title: Using a novel adsorbent macrocyclic compound cucurbit[8]uril for Pb2+removal from aqueous solution.
abstract: In this study, cucurbit[8]uril (CB[8]) was utilized as a kind of new adsorbent to remove Pb2+ions from aqueous solution. With the solution pH increased from 2 to 6, the removal efficiency of adsorption increased from 55.6% to 74.5%correspondingly. The uptake of Pb2+increased rapidly in the initial 30min, and then the adsorption rate became slower. The Pseudo-second order model could be used to interpret the adsorption kinetics satisfactorily; and the rate determining step in Pb2+adsorption onto CB[8] was the external mass transfer step. Equilibrium isotherm study reveals that the Langmuir model gave a better fitting result than Freundlich model. The maximum adsorption capacity calculated by the Langmuir model was 152.67mg/g for 298K, 149.70mg/g for 313K and 136.42mg/g for 323K, respectively. The adsorption is a spontaneous process of exothermic nature. The effect of the adsorbent dosage and the influences of solution pH and co-existing cations were also investigated. The CB[8] was synthesized and characterized by1H NMR, IR, ESI-MS spectra, SEM-EDAX, Zeta-potential and BET-analysis. The adsorption mechanism was due to the coordination between CB[8] molecule and Pb2+ions.
authors.affiliation: School of Chemical and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, China. Electronic address: sunxuzhuo@126.com.
authors.forename: Xuzhuo
authors.initials: X
authors.lastname: Sun
authors.affiliation: School of Chemical and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: School of Chemical and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, China. Electronic address: dongjinwan@yeah.net.
authors.forename: Dongjin
authors.initials: D
authors.lastname: Wan
authors.affiliation: School of Chemical and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D007700:Kinetics; D007854:Lead / Q000032:analysis / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008956:Models, Chemical; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D000099246:Cucurbit(n)urils
chemical_list: D007854:Lead; D047028:Macrocyclic Compounds; D014874:Water Pollutants, Chemical; D000099246:Cucurbit(n)urils
keywords: Adsorption; Cucurbit[8]uril; Equilibrium; Kinetics; Pb(2+)