Description
The SOLAR2CLEAN project aims at the achievement of a highly efficient engineered photocatalytic system, driven by solar light, of high applicability in real-life, targeting wastewater purification, i.e., the degradation of pollutants like microplastics and antibiotic residues generated by a high-value Portuguese industry. It involves a dynamic research plan fostering innovation, technology integration, and international collaborations.
The SOLAR2CLEAN project contributes with new and affordable technologies and methodologies for better water management and sanitation, less pollution, reduction of hazardous chemicals and materials in the oceans and rivers, and for sustainable and modern energy solutions, aligned with goals 6 and 7 of the UN 2030 Agenda for Sustainable Development. The clean and environmentally sound technology envisaged in this project aligns with the urgent needs for industrial processes, namely in the treatment of effluents and addressing SDGs 9, 12, and 13, i.e., sustainable industrialization, responsible production, and climate change.
The project involves the synthesis of new nanomaterials supported on porous spheres, called MICROSCAFS®, that the group develops. Furthermore, the photocatalyst is modified with dopants to achieve better visible light response and maximize photodegradation properties. The supported photocatalyst is employed in a batch and in a continuous setup, and we also explore the kinetics and the by-products of the photodegradation process.
Funding
PTDC/EQU/EQU/1056/2020
DOI
doi.org/10.54499/PTDC/EQU-EQU/1056/2020
FUNDING (FCT)
250 000,00 € (IST-ID, CERENA)
DURATION
01.02.2021 – 31.10.2024
44 months
PRINCIPAL INVESTIGATOR (PI)
ana.marques@tecnico.ulisboa.pt
web.tecnico.ulisboa.pt/ist45873/
Co-PI
Prof. Susete Martins Dias
Goals
The main goal of the project is to prepare supported solar-driven photocatalysts for pollutants (methyl orange, minocycline, and low-density polyethylene) photodegradation from wastewaters. The reactions will be performed in batch and continuous flow setup and the biodegradability and toxicity of the by-products will be evaluated.
Task 4
Assessment of minocycline and LDPE microplastics degradation by the new engineered photocatalytic system
Methodology
Water scarcity has made water reuse from wastewater treatment plants crucial, requiring innovative, low-cost purification technologies. Heterogeneous solar photocatalysis offers a promising and sustainable approach to water treatment. Optimized TiO2 NPs are an ideal choice due to their low cost, chemical stability, and low toxicity. Doping specific elements onto these NPs enables their activation under visible light, making them effective for solar-driven photocatalysis. The design of the reactor is critical for efficient wastewater treatment under sunlight exposure. The continuous flow-through reactor is preferred as it is more attractive for industrial processes while ensuring proper contact with photocatalytic species. Further optimization of this reactor design is a significant goal in the SOLAR2CLEAN project.
To achieve a sustainable and economically viable process, recovering and reusing photocatalytic materials is essential. Immobilizing the NPs onto a support material (MICROSCAFS®) enables easy recovery and handling while maintaining high photocatalytic efficiency. Additionally, immobilization might prevent NP aggregation, further enhancing their performance. In summary, the future of water supply depends on innovative wastewater treatment technologies like solar photocatalysis. Optimized TiO2 NPs doped with specific elements offer a sustainable and cost-effective solution. The continuous flow-through reactor design ensures efficient water treatment and sunlight exposure. Through immobilization and careful catalyst selection, we can create a cleaner and more sustainable water future.
Results
MICROSCAFS® preparation and characterization
General scheme of silica-titania MICROSCAFS® preparation, exhibiting the different main stages and associated optical microscopy images (scale bar = 400 μm). Adapted from RSC Advances, 13(19), 12951–12965 (2023). https://doi.org/10.1039/D3RA00895A
Cryo-SEM images of MICROSCAFS® located within the emulsion's oil phase (bar scale = 60 μm) (a, b) particle in an early development stage, one minute after the addition of the ammonia catalyst and (c) particle in a later development stage, wet gel MICROSCAFS® particle. Adapted from RSC Advances, 13(19), 12951–12965 (2023). https://doi.org/10.1039/D3RA00895A
SEM images of MICROSCAFS® with different morphologies and compositions.
