C3N4/SNF nanofluidic membrane for coupled salinity gradient power generation and Cu(II) reduction
Zhang, Zhen ; Wu, Bing ; Lipnizki, Frank LU
; Wang, Chi
; Geng, Zhi
and Sun, Meng
(2026)
In Separation and Purification Technology
414.
- Abstract
Wastewater has been recognized as a source of valuable energy and water resources, and high-salinity wastewater in particular provides an opportunity to harness salinity gradient energy. In this study, cation-selective graphitic carbon nitride/silk nanofiber (C3N4/SNF) nanofluidic membranes with different SNF amounts were fabricated and characterized. The C3N4/SNF membrane (with 10 wt% SNF) displayed the highest power density of 3.29 W m−2 under 0.5 M/0.01 M NaCl gradient, exceeding those of the other fabricated membranes. The salinity-gradient-driven ion transport was governed by the combined effects of concentration driving force and negatively charged nanochannels, where electric... (More)
Wastewater has been recognized as a source of valuable energy and water resources, and high-salinity wastewater in particular provides an opportunity to harness salinity gradient energy. In this study, cation-selective graphitic carbon nitride/silk nanofiber (C3N4/SNF) nanofluidic membranes with different SNF amounts were fabricated and characterized. The C3N4/SNF membrane (with 10 wt% SNF) displayed the highest power density of 3.29 W m−2 under 0.5 M/0.01 M NaCl gradient, exceeding those of the other fabricated membranes. The salinity-gradient-driven ion transport was governed by the combined effects of concentration driving force and negatively charged nanochannels, where electric double layer overlap promoted preferential cation transport. Further simulations revealed that confined sub-nanometer channels promoted cation enrichment and supported efficient ion-selective transport. With synthetic high-salinity wastewater and Cu(II)-containing wastewater, the membrane delivered a power density of 2.95 W m−2 and achieved a Cu(II) reduction rate of 0.012 mol m−2 h−1. Cu(II) reduction remained effective under weakly acidic conditions and was further enhanced at higher salinity gradients, supporting the feasibility of salinity-gradient-driven heavy metal recovery in complex aqueous environments. Overall, this study demonstrated the feasibility of employing high-salinity wastewater as a driving energy source to produce energy for metal resource recovery, offering a low-energy route for simultaneous wastewater treatment and resource utilization.
(Less)
- author
- Zhang, Zhen
; Wu, Bing
; Lipnizki, Frank
LU
; Wang, Chi
; Geng, Zhi
and Sun, Meng
- organization
- publishing date
- 2026-11-16
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- High-salinity wastewater, Ion-selective transport, Metal recovery, Nanofluidic membrane, Salinity-gradient-driven
- in
- Separation and Purification Technology
- volume
- 414
- article number
- 139725
- pages
- 10 pages
- publisher
- Elsevier
- external identifiers
-
- scopus:105047322711
- ISSN
- 1383-5866
- DOI
- 10.1016/j.seppur.2026.139725
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2026 Elsevier B.V.
- id
- f0f19dcf-826e-4491-8f90-f63a9a2e48e2
- date added to LUP
- 2026-08-27 09:08:36
- date last changed
- 2026-09-10 09:59:24
@article{f0f19dcf-826e-4491-8f90-f63a9a2e48e2,
abstract = {{<p>Wastewater has been recognized as a source of valuable energy and water resources, and high-salinity wastewater in particular provides an opportunity to harness salinity gradient energy. In this study, cation-selective graphitic carbon nitride/silk nanofiber (C<sub>3</sub>N<sub>4</sub>/SNF) nanofluidic membranes with different SNF amounts were fabricated and characterized. The C<sub>3</sub>N<sub>4</sub>/SNF membrane (with 10 wt% SNF) displayed the highest power density of 3.29 W m<sup>−2</sup> under 0.5 M/0.01 M NaCl gradient, exceeding those of the other fabricated membranes. The salinity-gradient-driven ion transport was governed by the combined effects of concentration driving force and negatively charged nanochannels, where electric double layer overlap promoted preferential cation transport. Further simulations revealed that confined sub-nanometer channels promoted cation enrichment and supported efficient ion-selective transport. With synthetic high-salinity wastewater and Cu(II)-containing wastewater, the membrane delivered a power density of 2.95 W m<sup>−2</sup> and achieved a Cu(II) reduction rate of 0.012 mol m<sup>−2</sup> h<sup>−1</sup>. Cu(II) reduction remained effective under weakly acidic conditions and was further enhanced at higher salinity gradients, supporting the feasibility of salinity-gradient-driven heavy metal recovery in complex aqueous environments. Overall, this study demonstrated the feasibility of employing high-salinity wastewater as a driving energy source to produce energy for metal resource recovery, offering a low-energy route for simultaneous wastewater treatment and resource utilization.</p>}},
author = {{Zhang, Zhen and Wu, Bing and Lipnizki, Frank and Wang, Chi and Geng, Zhi and Sun, Meng}},
issn = {{1383-5866}},
keywords = {{High-salinity wastewater; Ion-selective transport; Metal recovery; Nanofluidic membrane; Salinity-gradient-driven}},
language = {{eng}},
month = {{11}},
publisher = {{Elsevier}},
series = {{Separation and Purification Technology}},
title = {{C<sub>3</sub>N<sub>4</sub>/SNF nanofluidic membrane for coupled salinity gradient power generation and Cu(II) reduction}},
url = {{http://dx.doi.org/10.1016/j.seppur.2026.139725}},
doi = {{10.1016/j.seppur.2026.139725}},
volume = {{414}},
year = {{2026}},
}