0000000000181505
AUTHOR
A. Saoiabi
showing 5 related works from this author
Thermodynamic and kinetic control over the oxidation mechanism of the natural vanadyl porphyrin series (DPEP)VO in methylene chloride: electrogenerat…
2006
The electrochemical behavior of the natural (DPEP)VO series (where DPEP is the dianion deoxophylloerythroetioporphyrinate) is studied in methylene chloride. The investigated compounds, which were extracted from oil shales of Tarfaya (Morocco), exhibit a typical electrochemical behavior as compared to that of related synthetic vanadyl porphyrins. The electro-oxidation of (DPEP)VO is characterized by a splitting of the peaks when carried out at a glassy carbon electrode. This can be explained by two possible paths (CE and EC mechanisms) which are characterized by a “square diagram” where the chemical step, C, corresponds to a dimerization (radical–radical or substrate–substrate reaction). The…
Some factors affecting the removal of lead(II) ions from aqueous solution by porous hydroxyapatite: relationships between surface and adsorption prop…
2006
A porous hydroxyapatite (p-HAp) was prepared and employed for the removal of lead(II) ions at different concentrations from aqueous solution to determine the adsorption properties of p-HAp and compare them with those of a commercial hydroxyapatite (CAp) sample. The kinetic data obtained indicated that the adsorption performances of the adsorbents depended both on their specific surface area and crystallinity. Complexation of the Pb(II) ion on the adsorbent surface favoured the dissolution of hydroxyapatites characterized by a Ca/Pb molar ratio in the 0.85–1.5 range. The maximum adsorption capacity of p-Hap for Pb(II) ions at 30 ± 2°C was 2.30 mmol/g relative to 1.38 mmol/g for the commercia…
Separation and identification of petroporphyrins extracted from the oil shales of Tarfaya: geochemical study
2002
Abstract Vanadyl and nickel porphyrins were isolated from the oil shales of Tarfaya (Morocco) by extraction followed by column chromatography. The ratios and characteristics of these porphyrin complexes were essentially obtained on the basis of UV–visible and mass spectrometry data. Geochemical information could be drawn from these data. The nature and the contents of the metals coordinated and non-coordinated to porphyrin systems were also determined in this study.
Further data on the levels of emerging Fusarium mycotoxins enniatins (A, A1, B, B1), beauvericin and fusaproliferin in breakfast and infant cereals f…
2011
Abstract Sixty-eight samples of cereals products, including breakfast cereals ( n = 48) and infant cereals ( n = 20), purchased from supermarkets and pharmacies in Rabat-Sale area from Morocco were analysed for the determination of six emerging mycotoxins: four enniatins ENs (ENA, ENA1, ENB and ENB1), beauvericin (BEA) and fusaproliferin (FUS). Samples were extracted with a mixture of acetonitrile:water (85:15, v/v), using an Ultra-Turrax® homogeniser. Mycotoxins were then identified and quantified by liquid chromatography (LC) with diode array detection (DAD). Positive samples were confirmed by LC–MS/MS. Analytical results showed that the percentages of analysed samples contaminated with…
Chemical modification of porous calcium hydroxyapatite surfaces by grafting phenylphosphonic and phenylphosphite acids
2006
Abstract It is well known that the incorporation of organic molecules can provide an effective route to modify the surface properties of apatite ceramics. The present study shows that phosphonates can react with calcium ions to control the formation of the hydroxyapatite structures. The grafting of C6H5PO(OH)2 (PPOH) and C6H5PO(OH)H (PPH) was used to increase the specific surface area as well as the porosity of hydroxyapatite materials. The higher specific surface area for HAp treated by PPOH is around 267 m2/g compared to the pure HAp (140 m2/g). The phenyl (C6H5) groups are removed by thermal treatment around 500 °C. After treatment at 800 °C, organoapatites (PP-HAp) are converted to stoi…