title: Porous CS monoliths and their adsorption ability for heavy metal ions.
abstract: Highly porous chitosan (CS) monoliths were prepared by a unidirectional freeze-drying method and the adsorption performance of the monoliths for metal ions in aqueous solution was evaluated. The porous CS monoliths have excellent adsorption for a range of metal ions. The effect of the amount of porous CS monoliths, the pH, the adsorption time, the amount of the cross-linking agent, and the amount of disodium ethylenediamine tetraacetate (EDTA) on the saturated adsorption efficiency (Ade) were determined. The pH had the greatest influence on the adsorption behavior. Under optimal conditions (C(CU²⁺) = 800 mg/L, pH 6, and cross-linking agent = 0.15%) for the CS monoliths, the Ade for Cu(2+) exceeded 99%, and the saturated adsorption capacity (Q(s)) reached a value of 141.8 mg/g (2.23 mmol/g) in 4h. Moreover, the addition of EDTA can both increase the Q(s) and shorten the time that achieved the level. If EDTA was added, this level was achieved in 2h. The porous CS monoliths can be regenerated by soaking them in acid and their Ade is maintained.
authors.affiliation: School of Science, Tianjin University, Tianjin 300072, PR China.
authors.forename: Fangqiang
authors.initials: F
authors.lastname: Xu
authors.forename: Nana
authors.initials: N
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Long
authors.forename: Youmiao
authors.initials: Y
authors.lastname: Si
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Xue
authors.initials: X
authors.lastname: Mi
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Wang
authors.forename: Fubao
authors.initials: F
authors.lastname: Xing
authors.forename: Xiudong
authors.initials: X
authors.lastname: You
authors.forename: Jianping
authors.initials: J
authors.lastname: Gao
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019216:Metals, Heavy / Q000302:isolation & purification*; D016062:Porosity; D014874:Water Pollutants, Chemical / Q000302:isolation & purification
chemical_list: D003432:Cross-Linking Reagents; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D048271:Chitosan