Morphology of silica-titania MICROSCAFS® with increasing GPTMS precursor. Top left: Optical microscopy photographs (scale bar = 600 μm); Top right: SEM images (scale bar = 8 μm) of a particle cross-section; Bottom left: particle size distributions; Bottom right: MIP pore size distribution curves. Adapted from RSC Advances, 13(19), 12951–12965 (2023). https://doi.org/10.1039/D3RA00895A
Cross-sectional 3D CT image of the powder (top line) and a single microsphere (bottom line) of different MICROSCAFS® (scale, distance between points: top left = 250 μm, top right = 250 μm, bottom left = 5 μm, bottom right = 10 μm). Adapted from RSC Advances, 13(19), 12951–12965 (2023). https://doi.org/10.1039/D3RA00895A
Photocatalysis experiments
Batch setup under solar light irradiation (@IST).
Set-up involving a designed continuous flow reactor (in collaboration with ETH Zurich, Prof. Niederberger´s group), with total recirculation to a reservoir (@IST): (1) Sample holder (solar reactor), (2) glass reservoir containing the pollutant solution, (3) peristaltic pump, (4) rubber tubing, (5) solar simulator.
Plots of C/Co versus time for the unloaded and TiO2 NPs loaded silica MICROSCAFS® ((SiO2 MS). Methyl orange (MO) shows no photodegradation at all during the experiment time, in the absence of photocatalyst. Experimental conditions: 25 °C, pH = 7, mass (TiO2 NPs)/mass(MO) = 25, 100 mL of 20 ppm MO aq. solution, 300 mg of TiO2 NPs loaded SiO2MSs (66 mg TiO2), flow = 5 mL min−1 , irradiance = 1000 W m−2 (1 sun). Adapted from Global Challenges, 5(5), 2000116 (2021). https://doi.org/10.1002/gch2.202000116
Internship of Sofia Moreira Fernandes at ETH-Zurich within the group of Prof. M. Niederberger (MFM group)
(a) (b)
Nanoparticles´ synthesis in a microwave reactor: (a) pre-synthesis solution of the precursors; (b) post-synthesis dispersion of TiO2 nanoparticles.
Publications
1.
Tiago et al. (2025). Promoting LDPE microplastic biodegradability: The combined effects of solar and gamma irradiation on photodegradation. Journal of Hazardous Materials, 492, 138227. https://doi.org/10.1016/J.JHAZMAT.2025.138227
2.
Bertagna et al. (2025). TiO₂-based photocatalytic degradation of microplastics in water: Current status, challenges and future perspectives. Journal of Water Process Engineering, 72, 107465. https://doi.org/10.1016/J.JWPE.2025.107465
3.
Barrocas et al. (2025). Optimization of TiO2 loaded sol-gel derived MICROSCAFS® for enhanced minocycline removal from water and real wastewater. Journal of Sol-Gel Science and Technology. https://doi.org/10.1007/s10971-025-06759-9
4.
Langiano et al. (2025). Rice husk silica derived MICROSCAFS® for a green solar-driven photodegradation of minocycline in aqueous media. Journal of Water Process Engineering, 70, 107003. https://doi.org/10.1016/J.JWPE.2025.107003
5.
Moreira Fernandes et al. (2025). MICROSCAFS® for minocycline elimination from water and real wastewater: Porosity and TiO2 nanoparticles effect. Chemical Engineering Journal, 504, 158771. https://doi.org/10.1016/J.CEJ.2024.158771
6.
Silva et al. (2024). Biopolyurethane coatings with silica-titania microspheres (MICROSCAFS®) as functional filler for corrosion protection. Surface and Coatings Technology, 494, 131376. https://doi.org/10.1016/J.SURFCOAT.2024.131376
7.
Vale et al. (2024). Robust Photocatalytic MICROSCAFS® with Interconnected Macropores for Sustainable Solar-Driven Water Purification. International Journal of Molecular Sciences, 125, 5958. https://doi.org/10.3390/ijms25115958
8.
Moreira Fernandes et al. (2024). Maximizing photocatalytic efficiency with minimal amount of gold: Solar-driven TiO2 photocatalysis supported by MICROSCAFS® for facile catalyst recovery. Journal of Environmental Chemical Engineering, 12, 112043. https://doi.org/10.1016/j.jece.2024.112043
9.
Vale et al. (2023). Mechanistic Study of the Formation of Multicomponent Oxide Porous Microspheres (MICROSCAFS®) by Cryo-Scanning Electron Microscopy. Gels, 9(9). https://doi.org/10.3390/GELS9090704
10.
