Zeinab Saad

Releases of phosphate fertilizer industry in the surrounding environment: Investigation on heavy metals and polonium-210 in soil

Distribution of Cu, Zn, Pb, Cr, Ni, Mn concentrations and the activity of polonium-210 in the surrounding area of a phosphate fertilizer industry located on the eastern coast of the Mediterranean Sea has been determined. Nineteen sampling sites were distributed around the industrial zone on a surface area of about 100,000 m2. Atomic absorption spectroscopy and Alpha spectroscopy were used to quantify the heavy elements and polonium-210, respectively. Investigation on a particle scale was conducted by TEM and SEM coupled to EDX and X-ray cartography to determine the nature of heavy elements carriers and their distribution. Heavy elements were mainly concentrated inside the particle size fraction < 50 microm. Their levels decreased with distance increasing from the industry. According to the reference soil, enrichment factors were about 10, 15, 32 and 100 times for Zn, Pb, Cu, and Cr, respectively inside the particle size fraction < 50 microm on the closest sites to the industry. The main contaminant sources were transport and storage of row materials and the free release of phosphogypsum waste. Heavy elements were entrapped inside agglomerates of sulfates, phosphates and iron oxihydroxides in a diffused shape. Polonium-210 with an enrichment factor of about 56, showed the same behavior of the spatial distribution of the trace elements.

Synergy in Photomagnetic/Ferromagnetic Sub-50 nm Core-Multishell Nanoparticles

Based on nickel hexacyanidochromate and cobalt hexacyanidoferrate Prussian blue analogues, two series of photomagnetic/ferromagnetic sub-50 nm core multishell coordination nanoparticles have been synthesized in a surfactant-free one-pot multistep procedure with good control over the dispersity (10% standard deviation) and good agreement with the targeted size at each step. The composition and the valence state of each shell have been probed by different techniques that have revealed the predominance of Co(II)-NC-Fe(III) pairs in a series synthesized without alkali while Co(III)-NC-Fe(II) photoswitchable pairs have been successfully obtained in the photoactive coordination nanoparticles by control of Cs(+) insertion. When compared, the photoinduced behavior of the latter compound is in good agreement with that of the model one. Exchange coupling favors a uniform reversal of the magnetization of the heterostructured nanoparticles, with a large magnetization brought by a soft ferromagnetic shell and a large coercivity due to a harder photomagnetic shell. Moreover, a persistent increase of the photoinduced magnetization is observed for the first time up to the ordering temperature (60 K) of the ferromagnetic component because of a unique synergy.

Role of iron oxidation byproducts in the removal of phosphate from aqueous solution

Zero Valent Iron (ZVI) is widely investigated in water treatment processes; the removal of contaminants may take place at the surface of ZVI or at the surface of its oxidation byproducts that have flaked off into the bulk solution. In this work, iron byproducts were synthetized under different aeration conditions (4 or 8 mg O2 per L) and aging times (40 h or 6 days). The prepared iron oxidation byproducts were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman spectroscopy, zeta potential, BET surface area, and particle size analyses. XRD analysis showed that the prepared iron oxidation byproducts were composed mostly of lepidocrocite, maghemite, and magnetite. These flaked off iron oxidation byproducts were used alone (without ZVI) to remove phosphate. Equilibrium and kinetic studies were conducted to determine the sorption capacities and the rate of phosphate ion uptake at various pH values by the prepared byproducts. The experimental data showed that phosphate sorption adhered to a pseudo second order kinetic model and the maximum sorption capacity was determined at 2.5 mg P per g. Phosphate removal capacities of synthetic pure iron oxides and oxy-hydroxides were also determined. Raman and FTIR spectroscopy showed that phosphate was retained by inner sphere complexation.

Design and Magnetic Properties of a Mononuclear Co(II) Single Molecule Magnet and Its Antiferromagnetically Coupled Binuclear Derivative

The preparations of related mononuclear and binuclear Co(II) complexes with a quasi-identical local C3v symmetry using a cryptand organic ligand are reported. The mononuclear complex behaves as a single molecule magnet (SMM). A relatively weak antiferromagnetic exchange coupling (J) of the same order of magnitude as the local magnetic anisotropy (D) is determined experimentally and theoretically for the binuclear complex. The weak magnitude of the antiferromagnetic exchange coupling, analyzed using a combination of broken-symmetry density functional theory and wave function based calculations, is ascribed to the weak overlap between the singly occupied orbitals because of the local C3v symmetry of the Co(II) ions; the organic ligand was found to contribute to the exchange coupling as the azido bridge that directly links the Co(II) ions. Calculation of the energy and wave functions of the spin states for the binuclear complex, in the general case, allows analysis of the effect of the |J/D| ratio on the magnetic behavior of the binuclear complex and prediction of the optimum range of values for the complex to behave as two weakly interacting SMMs.

