University of Oulu

Kimbi Yaah, V. B., Ojala, S., Khallok, H., Laitinen, T., Selent, M., Zhao, H., … de Oliveira, S. B. (2021). Development and Characterization of Composite Carbon Adsorbents with Photocatalytic Regeneration Ability: Application to Diclofenac Removal from Water. Catalysts, 11(2), 173. doi:10.3390/catal11020173

Development and characterization of composite carbon adsorbents with photocatalytic regeneration ability : application to diclofenac removal from water

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Author: Kimbi Yaah, Velma Beri1; Ojala, Satu1; Khallok, Hamza1;
Organizations: 1Environmental and Chemical Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Linnanmaa, Finland
2Centre for Material Analysis, University of Oulu, P.O. Box 8000, FI-90014 Oulu, Finland
3Optoelectronics and Measurement Techniques Laboratory, Faculty of Information Technology and Electrical Engineering, University of Oulu, P.O. Box 4500, FI-90014 Oulu, Finland
4Federal Institute of Goiás, Department of Academic Areas II, 74055-110 Goiânia, Brazil
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.2 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2021
Publish Date: 2021-01-28


This paper presents results related to the development of a carbon composite intended for water purification. The aim was to develop an adsorbent that could be regenerated using light leading to complete degradation of pollutants and avoiding the secondary pollution caused by regeneration. The composites were prepared by hydrothermal carbonization of palm kernel shells, TiO₂, and W followed by activation at 400 °C under N₂ flow. To evaluate the regeneration using light, photocatalytic experiments were carried out under UV-A, UV-B, and visible lights. The materials were thoroughly characterized, and their performance was evaluated for diclofenac removal. A maximum of 74% removal was observed with the composite containing TiO₂, carbon, and W (HCP25W) under UV-B irradiation and non-adjusted pH (~5). Almost similar results were observed for the material that did not contain tungsten. The best results using visible light were achieved with HCP25W providing 24% removal of diclofenac, demonstrating the effect of W in the composite. Both the composites had significant amounts of oxygen-containing functional groups. The specific surface area of HCP25W was about 3 m²g⁻¹, while for HCP25, it was 160 m²g⁻¹. Increasing the specific surface area using a higher activation temperature (600 °C) adversely affected diclofenac removal due to the loss of the surface functional groups. Regeneration of the composite under UV-B light led to a complete recovery of the adsorption capacity. These results show that TiO₂- and W-containing carbon composites are interesting materials for water treatment and they could be regenerated using photocatalysis.

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Series: Catalysts
ISSN: 2073-4344
ISSN-E: 2073-4344
ISSN-L: 2073-4344
Volume: 11
Issue: 2
Article number: 173
DOI: 10.3390/catal11020173
Type of Publication: A1 Journal article – refereed
Field of Science: 218 Environmental engineering
Funding: This work was funded by the I4Future doctoral program, which has received funding from the EU H2020 under the Marie Sklodowska Curie grant agreement No. 713606, and Academy of Finland via the ELECTRA project.
EU Grant Number: (713606) I4FUTURE - Novel Imaging and Characterisation Methods in Bio, Medical, and Environmental Research and Technology Innovations
Dataset Reference: Supplementary material:
Copyright information: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CCBY) license (