Browsing by Author "Zighed, Mohammed"

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Biodegradability assessment of HDPE-based biocomposites: Influence of starch and fiber composition
(Elsevier Ltd, 2024) Zighed, Mohammed; Benotmane, Bénamar; Ferkous, Hana; Ramdane, Nora; Boublia, Abir; Ahmed, Mukhtar; Bourbia, Amel; Lemboub, Samia; Yadav, Krishna Kumar; Benguerba, Yacine
This research aims to analyze the biodegradation dynamics of a tertiary composite blend, including High-Density Polyethylene (HDPE), starch and linen fiber, and their combined effect on decay processes in authentic environmental settings. It investigates the relationship between fiber content and decomposition rates, details the biodegradation mechanisms, and evaluates the reactive profiles of the involved constituents. Decay kinetics and the biodegradation mechanism of three formulations: HDPE60S40, HDPE60S20F20, and HDPE60S30F10, representing composites with 60 % HDPE, complemented by 40 %, 20 % starch and 20 %, 10 % linen fiber, respectively, are examined. HDPE60S30F10 is noted for its superior biodegradation rates, showing a 1.2 % weight loss in soil and 9.89 % in marine conditions and an increased resistance to shearing forces, whereas HDPE60S40 recorded a weight loss of 0,63 % in soil and 2.59 % in seawater against 1,7 % and 6.64 % in soil and seawtaer, respectively recorded with HDPE60S20F20. Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations complement these findings, presenting HDPE60S40 as the most rigid, HDPE60S20F20 as the most ductile with a bulk modulus of 13.34 GPa, and HDPE60S30F10 exhibiting the best shear resistance with a shear modulus of 12.48 GPa. Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR) analyses confirm microbial involvement and significant surface erosion, particularly indicating particularly starch degradation. The results suggest that integrating linen fiber into the composites enhances biodegradation.
Biosorption of zinc (II) from synthetic wastewater by using Inula Viscosa leaves as a low-cost biosorbent : experimental and molecular modeling studies
(Elsevier, 2023) Rouibah, Karima; Ferkous, Hana; Delimi, Amel; Himeur, Touhida; Benamira, Messaoud; Zighed, Mohammed; Darwish, Ahmad S.; Lemaoui, Tarek; Yadav, Krishna Kumar; Bhutto, Javed Khan; Ahmad, Akil; Benguerba, Yacine
The use of biosorption as a strategy for lowering the amount of pollution caused by heavy metals is particularly encouraging. In this investigation, a low-cost and efficient biosorbent, Inula Viscosa leaves were used to remove zinc ions (Zn2+) from synthetic wastewater. A Fourier transform infrared spectroscopy experiment, a scanning electron microscopy experiment, and an energy dispersive X-ray spectroscopy experiment were used to describe the support. Several different physicochemical factors, such as the beginning pH value, contact duration, initial zinc concentration, biosorbent dose, and temperature, were investigated in this study. When the Langmuir, Freundlich, Temkin, Toth, and Redlich-Peterson models were used to match the data from the Inula Viscosa leaves biosorption isotherms, it was found that the biosorption isotherms correspond most closely with the Langmuir isotherm. On the other hand, the kinetic biosorption process was investigated using pseudo-first-order, pseudo-second-order (PS2), and Elovich models. The PS2 model was the one that provided the most accurate description of the biosorption kinetics. The thermodynamics process shows the spontaneous and endothermic character of Zn2+ sorption on Inula Viscosa leaves, which also entails the participation of physical interactions. In addition, the atom-in-molecule analysis, density functional theory, and the conductor like screening model for real solvents, were used to investigate the relationship that exists between quantum calculations and experimental outcomes
Elaboration et caractérisation de bio composites à base de PEHD/ amidon renforcés par les fibres de lin
(Université M'Hamed Bougara : Faculté de Technologie, 2022) Zighed, Mohammed; Benotmane, Bénamar(Directeur de thèse)
Ce travail de thèse a pour objectif d’élaborer un matériau biocomposite en associant le polyéthylène haute densité (PEHD) avec de l’amidon renforcés par les fibres de lin et susceptible d’être utilisé dans le domaine de l’emballage, de la manufacture ou autres application industrielles avec le respect des exigences économiques et environnementales. Les fibres de lin courtes sont modifiées par un traitement alcalin et incorporées dans La matrice constituée du mélange PEHD/amidon sans ajout de compatibilisant selon un processus en deux étapes : mixage et thermocompression. Les propriétés de ces biocomposites ont été étudiées moyennant la spectroscopie infrarouge à transformée de Fourier (FTIR-ATR), la diffraction de rayons X (DRX), l'analyse thermogravimétrique (TGA), la calorimétrie différentielle à