aenesca@unitbv.ro

+ 40 268 413 000

The last stage (January - December 2024) of the project was dedicated to the evaluation and testing of the working mechanism of the microreactors in various working environments. Six important steps were taken:

1. Evaluation of the photocatalytic mechanism of the microreactors in which the energy diagrams of the various heterostructures involved were determined, as well as their synergy with the polymer structure in which they are embedded.

2. The toxicological evaluation of the microreactors included a detailed study of the toxicological influence of each component within the microreactors on Chlorella Vulgaris. The evaluation indicated that it is recommended to avoid the use of TiO2-based materials that produce long oxidative reactions. The other components of the microreactors did not indicate significant toxicological problems.

3. The optimization of the toxicological and photocatalytic properties mainly aimed at the compatibility of the polymer membrane with the heterostructure from which the photocatalytic material is formed. These studies indicated a significant increase in photocatalytic efficiency for open-type systems than semipermeable ones.

4. The evaluation of the technological parameters in a static regime was carried out in a modular multi-reactor that allows changes in the type and light intensity as well as the control of parameters such as the degree of humidity and temperature.

5. The evaluation of the technological parameters in a dynamic regime was carried out in a reactor with recirculation, which rewards the collection of samples from several points of the technological process. The experiments followed two different scenarios and indicated that the microreactors are also efficient in dynamic mode of operation.

6. The statistical evaluation of the results sought the integration of a significant amount of data (porosity, surface energy, energy bands, etc.) in a comprehensive evaluation capable of indicating the most optimal technological operation conditions.

he second stage (January - December 2023) of the project was dedicated to the development of microreactors with photocatalytic properties to be tested and improved in the last stage. Three important steps were taken:

1. The development of di-block polymers capable of forming vesicles in which the photocatalytic heterostructures will be implanted. In this sense, four types of di-block polymers were developed with the support of colleagues from the University of Dublin. A-type microvesicle supramolecular assemblies were generated by self-assembly of amphiphilic copolymers. The first microvesicle of this kind was composed and synthesized by the Bayer-Villiger method.

2. The second step was the creation and optimization of new photocatalytic heterostructures active both in the UV and Vis. Two types of heterostructures were realized: CuO/CuS/WO3 and WO3/Bi2S3/Cu2S. The obtaining method was sol-gel, which allowed the significant reduction of production costs. The optimization of the two heterostructures was achieved by introducing the polyaniline polymer (for CuO/CuS/WO3) and graphene oxide and carbon nanotubes (for WO3/Bi2S3/Cu2S) into their structure. Photocatalysis tests indicated that these optimized heterostructures have superior efficiencies (between 75-95%) in the removal of active pharmaceutical compounds such as: pelicillin G, ampicillin and amoxicillin.

3. In the last step, the experiments on the incorporation of the photocatalytic heterostructure into the polymer vesicles and the formation of the microreactors took place. The experiments involved laborious work because the formation of the vesicle around the heterostructure depended on the self-arrangement of the hydroxide functional group inside. In this case, tests were performed at different pH values and using different re-hydration/dispersion media. In the end, the passing through successive stages of formation of the spherical-type micelles, then the worm-type micelles, in order to finally form the actual vesicle containing the photocatalytic heterostructure inside, were observed.

In the first stage of the project (June - December 2022), 7 different nano-powder synthesis methods were developed as follows: TiO2 (Sol-gel Method), WO3 (Sol-gel Method), ZnO (Sol-gel Method), CuO (Co- precipitation and sol-gel), CuxS (Co-precipitation method) and CuInS2 (Sol-gel method). Diffraction and EDX analyzes indicated that all nano-powders were obtained in a crystalline state and having the anticipated composition. The next step was the integration of nano-powders into heterostructures. In this sense, four types of powder-type heterostructures were obtained by the sol-gel method: SnO2/CuxO/TiO2, SnO2/CuxS/TiO2, ZnO/TiO2/CIS and TiO2/CIS/WO3. These heterostructures were optimized by modifying the synthesis parameters so that they could be used in further photocatalytic applications.
SnO2/CuxO/TiO2, SnO2/CuxS/TiO2, ZnO/TiO2/CIS and TiO2/CIS/WO3 heterostructures were covered from nano-powders in thin layers using both dip-coating and low-temperature sputtering methods. The materials were thermally treated differently depending on their composition and structure. As can be seen from Figure 1, the materials contain all the crystalline structures necessary to obtain catalytically active heterostructures in the presence of UV and Vis radiation. In Figure 2 it can be seen that the heterostructures have a homogeneous morphology as well as the fact that a uniform contact was obtained between the materials constituting the photocatalytic layer.
The results obtained in Stage 1 encouraged us to start the preliminary steps for Stage 2 so that most of them have already been published in ISI journals of type Q1 (Nanomaterials, Polymers, etc.).

Our mission
The project aims to develop photocatalytic materials active in the UV-Vis field and capable of removing active pharmaceutical compounds from wastewater. In this sense, the project team develops hybrid heterostructures with a unique and stable structure that will have a significant impact in protecting the environment.

Contact

email: aenesca@unitbv.ro

 +40 268 413 000

University Street, Nb. 1

Building F, Office FI7, Brasov

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