Preparation of TiN-WN composite particles for selective adsorption of methylene blue dyes in water

• Published in: Advanced powder technology : the international journal of the Society of Powder Technology, Japan Japan, 2022-02, Vol.33 (2), p.103423, Article 103423
• Main Authors: Chen, Chu-Yueh, Tseng, Wenjea J.
• Format: Article
• Language: English
• Subjects: Composite; Dye adsorption; Photocatalysis; TiN
• ISSN: 0921-8831; 1568-5527
• DOI: 10.1016/j.apt.2021.103423

[Display omitted] •TiN-WN composite particles were prepared by a urea-assisted nitridation route.•The composites show a selective adsorption to methylene blue dyes in water.•The composites show virtually negligible adsorption to methyl orange dye.•The selective adsorption stems partly from the electrostatic interaction.•A moderate photocatalytic MB degradation results by visible light illuminations. This study synthesizes TiN-WN composite nanoparticles with a broad Ti molar ratio, i.e., fTi ranging from 0.18 to 0.94, by a facile urea-assisted nitridation route at 800 °C in flowing nitrogen atmosphere. The particles comprise mainly mixtures of TiN and WN nanocrystallites when fTi ≤ 0.80. The composites show a selective adsorption against methylene blue (MB) dyes in water; to which, the adsorption under dark situations reaches as much as 90% within 90 min duration when using an initial MB concentration of 10−5 M. In comparison, the composites show virtually negligible adsorption to methyl orange dye. This selective adsorption stems partly from the electrostatic interaction since surface of the composite particles bears a negative net charge for the cationic MB molecules. In addition, the composite particles also render a moderate photocatalytic degradation to the MB molecules under visible light illuminations.