Vander Alkmin dos Santos Ribeiro
Universidade Federal de Itajubá (UNIFEI), Av. BPS, 1303, Itajubá, Minas Gerais, 37500-903, Brazil

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Graphene Oxide–TiO2 composite materials for photocatalytic degradation of organic pollutants in water treatment Caroliny Fernandes de Carvalho; Adhimar Flávio Oliveira; Maria Elena Leyva Gonzalez; Vander Alkmin dos Santos Ribeiro; Celso Henrique Correa Carvalho
Journal of Applied Materials and Technology Vol. 7 No. 2 (2026): March 2026
Publisher : Faculty of Engineering Universitas Riau and Applied Materials and Technology Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31258/Jamt.7.2.74-84

Abstract

The increasing presence of recalcitrant organic pollutants in water bodies has driven the development of advanced treatment technologies capable of promoting effective degradation beyond conventional processes. In this study, a graphene oxide (GO)–titanium dioxide (TiO2) composite was synthesized via a chemical route and evaluated for photocatalytic degradation of methylene blue under UVC irradiation. Graphene oxide was produced by electrochemical exfoliation of graphite, followed by incorporation into TiO2 at 5 wt.% to form the TiO2:GO5 composite. Structural and morphological characterizations by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and FTIR confirmed the formation of anatase-phase TiO2 and successful integration of GO without secondary phase formation. Photocatalytic performance was assessed by monitoring dye concentration decay over 5 h of irradiation. The TiO2:GO5 composite achieved more than 70% methylene blue removal, reaching a final C/C0 value of 0.28, compared to 0.29 for pure TiO? under identical conditions. The degradation followed pseudo-first-order kinetics, with apparent rate constants of 2.302 × 10-¹ h-¹ for the composite and 2.241 × 10-¹ h-¹ for pure TiO2, corresponding to a 2.7% increase in reaction rate. Enhanced initial adsorption and slightly faster absorbance decay were observed for the composite throughout the irradiation period. Although the performance enhancement is moderate, the incorporation of graphene oxide improved charge separation and adsorption behavior without requiring high-temperature calcination. These findings demonstrate that GO modification represents a viable strategy to enhance TiO2 photocatalytic activity under energy-efficient synthesis conditions, highlighting its potential application in advanced water and wastewater treatment systems.
Development, microstructural characterization, and photocatalytic evaluation of TiO2-modified rendering mortars vander alkmin dos Santos Ribeiro; Adhimar Flávio Oliveira; Celso Henrique Correa Carvalho; Lucas Pacca e Silva
Journal of Applied Materials and Technology Vol. 8 No. 1 (2026): September 2026
Publisher : Faculty of Engineering Universitas Riau and Applied Materials and Technology Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31258/Jamt.8.1.41-54

Abstract

The growing demand for sustainable construction materials has spurred research into cement-based composites that can contribute to environmental remediation. In this context, photocatalytic materials containing titanium dioxide (TiO?) have attracted considerable attention due to their ability to degrade organic pollutants under ultraviolet radiation. This study aimed to develop and evaluate TiO?-modified rendering mortars with enhanced photocatalytic performance for potential application in building facades and surface coatings. Mortar mixtures were produced with 0%, 2%, 6%, and 10% TiO?, expressed as a percentage of cement mass. The materials were characterized through ultraviolet–visible (UV–Vis) spectroscopy, scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM/EDS), and X-ray diffraction (XRD). Photocatalytic activity was assessed using methylene blue degradation tests under UV irradiation. The results demonstrated that TiO? incorporation influenced the methylene blue removal behavior of the mortars under UV irradiation. Among the TiO?-modified formulations, the mortar containing 10 wt.% TiO? exhibited the highest overall removal efficiency. Because no adsorption–desorption equilibrium was established before irradiation, the measured dye removal represents the combined effects of adsorption and photocatalytic degradation. Microstructural analyses confirmed the presence and distribution of TiO? particles within the cementitious matrix and indicated changes associated with increasing nanoparticle content. Although higher TiO? additions enhanced photocatalytic performance, they also reduced the workability of the fresh mortars. Overall, the findings demonstrate the potential of TiO?-modified rendering mortars as multifunctional construction materials capable of combining conventional protective functions with photocatalytic properties for environmental remediation applications.