Dye removal of activated carbons prepared from NaOH-pretreated rice husks by low-temperature solution-processed carbonization and H3PO4 activation

• Published in: Bioresource technology 2013-09, Vol.144, p.401-409
• Main Authors: Chen, Yun, Zhai, Shang-Ru, Liu, Na, Song, Yu, An, Qing-Da, Song, Xiao-Wei
• Format: Article
• Language: English
• Subjects: Activated carbon; Activated carbons; Activation; Adsorption; Adsorption - drug effects; Biological and medical sciences; Carbon - chemistry; Carbonization; Charcoal - chemistry; Cold Temperature; Coloring Agents - isolation & purification; Dye molecules; Food industries; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration - drug effects; Kinetics; Mathematical models; Methylene blue; Methylene Blue - isolation & purification; Oryza - chemistry; Oryza - drug effects; Phosphoric Acids - pharmacology; Photoelectron Spectroscopy; Porosity; Rice; Sodium Hydroxide - pharmacology; Solution-processed carbonization; Solutions; Surface chemistry; Time Factors; Use and upgrading of agricultural and food by-products. Biotechnology; Waste Products - analysis
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2013.07.002

•Preparation of activated carbons by coupling of H2SO4-assisted carbonization and H3PO4 activation.•Optimization of preparative conditions and systematic analysis of surface functional groups.•Relationship of dye removal of activated carbons on processing conditions. A coupling of low-temperature sulfuric acid-assisted carbonization and H3PO4 activation was employed to convert NaOH-pretreated rice husks into activated carbons with extremely high surface area (2028m2g−1) and integrated characteristics. The influences of the activation temperature and impregnation ratio on the surface area, pore volume of activated carbons were thoroughly investigated. The morphology and surface chemistry of activated carbons were characterized using N2 sorption, FTIR, XPS, SEM, TEM, etc. The adsorption capacity of resulting carbons obtained under optimum preparation conditions was systematically evaluated using methylene blue under various simulated conditions. The adsorption process can be well described by both Langmuir isotherm model and the pseudo-second order kinetics models; and the maximum monolayer capacity of methylene blue was ca. 578mgg−1.