title: Kinetic and thermodynamic studies of toluene, ethylbenzene, and m-xylene adsorption from aqueous solutions onto KOH-activated multiwalled carbon nanotubes.
abstract: Multiwalled carbon nanotubes activated by KOH (CNTs-KOH) were synthesized and employed as adsorbents to study adsorption characteristics of toluene, ethylbenzene, and m-xylene (TEX) from aqueous solutions. Kinetics data were fitted by pseudo-second-order model, and intraparticle diffusion was not the only rate-controlling step. Adsorption isotherm data could fit well with Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models. The maximum adsorption capacities on CNTs-KOH are 87.12, 322.05, and 247.83 mg/g for toluene, ethylbenzene, and m-xylene, respectively. The adsorption capacities of TEX onto CNTs-KOH increased with contact time and decreased with temperature and are not significantly affected by humic acid. However, Cr(6+) could decrease adsorption of TEX by 17.66, 4.51, and 12.69% as (K(d)(1) - K(d)(2))/K(d)(1), respectively. The thermodynamics parameters indicated that adsorption was a feasible, exothermic, and spontaneous process in nature and a physisorption process. The present CNTs-KOH show a better EX adsorption performance than other adsorbents, suggesting that CNTs-KOH are promising EX adsorbents in wastewater treatment.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Wu
authors.forename: Xiaoman
authors.initials: X
authors.lastname: Li
authors.forename: Jie
authors.initials: J
authors.lastname: Ma
mesh_terms: D001555:Benzene Derivatives / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon; D017680:Potassium Compounds / Q000737:chemistry*; D013816:Thermodynamics; D014050:Toluene / Q000737:chemistry*; D014992:Xylenes / Q000737:chemistry*
chemical_list: D001555:Benzene Derivatives; D006878:Hydroxides; D037742:Nanotubes, Carbon; D017680:Potassium Compounds; D014992:Xylenes; D014050:Toluene; C004912:ethylbenzene; C031285:3-xylene; C029943:potassium hydroxide