Open Access

ARTICLE

Polydopamine-Coated Waste Cardboard Roll Evaporator for High-Performance Solar Desalination

Zheng Li^1,2, Xiaohan Li², Qiang Yin^3,*, Jingkun Xu^1,*
1 School of Water Resources & Environmental Engineering, East China University of Technology, Nanchang, China
2 Jiangxi Provincial Key Laboratory of Flexible Electronics, Flexible Electronics Innovation Institute, Jiangxi Science & Technology Normal University, Nanchang, China
3 School of Chemistry and Materials Science, East China University of Technology, Nanchang, China
* Corresponding Author: Qiang Yin. Email: ; Jingkun Xu. Email:

Journal of Polymer Materials https://doi.org/10.32604/jpm.2026.087145

Received 11 June 2026; Accepted 02 September 2026; Published online 08 September 2026

Abstract

Global freshwater scarcity has stimulated increasing interest in solar-driven interfacial evaporation for decentralized water purification. However, the development of low-cost evaporators that simultaneously achieve efficient photothermal conversion, continuous water supply, and functional separation of light harvesting and water transport remains a major challenge. Herein, we report a waste-cardboard-derived Janus cylindrical evaporator that integrates spatially separated photothermal conversion and water transport functions through a simple edge-immersion polydopamine (PDA) coating strategy followed by a rolling process. The PDA-coated upper region serves as a broad-band light absorber with a solar absorption exceeding 95% across 250–2500 nm and exhibits hydrophilicity, while the uncoated lower region retains the natural capillary network of cellulose fibers for continuous water supply. Under one-sun illumination, the evaporator delivers an evaporation rate of 2.07 kg m⁻² h⁻¹ with a photothermal conversion efficiency of 88.1%. In practical tests, it achieves over 99.9% rejection of primary ions (Na⁺, Mg²⁺, K⁺, Ca²⁺) and removes organic dyes with efficiencies exceeding 99%. This work presents a sustainable “waste-to-clean-water” strategy that valorizes discarded cardboard, offering a promising pathway toward decentralized and low-cost solar water purification.

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Keywords

Solar interfacial evaporation; waste cardboard; polydopamine; Janus evaporator; sea-water desalination

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