From waste to catalyst : cobalt-functionalized silica as a photocatalyst for water purification

Zeljković, Saša (author), Šuligoj, Andraž (author), Kosić, Milica (author), Dražić, Goran (author), Ristić, Alenka (author), Zabukovec Logar, Nataša (author), Novak Tušar, Nataša (author)

The repurposing of waste industrial materials for use in environmental remediation is of great interest in terms of the circular economy as well as public health and safety efforts. Herein, an innovative approach is presented to synthesize a cobalt-functionalized waste silica (Co-MS) utilizing a green, solvent-deficient method (SDM), using industrial waste micron-sized silica (MS) as a sustainable support material. The resulting Co-MS composite is evaluated as a photocatalyst for the removal of methylene blue (MB) under natural sunlight, offering an energy-efficient and environmentally friendly treatment method. Comprehensive characterization confirmed the formation of multiple-valence-state cobalt nanoparticles─Co, CoO, and Co$_3$O$_4$ on the waste silica support. The resulting optimal composite includes 9.1 wt % cobalt oxide species and shows a polyoxide nature with finely dispersed cobalt oxide nanoparticles that are less aggregated compared to bulk Co$_3$O$_4$ and show an improved photocatalytic performance under solar light. Incorporation of cobalt oxide species into MS also results in an SBET increase from 43 m$^2$ g$^{–1}$ for bulk Co$_3$O$_4$ to 91 m$^2$ g$^{–1}$ for the Co-MS composite. The selected composite Co-MS thus achieves 87.5% MB removal efficiency within 1 h, demonstrating its potential as a low-cost, sustainable photocatalyst for wastewater treatment applications.

• Language: English
• Keywords: green chemistry, novel photocatalyst, water purification, photocatalysis
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: Str. 43203-43214
• Numbering: Vol. 11, iss. 29
• PID: 20.500.12556/RUL-188120
• UDC: 544.526.5
• ISSN on article: 2470-1343
• DOI: 10.1021/acsomega.6c00378
• COBISS.SI-ID: 286112259
• Publication date in RUL: 18.09.2026

Record is a part of a journal

• Title: ACS omega
• Shortened title: ACS omega
• Publisher: American Chemical Society
• ISSN: 2470-1343
• COBISS.SI-ID: 525873945

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: zelena kemija, nov fotokatalizator, čiščenje vode, fotokataliza