Algerian Journal of  Materials Chemistry  

October 28, 2019

Soumia Abdelkrim, Adel Mokhtar, Abdelkader Bengueddach & Mohamed Sassi

1- Laboratoire de Chimie des Matériaux (LCM), Faculté des Sciences Exactes et Appliquées, Université Oran1, BP 1524, Oran El M’Naouer, 31000 Oran, Algeria.

2- Département Génie des Procédés, Institut des Sciences et Technologies, Centre Universitaire Ahmed Zabana Relizane, Algeria

Abstract. In the present work, Chitosan/bentonite, Chitosan/Ag-Bentonite and Chitosan/AgNPs-Bentonite composite materials were prepared and shaped in form of beads, and characterized using several methods. After that, their thermal stability, swelling properties and antibacterial and antifungal activity were evaluated. In the case of Chitosan/AgNPs-Bentonite, the XRD analysis confirms the partial intercalation of chitosan in the interlayer of bentonite and the formation of silver nanoparticles, AgNPs, with an average diameter between 10nm and 25nm. The latter is confirmed by UV-Visible diffuse reflectance (UV-Vis DR) spectroscopy by the apparition of the large absorption band at 442 nm. For all prepared materials, the FTIR analysis shows the presence of strong interaction between chitosan reactive groups and bentonite interlayer materials. This result is confirmed by thermal analysis where it is observed that these composite materials exhibit a higher thermal stability than the biopolymer alone. The composite materials present also a very good swelling capacity. Indeed, the swelling rate carried out in water media at pH 7 and a temperature of 30°C is 160% higher than that of the corresponding dried material. Otherwise, Chitosan/AgNPs-Bentonite sample displays a very high antibacterial activity against pathogen bacteria strains such as Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853. This activity is less important for Staphylococcus aureus ATCC 43300 and no activity is observed for Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. Since the starting chitosan and bentonite materials showed no antibacterial or antifungal activity, the antibacterial activity of Chitosan/AgNPs-Bentonite sample is attributed to loaded AgNPs species.

Keywords: Chitosan; Bentonite; Silver Nanoparticles; Chemical reduction; Swelling; Antimicrobial Activities.

Vol.2 Issue 2, pp 86–100, (2019)

October 28, 2019

Tounsia AKSIL, Moussa ABBAS, Mohamed TRARI and Salem BENAMARA

1- Laboratory of Soft Technologies and Biodiversity (LTDVPMB/F S), University M’hamed Bougara 35000 Boumerdès, Algeria

2- Labotory of Storage and Valorization of Renewable Energies, Faculty of chemistry (USTHB) BP 32-16111 El-Alia, Bab Ezzouar Algeria.

3- Research Laboratory in Food Technology (LRTA) Faculty of Engineering Science University M’hamed Bougara 35000 Boumerdès, Algeria

Abstract. The present work aims to investigate the moisture adsorption characteristics of Lyophilized Algerian Arbutus unedo L. fruit powder (LP). First, the LP was evaluated for some of its physicohemical parameters, including X-ray diffraction (XRD) properties, crude fiber, titrable, etc. Second, the experimental sorption curves, determined at 20, 30 and 40 °C with the standard static-gravimetric method, were fitted to six isotherm models (Kühn, Caurie, Smith, Halsey, Oswin and GAB). Results showed also that the moisture adsorption isotherms of LP are of S – shaped profile (Type II), generally obtained for biomaterials. Among all tested models, those of Halsey and GAB (T=20 and 30 °C) gave the best fits at 20 and 30 °C, with the mean relative percentage deviation modulus (E%) less than 1%, χ2 ≤ 2.68 10-1 and a root mean square error (RMSE) ≤ 0.2808). The K parameter of GAB model was found to increase with increasing temperature, whereas the monolayer moisture content (X0) decreased with increasing temperature. Such data are represent a usefull tool for choose appropriate storage conditions of LP.

Keywords: Keywords: lyophilized powder; sorption isotherm; modeling; gravimetric method; Water Activity

Vol.2 Issue 2, pp 75–85, (2019)

October 28, 2019

Sonya REDJALA, Nourredine AÏT HOCINE, Rabah FERHOUM, Said AZEM

1- LEC2M, Université Mouloud Mammeri, BP 17, Tizi-Ouzou 15000, Algérie

2- LaMé, INSA Centre Val de Loire, 3 rue de la Chocolaterie, BP 3410, 41034 Blois, France

Abstract. The objective of this work is to highlight the effect of the exposure time of polycarbonate (PC) at low temperature, under air. As a result, its maintenance at 40°C causes damage revealed by microstructural observations. Physical-chemical analyzes made it possible to note changes in the molecular chains as well as changes in mechanical properties confirmed by mechanical tests.

Keywords: Polycarbonate, Thermal aging, Chain Scission, XRD, Mechanical properties.

Vol.02 Issue 02, pp 70–74, (2019)

September 08, 2019

Lilia BENCHIKH, Abdelhafid MERZOUKI

-Laboratoire de Physico-Chimie des Hauts Polymères, Département de Génie des Procédés, Faculté de Technologie, Université Ferhat Abbas Sétif 1, Algérie

Abstract. The present work is a study on cellulose nanocrystals extracted from the wood Pulp of the joineries in order to exploit this cellulosic waste (recycling). After a bibliographic study, we selected four different extraction technics to be followed. The extracts obtained have undergone several physical and structural characterizations to evaluate the influence of the extraction method on the yield in quality and quantity of the CNCs.

