Photoelectrocatalytic modification of nanofiltration membranes with SrF2/Ti3C2Tx to simultaneously enhance heavy metal ions rejection and permeability

Huiqi Zheng; Xiaorong Meng; Jiao Wu; Danghao Liu; Shanshan Huo

doi:10.1016/j.chemosphere.2023.140152

Photoelectrocatalytic modification of nanofiltration membranes with SrF₂/Ti₃C₂T_x to simultaneously enhance heavy metal ions rejection and permeability

Chemosphere. 2023 Nov:342:140152. doi: 10.1016/j.chemosphere.2023.140152. Epub 2023 Sep 13.

Authors

Huiqi Zheng¹, Xiaorong Meng², Jiao Wu³, Danghao Liu⁴, Shanshan Huo⁵

Affiliations

¹ School of Chemistry and Chemical Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
² School of Chemistry and Chemical Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Laboratory of Membrane Separation of Shaanxi Province, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: mxr5@163.com.
³ School of Chemistry and Chemical Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
⁴ School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
⁵ Research Institute of Membrane Separation Technology of Shaanxi Province Co., Ltd, Xi'an 710055, China.

PMID: 37714470
DOI: 10.1016/j.chemosphere.2023.140152

Abstract

Heavy metal pollution can significantly harm water systems and human health. Combining photoelectrocatalytic (PEC) and nanofiltration (NF) membrane separation technologies can effectively remove heavy metal ions from wastewater. In this study, a water bath method was used to form SrF₂/Ti₃C₂T_x (ST) nanoparticles on the surface of polyvinylidene fluoride (PVDF) membranes and an additional polyamide (PA) functional layer was formed at the interface by crosslinking. ST@PA composite NF membranes (STPP) with good photocatalytic performance were obtained. The separation and catalytic properties of the STPP membranes were controlled by the ST content, which modifies the surface structure and properties of the membranes. The membrane with optimal ST crosslinking exhibited a water contact angle of 50.8°, pure water flux of 24.6 L·m^-2·h^-1·bar^-1, and rejection rates of Mn²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ of 98.8%, 95.3%, 95.7%, and 97.3%, respectively, under PEC-assisted separation with visible light illumination from a Xe lamp (300 W) and an applied voltage (2 V). The STPP membranes showed improved rejection rates of heavy metal ions under PEC-assisted operation. The mechanism for the improved membrane performance under PEC conditions was preliminarily clarified considering the relationship between the photocatalytic and filtration properties of STPP membranes along with the influence of light irradiation and an external voltage on the heavy metal ions. The generation of electrons, holes, superoxide radicals, and hydroxyl radicals during membrane operation enhances the rejection rates of heavy metal ions. Based on these results, STPP membranes are considered a promising technology for industrial applications in heavy metal removal.

Keywords: Filtration separation; Heavy metal ions; Nanofiltration membranes; Photoelectrocatalysis; SrF(2)/Ti(3)C(2)T(x).

MeSH terms

Humans
Ions
Membranes, Artificial
Metals, Heavy* / chemistry
Permeability
Titanium
Water
Water Purification* / methods

Substances

Titanium
Metals, Heavy
Ions
Water
Membranes, Artificial