balayage (DSC), la microscopie électronique à balayage (MEB), l’indice de fluidité (MFI), les tests de résistance au choc ou impact Izod, les essais de résistance à la traction uniaxiale et les essais de biodégradabilité par enfouissement sous le sol et immersion dans l’eau de mer. Les spectres FTIR-ATR et les images au MEB ont révélé que la teneur en amidon au-delà de 40% en poids dans le mélange PEHD/amidon réduit significativement la compatibilité du mélange. En revanche, en incorporant les fibres de lin dans le mélange, ces dernières agissent comme un pont entre le PEHD et l'amidon, assurent un ancrage mécanique entre les deux polymères et renforcent la structure du biocomposite ainsi obtenu. Les analyses thermiques ATG et DSC ont montré une stabilité thermique limitée en deçà de 250°C, température de début de dégradation de l’amidon, et une cristallinité améliorée grâce aux effets de nucléation de l’amidon sur le processus de cristallisation du PEHD. En outre, les propriétés physiques, y compris la densité et les propriétés mécaniques, notamment la résilience, la rigidité et la résistance à la traction de ces matériaux ont enregistré des valeurs appropriées en raison de l'action des fibres de lin de transférer les contraintes mécaniques dans l’ensemble de la matrice PEHD/amidon ce qui a contribué à compenser l’incidence de la miscibilité partielle des composants. En revanche, l’indice de fluidité et l’allongement à la rupture de ces biocomposites ont montré de faibles valeurs en raison de la présence dans le mélange de l’amidon, dont la fluidité est très basse par rapport à celle du PEHD. Les résultats de biodégradabilité des biocomposites, enfouis dans le sol et immergés dans l’eau de mer, ont montré une perte de masse évaluée à 1.9% et 6.1% respectivement. Ces résultats ont été confirmés par les spectres FTIR-ATR et images du MEB des échantillons testés. Cette dégradation se produit sur le compte de la décomposition des molécules d’amidon et de fibres de lin hydrolysables et vulnérables aux attaques microbiologiques.
The impact of Covid-19 on energy consumption in Algeria- study and outlook
(Web of Science, 2021) Zighed, Mohammed; Benotmane, Benamar
Energy consumption is a major concern in the world, and even in Algeria, because of its eco- nomic and social impact on people’s way of life. All aspects and activities of life, including energy consumption, have been influenced by the deep sanitary crisis related to the Covid-19 pandemic, which has affected the world from 2020 until today. This study examines the energy consumption in Algeria for 2020 during the coronavirus pandemic. It was reported that a huge decline of 13% was recorded in the national consumption of energy in 2020 (petroleum products and natural gas) compared to 2019, falling from 67 MTOE to 59 MTEO. Electricity consumption has also dropped at a rate of 4%. This trend was due to the lockdown and containment policies implying a set of mea- sures serving as a non-clinical approach to mitigate the spread of the virus and better managing this sanitary crisis. Some of these measures could benefit the national energy-saving strategy out- side of the Covid-19 crisis. However, more technical and behavioral measures are highly required to ensure more effective saving and rationalize the use of energy, the main drive of the economy.
Performance of high-density polyethylene–starch–linen fiber biocomposite
(2022) Zighed, Mohammed; Benotmane, Benamar
This study was carried out on the physicochemical and mechanical characterization of a biocomposite consisting of high-density polyethylene (HDPE)/starch matrix reinforced with linen fiber which is renewable, inexpensive and biodegradable material. The linen fibers were modified through the alkaline treatment, and the polymers HDPE and starch were blended without compatibilizers. The composites were fabricated using a two-stage process: mixing and thermocompression. Characterizations were analyzed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Izod impact, and tensile strength tests. The FTIR spectra and SEM analysis showed weak compatibility between HDPE and starch. Compared to HDPE, the crystallinity of the HDPE/starch blend was enhanced and the thermal stability was reduced as revealed by ATG and DSC analyses. The mechanical Izod impact and tensile tests revealed improved stiffness and Young’s modulus with decreased impact strength, tensile stress and elongation-at-break. Alternatively, the HDPE/starch/linen fiber biocomposite exhibited better improved mechanical proprieties while maintaining good crystallinity and thermal stability, on account of the high fracture resistance and reinforcement of the linen. The biocomposite with 60% HDPE, 20% starch, and 20% linen fiber can be considered for use in industrial applications such as manufacturing and packaging, in accordance with economic and environmental requirements