Engineered TiO2 polymorphs with superior photocatalytic activity for silver recovery from industrial cyanide-based plating effluent
Issued Date
2025-12-20
Resource Type
ISSN
09277757
eISSN
18734359
Scopus ID
2-s2.0-105016649282
Journal Title
Colloids and Surfaces A Physicochemical and Engineering Aspects
Volume
727
Rights Holder(s)
SCOPUS
Bibliographic Citation
Colloids and Surfaces A Physicochemical and Engineering Aspects Vol.727 (2025)
Suggested Citation
Tanaka M., Thoumrungroj A., Sutthiphong T., Longchin P., Hunsom M. Engineered TiO2 polymorphs with superior photocatalytic activity for silver recovery from industrial cyanide-based plating effluent. Colloids and Surfaces A Physicochemical and Engineering Aspects Vol.727 (2025). doi:10.1016/j.colsurfa.2025.138420 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/112345
Title
Engineered TiO2 polymorphs with superior photocatalytic activity for silver recovery from industrial cyanide-based plating effluent
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Abstract
A high-surface-area mesoporous TiO<inf>2</inf> photocatalyst was synthesized through a sequential hydrothermal-calcination process for the photocatalytic recovery of silver from industrial cyanide-based plating effluent. Preliminary results indicated that TiO<inf>2</inf> synthesized at low calcination temperatures (e.g., < 500 °C) exhibited low crystallinity, high BET surface area, an anatase-brookite mixed phase, and high bandgap values. In contrast, TiO<inf>2</inf> synthesized at higher temperatures (650 – 700 °C) showed high crystallinity, low BET surface area, an anatase–rutile mixed phase, and lower bandgap values. Specifically, TiO<inf>2</inf> synthesized at a calcination temperature of 500 °C (HT50) exhibited the highest activity for silver recovery from industrial cyanide-based plating effluent. Approximately 94.13 % of silver ions were recovered within 20 min under UV light irradiation, in the presence of 3.0 vol% ethanol as a hole scavenger and a catalyst loading of 1.5 g/L. This superior performance is likely due to the optimal content of anatase-brookite polymorphs. Besides, HT50 maintained consistent activity over four consecutive uses. The spent TiO<inf>2</inf>, found in the form of Ag/TiO<inf>2</inf>, also exhibited excellent photocatalytic activity for H<inf>2</inf> production under UV light irradiation. The results obtained from this study highlight a strategy for tuning the intrinsic properties of TiO<inf>2</inf> photocatalysts for photocatalytic precious metal recovery, as well as for upcycling metal ions from wastewater by depositing them onto the photocatalyst surface, leading to the formation of a new type of metal-doped photocatalyst that can be further applied in sustainable green energy production.