:chemistry*; D007700:Kinetics; D008031:Lignin / Q000737:chemistry; D008751:Methylene Blue / Q000737:chemistry / Q000302:isolation & purification; D009584:Nitrogen / Q000737:chemistry; D012275:Oryza / Q000737:chemistry*; D016062:Porosity; D017680:Potassium Compounds / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
D006878:Hydroxides; D017680:Potassium Compounds; C036909:lignocellulose; D002606:Charcoal; D008031:Lignin; D009584:Nitrogen; D008751:Methylene Blue; C029943:potassium hydroxide