JOURNAL of the Tunisian Chemical Society

serving the Research, the Education and the Industry

Corrosion prevention of mild steel in a simulated concrete medium by the electro-application of a polyaniline coating

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Polyaniline (PANI) film was successively electrodeposited onto mild steel (MS) by cyclic voltammetry from oxalic acid solution. The anticorrosion performance of PANI was investigated in a simulated concrete medium consisted on a filtered saturated lime solution contaminated with 0.5 M NaCl. Corrosion studies were carried out using standard electrochemical methods, electrochemical impedance spectroscopy (EIS) and SEM analysis. PANI proved high inhibition efficiency against MS corrosion. The anticorrosive action of PANI was related, on one hand, to its catalytic behaviour in the oxides layer healing mechanism taking place at the polymer/MS interface and, on another hand, to its physical barrier property against diffusion of corrosives species toward MS surface. 

M. Mrad, L. Dhouibi

PANI, electropolymerization, MS, simulated concrete medium, corrosion

Pages 359-367

Evaluation of antioxidant activity of selected new synthesized oxazolidin-2-one derivatives

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Background: In order to envisage that the two bioactive molecules (pharmacophores) if linked together could generate novel molecular templates which are likely to exhibit interesting biological properties, gathering the two patterns in one molecule and combining their properties was our purpose and presents a new way to increase the efficiency of biologically active molecules. This field of research have gained too much interest as proven by large number of reviews and research articles published in the current years.
Objective: To the best of our knowledge, oxazolidinone derivatives are widely used as antipenetrant agents in a cosmetic and/or dermatologie composition but knowledge of their antioxidant properties is limited or even missing. Therefore, as a part of our ongoing studies toward the development of novel interesting biologically active agents, the evaluation of antioxidant activity of a series of ω-(oxathiolan-2-thion-5-yl)-α-oxazolidin-2-ones (1-3)a-b will be discussed in this study.

S. Ghrab, K. Lahbib, L. Aroua, M. Beji

Biheterocycles, 2-oxazolidinones, oxathiolane-2-thione, PEG chain, antioxidant activity

Pages 368-374

Correlation between the electronic structure and the inhibition efficiency of Capparis Spinosa L. extract for iron and copper corrosion in chloride media

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The inhibiting effect of Capparis Spinosa L. extract was studied for iron and copper corrosion in aqueous chloride medium using quantum chemical calculations. Analysis of the extract composition using GC/MS chromatography showed the presence of various fatty acid compounds including three main molecule which were(9Z,12Z)-octadeca-9,12-dienoic acid (A2), 8E-octadec-8-enoic acid (A1) and hexadecanoic acid (A0). The theoretical investigation were performed with DFT methods at the B3LYP/6-311G (d) and B3LYP/3-21G* basis set. The results allowed identifying the optimal geometries, the vibration frequencies, orbital borders and morphologies that the dipole moment (µ), the energy of the highest occupied molecular orbital (EHOMO) and the energy of the lowest unoccupied molecular orbital (ELUMO). In addition, the electron fraction transferred molecules (ΔN) was determined in order to understand the interaction-extracted surface. Thus, the index calculations Fukui (f -, f +) and the Quantitative Structure-Activity Relationship Modelshave been made in order to illustrate the mechanism of inhibition of this extract on iron and copper surfaces. Satisfactory theoretical correlation was observed by a proposal of a metallic surface interaction mechanism of the extract.

I. Abidli, K. Essalah, N. Souissi

Green inhibitor, DFT calculations, Fukui indices, Quantitative Structure-Activity Relationship Models

Pages 375-380

Kinetic, thermodynamic and structural study of the biosorption of lead and cadmium by red macroalga ( Ceramium virgatum)

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In this study a red macroalga Ceramium virgatum has been classified and used for removal of Cd(II) and Pb(II) from aqueous mediums. The effects of pH, adsorbant concentration, contact time and temperature on biosorption process were studied in batch experiments. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the metal ions by C. virgatum biomass. The biosorption data were well described by Langmuir than Freundlich isotherm. The monolayer biosorption capacity of C. virgatum biomass for Pb(II) and Cd(II) ions was found to 53.9 mg.g-1 and 51.6 mg.g-1, respectively. The mean free energy calculated from Dubinin-Radushkevitch isotherm indicate that the biosorption of Pb(II) and Cd(II) onto C.virgatum macroalga was taken place by chemical sorption. The thermodynamic studies showed that the biosorption was spontaneous and exothermic in nature. Kinetics data of both metal ions were best described by pseudo second order model. The analysis with FTIR indicated that the carboxyl (-CO), hydroxyl (-OH), and amine (-NH) groups are responsible for binding of metal ions. Desorption experiment of metallic ions gives a high regeneration yield (over 90 %) reached after three sorption/desorption cycles showing a good reusability of the biomass.

