Selective transformation and removal of As(III) by constructed Fe-N bonds: The generation of singlet oxygen from the photoexcitation of MnPc leads to abundant ZnFe-LDH interface OH radical

Huidi Zhang; Yao Deng; Junhui Yang; Jinglin Yin; Jing Wang; Hongbo Xiao; Lizhi Wang; Cuihong Zhang; Wenlei Wang

doi:10.1016/j.scitotenv.2023.164314

Selective transformation and removal of As(III) by constructed Fe-N bonds: The generation of singlet oxygen from the photoexcitation of MnPc leads to abundant ZnFe-LDH interface OH radical

Sci Total Environ. 2023 Sep 10:890:164314. doi: 10.1016/j.scitotenv.2023.164314. Epub 2023 May 23.

Authors

Huidi Zhang¹, Yao Deng², Junhui Yang¹, Jinglin Yin², Jing Wang¹, Hongbo Xiao³, Lizhi Wang³, Cuihong Zhang⁴, Wenlei Wang⁵

Affiliations

¹ College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
² College of Science, Central South University of Forestry and Technology, Changsha 410004, China.
³ College of Science, Central South University of Forestry and Technology, Changsha 410004, China; Institute of Chemical Disposal and Resource Utilization of Hazardous Wastes, Central South University of Forestry and Technology, Changsha 410004, China.
⁴ Institute of Chemical Disposal and Resource Utilization of Hazardous Wastes, Central South University of Forestry and Technology, Changsha 410004, China.
⁵ College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China; College of Science, Central South University of Forestry and Technology, Changsha 410004, China; Institute of Chemical Disposal and Resource Utilization of Hazardous Wastes, Central South University of Forestry and Technology, Changsha 410004, China. Electronic address: wenlei_wang@hotmail.com.

PMID: 37230356
DOI: 10.1016/j.scitotenv.2023.164314

Abstract

In this study, MnPc intercalated Zn/Fe layered double hydroxides (MnPc/ZF-LDH) were synthesized by pillared intercalation modification with different MnPc intercalation amounts and used for the selective transformation and removal of As(III) from the arsenate-phosphate mixed solution. Fe-N bonds were constructed by the complexation of MnPc and iron ions on the Zn/Fe layered double hydroxides (ZF-LDH) interface. The DFT calculation results show that the binding energy of Fe-N bonded to arsenite (-3.75 eV) was higher than that of phosphate (-3.16 eV), resulting in MnPc/ZnFe-LDH exhibiting high As(III) selective adsorption performance and anchoring it rapidly in the arsenite -phosphate mixed solution. The maximum adsorption capacity of 1MnPc/ZF-LDH for As(III) could reach 180.7 mg·g^-1 under dark conditions. MnPc also acts as a photosensitizer to provide more active species for the photocatalytic reaction. A series of experiments demonstrated that MnPc/ZF-LDH exhibits high As(III) selective photocatalytic performance. A total of 10 mg·L^-1 of As(III) was completely removed in the reaction system within 50 min in a single As(III) environment. In an environment with As(III) and PO₄^3-, it achieved 80.0 % removal efficiency of As(III) and showed a good reuse effect. The introduction of MnPc could improve the utilization of visible light by the MnPc/ZnFe-LDH. The singlet oxygen generated from photoexciting MnPc leads to abundant ZnFe-LDH interface OH. In addition, MnPc/ZnFe-LDH shows good recyclability, making it a promising multifunctional material for the purification of arsenic-polluted sewage.

Keywords: Fe−N bonds; Interface OH; MnPc/ZnFe−LDH; Selective transformation; Singlet oxygen.

MeSH terms

Adsorption
Arsenic* / chemistry
Arsenites*
Hydroxides / chemistry
Iron / chemistry
Singlet Oxygen
Water Pollutants, Chemical* / chemistry

Substances

Singlet Oxygen
Arsenites
Hydroxides
Iron
Arsenic
Water Pollutants, Chemical