Fluidized bed reactor for 4-chlorophenol photodegradation via solar and visible radiation using ZnO/g-C3N4/carbon xerogel as a photocatalyst

Author(s)

Gouvea, Maira Elizabeth Vicente ; Boldrin, Flavio Henrique Covolam ; da Silva, Bruno Henrique Baena ; Paiva, Livia Kent ; de Moraes, Nicolas Perciani ; de Aguiar, Leandro Goncalves ; Rodrigues, Liana Alvares

• Document type: Journal article
• Source: CHEMICAL PHYSICS IMPACT; v. 8, p. 12-pg., 2023-12-13.

Abstract

This study investigates the feasibility of employing a fluidized bed reactor for the degradation of 4-chlorophenol (4CP), considering multiple operational parameters (type of radiation, fresh inlet flow rate and recycle flow rate). The selection of the ZnO/g-C3N4/carbon xerogel as photocatalyst, a choice motivated by the improved charge transfer and increased catalyst activity under visible radiation provided by the presence of carbon xerogel and gC3N4, was previously determined through tests conducted in a jacketed batch reactor under visible radiation, in which the ternary material efficiency was compared to their constituting counterpart materials. The semiconductors constituting the unary, binary, and ternary materials were chosen based on considerations of availability, sustainability, and abundance in nature. The use of the proposed fluidized bed reactor brings advantages in scalability, distribution of irradiated light and overall costs when compared to commonly used batch reactors, whereas the investigation of the flow parameters involved in such process is of great importance to understand and optimize the efficiency of the pollutant degradation process. Regarding the ternary photocatalyst, X-ray diffractometry (XRD) revealed the presence of zinc oxide's hexagonal crystalline structure. Moreover, additional characterization using Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDS) confirmed the presence not only of ZnO but also of carbon xerogel and g-C3N4 in the composite. From the photodegradation experiments, it was determined that the optimal fresh inlet flow rate to achieve the best degradation, as well as the recycle flow rate for this purpose, were 0.07 and 25 L h-1, respectively. Mathematical simulations described that the model that best fits the system's behavior considers the specific reaction rate as dependent on the concentration of the catalyst in the medium. (AU)

• FAPESP's process: 18/06361-9 - Photocatalytic evaluation of the composite g-C3N4/ZnO/carbon xerogel in the photodegradation of 4-chlorophenol in both fluidized bed and batch reactors
• Grantee: Livia Kent Paiva
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 18/10492-1 - Photocatalytic evaluation of heterojunctions semiconductor/ZnO/carbon xerogel in the photodegradation of 4-chlorophenol in both fluidized bed and batch reactors
• Grantee: Liana Alvares Rodrigues
• Support Opportunities: Regular Research Grants
• FAPESP's process: 22/04058-2 - Photoelectrocatalytic degradation of pollutants (bisphenol-A, sulfamerazine, and 2,4-D) using H2O2 electrogenerated in carbonaceous matrices obtained from sustainable sources
• Grantee: Nicolas Perciani de Moraes
• Support Opportunities: Scholarships in Brazil - Post-Doctoral