ABSTRACT
In this research, magnetic MgFe2O4-CaFe2O4 photocatalyst powder was prepared from recycling of electric arc furnace (EAF) dust as a secondary source through a two-step leaching process followed by co-precipitation method. To maximize the total Fe to Ca recovery ratio (F/C) and evaluate the effective parameters of sulfuric acid concentration and temperature, response surface methodology (RSM) as a design of experiment was used. The best temperature and acid concentration were obtained as 85 °C and 1 M, respectively for the second step of the leaching process. X-ray diffraction (XRD) results indicated that the synthesized nanocomposite sample contains MgFe2O4 and CaFe2O4 phases together with a small amount of Ca2Fe2O5. The saturation magnetization and optical band gap of the synthesized composite powder were 24 emu/g and 2.17 eV, respectively. X-Ray photoelectron spectroscopy (XPS) result revealed the oxidation states as Fe3+, Ca2+, Mg2+ and O2-. Energy dispersive X-ray spectroscopy (EDS) showed that the elements were uniformly distributed within the nanostructured particles. Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) results indicated the presence of CaFe2O4 and MgFe2O4 nanoparticles with good contact between them. The nanocomposite sample showed the capability of 45% for degrading methylene blue (MB) dye under 240 min visible light irradiation. The reusability tests showed that the photocatalytic activity of the nanocomposite was not considerably changed after three cycles.
Subject(s)
Dust , Nanocomposites , Catalysis , Light , RecyclingABSTRACT
In this work a magnetic nano-composite was synthesized by modified incorporation of iron-barium complex into ordered meso-porous silica (MCM-41) as a matrix. The MCM-41 was synthesized by silylation treatment which was accompanied by pH adjusting. Low angle XRD patterns of both annealed MCM-41 and resulted composite exhibited the characteristic reflection of high quality hexagonal meso-structures. TEM image of the composite material revealed that the hexagonal ordered meso-structure host material was not affected by wet impregnation and subsequent calcination in order to incorporate with barium hexaferrite. Also, TEM images accompanied by EDS analysis confirmed the formation of second phase consists of barium and iron ions inside the MCM-41 channels. The resulted composite material showed a super-paramagnetic nature at room temperature.
ABSTRACT
BACKGROUND AND THE PURPOSE OF THE STUDY: Aging is the major risk factor for neurodegenerative diseases and oxidative stress is involved in the pathophysiology of them. Oxidative stress can induce neuronal damages and modulate intracellular signaling, ultimately leading to neuronal death by apoptosis or necrosis. In this study, the possible antioxidant and neuroprotective properties of the natural polyphenolic antioxidant compound, curcumin against homocysteine (Hcy) neurotoxicity was investigated. METHODS: Curcumin (5, 15, 45 mg/kg) was injected intraperitonealy (i.p.) once daily for a period of 10 days beginning 5 days prior to Hcy (0.2 µmol/µl) intracerebroventricular (i.c.v) injection in rats. Biochemical and behavioral studies, including passive avoidance learning and locomotor activity tests were studied 24 hrs after the last curcumin or its vehicle injection. The cell density of hippocampus layers and apoptosis in rats' hippocampi by immunohistochical methods were also studied. RESULTS AND MAJOR CONCLUSION: Results indicated that Hcy could induce lipid peroxidation and increase Malondialdehyde (MDA) and Super Oxide Anion (SOA) levels in rat's brain. Additionally, Hcy impaired memory retention in passive avoidance learning test. However, curcumin decreased MDA and SOA levels significantly and improved learning and memory in rats. On the other hand Hcy could induce cell death and apoptosis in rats' hippocampi which was inhibited by curcumin. These results suggest that Hcy may induce lipid peroxidation in rat's brain. and polyphenol treatment (curcumin) improves learning and memory deficits by protecting the nervous system against Oxidative stress.
