This work reports the development of ultralight interwoven ultrathin graphitic carbon nitride (g-CN) nanosheets for use as a potential adsorbent in a passive sampler (PAS) designed to bind Hg2+ ions. The g-CN nanosheets were prepared from bulk g-CN synthesised via a modified high-temperature short-time (HTST) polycondensation process. The crystal structure, surface functional groups, and morphology of the g-CN nanosheets were characterised using a battery of instruments. The results confirmed that the as-synthesized product is composed of few-layered nanosheets. The adsorption efficiency of g-CN for binding Hg2+ (100 ng mL-1) in sea, river, rain, and Milli-Q quality water was 89%, 93%, 97%, and 100%, respectively, at natural pH. Interference studies found that the cations tested (Co2+, Ca2+, Zn2+, Fe2+, Mn2+, Ni2+, Bi3+, Na+, and K+) had no significant effect on the adsorption efficiency of Hg2+. Different parameters were optimised to improve the performance of g-CN such as pH, contact time, and amount of adsorbent. Optimum conditions were pH 7, 120 min incubation time and 10 mg of nanosheets. The yield of nanosheets was 72.5%, which is higher compared to other polycondensation processes using different monomers. The g-CN sheets could also be regenerated up to eight times with only a 20% loss in binding efficiency. Overall, nano-knitted g-CN is a promising low-cost green adsorbent for use in passive samplers or as a transducing material in sensor applications.
COBISS.SI-ID: 32549159
Today, tris-s-triazine based graphitic carbon nitride (g-C3N4) is a new research hot topic. It has a unique electronic band structure, high physicochemical stability, large surface area, and is “earth-abundant.” These and other properties have made it a highly researched material especially for visible light photocatalysis and photodegradation applications and as the starting material from which to develop novel electrochemical sensing platforms. In this review, the state-of-the-art technologies utilizing tris-s-triazine graphitic carbon nitride as a tailorable signal-transducing nanostructured material for sensing applications is presented in detail. Initially, the electronic structure of g-C3N4, morphologies, doping, heterojunctions, its combination with other carbon materials, and defect formation, is described, which is followed by a discussion on its role in electrochemiluminescence, photoelectrochemical, fluorescence sensors and gas sensors as a signal transducer with appropriate examples. This review concludes with a discussion summarizing state-of-the-art and both future perspectives and challenges at the cutting edge of this research.
COBISS.SI-ID: 45035267
Bacterial attachment is crucial in many biotechnological applications, but many important bacterial strains cannot form biofilms. Since bacteria need to overcome a high repulsive force to attach to the surface and later to grow and multiply on it, electrostatic modification of the surfaces of cells or the material by polyelectrolytes (PE) was used in our approach, enabling efficient attachment of viable bacterial cells. In our study bacterial strains were selected according to their intrinsic capability of biofilm formation, their shape variety and cell wall structure. These strains were tested to compare how the artificially prepared versus natural biofilms can be used to populate the surface with beneficial bacteria. This study also revealed that the modification of the surfaces of cells or material by polyelectrolytes allows the deposition of bacterial cells, biofilm formation and attachment of biofilm non-forming cells onto surfaces. In this way, artificial biofilms with extended stability can be constructed, leading to selective pressure on further colonization of environmental bacteria.
COBISS.SI-ID: 61416963