Tiago et al. (2023). The problem of polyethylene waste – recent attempts for its mitigation. Science of The Total Environment, 892, 164629. https://doi.org/10.1016/J.SCITOTENV.2023.164629
11.
Vale et al. (2023). Multicomponent oxide microspheres with designed macroporosity (MICROSCAFS®): a customized platform for chemicals immobilization. RSC Advances, 13(19), 12951–12965. https://doi.org/10.1039/D3RA00895A
12.
Marques et al. (2021). Macroporosity Control by Phase Separation in Sol-Gel Derived Monoliths and Microspheres. Materials 2021, Vol. 14, Page 4247, 14(15), 4247. https://doi.org/10.3390/MA14154247
13.
Marques et al. (2021). Porous Silica Microspheres with Immobilized Titania Nanoparticles for In‐Flow Solar‐Driven Purification of Wastewater. Global Challenges, 5(5), 2000116. https://doi.org/10.1002/gch2.202000116
Oral communications
SolGel (2024)
Oral presentation by Ana C. Marques at the SolGel conference, Germany, (2024): Engineered supported photocatalysts for solar light-driven environmental remediation.
XIV Convegno INSTM (2024)
Oral presentation by Daniele Montini at XIV Convegno INSTM, Italy (2024): Silica from waste of fluorine-derivatives industry applied for MICROSCAFS® synthesis.
Invited talk at Ca´Foscary University of Venice (2024)
Invited oral presentation by Ana C. Marques at Ca´Foscary University of Venice, Italy (2024): Interconnected macroporosity tailoring within confined spaces: MICROSCAFS®.
Invited talk at the University of Milano - Bicocca (2024)
Invited oral presentation by Sofia Moreira Fernandes at the University of Milano - Bicocca (2024): Engineered solar light driven photocatalytic systems for wastewater purification.
Invited talk at the ISGS e-seminar (2024)
Invited oral presentation, by Ana C. Marques at ISGS e-seminar, online event (2024): Interconnected macroporosity tailoring within confined spaces: MICROSCAFS®.
ISGS PhD Students eMarathon (2024)
Oral presentation by Sofia Moreira Fernandes at the ISGS PhD Students eMarathon, online event (2024): MICROSCAFS®: Microspheres with tailored porosity for diverse applications.
Invited talk at SPASEC-27 & AOTs-28 (2024)
Invited oral presentation by Beatriz Barrocas at the SPASEC-27 & AOTs-28 conference, Cyprus (2024): Novel supported photocatalysts for solar-assisted environmental remediation.
Invited talk at PolyScience (2023)
Invited oral presentation by Ana C. Marques at PolyScience, Portugal (2023): Enlightenment of porous microspheres generation and their use as supports for solar-light driven photocatalysts.
SUSGEM (2023)
Oral presentation by Sofia Moreira Fernandes at SUSGEM, Spain (2023): Improved photocatalysis with minimal Gold: Solar-driven TiO2 photocatalysis supported by MICROSCAFS® for facile catalyst recovery.
TPMI (2023)
Oral presentation by Ana C. Marques at the TPMI2023 Workshop, Portugal (2023): Presentation of the Technology Platform on Microencapsulation and Immobilization (TPMI): Microcapsules and MICROSCAFS®.
TPMI (2023)
Oral presentation by Mário Vale at the TPMI2023 Workshop, Portugal (2023): Immobilization on tailored porous microspheres (MICROSCAFS®) and its applications.
TPMI (2023)
Oral presentation by Sofia Moreira Fernandes at the TPMI2023 Workshop, Portugal (2023): Porous Microspheres (MICROSCAFS®) as noble hosts: Immobilizing noble metal nanoparticles for enhanced photocatalysis.
TPMI (2023)
Oral presentation by Beatriz Barrocas at the TPMI2023 Workshop, Portugal (2023): Detection of degraded species in a photocatalytic process.
SolGel (2022)
Oral presentation by Ana C. Marques at the SolGel conference, France (2022): Insights on porous microspheres generation and their doping for solar-light driven photocatalysis.
Invited keynote talk at the International Conference on Applied Surface Science (2022)
Invited keynote oral presentation by Ana C. Marques at the 5th International Conference on Applied Surface Science, Spain, (2022): Tailored microscaffolds for solar-driven photocatalytic systems.
