Dual-stage treatment of waste printed circuit boards for Cu2+, Pb2+, and Zn2+ recovery: A precipitation-adsorption hybrid process
Abstract
Sustainable treatment of metal-rich effluents generated during printed circuit board (PCB) recycling is complicated by their high metal concentrations and strong competition in multicomponent systems. This study develops and evaluates a dual-stage precipitation-adsorption hybrid process for selective recovery of Cu2+, Pb2+, and Zn2+ from nitric-acid PCB leachates. In the first stage, sulfide precipitation using Na2S achieved near-quantitative Cu2+ recovery (97.71 ± 0.40%) at an optimized Cu/S molar ratio of 1:1.8, while Pb2+ and Zn2+ largely remained in solution. Structural analyses (SEM-EDX, XRD, XRF) confirmed the formation of high-purity crystalline CuS with minimal co-precipitation of other metals. In the second stage, residual metals were captured via adsorption onto an olive stone-derived KOH-activated carbon (OSACK). Single-metal adsorption experiments at different concentrations revealed a clear affinity order of Pb2+ > Cu2+ > Zn2+, exhibiting the highest uptake capacities of 159.58 ± 3.12, 64.41 ± 5.24, and 28.09 ± 4.56 mg g−1, respectively, obtained at 3.4 g L−1 adsorbent dosage and initial concentrations of 1300 mg L−1 (Pb2+), 1200 mg L−1 (Cu2+), and 800 mg L−1 (Zn2+). Binary-metal systems (Cu2+-Pb2+, Cu2+-Zn2+, Pb2+-Zn2+) demonstrated pronounced competitive effects, significantly suppressing Cu2+ and Zn2+ adsorption in the presence of Pb2+, while Pb2+ retention remained largely unaffected. Adsorption followed Freundlich isotherms and Elovich kinetics, indicating heterogeneous, predominantly chemisorptive interactions. Regeneration studies showed stable carbon performance over multiple adsorption-desorption cycles. Validation with real PCB leachates highlighted the robustness and scalability of the proposed hybrid process for integrated metal recovery and effluent treatment.
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BibTeX
@article{rahimi2026dualstage,
title = {{Dual-stage treatment of waste printed circuit boards for Cu2+, Pb2+, and Zn2+ recovery: A precipitation-adsorption hybrid process}},
author = {Vahid Rahimi and Aicha Samet and Catarina Helena Pimentel and Diego Gomez-Diaz and M. Sonia Freire and Massimo Lazzari and Julia Gonzalez-Alvarez},
journal = {Separation and Purification Technology},
year = {2026},
month = aug,
doi = {10.1016/j.seppur.2026.139797},
url = {https://hal.science/hal-05741443v1},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Dual-stage treatment of waste printed circuit boards for Cu2+, Pb2+, and Zn2+ recovery: A precipitation-adsorption hybrid process
AU - Vahid Rahimi
AU - Aicha Samet
AU - Catarina Helena Pimentel
AU - Diego Gomez-Diaz
AU - M. Sonia Freire
AU - Massimo Lazzari
AU - Julia Gonzalez-Alvarez
PY - 2026
DA - 2026/08/18
JO - Separation and Purification Technology
DO - 10.1016/j.seppur.2026.139797
UR - https://hal.science/hal-05741443v1
AB - Sustainable treatment of metal-rich effluents generated during printed circuit board (PCB) recycling is complicated by their high metal concentrations and strong competition in multicomponent systems. This study develops and evaluates a dual-stage precipitation-adsorption hybrid process for selective recovery of Cu2+, Pb2+, and Zn2+ from nitric-acid PCB leachates. In the first stage, sulfide precipitation using Na2S achieved near-quantitative Cu2+ recovery (97.71 ± 0.40%) at an optimized Cu/S molar ratio of 1:1.8, while Pb2+ and Zn2+ largely remained in solution. Structural analyses (SEM-EDX, XRD, XRF) confirmed the formation of high-purity crystalline CuS with minimal co-precipitation of other metals. In the second stage, residual metals were captured via adsorption onto an olive stone-derived KOH-activated carbon (OSACK). Single-metal adsorption experiments at different concentrations revealed a clear affinity order of Pb2+ > Cu2+ > Zn2+, exhibiting the highest uptake capacities of 159.58 ± 3.12, 64.41 ± 5.24, and 28.09 ± 4.56 mg g−1, respectively, obtained at 3.4 g L−1 adsorbent dosage and initial concentrations of 1300 mg L−1 (Pb2+), 1200 mg L−1 (Cu2+), and 800 mg L−1 (Zn2+). Binary-metal systems (Cu2+-Pb2+, Cu2+-Zn2+, Pb2+-Zn2+) demonstrated pronounced competitive effects, significantly suppressing Cu2+ and Zn2+ adsorption in the presence of Pb2+, while Pb2+ retention remained largely unaffected. Adsorption followed Freundlich isotherms and Elovich kinetics, indicating heterogeneous, predominantly chemisorptive interactions. Regeneration studies showed stable carbon performance over multiple adsorption-desorption cycles. Validation with real PCB leachates highlighted the robustness and scalability of the proposed hybrid process for integrated metal recovery and effluent treatment.
SN - 1383-5866
ER -