Design of a Binuclear Ni(II) Complex with Large Ising-type Anisotropy and Weak Anti-Ferromagnetic Coupling

The preparation of a binuclear Ni(II) complex with a pentacoordinate environment using a cryptand organic ligand and the imidazolate bridge is reported. The coordination sphere is close to trigonal bipyramidal (tbp) for one Ni(II) and to square pyramidal (spy) for the other. The use of the imidazolate bridge that undergoes π-π stacking with two benzene rings of the chelating ligand induces steric hindrance that stabilizes the pentacoordinate environment. Magnetic measurements together with theoretical studies of the spin states energy levels allow fitting the data and reveal a large Ising-type anisotropy and a weak anti-ferromagnetic exchange coupling between the metal ions. The magnitude and the nature of the magnetic anisotropy and the difference in anisotropy between the two metal ions are rationalized using wave-function-based calculations. We show that a slight distortion of the coordination sphere of Ni(II) from spy to tbp leads to an Ising-type anisotropy. Broken-symmetry density functional calculations rationalize the weak anti-ferromagnetic exchange coupling through the imidazolate bridge.

Protein Bread Fortification with Cumin and Caraway Seeds and By-Product Flour

Malnutrition continues to be a key health problem in developing regions. The valorization of food waste appears as an ideal way to prevent malnutrition and improve people’s access to food. Cumin (Cuminum cyminum L.) and caraway (Carum carvi L.) oilseeds are commonly used for cuisine and medicinal purposes. However, remaining cakes after oil extraction are usually underutilized. In order to assess the usefulness of these by-products in food applications, this study investigated the effect of their addition to protein bread formulations. Different levels (2, 4 and 6%) of whole seeds and cakes flour were used in the study. Fortified protein bread samples were compared to control protein bread and evaluated for their sensory, color, moisture, hardness properties, nutritional values as well as their biological activity. Results indicated that bread fortification shows a significant effect on bread properties depending on fortification level. A higher acceptability was observed specially for bread fortified with by-products flour. Increased tendencies of color darkness, moisture content, bread hardness, nutritional values as well as total phenolic content and radical scavenging activity compared to control bread were observed as the percentage of fortification increased in both cases. The overall results showed that the addition of cumin and caraway seeds and by-product flour can improve the antioxidant potential and overall quality of protein bread.

Effect of Addition of Fennel (Foeniculum vulgare L.) on the Quality of Protein Bread

Abstract Fennel (Foeniculum vulgare L.) is an aromatic plant belonging to Apiaceae family widely cultivated elsewhere for its strongly flavoured leaves and seeds. Fennel seeds are of particular interest as a rich source of both vegetable and essential oils with high amounts of valuable components. However, residual cakes after oil extraction were typically considered as byproducts, in the present framework, the potential added value of these cakes was studied. The aim of this study was to investigate the effect of addition of fennel cake and seeds to protein bread quality. In the current research, a single-screw extruder, which is a solvent-free technique, was used for fennel seed oil extraction. For the protein bread making, fennel seed and cake flour in concentrations from 1 to 6% were used. Moisture, colour L*a*b*, hardness, total phenolic concentration, DPPH radical scavenging activity, and nutritional value of protein bread were determined. The addition of fennel cake and seeds had significant (p < 0.05) effect on bread crumb colour and hardness attribute, whereby the bread became darker and harder in texture than the control. Moreover, higher antioxidant activity and total phenolic concentration were observed for both protein breads enriched with fennel cake and seed flour. The overall results showed that addition of fennel cake and seed had beneficial effects on phenolic concentration, antioxidant activity and quality of protein bread. This result suggests also that added value of fennel seeds oil by-products could be increased by their utilisation in bread production.

Evaluation of Nutritional and Technological Attributes of Whole Wheat Based Bread Fortified with Chia Flour

The aim of this study was to investigate and compare the effect of wheat bread fortification with varied levels (2%, 4%, and 6%) of chia seed powder (full fat) and cakes (defatted, residue after oil extraction). Chia flour was added to whole wheat bread rich in vital wheat gluten for the first time. The breadcrumbs were assessed for their antioxidant activity, nutritional content, textural properties, color, and sensory profiles. The addition of chia seed powder, particularly in high levels, was more effective in improving antioxidant activity compared to bread fortified with chia cakes. Bread supplementation with chia flour improves its nutritional value, especially in the case of chia cakes. A higher moisture content and lower hardness were observed after bread fortification, the influence was more evident with the defatted cake than with seed powder. Fortification with chia flour led to darker breads without significantly affecting their global acceptability. However, the fortified bread showed better values than control in terms of sensory profile. These results suggest that the addition of chia seed powder and defatted cake can enhance the overall whole wheat bread quality. Our results also highlight that bread making could be an unconventional alternative for the exploitation of defatted chia seed.