{Bentonite-TQD: photodegradation and recycling process for organic pollutants removal and industrial wastewater treatment

A novel nanocomposite, Bentonite-TiO₂ Quantum Dots (BTQD), meticulously designed for the photocatalytic degradation of Brilliant Blue R (BBR) dye, a representative contaminant in textile wastewater. The BTQD material was synthesized utilizing a co-precipitation technique, which effectively promoted a uniform distribution of TiO₂ quantum dots (TQD) upon the bentonite support. This strategic functionalization resulted in a significant enhancement of the specific surface area to 212.25 m²/g for the BTQD, a substantial increase over pristine bentonite, thereby augmenting the density of active sites crucial for pollutant adsorption and photocatalytic efficacy. Characterization using transmission electron microscopy confirmed the TQD possessed an average particle size of 5–8 nm, a dimension optimal for leveraging quantum size effects to bolster photocatalytic activity and have an intermediate optical bandgap of 3.00 eV, facilitating photocatalytic processes under both UV and visible light irradiation. X-ray diffraction patterns verified the anatase crystalline phase of the TiO₂ component, which is well-established for its high photocatalytic efficiency. The photocatalytic degradation of BBR dye using the BTQD composite was systematically evaluated, revealing adherence to first-order reaction kinetics. Furthermore, the material displayed excellent stability and recyclability, maintaining robust degradation efficiency over successive operational cycles, which is a critical factor for practical wastewater treatment applications. Concomitantly, significant reductions in chemical oxygen demand (COD) and total organic carbon (TOC) were observed post-treatment, indicating extensive mineralization of organic pollutants. This work presents a promising and economically viable pathway for the remediation of industrial effluents containing recalcitrant organic dyes and associated contaminants.