title: Selective adsorption and separation of organic dyes from aqueous solution on polydopamine microspheres.
abstract: Polydopamine (PDA) microspheres, synthesized by a facile oxidation polymerization route, were evaluated as a potential adsorbent for selective adsorption and separation of organic dyes. The adsorption processes towards nine water-soluble dyes (anionic dyes: methyl orange (MO), eosin-Y (EY), eosin-B (EB), acid chrome blue K (ACBK), neutral dye: neutral red (NR), and cationic dyes: rhodamine B (RhB), malachite green (MG), methylene blue (MB), safranine T (ST)) were thoroughly investigated. The adsorption selectivity of organic dyes onto PDA microspheres was successfully applied for the separation of dyes mixtures. Various influential factors such as solution pH, temperature, and contact time were employed to ascertain the optimal condition for adsorption of representative organic dyes including MB, MG and NR. The pseudo-first-order and pseudo-second-order kinetics models were used to fit the adsorption kinetics process. Five isothermal adsorption models (Langmuir, Dubnin-Radushkevich, Temkin, Freundlich and Harkins-Jura) were used to investigate the adsorption thermodynamics properties. The results showed that the PDA microspheres owned good selective adsorption ability towards cationic dyes. The adsorption kinetics process conformed to the pseudo-second-order kinetics model and the Langmuir isotherm model was more appropriate for tracing the adsorption behavior than other isotherm models. Thus, we can conclude PDA microspheres may be a high-efficiency selective adsorbent towards some cationic dyes.
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China. Electronic address: jwfu@zzu.edu.cn.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Fu
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Xin
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China.
authors.forename: Xuechen
authors.initials: X
authors.lastname: Wu
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China.
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Chen
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Yan
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China.
authors.forename: Shujun
authors.initials: S
authors.lastname: Liu
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China.
authors.forename: Minghuan
authors.initials: M
authors.lastname: Wang
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China. Electronic address: qunxu@zzu.edu.cn.
authors.forename: Qun
authors.initials: Q
authors.lastname: Xu
mesh_terms: D000327:Adsorption; D004396:Coloring Agents / Q000737:chemistry* / Q000302:isolation & purification*; D007211:Indoles / Q000737:chemistry*; D008863:Microspheres; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D007211:Indoles; D011108:Polymers; D012996:Solutions; C568283:polydopamine; D014867:Water
keywords: Adsorption; Dyes; Isotherm; Kinetics; Mechanism; Microspheres; Polydopamine; Selective adsorbent