فهرست مطالب luma m. ahmed

The enhancement of solar cell efficiency, is required to use materials of a good electrical properties. In this work, the graphene quantum dots (GQD) created from starch as precursor has been performed in single pot using a hydrothermal process. The TiO2/GQD nano-composite was prepared using an in-depth ultrasonic technique to use as a semiconductor in a solar cell. The investigated using techniques such as: FT-IR, FE-SEM, XRD, Raman spectrum. Additionally, the synthesis and the characterization of novel porphyrin derivatives with amide, were designed as sensitizers in dye-synthesized solar cells (DSSCs). Five derivatives were synthesized via a one-pot reaction of porphyrin with amines, and their optimal yield was obtained under various conditions. The synthesized dyes were characterized using techniques such as melting point analysis, mass spectroscopy, FT-IR, 1H,13C-NMR and ESI-Mass. The obtained results demonstrated that the 6b dye exhibited with the high efficiency of 1.86 % at AM 1.5, followed by 6a with 1.82 %, 8a with 1.34 %, and 8b with 1.14 %, as compared to the control cell (N719) with an efficiency of 5.4 %.

Due to its crucial function in environmental cleanup, superparamagnetic iron oxide nanoparticles continue to be the topic of intensive research in the present day. The elimination of textile effluent dye is the subject of the current investigation. Inverse spinel (Fe2O3. FeO) was produced as magnetic iron oxide (Fe3O4) nanoparticles using an unique precipitation approach that relied on the preparation of the particles without any calcination under oxygen gas. The iron sulfate solution was combined with an aqueous mixture of sodium hydroxide and sodium nitrate to create the Fe3O4 nanoparticles, both without and with the use of surfactant like cetramide as templates. FT-IR spectra showed that Fe-O octahedral and tetrahedral bindings at 744 cm-1 and 598 cm-1, respectively, indicated to form an inverse spinel particle. The X-ray diffraction (XRD) research explained that the mean crystal size of Fe3O4 nanoparticle increased from 8.5 nm for Fe3O4 nanoparticle to 22.53 nm for prepared Fe3O4 in presence of cetramide as a template. SEM found the produced shapes as spherical like brooklei. The thermodynamic analysis demonstrated that prepared Fe3O4 in the presence of cetramide underwent endothermic adsorption with chemisorption, while the magnetite prepared without using cetramide is exothermic with physisorption. The magnetite with cetramide a better fit for Freundlich model, and proved it chemisorption. The findings showed that Fe3O4 produced with cetramide is a better adsorbent for removing anionic dye and it is utilized to remove water contaminants.

Normal Spinel Zinc ferrite (ZnFe2O4 or ZnO.Fe2O3) nanoparticle has been synthesized as a dark reddish brown powder using precipitation method. The solvothermal method assisted the preparation route using ethanol at 180 oC for 90 min. The non-ionic surfactant Hexamethylenetetramine (hexamine) is employed as a capping agent, stabilizer and template. The XRD datum demonstrated the ZnFe2O4 peaks were embedded in an amorphous matrix giving broad peaks with a small mean crystal size (16.98 nm). The SEM analysis revealed the ZnFe2O4 was found to be homogenous agglomerated like-cauliflower, with particle size 27.78 nm. The EDX analysis evidence the ZnFe2O4 was purely prepared from Zn, Fe and O in wt % equal 100. The FT-IR analysis proved the ZnFe2O4 nanoparticle is synthesis as a normal spinel type, and found two reasonable peaks of M-O bond  in crystal lattices of ZnFe2O4 nanoparticle first for (Fe3+ -O2-) octahedral site and the other for (Zn2+- O2-) tetrahedral sits for. The band gap found to be 2.10 eV as an indirect band gap. The best dose of spinel to decolorize alkali blue 4B dye was 0.025 g/ 100 mL with efficiency 97.3 % at 30 min. The high increased in ZnFe2O4 dose leads to the screen effect. The photodecolorization of dye obeys to pseudo-first order, and the activation energy is found to be 47.689 kJ/mol at temperature raged (15-35) oC. This photoreaction is endothermic and non-spontaneous that attributed to the raise in the solvation of the transition state between dye and hydroxyl radical.

This work is based on the density function theory (DFT) and time-dependent density function theory methods (TD-DFT) to investigate the density of states (DOS), FT-IR spectra, electro-optical and thermal, properties of Ga-doped Graphene molecule (GM). The Graphene molecule structure is found to be exhibiting semiconductor activity in a pure state with a wide band gap of 3.92301 eV. The defect of Graphene molecule with Ga has been demonstrated to depress the band gap values of GM structure significantly as a result of calculations. The electronic characteristics of graphene in its ground state and low-lying excited states may change based on the structural characteristics of Ga impurity in the GM structure. The results indicate that the electrical characteristics of GM are influenced by the geometrical distribution of Ga impurities in the GM structure. The consequences of Ga impurity are discussed for both GM ground and excited electronic states of GM are explored.

