FREE-FLOATING BACTERIAL NANOCELLULOSE (BC) AEROGEL SPHERES (BCS) AS POROUS SUPPORT FOR METAL OXIDES/SULFIDES PHOTOCATALYSTS/UPCONVERSION NANOPARTICLES FOR CONTINUOUS-FLOW WATER PURIFICATION IN ADVANCED PHOTOCATALYTIC REACTOR ASSEMBLY

• Grant number: 23/04112-0
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: June 01, 2025
• End date: August 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Rogéria Rocha Gonçalves
• Grantee: Rogéria Rocha Gonçalves
• Visiting researcher: Sajjad Ullah
• Visiting researcher institution: University Of Peshawar/Uop, Pakistan
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 21/08111-2 - Development of rare earth based light converters: luminescent markers, optical sensors, and amplifiers, AP.TEM

Abstract

This project aims to develop porous bacterial cellulose aerogels spheres (BCS) coated separately with different photocatalysts (TiO2, BiVO4, MoS2) for continuous-flow photocatalytic water purification in a practical photocatalytic reactor using intense natural sunlight from a solar concentrator. The visiting researcher and collaborators from Photonic Materials Research Group at IQ-UNESP have already developed BC/TiO2 and BC/MoS2 membranes for in-flow water purification but they suffer from two main problems: (i) short contact time between the membranes supported photocatalysts and the aqueous pollutants molecules flowing through the membranes and (ii) limited light absorption by each photocatalyst in a specific wavelength range and mostly on the light-exposed side of the photoactive membrane only. In addition, significant absorption (low transmission) of UV light (required for TiO2 photoexcitation) by the glass optical fiber guide connected to the solar concentrator is also a limiting factor when UV light is required for photocatalysis. To overcome these limitations and put forth a more practical approach to water purification, the proposed project will follow two strategies, namely (i) to employ free-floating BCS as photocatalysts supports of high surface area and yet easy recovery and coat them with different photocatalysts/cocatalysts (TiO2, BiVO4/MoS2) as well as mixed aerogels of upconversion nanoparticles (UCPs = NaYF4: Yb3+/Tm3+ ) and photocatalysts (BiVO4¬/TiO2¬) and (ii) to design an efficient continuous-flow photocatalytic reactor containing different BCS@Photocatalysts beads/spheres, each with its characteristic solar light absorption/application range. The inherent high UV photoactivity of TiO2 (Eg = 3.2 eV), visible light photoactivity of BiVO4 (Eg = 2.6 eV) and MoS2 (Eg = 1.41.9 eV) and NIR photoactivity of the UCPs/photocatalysts, together with the effective intense solar light illumination of the BCS@Photocatalysts assembly from a solar concentrator will allow real-time in-flow water purification with high efficiency. Various parameters such as photocatalysts composition, effect of photocatalysts deposition mode/loading, the photocatalytic reactor design and flow dynamics will be explored to be later continued by concerned graduate students at the host groups. Successful completion of the project will lead to a significant amount information about water purification and the development of practical water-purification reactor systems. In addition to the research project, Other activities to be performed during the visit include (i) a five-days workshop/short course on functional nanomaterials preparation and characterization using XRD, UV-visible DRS and SEM-EDX/WDX, (ii) delivering seminars about the research activities of the visiting researcher at the host as well as neighbor academic institutions, (iii) participation in the on-going research projects at the host institutions and (vi) assistance in data analysis and manuscript/articles writing. (AU)