Salah Ammar

Bio: Salah Ammar is an academic researcher from University of Gabès. The author has contributed to research in topics: Raman spectroscopy & Crystallite. The author has an hindex of 30, co-authored 101 publications receiving 3070 citations. Previous affiliations of Salah Ammar include École Normale Supérieure & Carthage University.

Control of the shape and size of iron oxide (α-Fe2O3) nanoparticles synthesized through the chemical precipitation method

Abstract: Hematite (α-Fe 2 O 3 ) nanoparticles were synthesized via a simple chemical precipitation method. The impact of varying the concentration of precursor on the crystalline phase, size and morphology of α-Fe 2 O 3 products was explored. The characteristic of the synthesized hematite nanoparticles were evaluated by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FT-IR) spectroscopy, Raman spectroscopy, Differential Thermal Analysis (DTA), Thermo Gravimetric Analysis (TGA), Ultraviolet–Visible (UV–Vis) analysis and Photoluminescence (PL). XRD data revealed a rhombohedral (hexagonal) structure with the space group R -3 c in all samples. Uniform spherical like morphology was confirmed by TEM and SEM. The result revealed that the particle sizes were varied between 21 and 82 nm and that the increase in precursor concentration (FeCl 3 , 6H 2 O) is accompanied by an increase in the particle size of 21 nm for pure α-Fe 2 O 3 synthesized with [Fe 3+ ] = 0.05 M at 82 nm for pure α-Fe 2 O 3 synthesized with [Fe 3+ ] = 0.4 M. FT-IR confirms the phase purity of the nanoparticles synthesized. The Raman spectroscopy was used not only to prove that we have synthesized pure hematite but also to identify their phonon modes. The thermal behavior of compound was studied by using TGA/DTA results: The TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. Besides, the optical investigation revealed that samples have an optical gap of about 2.1 eV and that this value varies as a function of the precursor concentration.

Electro-Fenton and photoelectro-Fenton degradation of indigo carmine in acidic aqueous medium

Abstract: Acidic aqueous solutions containing concentrations of the dye indigo carmine up to 09 g l−1 have been degraded by environmentally friendly electrochemical methods such as electro-Fenton and photoelectro-Fenton using an undivided cell with a Pt or boron-doped diamond (BDD) anode and an O2-diffusion cathode at 350 °C The great oxidation ability of these systems is due to the large production of hydroxyl radical ( OH) at the anode surface from water oxidation and in the medium mainly from Fenton's reaction between catalytic Fe2+ and cathodically generated H2O2 Complete mineralization is feasible using electro-Fenton with a BDD anode and 10 mM Fe2+ and when 10 mM Fe2+ and 025 mM Cu2+ are combined as catalysts in photoelectro-Fenton with a Pt anode The first method yields similar degradation rate in the pH range 20–40, whereas the second one is more potent up to 044 g l−1 of the dye at pH 30 Mineralization is enhanced with increasing current density and initial dye concentration The indigo carmine decay always follows a pseudo zero-order reaction Isatin 5-sulfonic acid, indigo and isatin are detected as aromatic products, which are degraded to oxalic and oxamic acids The electro-Fenton process with BDD yields the destruction of Fe3+-oxalate and Fe3+-oxamate complexes by OH at the anode surface In the presence of Fe2+ and Cu2+ the photoelectro-Fenton process with Pt involves the photolysis of Fe3+-oxalate complexes under the action of UVA light, while competitive Cu2+-oxalate and Cu2+-oxamate complexes are mineralized with OH produced by Fenton's reaction The nitrogen of the dye is mainly converted into NH4+

Kinetics of oxidative degradation/mineralization pathways of the antibiotic tetracycline by the novel heterogeneous electro-Fenton process with solid catalyst chalcopyrite

