Advanced techniques for the in situ investigations of bacteria sorption phenomenon on the surface of new graphene nanohybrid sorbents in water systems

Acronym: not applicable
No.: UMO-2013/09/D/ST8/04001
Program: Sonata 5
Financing unit: NCN
Project leader: professor Agnieszka Jastrzębska
Function: leader
Timeframe: 2014-2017

Understanding the basics of bacterial sorption on the surface of graphene sorbents will be extremely important not only in water filtration but also in such disciplines as environmental protection, medicine and even biomedical engineering and biotechnology.

As part of the project, nanohybrid bioactive and biosorption systems added with graphene were developed, and produced by covalent modification of the graphene surface with nanoparticles. The subject of the research work concerned the modification of graphene materials using nanoparticles, bioactivity studies and investigations on the related phenomenon of biosorption, studies of their zeta potential and development of a model for non-spherical systems. The project's particular achievements in this area include:

1. Designing the structure and chemical composition of nanocomposite systems with graphene materials, i.e. RGO/metal oxide systems (Al2O3, TiO2, SiO2, ZnO2), RGO/TiO2-Me as well as RGO/Al2O3-Me systems characterized by bioactive and biosorptive properties.
2. Development of innovative methods for covalent modification of graphene materials with nanoparticles (i.e., the "dry" and "simplified" sol-gel methods) and optimization of synthesis parameters. The obtained results allowed the development of patent applications for the production of nanocomposites RGO/Al2O3 by two methods, and nanocomposites RGO/TiO2, RGO/TiO2-Me and RGO/Al2O3-Me.
3. Confirmation of the existence of a covalent bonding between the surface of the graphene material and nanoparticles, and proposing a mechanism for the synthesis of nanocomposite systems RGO/TiO2, RGO/TiO2-Me and RGO/Al2O3 and RGO/Al2O3-Me, associated with the in situ reduction of GO to RGO.
4. Performing a comprehensive and thorough characterization of morphology, structure and physicochemical properties of the produced bioactive and biosorptive nanocomposite systems with graphene materials.
5. Building up a unique research workshop, allowing the analysis of bioactive and biosorption properties of nanocomposite systems with graphene, based on experience and innovative research methodology.
6. Demonstration of biocidal properties for the nanocomposite systems i.e., RGO modified with Al2O3-Ag, SiO2-Ag and ZnO2-Ag nanoparticles.
7. Demonstration of effective biosorption properties for the nanocomposite system i.e., RGO modified with Al2O3-Au and Al2O3-Ag nanoparticles.
8. Selection of a nanocomposite with the composition of RGO/Al2O3-Ag as the most promising - effective material in terms of assumed bioadsorption and biocidal properties. The combination of these two parameters allowed for effective attraction of bacterial cells to the surface of RGO/Al2O3-Ag nanocomposites and their complete deactivation.

 The produced materials were tested in a comprehensive and thorough way, which allowed confirming the assumed properties and choosing among the examined group of systems characterized by optimal bioactive and biosorptive properties. Thus, the validity of using nanocomposite bioactive and biosorptive systems with graphene in water filtration was confirmed.

The scientific achievements of this project will also allow in the future to design and produce new generation nanohybrid graphene sorption materials, characterized by stable and easily manipulated filtration properties, thanks to which they can be used in various water filtration technologies.