Design of cryogel based CNTs-anchored polyacrylonitrile honeycomb film with ultra-high S-NZVI incorporation for enhanced synergistic reduction of Cr(VI)

Kaini Yang; Xiangyu Wang; Iseult Lynch; Zhiling Guo; Peng Zhang; Lisi Wu; Jun Ma

doi:10.1016/j.jhazmat.2022.129923

Design of cryogel based CNTs-anchored polyacrylonitrile honeycomb film with ultra-high S-NZVI incorporation for enhanced synergistic reduction of Cr(VI)

J Hazard Mater. 2023 Jan 15:442:129923. doi: 10.1016/j.jhazmat.2022.129923. Epub 2022 Sep 7.

Authors

Kaini Yang¹, Xiangyu Wang², Iseult Lynch³, Zhiling Guo³, Peng Zhang³, Lisi Wu³, Jun Ma⁴

Affiliations

¹ Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
² Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China; School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK. Electronic address: imusthlee2014@sina.com.
³ School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
⁴ State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.

PMID: 36206708
DOI: 10.1016/j.jhazmat.2022.129923

Abstract

An ultra-high NZVI-loaded PAN film (S-CPN) with a unique 3D honeycomb structure was designed based on the cryogel method of green solvent-induced pores and confinement of the spatially free conformation of films by anchoring carbon nanotubes (CNTs), supplemented sulfidation for removing hexavalent chromium (Cr(VI)), and characterized by SEM, AFM, BET, XRD, XPS, and electrochemical corrosion. The doping amounts of the compounds for S-CPN synthesis were optimized to be 0.075 g CNTs, 0.25 g Na₂S, and 0.3 M FeSO₄. S-CPN possessed a 175.247 m²/g specific surface area, -0.365 V reduction potential, and 46.54 mg/g ultra-high NZVI-loading. S-CPN had the strong activity of Cr(VI) removal and tolerance to coexisting ions. The removal efficiency remained at 80 % after age for 30 days or 5 cycles. The pseudo-first-order kinetics and Langmuir model were more favorable to simulate the adsorption of Cr(VI) on S-CPN. The thermodynamics show that S-CPN removing Cr(VI) was a spontaneous exothermic reaction. The reasons for these excellent properties were that CNTs improve the film porosity and ultra-high NZVI-loading, and synergistic the FeS_X layer to chelates-reduces Cr(VI). This was the first time that honeycomb film with 3D structure and potential applications in heavy metal removal was developed via an eco-friendly strategy.

Keywords: Anchoring carbon nanotubes; Honeycomb PAN film; Nanoscale zero-valent iron; Polyacrylonitrile cryogel; Sulfidation.