Abstract: The degradation of solutions of the antibiotic tetracycline (TC) has been studied by a novel electrochemical advanced oxidation process, consisting in electro-Fenton (EF) process using chalcopyrite as heterogeneous catalyst. In fact, chalcopyrite powder was the source of Fe 2+ and Cu 2+ ions instead of a soluble catalyst salt used in conventional EF. Experiments were performed in an undivided cell equipped with a Pt or boron-doped diamond (BDD) anode and a carbon felt cathode, where TC and its oxidation intermediate products were destroyed by hydroxyl radicals ( OH) formed both, in the bulk solution from electrochemically induced Fenton’s reaction (Fe 2+ and H 2 O 2 ) and Fenton’s-like reaction (Cu + and H 2 O 2 ), and at the anode surface from water oxidation. The effects of operating parameters such as applied current, chalcopyrite concentration and anode material were investigated. TC decay followed pseudo-first-order reaction kinetics. The absolute rate constant for TC oxidation by OH was found to be 3.2 × 10 9 M −1 s −1 , as determined by the competition kinetic method. EF process using chalcopyrite as heterogeneous catalyst showed to be more efficient than conventional EF, achieving almost total mineralization of the TC solution (98% of total organic carbon removal) after 360 min under optimum operating conditions. A plausible mineralization pathway for mineralization of TC aqueous solution by OH was proposed based on the identification of different oxidation by-products. Moreover, toxicity tests pointed out that this heterogeneous EF process was able to detoxify the TC solutions.

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Decontamination of wastewaters containing synthetic organic dyes by electrochemical methods. An updated review

Abstract: As the environment preservation gradually becomes a matter of major social concern and more strict legislation is being imposed on effluent discharge, more effective processes are required to deal with non-readily biodegradable and toxic pollutants. Synthetic organic dyes in industrial effluents cannot be destroyed in conventional wastewater treatment and consequently, an urgent challenge is the development of new environmentally benign technologies able to mineralize completely these non-biodegradable compounds. This review aims to increase the knowledge on the electrochemical methods used at lab and pilot plant scale to decontaminate synthetic and real effluents containing dyes, considering the period from 2009 to 2013, as an update of our previous review up to 2008. Fundamentals and main applications of electrochemical advanced oxidation processes and the other electrochemical approaches are described. Typical methods such as electrocoagulation, electrochemical reduction, electrochemical oxidation and indirect electro-oxidation with active chlorine species are discussed. Recent advances on electrocatalysis related to the nature of anode material to generate strong heterogeneous OH as mediated oxidant of dyes in electrochemical oxidation are extensively examined. The fast destruction of dyestuffs mediated with electrogenerated active chlorine is analyzed. Electro-Fenton and photo-assisted electrochemical methods like photoelectrocatalysis and photoelectro-Fenton, which destroy dyes by heterogeneous OH and/or homogeneous OH produced in the solution bulk, are described. Current advantages of the exposition of effluents to sunlight in the emerging photo-assisted procedures of solar photoelectrocatalysis and solar photoelectro-Fenton are detailed. The characteristics of novel combined methods involving photocatalysis, adsorption, nanofiltration, microwaves and ultrasounds among others and the use of microbial fuel cells are finally discussed.

Electro-Fenton process and related electrochemical technologies based on Fenton's reaction chemistry

Abstract: 2.2. Fenton’s Chemistry 6575 2.2.1. Origins 6575 2.2.2. Fenton Process 6575 2.3. Photo-Fenton Process 6577 3. H2O2 Electrogeneration for Water Treatment 6577 3.1. Fundamentals 6578 3.2. Cathode Materials 6579 3.3. Divided Cells 6580 3.4. Undivided Cells 6583 4. Electro-Fenton (EF) Process 6585 4.1. Origins 6585 4.2. Fundamentals of EF for Water Remediation 6586 4.2.1. Cell Configuration 6586 4.2.2. Cathodic Fe2+ Regeneration 6586 4.2.3. Anodic Generation of Heterogeneous Hydroxyl Radical 6587

X-Ray Diffraction

Abstract: Interpretation of X-ray Powder Diffraction Patterns . By H. Lipson and H. Steeple. Pp. viii + 335 + 3 plates. (Mac-millan: London; St Martins Press: New York, May 1970.) £4.