Removal and recovery of silver nanoparticles by hierarchical mesoporous calcite: Performance, mechanism, and sustainable application

Wei Yin; Meng Liu; Tian-Lei Zhao; Fei-Jin Qian; Han Li; Qi-Zhi Yao; Sheng-Quan Fu; Gen-Tao Zhou

doi:10.1016/j.envres.2020.109699

Removal and recovery of silver nanoparticles by hierarchical mesoporous calcite: Performance, mechanism, and sustainable application

Environ Res. 2020 Aug:187:109699. doi: 10.1016/j.envres.2020.109699. Epub 2020 May 20.

Authors

Wei Yin¹, Meng Liu¹, Tian-Lei Zhao¹, Fei-Jin Qian¹, Han Li¹, Qi-Zhi Yao², Sheng-Quan Fu³, Gen-Tao Zhou⁴

Affiliations

¹ CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China.
² School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, 230026, China. Electronic address: qzyao@ustc.edu.cn.
³ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, China.
⁴ CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China; CAS Center for Excellence in Comparative Planetology, University of Science and Technology of China, Hefei, 230026, China. Electronic address: gtzhou@ustc.edu.cn.

PMID: 32480024
DOI: 10.1016/j.envres.2020.109699

Abstract

The widespread use of silver nanoparticles (AgNPs) inevitably leads to the environmental release of AgNPs. The released AgNPs can pose ecological risks because of their specific toxicity. However, they can also be used as secondary sources of silver metal. Herein, hierarchical mesoporous calcite (HMC) was prepared and used to remove and recover AgNPs from an aqueous solution. The batch experiments show that the HMC has high removal percentages for polyvinylpyrrolidone- and poly (vinyl alcohol)-coated AgNPs (PVP- and PVA-AgNPs) over a wide pH range of 6-10. The adsorption isotherms indicate that the maximum removal capacities are 55 and 19 mg g^-1 for PVP-AgNPs and PVA-AgNPs, respectively, corresponding to partition coefficients (PCs) of 0.55 and 0.77 mg g^-1 μM^-1. Furthermore, the removal performance is also not impaired by coexisting anions, such as Cl^-, NO₃^-, SO₄^2-, and CO₃^2-. Their removal mechanisms can be ascribed to the electrostatic attraction and chemical adsorption between the HMC and polymer-coated AgNPs. Calcium ions on the HMC surface serve as active sites for coordination with the oxygen-bearing functional groups of AgNP coatings. Moreover, the AgNPs adsorbed onto HMC show high catalytic activity and good reusability for the reduction of the organic pollutant 4-nitrophenol. This work may pave the way not only to remove metal nanopollutants from waters but also to convert them into functional materials.

Keywords: Adsorption; CaCO(3); Catalysis; Nanopollutant; Polymer-coated AgNP.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adsorption
Calcium Carbonate
Metal Nanoparticles*
Polymers
Silver*

Substances

Polymers
Silver
Calcium Carbonate