Study: Electrically conducting carbon nanotubes/graphene membrane composites for self-cleaning biofouling via bubble generation. Image Credit: Aytug askin / Shutterstock.com
Biofouling – Facilitator of bio-invasion
Biofouling is the unwanted accumulation of algae and micro-organisms on submerged assemblages (particularly outdoor boats), and is a major facilitator of biofouling. Studies have proven that biofouling is a major vector for the spread of invasive aquatic organisms.
Ships carrying biofoulings may introduce invasive marine species into government waterways, harming humans, animals, plants, and socioeconomic activities, as well as freshwater habitats.
The role of biofilms in biofouling
Biofouling is facilitated by the formation of biofilms. Biofilms form when microorganisms cling to materials. Biofilm-associated cells can be distinguished from their efflux counterparts through production of an extracellular polymeric material (EPS) structure, slower growth rates, and gene regulation. Adhesion is a complex process affected by growth media, substrate, and the cytoplasm.
Understanding biofilms is critically important to the well-being of society due to their involvement in some infectious diseases and their importance in a range of device-related contaminations. Detailed understanding of microbiomes should lead to new and better surgical biofilm monitoring procedures, while contributing to better patient care.
Bio-invasive removal methods
Membranes mark the barriers that allow the separation of components of different dimensions or physicochemical properties. The choice as well as the porosity of the films used determine the effectiveness of the separation process.
Rejection of the unwanted component and penetration of the desired molecule determines the selectivity, or the ability to separate solutes, contaminants, particles of different sizes or physical/chemical properties. Transmembrane flow is used to measure membrane permeability, which is controlled by pore diameter and surface properties.
Problems with these methods
As a result of the absorption and accumulation of impurities contained in the feed mixtures on the porous matrix, the effectiveness of the membrane pores may be damaged. Moreover, contamination on the membrane surface requires vigorous and regular physical and biological cleaning, which raises the operational costs of the membrane process.
Several chemical procedures are used to get rid of bacteria and to remove biofouling from membranes. On the other hand, chemical cleaning procedures pose the problem of resistance generation in microbes and erosion of the membrane surface.
Electrified membranes – a possible solution
It has recently been demonstrated that electrophoresis membranes (EMs) have the ability to resolve membrane contamination by adding electrical activity as a new membrane function.
Electromagnetism aims to enhance the importance of the membrane further than direct separation by utilizing a number of processes, such as electrolytic reduction and oxidation, while adding classic membrane functions of solute separation via hydrophobic interactions and charge confinement.
Electrically conductive materials (for example, metallic alloys, carbon-based nanostructures and composites) are seamlessly incorporated into the membrane as permeable electrodes to eliminate biofouling, and an electromotive force is applied across the electrodes to achieve this advantage.
Investigation of a bubble generation method for biofouling disposal
In this study, the utility of electrically conducting carbon nanotube films was investigated. The researchers created a graphene-based nano-membrane for self-cleaning biofouling by applying electrical potential and generating a bubble across the membrane to get rid of microorganisms on the surface.
The membrane was made by combining CNTs and graphene, which also allowed the researchers to test the microbial neutrality of the structure. The resulting membrane was used as an electrode for in situ chemotherapy with a common biological material (microbial, for example). The consequences of different potential periods and self-cleaning on flow recovery have also been systematically studied.
The results of this study demonstrate the efficacy of extraction and highlight the exclusion target of biofouling self-cleaning, as well as the self-cleaning approach.
The future – what are we looking forward to?
As clinical and public health microbiologists recognize that microbial biofilms are pervasive in nature, a variety of infectious clinical situations have been studied from the biofilms point of view. Efforts are being made to understand the processes of removing these microorganisms from the structure.
Lee, J. H., Yun, E.-T, Ham, S.-Y. , Kim, H.-S. Sun, P.-F, & Park, H.-D. (2022). Electrically conductive carbon nanotubes/composite graphene membrane for self-cleaning biofouling via bubble generation. Water desalination. Available at: https://www.sciencedirect.com/science/article/pii/S001191642200296X? via %3Dihub