Real-Time Monitoring Technology and Nanotechnology Applications on Different Environmental Scenarios
Sensing technology has been widely applied in environmental oil detection. This research proposes for the first time the use of confocal laser fluorescence microscopy (CLFM) as an enabling technology to quantify oil prior to produced water disposal. This method takes advantage of the self-fluorescing properties of oil to visualize and quantify in 3D oil droplets in water in real-time. This study initially involves the optimization of CLFM measurement parameters, followed by investigation of CLFM measurement accuracy and precision changes under various environmental condition. Interfacial tension analyses in combination with the Derjaguin, Landau, Verwey, and Overbeek (DLVO) calculation were employed to gain a better understanding of how environmental conditions affect oil droplets stability and therefore impact the precision of CLFM measurements. Finally, the quantification of oil content in three different real produced water samples were compared between CLFM and the EPA 1664 method. This technology has several advantages over other methods, such as solvent free and can be automated for real-time online applications. In addition of investigating CLFM as a sensing technology, this research also explores nanotechnology for environmental applications. We demonstrate for the first time that suspensions of single-layered MoS2 nanosheets can act as photocatalytic antimicrobial materials under visible light in the presence of electron donor. Ex-MoS2 with the presence of EDTA could inactivate 97% and 65% of planktonic and mature E.coli K12 biofilms, respectively, without significant cytotoxicity to mammalian fibroblast cells. The suspension of single-layered MoS2 nanosheets opens up new opportunities for the development of advanced functional nanomaterials for biomedical and environmental applications. In addition, the end of life fate of nanocomposites is also an important aspect to take into consideration for nanotechnology application. In this study, we investigate the ability of wastewater microorganisms to biodegrade nanocomposite films containing different graphene oxide (GO) loads embedded in a model biopolymer (i.e. chitosan). Results showed that microorganisms present in the activated sludge can grow on the surface of the nanocomposites and biodegrade the polymer surrounding the graphene oxide nanoplatelets. As the biopolymer gets degraded, there is increasing exposure of GO on the surface, which yields microbial inactivation and biofilm growth inhibition.