Magnetic iron oxide nanoparticles (Fe3O4 NPs) were synthesized by novel precipitation method as inverse spinel (Fe2O3. FeO). They are directly prepared without calcination under oxygen gas. The Fe3O4 NPs had been prepared by combining the iron sulfate solution with the aqueous mixture including sodium hydroxide and sodium nitrate, without and with using various surfactants such as sodium dodecyl sulfate (SDS), triton X100, cetrimonium bromide (CTAB) and cetramide (CT) as templates.  The FT-IR analysis demonstrated the Fe-O octahedral and tetrahedral bending at 744 cm-1 and 598 cm-1 respectively. The XRD analysis discovered  the mean crystal size of  Fe3O4 NPs is smaller than that presence of surfactants, and its value increment from 8.5 nm for Fe3O4 NPs to 21.55 nm, 22.53 nm, 27.66 nm, and 27.72 nm for Fe3O4 + Triton X-100, Fe3O4 + CT, Fe3O4 + SDS, and Fe3O4 + CTAB, respectively. SEM revealed their samples are nanoparticles and aggregated together like broccoli.  The possibility of using Fe3O4 NPs as magnetic adsorbents to remove the eosin yellow dye from aqueous solutions was successes and economy, due to collect by magnets without need for a long time to separate with centrifuge or filter paper. The maximum chemisorption of dye was 94.48 % using Fe3O4 NPs + CT at shaking 1hour, because CT has a positive part as a hydrophilic moiety and the used dye is acidic nature so will attract and dye easy removal, and the reuse reached to five times with efficiency depressed to 75.61 %.

In this work, CuO/CeO2 nancomposite was prepared via hydrothermal route. The product was prepared under 12 h and 150 oC. The shape, size, and crystalline structure have been investigated through using various techniques such as the scanning electron microscopy (SEM), with energy dispersive X-ray (EDX), the X-ray diffraction analysis (XRD), the Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The magnetic properties of prepared nanocomposites were studied via vibrating-sample magnetometer (VSM). Consequently, acid violet and rhodamine B dyes were applied for investigation the photocatalytic activity of prepared CuO/CeO2 nanocomposite. Results showed that Acid violet and rhodamine B were photo-decolorization under UV irradiation after 120 minutes with 95.8 % and 88.2% respectively. This excellent performance was due to the suitable band structure of synthesized CuO/CeO2 nanocomposites which led to depress the recombination of photo-generated electrons and holes with increased the acidity of CeO2 after incorporation it with CuO in the crystal lattice. This work introduces new nanocomposites for decolorization of organic pollutants from wastewater.

Inverse spinel nickel ferrite (NiFe2O4 (or) NiO.Fe2O3) like- broccoli shape was manufactured as a brown nanoparticle. The NiFe2O4 preparation is done in the presence of the mixture of precursor salts in a ratio (2:1) of the iron ion with nickel ion prior to the presence of a nonpolar surfactant (hexamine). Hexamine acts as a capping agent before adding ammonia to solution; template and stabilizer via growth and storage of its powder. The solvothermal technique aided the precipitation route by using ethanol solvent at 180°C for 90 minutes to depress the defect in the prepared nanoparticle. The XRD data revealed that the NiFe2O4 peaks were wide and had a modest mean crystal size (20.13 nm). The broccoli-like NiFe2O4 nanoparticles with homogenous agglomerations were investigated using SEM- EDX analysis. The particle size is found to be 30.67 nm composing 100% of Ni, Fe, and O atoms. The - FT-IR analysis exhibited the positions of the tetrahedral site for (Fe3+-O2-) and octahedral site peaks for (Ni2+- O2-), and proved the type of NiFe2O4 is an inverse spinal structure. The NiFe2O4 has been owned as an excellent optical property with a small indirect band gap value (2.05 eV). Following this fact, this spinal can be used as a photocatalyst. The best photo-decolorization of this dye took place at pH 7 as a pseudo-first order with efficiency (98 %). This photoreaction is fast, endothermic and non-spontaneous. Negative entropy value refers to the products in this dye decolorization being more regular than the reactant (dye) structure.

In this work new thiosemicarbazide derivatives were synthesized to obtain the intermediate of thiosemcarbazone compounds (1-5) by thiosemicarbazide reaction with several aromatic aldehydes, following treatment of compounds (1-5) with 2-chloroethanoic acid with sodium acetate, a series of compounds (6-8) was prepared. There were 1,3-oxazepine-4,7-dione derivatives compounds (9,10) with phthalic anhydride. By heating thiosemicarbazide with carbon disulfide and anhydrous sodium carbonate in absolute ethanol, 5-amino-1,3,4-thiadiazole-5-thiol compound (11) was prepared. The azomethines synthesized by reaction of compound (11) with aromatic aldehyde compounds (12-14), then processed to obtain mercaptoacetic acid as compounds (15-17). The compound (18) was made with ethylchloroacetate from the cyclization thiosemcarbazone compound (2) in the presence of fused sodium acetate. The reaction of compound (11) with chloroacetylchloride produced compound (19) then treated with urea to obtained compound (20) followed by 4- phenyl phenacyl bromide to prepare compound (21). The characterization outcomes for the prepared compounds verified their chemical structures using IR spectroscopy, NMR, and melting points.

The purpose of this manuscript was to remove and decolorize vitamin B12 from an aqueous solution of drug tablets using ZrO2 as an environmentally friendly method via advanced oxidation processes. Some oxidant agents such as Fe2+, H2O2, K2S2O8 and their mixture of were performed, and the best adsorption sequences have occurred with increased adsorption capacity: q(K2S2O8 + H2O2)>q(H2O2) >q (K2S2O8) >q (Fe2+ + H2O2) >q (Fe2+)>q (without) Endothermic and physical adsorption occurred of this vitamin on the ZrO2 surface with and without the addition of K2S2O8 +H2O2. On the other side, the photoreaction for this vitamin with and without the addition of K2S2O8 +H2O2 was found to be quick, endothermic, less random, and spontaneous. At 15 min, 33.223 % and 98. 684% were calculated as the maximum percentage of removal in the dark reaction and the maximum decolorization in the photocatalytic reaction respectively.