Enhancing the generation and stabilization of ZnO nanoparticles on modified clay with polyethylenimine to improve the photodegradation of dyes in textile wastewater

Dyes in textile wastewater (TWW) can be removed through costly intensive processes. Among water treatment techniques, photocatalysis can emerge as efficient and cost-effective. Thus, enhancing the efficiency of photocatalyst for dye degradation in actual TWW continues to be a significant challenge. In this study, a new PTC was synthesized using a simple in situ approach that involved immobilizing zinc oxide on polyethylenimine modified montmorillonite to create a novel nanocomposite (ZnO@HNCs) for photocatalysis applications. Bonding and intercalation of the polymer induce high dispersion and facilitate the formation of a homogeneous and stable coating layer with ZnO. NCs' structure and morphology were characterized using FTIR spectroscopy, X-ray diffraction, SEM, and X-ray photoelectron spectroscopy. The photodegradation efficiency was assessed using Blue Basic 41 dye under ultraviolet light. Optimization of the UV degradation was determined thanks to the response surface methodology, considering three input variables, which are catalyst loading (0.2–0.6 g.L⁻¹), initial concentration (5–15 mg.L⁻¹) of BB41 dye, and pH (2–10). The optimal conditions showed a degradation efficiency of 95 % for catalyst loading (0.4 g.L⁻¹), initial concentration (5 mg.L⁻¹), and pH 6. The free radical scavenging assays confirmed that hydroxyl radicals (OH) and holes (h⁺) were responsible for the BB41 conversion. Hybrid NCs, ZnO@HNCs, exhibited high efficiency in removing BB41 and showed potential for removing other pollutants from aqueous solutions. ZnO@HNCs' performance revealed the photo-mediated decontamination's effectiveness of textile effluents (total organic carbon removal 55.7 %). Additionally, the photocatalyst holds significant potential and can be recycled several times, demonstrating its effectiveness for treating real wastewater.