title: [Adsorption of Cd2+ on biochar from aqueous solution].
abstract: Biomass-based materials such as biochar have a good performance in heavy metal adsorption. The adsorption of Cd2+ on biochar converted from cotton straw was studied. Adsorption isotherm, kinetics and effect factors such as temperature, pH and ionic strength were investigated. The adsorption of Cd2+ on biochar can be fitted by the Freundlich isotherm better than the Langmuir isotherm. The maximum adsorption amounts of Cd2+ at different temperatures were 9.738 mg x g(-1) (288.15 K), 10.14 mg x g(-1) (298.15 K), 10.40 mg x g(-1) (308.15 K) and 10.71 mg x g(-1) (318.15 K), respectively. The free energies AG(theta) were from -8.346 kJ x mol(-1) to -10.276 kJ x mol(-1) at different temperatures, indicating that the adsorption of Cd2+ onto biochar is spontaneous and is an endothermic process. The adsorption process can reach equilibrium within 40 minutes and can be fitted by the pseudo second order kinetic model. pH showed a significant effect on the adsorption of Cd2+ on biochar in the range of 2-8. The adsorption amount of Cd2+ on biochar shows a reducing trend with the increasing ionic strength.
authors.affiliation: Key Laboratory of Original Environmental Quality of Ministry of Agriculture/Tianjin Key Laboratory of Agro-Environment & Safe-Product, Agro-Environmental Protection Institute,Ministry of Agriculture, Tianjin 300191, China. guo_wenjuan_ok@126.com
authors.forename: Wen-juan
authors.initials: WJ
authors.lastname: Guo
authors.forename: Xue-feng
authors.initials: XF
authors.lastname: Liang
authors.forename: Da-song
authors.initials: DS
authors.lastname: Lin
authors.forename: Ying-ming
authors.initials: YM
authors.lastname: Xu
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Yue-bing
authors.initials: YB
authors.lastname: Sun
authors.forename: Xu
authors.initials: X
authors.lastname: Qin
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D007700:Kinetics; D013696:Temperature
chemical_list: C540010:biochar; D002104:Cadmium; D002606:Charcoal