Fourier transform infrared spectroscopy (FT-IR) was used to highlight the evolution of the chemical composition thus confirming the elimination of extracellulosic substances during the chemical treatment of the extraction process. X-ray diffraction analysis determined the crystallinity of the CNC. According to the results of the thermogravimetric analyzes, the degradation of the CNCs occurs at a low temperature in the region of 200 ° C. The morphology of cellulose nanocrystals has been studied by optical microscopy.

Keywords: biopolymer, biomass, cellulose, cellulose nanocrystals, whiskers.

Vol.2 Issue 2, pp 62–69, (2019)

August 28, 2019

Sihem Sadaoui-Kacel 1*, Sihem Zaater 2 and Safia Djebbar 3

1-Département de Chimie, Faculté des Sciences, Université de M´hamed Bougara , Boumerdès, Algérie..

2-  Laboratoire de Physico-Chimie théorique et Chimie Informatique, Faculté de  Chimie, Université de Houari Boumediene Sciences et Technologie, BP 32 El Alia,  16111 Alger, Algérie.

3- Laboratoire d’Hydrométallurgie et  Chimie Inorganique Moléculaire, Faculté de  Chimie, Université de Houari Boumediene Sciences et Technologie, BP 32 El Alia,  16111 Alger, Algérie

Abstract. The protonation constants of the repaglinide ligand: 2-Ethoxy-4-[N-[1-(2piperidinophenyl)-3-methyl-1-1butyl] aminocarbonylmethyl] benzoic acid (L) and the stability constants of manganese(II), iron(III), copper(II) and zinc(II) complexes were evaluated by potentiometric method at 298 K in ethanol-water mixture by the Sirko program. The study has been completed by Density Functional Theory (DFT) calculations using the B3LYP method with LANL2DZ basis set in order to confirm the stability study. The stability order obtained is in agreement with the results of binding energies for the complexes. The presence of repaglinide stabilises its complexes in an octahedral geometry around the metallic center. Repaglinide complexation stabilises the degree (II) for manganese, copper and zinc and the degree (III) for iron. Repaglinide complex with iron has the lowest complexation energy. The antioxidant activities of the complexes were evaluated against ascorbic acid (AA) to assess their antioxidant potentials. The results were correlated with frontier orbital energies of the complexes. The repaglinide presents higher antioxidant activity when coordinated to manganese ion.  

Keywords:, Repaglinide, manganese complex, Density Functional Theory, stability constants and antioxidant activity.

Vol.2 Issue 2, pp 49–61, (2019)

August 28, 2019

F. Ait Medjber1,2,*, M. Saidi1

1- Unité de recherche : Matériaux, Procédés et Environnement (UR-MPE): Faculté des Sciences de l’Ingénieur ; Université M’Hamed Bougara –Boumerdès, Algérie

2- Université Mouloud Mammeri–Tizi Ouzou, Algérie

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Abstract. L’objectif de cette recherche consiste à étudier la durabilité des éprouvettes d’un béton fibré ultra performant (BFUP) dans deux milieux agressifs concentrés à 10% et à PH= 1,34(acide chlorhydrique et acide nitrique). L’étude de la durabilité à montré que les éprouvettes élaborées à base du ciment substitué par la pouzzolane présentent des meilleures résistances chimiques dans les deux solutions acides, et que les éprouvettes de BFUP élaborées avec 10% de pouzzolane, résistent mieux dans ces milieux agressifs et présentent des pertes de masses de 5,49% et 3,76% dans l’acide chlorhydrique et l’acide nitrique respectivement après 28 jours d’immersion.

Keywords: BFUP, résistances chimiques, durabilité, caractérisation mécanique.

Vol.2 Issue 2, pp 44–48, (2019)

August 28, 2019

Moussa ABBAS *1, Zahia HARRACHE 1, Tounsia AKSIL 1 and Mohamed TRARI 2

1-  Laboratory of Soft Technology and Biodiversity, Faculty of science, University M’hamed Bougara of Boumerdes, 35000, Algeria

2-  Laboratory of Storiage and Valorization of Renewable Energy, Faculty of Chemistry USTHB BP 32 -16111 El alia Bab Ezzouar  

Abstract. The quantitative kinetic and equilibrium adsorption parameters for Crystal Violet (CV) removed by commercial activated carbon (AC) were studied by UV visible absorption spectroscopy. (AC) with a high specific surface area (1250.320m2/g) was characterized by the Brunauer-Emmett-Teller (BET) method and the zero charge point (pzc).The adsorptive properties of (AC) with (CV) was conducted at variable stirring speed , adsorbent dose, solution pH, initial (CV) concentrations, contact time and temperature using batch mode operation to find the optimal conditions for a maximum  adsorption. The adsorption mechanism of CV onto (AC) was studied using the first pseudo order, second pseudo order and Elovich kinetic models. The kinetic was found to follow a pseudo-second order kinetic model. The equilibrium adsorption data for CV on AC were analyzed by the Langmuir, Freundlich, Elovich and Temkin models. The results indicate that the Langmuir model provides the best correlation (qmax = 35.71, 90.91 mg/g at 25 °C and 40 °C respectively).The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters i.e. the free energy (ΔGo = -2.30 to -5.34 kJ/mol), enthalpy (ΔHo = 36.966 kJ/mol), entropy (ΔSo = 0.131 kJ/mol K) and activation energy (Ea) 40.208 kJ/mol of adsorption. The negative ΔGo and positive ΔHo values indicate that the overall adsorption is spontaneous and endothermic in nature.

Keywords: Crystal Violet, Adsorption, isotherm, Kinetics, Thermodynamics, Equilibrium, Modeling

Vol.2 Issue 2, pp 33–43, (2019)