Agradecimentos: The Article Processing Charge for the publication of this research was funded by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), Brazil (ROR identifier: 00x0ma614). This study was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brazil (CAPES) [Financial Code 001], the Conselho Nacional de Desenvolvimento Científico e Tecnológico-(CNPq), and the Fundação de Amparo à Pesquisa do Estado do Espírito Santo (FAPES). Additionally, we are thankful to professor Dr. Valmor Roberto Mastelaro from the Centro de Desenvolvimento de Materiais Funcionais-CDMF at the University of São Paulo for conducting the X-ray photoelectron spectroscopy (XPS) analyzes and FAPESP funding projects 2013/07296-2, 2022/06126-5, 2024/07600-8 Ver menos

Abstract: 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/TiO2-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/TiO2 surface, marked by the appearance of a sulfone group band. Raman and XPS analyses indicated reduced Sp2 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 m2 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 degrees 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 degrees C. Thermodynamic analysis confirmed an entropically controlled, endothermic, spontaneous process at high temperatures. These aspects confirm the potential of eco-friendly C/TiO2 composite for effective RB-5 removal from aqueous solutions Ver menos