Profound Understanding of Effect of Transition Metal Dopant, Sintering Temperature, and pO2 on the Electrical and Optical Properties of Proton Conducting BaCe0.9Sm0.1O3-δ.

This study reports the effect of transition metal (TM) substitution on the electrical and optical properties of BaCe0.9Sm0.1O3-δ (BCS). Concentrations of 5-10 mol % of each of Fe and Co have been doped for the B-site of BCS by citric acid autocombustion method. Powder X-ray diffraction has revealed the formation of an orthorhombic perovskite-type structure. FTIR confirmed a distortion in the lattice upon TM-doping in BCS. Scanning electron microscopy (SEM) images of 1400 °C sintered samples have manifested a higher densification in BaCe0.8Sm0.1Co0.1O3-δ (BCSC10) with a grain size ∼11 µm compared to the parent compound BCS (∼2 µm). Thermogravimetric (TG) analysis showed a water uptake in case of BaCe0.85Sm0.1Co0.05O3-δ (BCSC5), while BaCe0.85Sm0.1Fe0.05O3-δ (BCSF5) did not show a noteworthy uptake of water. TG has also proved that the incorporation of Fe and Co in BCS did not improve the chemical stability in CO2 at elevated temperature. The band gap estimated using Kubelka-Munk model based on the diffuse reflectance data was found to be the lowest for BCSC5 (2.47 eV). However, it increases upon lowering oxygen partial pressure (pO2), which was interpreted by a band structure modifications. Among the samples investigated, BCSC10 sintered at 1400 °C showed the highest electrical conductivity of 0.02 S cm(-1) in air at 600 °C, while its proton mobility appears to be negligible under the investigated humidity atmosphere.

Fabrication and Optimisation of Alumina Nanoporous Membranes for Drug Delivery Applications: A Comparative Study.

Neurodegenerative disorders cause most physical and mental disabilities, and therefore require effective treatment. The blood-brain barrier (BBB) prevents drug molecules from crossing from the blood to the brain, making brain drug delivery difficult. Implantable devices could provide sustained and regulated medication to solve this problem. Two electrolytes (0.3 M oxalic acid and 0.3 M sulphuric acid) were used to anodise Al2O3 nanoporous membranes, followed by a third anodisation in concentrated H2SO4 to separate the through-hole membranes from the aluminium substrate. FTIR, AFM, and SEM/EDX were used to characterise the membranes' structure and morphology. The effects of the anodisation time and electrolyte type on the AAO layer pore density, diameter, interpore distance, and thickness were examined. As a model drug for neurodegenerative disorders, donepezil hydrochloride (DHC) was loaded onto thin alumina nanoporous membranes. The DHC release profiles were characterised at two concentrations using a UV-Vis spectrophotometer. Oxalic acid membranes demonstrated an average pore diameter of 39.6-32.5 nm, which was two times larger than sulphuric acid membranes (22.6-19.7 nm). After increasing the anodisation time from 3 to 5 h, all of the membranes showed a reduction in pore diameter that was stable regardless of the electrolyte type or period. Drug release from oxalic acid-fabricated membranes was controlled and sustained for over 2 weeks. Thus, nanoporous membranes as implantable drug delivery systems could improve neurodegenerative disease treatment.

Recycling for solar photocatalytic activity of Dianix blue dye and real industrial wastewater treatment process by zinc oxide quantum dots synthesized by solvothermal method.

Solar photocatalytic activity of zinc oxide quantum dots (ZOQDs) was investigated and two samples of ZOQDs were synthesized by solvothermal method and characterized using different spectroscopic techniques. Crystal and morphological properties were obtained from XRD and HRTEM showed the purity, high crystallinity single phase and the elongated shape of prepared quantum dots. The measured crystallite size of the S1 and S2 samples is 8.4 and 9.6 nm respectively. The results of BET analysis and the optical properties of the samples shown that the first sample have larger values for both the specific surface area and band gap energy. Estimation of the photocatalytic performance indicated that the first sample give the best degradation rate of the synthetic Dianix Blue dye (DB) dye (2.47 × 10-2 s-1). Likewise, in the photo-oxidation of coumarin, the sample with the smallest particle size achieves the highest by 20% fluorescence rate than the largest particle size sample. In addition, the work included a study of the mineralization and recycling efficiency of industrial wastewater as a study case in the presence of different doses of ZOQDs by sun light for a one year and this evaluation done according to Egyptian allowed COD limit according to local environmental ministry law.