Posters
Nanoseries (2024)
Poster by Sofia Moreira Fernandes at Nanoseries conference, Portugal (2024): Microwave-synthesized anatase TiO2 Nanoparticles Supported on MICROSCAFS® for Efficient Photodegradation of Pollutants in Water.
PhD Open Days (2023)
Poster by Sofia Moreira Fernandes at the IST PhD Open Days, Portugal (2023): MICROSCAFS® as micro-reactors for TiO2 nanoparticles production for photocatalytic applications.
HYMA (2022)
Poster by Sofia Moreira Fernandes at HYMA, Italy (2022): Porous MICROSCAFS® with Immobilized TiO2 for Wastewater Purification: Effects of Gold Nanoparticles.
SolGel (2022)
Poster by Mário Vale at SolGel conference, France (2022): Enlightenment of multicomponent oxide porous microspheres generation.
Theses
PhD thesis
Vale, M. (2024). Silica-based single and multicomponent oxide microspheres with interconnected macroporosity: MICROSCAFS®. Instituto Superior Técnico.
Master thesis
Langiano, F. (2024). From rice biomass to photocatalytically active silica-based microspheres for wastewater remediation. Ca´ Foscari University of Venice.
Master thesis
Oliveira, M. (2024). Microplastic-Free Encapsulation of Clomazone for a Sustainable Agriculture. IST-MEMat.
Master thesis
Alcobia, T. (2024). Systems for the photocatalytic degradation of microplastics and the antibiotic minocycline. IST-MEQ.
Master thesis
Dias, L. (2022). Reutilização de fios de poliamida na obtenção de membranas para o tratamento de efluentes contendo corantes têxteis. Universidade Estadual da Paraíba.
Master thesis
Carvalho, M. (2022). Economia Circular Azul como uma alternativa emergente na criação de novos produtos. Mestrado em Ciências do Mar, FCUL-UL.
Master thesis
Silva, P. (2021). Porous silica microscaffolds for nanoparticle immobilization. IST-MEQ.
Master thesis
Mariquito, A. (2021). Stability study of emulsions and correlation with the synthesis of microspheres. IST-MBioNano.
Others
Noite Europeia dos Investigadores 2024
Participation at the Noite Europeia dos Investigadores 2024.
IST Distinguished Lecture
Organization of a distinguished lecture by Markus Niederberger on Wet Chemical Synthesis and Processing of Nanoparticles at IST, Lisbon, Portugal (2024).
National Brand
National brand nº 684231 “MICROSCAFS®” GRANTED in 2022.07.11, published in the Industrial Property Bulletin nº 137/2022, 2022.07.14.
Workshop
Prof. Ana C. Marques organized the international TPMI2023 workshop on microencapsulation and immobilization, Lisbon, Portugal, May 2023. Beatriz Barrocas, Mário Vale, and Sofia Moreira Fernandes were co-organizers and speakers at the workshop.
Partners
Researchers
Core Team: Ana C. Marques (PI), Susete Dias (Co-PI), Luís Veiros, Luís Santos, M. Clara Gonçalves, M. Teresa Duarte, Rui M. Almeida, Markus Niederberger, ETH Zurich, Alessandro Lauria, ETH Zurich, Elena Tervoort, ETH Zurich, Murielle Schreck, ETH Zurich.
Post-docs: Beatriz Barrocas, Gonçalo Tiago.
PhD Students: Sofia Moreira Fernandes, Mário Vale.
Master Students: Teresa Menezes Garrett Alcobia, IST-MEQ, Margarida Figueiredo de Oliveira, IST-MEMat, Patrícia Isabel Pereira da Silva, IST-MEQ, Ricardo Delgado, IST-DEQ, Larissa Dias, CCT-UEPB, Miguel Lamúria, IST-MEQ, Mafalda Carvalho, FCUL-UL, António Mariquito, IST-MBioNano.
International Visiting Students and Researchers: Bleuwenn Ferrandon, Sorbonne Université (France), Diego Burri, ETH Zurich (Switzerland), Coline Rossel, INSA de Lyon (France), Pavol Rybár, University of Technology in Bratislava (Slovakia), Daniele Montini, University of Milano – Bicocca (Italy), Francesca Langiano, Ca' Foscari University of Venice (Italy), Dr. Izabela Stępińska, Łukasiewicz Research Network – Tele and Radio Research Institute (Poland), Rudolf Ricka, VŠB-Technical University of Ostrava (Czech Republic).