Highly-efficient and selective adsorption of anionic dyes onto hollow polymer microcapsules having a high surface-density of amino groups: Isotherms, kinetics, thermodynamics and mechanism

Jianwei Fu; Jianhua Zhu; Zhiwei Wang; Yahuan Wang; Shaomin Wang; Ruiqiang Yan; Qun Xu

doi:10.1016/j.jcis.2019.01.131

Highly-efficient and selective adsorption of anionic dyes onto hollow polymer microcapsules having a high surface-density of amino groups: Isotherms, kinetics, thermodynamics and mechanism

J Colloid Interface Sci. 2019 Apr 15:542:123-135. doi: 10.1016/j.jcis.2019.01.131. Epub 2019 Jan 31.

Authors

Jianwei Fu¹, Jianhua Zhu², Zhiwei Wang², Yahuan Wang², Shaomin Wang², Ruiqiang Yan³, Qun Xu⁴

Affiliations

¹ School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China. Electronic address: jwfu@zzu.edu.cn.
² School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China.
³ School of Pharmaceutical and Materials Engineering, Taizhou University, Taizhou 318000, PR China.
⁴ School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, PR China. Electronic address: qunxu@zzu.edu.cn.

PMID: 30735887
DOI: 10.1016/j.jcis.2019.01.131

Abstract

Organic dye pollution in the water environment is a problem of global concern. Adsorption is demonstrated as a promising technology to remove organic dyes from wastewater, in which the development of highly-efficient adsorbents is still the challenging task. Herein, we reported the facile fabrication of polyamine-based cyclophosphazene hybrid (PCP-NH₂) hollow microcapsules with cross-linked structure, generated by one-step precipitation polymerization between hexachlorocyclotriphosphazene and branched polyethyleneimine, and subsequent acetone treatment. Their morphology, composition and structure were confirmed by SEM, TEM, FTIR, TGA, and XPS. The endowment of hollow PCP-NH₂ microcapsules as potential adsorbents were thoroughly evaluated using eight organic dyes with different surface charges. The adsorption action of hollow PCP-NH₂ microcapsules highly depends on the surfaces charges, exhibiting highly-efficient and selective adsorption behavior towards anionic dyes. Especially, The adsorption capacity of the hollow PCP-NH₂ microcapsules towards anionic dyes of EY, ACBK, MO and EB reaches up to 1196.36, 1190.65, 1142.77 and 1040.92 mg/g at 25 °C, respectively. The adsorption kinetics shows a better fit to pseudo second-order kinetic model, compared to pseudo-first-order kinetic and Weber's intraparticle diffusion models. The adsorption equilibrium data followed the Langmuir isotherm well. The adsorption thermodynamic experiments demonstrated that adsorption was a physisorption process with endothermic and spontaneous characteristic.

Keywords: Adsorption; Anionic dyes; Kinetic model; Microcapsule; Polyamine.