Eco-friendly recovery of ZnO from alkaline batteries for photocatalytic water treatment

Huynh Chi Hieu; Van Thuan Le; Vy Anh Tran

doi:10.15625/2525-2518/23401

Author affiliations

Authors

Huynh Chi Hieu \(^1\) Institute of Applied Technology and Sustainable Development, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh Street, Xom Chieu Ward, Ho Chi Minh City, Viet Nam https://orcid.org/0009-0006-6851-8772
Van Thuan Le \(^2\) Center for Advanced Chemistry, Institute of Research and Development, Duy Tan University, 03 Quang Trung Street, Hai Chau Ward, Danang City, Viet Nam
Vy Anh Tran \(^3\) Faculty of Applied Science and Technology, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh Street, Xom Chieu Ward, Ho Chi Minh City, Viet Nam https://orcid.org/0000-0001-5533-8381

DOI:

https://doi.org/10.15625/2525-2518/23401

Keywords:

spent alkaline battery recycling, ZnO nanomaterials, photocatalysis, waste valorization, environmental remediation

Abstract

One viable solution to the present material shortages is the transformation of old electronics. Through eco-friendly and facile methods, our work demonstrates that old alkaline batteries can be transformed into effective zinc oxide materials. This method promotes a regenerative economic model that can satisfy the rising demand for high-tech materials while simultaneously reducing the negative effects of waste management. Even though reaction durations gradually increased due to surface fouling, ZnO-C₃N₄ demonstrated excellent long-term durability across four successive photocatalytic cycles. It was able to successfully remove over 99.3 % of methylene blue (MB) and over 99 % of crystal violet (CV). This was accomplished despite the fact that surface fouling caused the reaction times to gradually increase. The pH levels had a significant impact on the function of the catalyst, with degrading efficiency increasing from acidic to alkaline conditions. The catalyst reached its greatest effectiveness between pH 9 and 11, when it was able to remove nearly all of both dyes (99.47 to 99.81 % for MB and 99.21 to 99.6 % for CV). These findings underscore the strong reusability and pH adaptability of ZnO-C₃N₄. This study reveals that ZnO-C₃N₄ is a promising application for water remediation, especially dye waste.

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