Visible light responsive heterostructure HTDMA-BiPO4 modified clays for effective diclofenac sodium oxidation: Role of interface interactions and basal spacing

• Published in: Journal of water process engineering Vol. 48; p. 102788
• Main Authors: Fellah, Imen, Djellabi, Ridha, Amor, Hédi Ben, Abderrahim, Nesrine, Bianchi, Claudia L., Giordana, Alessia, Cerrato, Giuseppina, Di Michele, Alessandro, Hamdi, Noureddine
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2022
• Subjects: Adsorption; HDTMA-BiPO4; Heterostructures; Interfacial interaction; Solar photocatalysis; Water remediation; Solar photocatalysis; HDTMA-BiPO4; Water remediation; Adsorption; Interfacial interaction; Heterostructures
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2022.102788

In the present study, we investigated comparatively the role of hexadecyltrimethylammonium bromide (HDTMA) in enhancing the adsorption and photocatalytic activity of BiPO4 coated montmorillonite (M-BiPO4), and BiPO4 coated smectite (S-BiPO4). Montmorillonite has large interlayer spacing compared to smectite. Firstly, it was found that the simple hybridization of BiPO4 with clays led to enhance the visible light response. The co-fixation of BiPO4 and HDTMA on clay supports reduces the BET specific surface area, but it enhances significantly the adsorption ability. XPS analysis shows a notable Bi4f high resolution peak shifting in the case of HDTMA-S-BiPO4, while such a shifting was not observed in terms of HDTMA-M-BiPO4. Regarding the adsorption and photocatalytic tests, at lower concentration of diclofenac (20 ppm), M-BiPO4 was several times more effective than S-BiPO4. However, the coating of clays by BiPO4 and HDTMA showed a different manner, wherein HDTMA-S-BiPO4 achieved an oxidation rate of around 88% under solar light within 90 min at a concentration of 140 ppm of diclofenac. On the contrary, HDTMA-M-BiPO4 shows an oxidation rate of only 22% under the same conditions. It was deduced that the strong surface interactions between HDTMA and BiPO4 coated on smectite can form a strong interfacial bridge which boosts the visible light response and the separation of photogenerated charges. [Display omitted] •Montmorillonite and smectite were coated with BiPO4 and HTDMA.•The hybridization of BiPO4 with clays enhances the photoactivity under sunlight.•HTDMA has a significant role in enhancing the adsorption and photooxidation rates.•The interface interactions between BiPO4 and HTDMA are important factors.•Coating of BiPO4/HTDMA on clay with smaller basal spacing was more beneficial.