In situ recombination and recovery of photovoltaic waste Si through a mechanochemical strategy for application in Hg0 removal: Effect and mechanism

Xue-Lei Duan; Miao Bian; Xin-Yue Xu; Shu-Ting Zhan; Hui-Yan Zuo; Jiao-Jiao Xie; Ke-Gang Zhang; Chun-Gang Yuan

doi:10.1016/j.jenvman.2025.126339

In situ recombination and recovery of photovoltaic waste Si through a mechanochemical strategy for application in Hg⁰ removal: Effect and mechanism

J Environ Manage. 2025 Jun 27:390:126339. doi: 10.1016/j.jenvman.2025.126339. Online ahead of print.

Authors

Xue-Lei Duan¹, Miao Bian¹, Xin-Yue Xu¹, Shu-Ting Zhan¹, Hui-Yan Zuo¹, Jiao-Jiao Xie¹, Ke-Gang Zhang¹, Chun-Gang Yuan²

Affiliations

¹ Hebei Key Laboratory of New Energy Environmental Safety and Resource Utilization, Department of Environmental Science & Engineering, North China Electric Power University, Baoding, 071000, China.
² Hebei Key Laboratory of New Energy Environmental Safety and Resource Utilization, Department of Environmental Science & Engineering, North China Electric Power University, Baoding, 071000, China; MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China. Electronic address: cgyuan@ncepu.edu.cn.

PMID: 40580856
DOI: 10.1016/j.jenvman.2025.126339

Abstract

The discharge of untreated photovoltaic waste silicon powders (PWSP) causes significant environmental challenge and resource wastage. This work accomplished the recovery and sustainable application of PWSP for Hg⁰ removal through a one-step mechanochemical strategy. It also determined the mechanisms of mechanochemistry in PWSP recovery and Hg⁰ removal. We found all the examined silicon particles, those with a size of ≥140 mesh exhibited the greatest Ag enrichment and good Hg⁰ removal performance due to their sound surface structure and abundant active components. Interestingly, these silicon particles displayed excellent Hg⁰ removal efficiency (98.3 %) and good tolerance to simulated flue gas (SFG + HCl) after ball-milling. Here, we found that ball-milling induced the enhancement of (111) adsorption plane, the appearance of lattice distortion and defects, the improvement of physical-properties as well as the exposure of -OH, O∗ (Oα, Oβ, and Oγ) and Ag∗(Ag-OH and Ag⁺), contributing to the recombination of PWSP and efficient mercury removal. This work disclosed that the de-agglomeration of Ag cluster and an increase in oxygen density induced electron transfer (0.56e) from Ag to Si, triggering the recovery of PWSP. Moreover, iner-diffusion adsorption kinetic (R² = 0.997), high affinity reaction (Ag-Hg), low energy barrier (0.4eV) and electron exchange (0.33e) facilitated mercury immobilization (Hg⁰→HgO) and SFG + HCl tolerance. This work provides a facile, simple and sustainable way to recycling PWSP for Hg⁰ removal, which aligns the principles of sustainable energy development and environmental protection.

Keywords: Mechanochemical activation; Mercury removal; Recovery; Silicon waste.