Thai Journal of Nanoscience and Nanotechnology

Optical and Photocatalytic Properties of BiVO4 Particles Derived via rapid Synthesis Sonochemical Process

2023-12-19T18:24:49+07:00

Currently, the environmental pollutions are very critical to human health and nature. For solving these problems, photocatalytic degradation by metal oxide materials is among effective organic compound decomposition methods. BiVO₄ is an attractive material due to light activation under visible irradiation. This work focuses on the rapid synthesis of BiVO₄ via sonochemical process within 30 min. Ultrasonic irradiation time determined as a crucial parameter of particle formation was designated in range of 0 - 30 min. Crystallinity of synthesized materials was characterized by X-ray diffraction technique. Optical band gap energy was calculated by Kubellka-Munk function of collected data from diffuse reflectance spectroscopy and photoluminescence technique was used to determine the photogenerated behavior of photocatalyst material. Raman spectroscopy and X-ray absorption spectroscopy were employed to investigate their chemical bonding and oxidation state, respectively. Among all samples, the sample synthesized at 30 min irradiation time exhibited pure monoclinic structure with optical band gap of 2.5 eV and superiority in photodecomposition of RhB under visible light exposure.

The Influence Of Plastic Wrap Types On Oxygen Detection Property By Colorimetric Oxygen Indicator Based On TiO2/Methylene Blue Nanocomposite

2023-12-27T18:18:07+07:00

The work is focused on the oxygen detection of colorimetric oxygen indicators by covering the indicator surface with different plastic wrap types. The layer of colorimetric detection was composed of titanium dioxides nanoparticles (TiO₂), citric acid, methylene blue (MB) and polyvinyl alcohol (PVA). The precursor suspension was operated at 250 rpm by dry and wet milling process for 30 and 45 min. After that TiO₂/MB composite was coated by the spin coating technique with a spin speed of 3000 rpm and 5 film layers on a glass substrate. The oxygen indicator with TiO₂/MB composite film was presented in a blue film as indicated initial state. Then, plastic wraps with different types as polyvinylidene chloride (PVDC), polyvinyl chloride (PVC) and polyethylene (PE) were covered on the indicator surface to monitor its physical morphology, optical properties, and oxygen detection. Color changing in bleach and color state and oxygen detection of the indicators with the different plastic wraps were monitored by the snapshots in each hour for the cyan percentage analysis in the CMYK system. Meanwhile, the presence of bleach/color state in the indicators was confirmed by UV-Vis spectrophotometer focusing on the absorption range of MB dye to identify its state. The optimized covering plastic wrap on TiO₂/MB colorimetric indicator was obtained by polyvinyl chloride that showed the identical indicator efficiency compared with the original indicator without the plastic wrap owing to good oxygen gas flow on its membrane. While the retardation of color changing in the indicator occurred by the polyethylene wrap on its surface due to the unique property of blocking oxygen gas flow.

Optimization of SPIONs-Loaded PLGA Microdroplets for Targeted Magnetic Drug Delivery: A Microfluidic Approach

2023-12-21T14:55:53+07:00

This study investigates the potential of monodispersed superparamagnetic iron oxide nanoparticles (SPIONs)-loaded poly(lactic-co-glycolic acid) (PLGA) microdroplets, fabricated using droplet-based microfluidics, for targeted magnetic drug delivery applications. By adjusting the flow rate ratio (Q = Q_d/Q_c ) between the dispersed and continuous phases, the diameter of the monodispersed PLGA microdroplets could be controlled. With a flow rate ratio of Q = 0.05, SPIONs-loaded PLGA microdroplets with a diameter of 8.6 ± 0.6 μm were successfully formed. The magnetic properties of the encapsulated SPIONs were preserved, as evidenced by their response to an external magnetic field. Upon exposure to a magnetic field, the SPIONs-loaded PLGA microdroplets penetrated porcine skin to a depth of more than 140 μm within 5 minutes. The results demonstrate the potential of these monodispersed SPIONsloaded PLGA microdroplets for targeted magnetic drug delivery systems, as they possess controllable size and preserved magnetic properties, enabling enhanced penetration and localization when combined with external magnetic fields.