A. Ben Dekhil, M. Smiri, A. Hafiane

Red macroalga, lead and cadmium, biosorption, desorption

Pages 381-390

Removal and recovery of nutrients as organic fertilizer “solid washed” and inorganic fertilizer “Struvite” from raw and dried poultry manure

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Environmental agricultural protection is a concern due to the increase and poor exploitation of poultry manure. Two processes: (1) Thermal treatment and (2) quick wash were investigated to conserve the organic and mineral nutrients. The thermal treatment consists to minimize the weight and reduce the cost of preservation. The chemical treatment consists of a selective dissolution of phosphorus (P) with the most efficient acid from dried and wet poultry manure. Laboratory-scale trials have confirmed that the drying process is useful for reducing 85% total mass and has a disadvantage such as losing 38% nitrogen to air and 36% orthophosphorus in the liquid fraction which is a responsibility to runoff in water. The comparison between the inorganic acid (sulfuric, perchloric and Hydrochloric acid) and the organic acid (acetic acid) was carried out to dissolve more than 90% of P at pH 4.5 with all acids. The performance of sulfuric acid was confirmed; a small amount was consumed and the acid less expensive than the other acid. The centrifugation technique was tested by the reduction of 44% sulfuric acid with the same P extraction performance. As a result of P fresh manure extraction technique, two by-product are produced as organic fertilizer "solid washed" and inorganic fertilizer "struvite".

S. Abouda, N. Turki, M. Kasmi, I. Trabelsi, M. Ben Amor, A.H. Hamzaoui

Poultry manure, Organic fertilizer, Phosphorus, Acids, Struvite

Pages 391-401

A poly (vinyl chloride) functionalization by some amines. Electrical study and inductively coupled plasma study of the extraction of La(III) and Bi(III) by modified PVC polymers

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The aim of this work was to study the structural and electrical properties of a new polymer obtained by functionalization of a commercial poly (vinyl chloride) (PVC) (Mw = 48000) by 1-chloro-2-phenylaminomethyl-6-phenylaminomethylene-cyclohex-1-ene groups and to evaluate the efficiency of two new polymers obtained by functionalization of the same PVC by grafting L-alanine and 1-(2-aminoethyl) piperazine groups to extract some metal cations from aqueous solutions. The structural properties of the polymers were investigated by different analytical methods; namely elemental analysis (EA), infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) and the electrical properties of the polymer were studied by electrochemical impedance spectroscopy (EIS). The percentage of extraction was determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). One of the obtained polymers gave an extraction ratio of Bi3+ = 98.77% which highlight the importance of the substitution of chlorine atoms by amino groups.

F. Ammari, M. Kahlaoui, M. Dardouri

Poly (vinyl chloride), functionalization, electrical properties, metal cations, extraction, inductively coupled plasma- atomic emission spectrometry.

Pages 402-408

Mechanical alloying processing of solid solution Mg0.33Al0.66 and its substituted compound Mg0.33Al0.63Si0.03

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Optimization of mechanical alloying process for the synthesis of Mg0.33Al0.66 and Mg0.33Al0.63Si0.03 solid solution is carried out in this paper. These alloys are usually having a metastable character; we have done X-ray diffraction analysis (XRD) was for both synthesized compounds. In order to characterize and verify the morphology and the particles size, only the non-substituted alloy is analyzed by scanning electron microscopy (SEM).

H. Jaafar, A. Ayedi, M. Abdellaoui

Mechanical alloying, solid solution, Mg-Al alloys, Al substitution, Si insertion

Pages 409-413

Recovered poly(vinyl chloride) grafted by amino groups and evaluation in metal ions extraction

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The amount of plastic materials used is rapidly increasing and so are the problems caused by municipal plastic waste. Therefore this kind of waste requires an effective control to prevent its negative economic and environmental impact. For this reason the recycling process, chemical processing operations or purification of plastic waste have become an essential process for depollution nowadays. This work studies the purification of recovered Poly(vinyl chloride) (PVC) and its functionalization by grafting amino groups. The purified polymer was substituted with p-phenylenediamine and with p-methoxyaniline to obtain polymers (P1) and (P2). In another modification, diethylenetriamine was introduced on the modified PVC skeleton, obtaining polymers (P3) from (P1) and (P4) from (P2). The obtained polymers were characterized by elemental analysis (CHN), infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). After these chemical modifications, the modified polymers were tested for metal cation extraction from the aqueous phase containing (Cr(III), Pb(II), Cd(II), Zn(II) or Co(II)) using the solid-phase extraction (SPE) method. The study of these extractions with modified PVC (P1, P2, P3 and P4) was followed by Atomic Absorption measurements in aqueous solutions. The extraction percentage of Cd(II) was 84.8% by P3, 79.4% by P4, 18.7% by P2, and 25.8% by P1.

F. Mbarki, F. Ammari, K. Ben Abdessalem, F. Meganem

PVC grafting, p-phenylenediamine, p-methoxyaniline, diethylenetriamine, metal extraction

Pages 169-177

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