title: Effect of carboxyethylation degree on the adsorption capacity of Cu(II) by N-(2-carboxyethyl)chitosan from squid pens.
abstract: Chitosan was prepared by N-deacetylation of squid pens β-chitin, and N-carboxyethylated chitosan (N-CECS) with different degrees of substitution (DS) were synthesized. DS values of N-CECS derivatives calculated by (1)H nuclear magnetic resonance (NMR) spectroscopy were 0.60, 1.02 and 1.46, respectively. The adsorption capacity of Cu(II) by N-CECS correlated well with the DS and pH ranging from 3.2 to 5.8. The maximum Cu(II) adsorption capacity (qm) of all three N-CECS at pH 5.4 was 207.5mg g(-1), which was 1.4-fold higher than that of chitosan. The adsorption equilibrium process was better described by the Langmuir than Freundlich isotherm model. Adsorption of Cu(II) ion onto N-CECS followed a pseudo-second order mechanism with chemisorption as the rate-limiting step. In a ternary adsorption system, the adsorption capacity of Cu(II) by N-CECS also presented high values, and qm for Cu(II), Cd(II), and Pb(II) were 150.2, 28.8, and 187.9mg g(-1), respectively.
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Huang
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China.
authors.forename: Haihua
authors.initials: H
authors.lastname: Xie
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Ye
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China.
authors.forename: Tian
authors.initials: T
authors.lastname: Xie
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China.
authors.forename: Yuecheng
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China.
authors.forename: Jinyan
authors.initials: J
authors.lastname: Gong
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China.
authors.forename: Chengjun
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China.
authors.forename: Yuanfeng
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China.
authors.forename: Shiwang
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Cui
authors.affiliation: Key Laboratory of Agricultural Products Chemical and Biological Processing Technology of Zhejiang Province, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, PR China. Electronic address: zjhzmjw@163.com.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Mao
authors.affiliation: Department of Biological and Pharmaceutical Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, PR China. Electronic address: meilh@zju.edu.cn.
authors.forename: Lehe
authors.initials: L
authors.lastname: Mei
mesh_terms: D000327:Adsorption; D000818:Animals; D048271:Chitosan / Q000031:analogs & derivatives* / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D049832:Decapodiformes / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
chemical_list: C495631:N-(2-carboxyethyl)chitosan; D003300:Copper; D048271:Chitosan
keywords: Adsorption kinetics; Copper(II) ions; Langmuir isotherm; N-Carboxyethylated chitosan