No abstract

This work focuses on the degradation of methylene blue (MB), which has a toxic effect in water and cannot be completely removed by classical methods, i.e. under UV light. Photocatalytic nanoparticles produced in heterogeneous structure were carried out by examining the interaction of MB with our pegylated core-shell CdSe/ZnS@Fe2O3 nanocrystals under UV light in a dye-stuff solution medium. In our study CdSe/ZnS@Fe2O3 nanoparticles were synthesized and then, PEG has been attached to the surface upon careful surface engineering. The amount and time of catalyst upon degradation of MB under these conditions were investigated. The PEG:(CdSe/ZnS@Fe2O3) nanocomposite enable the degradation of MB with a photocataliytic degradation rate of 16,5*10− 3 min-1 in 30 mins, which is found to be more than 4,9 times when compared with the pegylated bare Fe2O3. It is worth noting that further optimizing the PEG:(CdSe/ZnS@Fe2O3) and the MB ratio the reaction rate reaches the maximum level of 63,12*10− 3 min-1. The PEG-(CdSe/ZnS@Fe2O3) nanocomposite exhibited a photocatalytic degradation efficiency of 84,2% within 30 min for methylene blue under visible light.

We have developed a robust synthesis methodology for quantum dots (QDs) nanoparticles with magnetic properties designed for biomodal imaging. These nanocrsytlas consists of a semiconductor quantum dot core with engineered fluorescence, which is located in a paramagnetic iron oxide shell that acts as a magnetic resonance imaging (MRI) contrast agent. Yolk-shell CdSe/ZnS@Fe 2 O 3 nanoparticles (NPs) are synthesized via sonochemical decomposition of iron pentacarbonyl (Fe(CO) 5 ) using the oleylamine (OAm) as the ligand. The sonochemical synthesis method of magnetic fluorescent NPs that can be used as MRI contrast agents provided advantages such as improved quantum efficiency and homogeneous size distributions. It has been determined that the luminescence efficiency of quantum dots decreases in coatings that can be made at high temperatures by thermal decomposition. In order to eliminate the disadvantage of elevated temperatures, the sonochemical decomposition method, which allows coating at low temperatures, has been used. With this method, yolk-shell (CdSe/ZnS@Fe 2 O 3 ) nanoparticles were produced with high photoluminescence quantum efficiency and homogeneous size distributions. The synthesis magnetic fluorescent NPs optimized was determined to have the injection temperature of Fe(CO) 5 at 60 °C, Fe(CO) 5 /CdSe@ZnS ratio 0.7, OAm/Fe(CO) 5 volume ratio 1.43 with an oxidation time 5 min. Under these conditions, the quantum efficiency was found to be 78 %, nanoparticle sizes between 11-14 nm and r 1 value was 0.199, r 2 value was 0.518 in MRI analysis. These optically active magnetic fluorescent nanoparticles as positive contrast agents (T1 weighted) are predicted to pave the way for the future of advanced bioimaging systems.