Synthesis, Characterization, and Application of an Ecofriendly C/TiO<sub>2</sub> Composite to Efficiently Remove Reactive Black 5 (RB-5) Textile Dye from Aqueous Solutions
Lucas Destefani Paquini, Lília Togneri Marconsini, Bruno Sanches de Lima, Luciene Paula Roberto Profeti, Josimar Ribeiro, Demetrius Profeti
Abstract
High Resolution Image Download MS PowerPoint Slide The textile industry is known for its high water consumption and production of toxic effluents, including azo dyes such as Reactive Black 5 (RB-5), which are resistant to removal. Adsorption offers a promising, cost-effective solution, particularly with value-added composites made from abundant materials. This study synthesized, characterized, and applied a C/TiO 2 -based composite to remove RB-5 from water. XRD analysis only confirmed anatase as the primary support, while FTIR detected adsorbate molecules on the C/TiO 2 surface, marked by the appearance of a sulfone group band. Raman and XPS analyses indicated reduced Sp 2 carbon content and lower graphitization after adsorption, probably due to mechanical stress. Additionally, nitrogen physisorption analysis demonstrated that the material is mesoporous, with a surface area of 56.24 m 2 g –1, and a pore diameter of 9.41 nm. The composite exhibited strong affinity for anionic species like RB-5, especially at pH values below the point of zero charge (7.47). Batch studies demonstrated Avrami kinetic adsorption at a rate of 0.3023 min –1 (at 25 °C), while temperature effects followed the Arrhenius model, with an activation energy of +41.10 kJ mol –1 . Sips isotherm data indicated a maximum adsorption capacity of 17.48 mg g –1 at 55 °C. Thermodynamic analysis confirmed an entropically controlled, endothermic, spontaneous process at high temperatures. These aspects confirm the potential of eco-friendly C/TiO 2 composite for effective RB-5 removal from aqueous solutions.