title: Equilibrium models and kinetic for the adsorption of methylene blue on Co-hectorites.
abstract: The adsorption of methylene blue (MB) onto the surface of cobalt doping hectorite (Co-hectorite) was systematically studied. The physical properties of Co-hectorites were investigated, where characterizations were carried out by X-ray diffraction (XRD) and Electron Diffraction Spectrum (EDS) techniques, and morphology was examined by nitrogen adsorption. The sample with a Co content 5% (m/m) had a higher specific surface area than other Co-hectorites. The pore diameters were distributed between 2.5 and 5.0 nm. The adsorption results revealed that Co-hectorite surfaces possessed effective interactions with MB and bases, and greatest adsorption capacity achieved with Co content 5%, where the best-fit isotherm model was the Langmuir adsorption model. Kinetic studies were fitted to the pseudo-second-order kinetic model. The intraparticle diffusion was not the rate-limiting step for the whole reaction.
authors.affiliation: Institute of Salt Lakes, Chinese Academy of Sciences, Xinning Road 18, Xining 810008, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.forename: Yong-Zhong
authors.initials: YZ
authors.lastname: Jia
authors.forename: Yan
authors.initials: Y
authors.lastname: Jing
authors.forename: Jin-He
authors.initials: JH
authors.lastname: Sun
authors.forename: Ying
authors.initials: Y
authors.lastname: Yao
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D002621:Chemistry / Q000379:methods; D003035:Cobalt / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry / Q000302:isolation & purification; D004058:Diffusion; D007700:Kinetics; D008751:Methylene Blue / Q000737:chemistry / Q000302:isolation & purification*; D008956:Models, Chemical; D009584:Nitrogen / Q000737:chemistry; D017640:Silicates / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D004396:Coloring Agents; D017640:Silicates; D014874:Water Pollutants, Chemical; C013547:hectorite; D003035:Cobalt; D009584:Nitrogen; D008751:Methylene Blue