Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques (CRAPC)
Recent publications
Hydrogel nanocomposites comprised of chitosan-grafted-hydrolyzed polyacrylamide as matrix and montmorillonite clay as nanofiller CTS-g-PAAm/MMT were synthesized in aqueous phase by using Triton X-100 surfactant as porogen agent with the aim to apply as adsorbents for the removal of Basic Red 46 (BR46) dye. The as-prepared ampholytic hydrogels, denoted as M/MMTx (x = 0, 2, 5, and 10 wt.% of clay loading), were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The nanohybrid hydrogels exhibited mostly exfoliated structure of the MMT layers and presented morphology that is more porous as compared to the virgin matrix. Also, the thermal stability was marginally affected by clay loading. Study on the swelling behavior showed remarkable water super-absorbing ability, salt-, and pH-sensitivity. The adsorption performances were evaluated by varying clay content, adsorbent dose, pH, initial dye concentration, contact time, and temperature. The results showed that the sorption rates were fast and more than 78% of adsorption capacities were achieved within nearly 30 min using 0.1 g L−1 sorbent dose in 200 mg L−1 of dye solution. The nonlinear kinetics and isotherm adsorption models fitted on the experimental data correlated well with pseudo-second-order kinetics and Langmuir models. Also, the intra-particle diffusion mechanism is not rate-limiting step and the adsorption was suggested to occur mainly via electrostatic interactions and hydrogen bonding. The maximum Langmuir adsorption capacities (qm) of the matrix and the optimized nanocomposite M/MMT2 were found to be 1553 and 1813 mg g−1, respectively. Thermodynamic parameters revealed that sorption process was endothermic and spontaneous. Moreover, effective regeneration was obtained in four adsorption–desorption cycles and about 92% of the adsorbed dye was released from hydrogels. Results obtained from this study suggest that the prepared hydrogel nanocomposites could be promising adsorbents for removing cationic dyes from polluted water.
The purpose of the present work is to experimentally investigate a new high-performance broadband photodetector (PD) based on all-amorphous ZnO/Si heterostructure incorporating Ag ultrathin films. The sensor was developed using the RF magnetron sputtering method at room temperature conditions. In this context, a-ZnO/Ag/a-ZnO/a-Si/Ag/a-Si embedded ultrathin-films were sputtered on the glass substrate. The device structural, morphological, optical, and photodetection characteristics were studied by performing XRD, SEM, EDX, UV–Vis–NIR spectroscopy, and photoresponse characterizations. The analysis showed an improved absorbance behavior over a wide spectral range. It was demonstrated that the use of a-ZnO/a-Si heterostructure with Ag intermediate ultrathin-films incorporation leads to achieving multiband photodetection property with low dark noise effects, where the photodetector provides high responsivity values of 208 mA/W, 160 mA/W, and 180 mA/W over UV, Visible and NIR spectral ranges. These improvements are attributed to the combined effects of improved light-scattering due to the effect of agglomeration of silver on the surface, and the absorbance improvement enabled by optical micro-cavity effects generated by the inserted Ag ultrathin-films. Therefore, the present experimental study can offer new strategies for the development of highly-detective broadband multispectral photosensors based on a-Si photonics platform, which are suitable for optoelectronic applications.
This work focuses on the preparation and characterization of new poly(GMA)@Fe3O4 and poly(GMA)@Fe3O4-NH2 nanocomposites. Firstly, the magnetite was synthesized and functionalized by different aminosilanes (mono, di and triamine); then, different percentages of these materials were dispersed by ultrasound in the poly(GMA) matrix. The structural, thermal and morphological properties of obtained composites were evaluated. For this, different characterizations such as Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectrometry, scanning electronic microscopy and thermogravimetric analysis were employed. It was shown that the aminosilanes nature, the percentage of nanofillers and the use of ultrasonic treatment play a very important role in the structural, thermal and morphological properties of the obtained composites; the results show that the best composites with improved stabilities were obtained by Fe3O4 and NH2-Fe3O4 functionalized by monoamine as nanofillers. The yields of the obtained composites were very high in a lower reaction time, which is mainly due to the sonication process. The use of ultrasound also allowed preserving the epoxy ring known to be a very reactive function and an easily opened ring; this huge advantage will allow a possible modification of these composites for any application. Graphical abstract
Nanocomposites based on styrene and maleic anhydride copolymers (SMA/Mag-CTA) are obtained through in situ polymerization method in the presence of Maghnite (Mag) a montmorillonite clay material as nano-reinforcing filler and benzoyl peroxide as a catalyst. The Mag-CTA is organophilic silicate clay prepared through a direct exchange process, using Cetyltrimethylammonium bromide in which it used as green nano-filler. The prepared SMA/Mag-CTA nanocomposites have been extensively characterized by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (TEM). TEM analysis confirms the results obtained by XRD and clearly show the nature of SMA/Mag-CTA nanocomposites. Mag-CTA layers are partially exfoliated for the lower amount of clay (3 wt%), intercalated for higher amounts of clay (5 and 7 wt%), and well dispersed in SMA copolymers. Moreover, thermogravimetric analysis data indicated an enhancement of thermal stability of nanocomposites compared with the pure copolymer.
Nanotherapeutic agents play a crucial role in medicine and the bio-nanotechnology field. Because of its cost-effectiveness, plant-based nanoparticle production has sparked a lot of attention, sustainable way, eco-friendly nature, and a plethora of applications. In the present study, the antioxidant and antimicrobial potential of silver nanoparticles (AgNPs) of aqueous extract of Nigella Sativa seeds have been investigated. AgNPs synthesized using N. Sativa extract, characterized by UV-Vis spectroscopy, FTIR, X-ray diffraction (XRD), SEM, and energy dispersive spectroscopy (EDX) techniques showed a peak at 430 nm, with size ranging between 12.97 and 16.37 nm with a spherical shape. Three assays were used to test the antioxidant activity of biosynthesized silver nanoparticles: DPPH, FRAP, and TAC radical scavenging assays, all of which showed strong antioxidant capacity. The disk diffusion method was used for determining the antimicrobial activity of AgNPs. Evaluation of the antimicrobial potential of biosynthesized AgNPs registered the highest inhibitory activity against S. aureus (17.38 mm) followed by E. coli (16.45 mm), B. subtilis (15.5 mm), P. aeruginosa (14.6 mm), and S. Typhimurium (14.35 mm). It was noted that the increased extract concentration in biosynthesized AgNPs leads to a higher zone of inhibition. These results indicated that AgNPs have an effective and strong antimicrobial activity that provides a marvelous source for the development of a new antibacterial drug that can be used for solving the problem of microbial resistance.
In the present work, we report a simple synthesis method for preparation of copolymers and nanocomposites from limonene and styrene using clay as a catalyst. The copolymerization reaction is carried out by using a proton exchanged clay as a catalyst called Mag-H+. The effect of temperature, reaction time and amount of catalyst were studied, and the obtained copolymer structure (lim-co-sty) is characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H-NMR) and differential scanning calorimetry (DSC). The molecular weight of the obtained copolymer is determined by gel permeation chromatography (GPC) and is about 4500 g·mol−1. The (lim-co-sty/Mag 1%, 3%, 7% and 10% by weight of clay) nanocomposites were prepared through polymer/clay mixture in solution method using ultrasonic irradiation, in the presence of Mag-CTA+ as green nano-reinforcing filler. The Mag-CTA+ is organophilic silicate clay prepared through a direct exchange process, using cetyltrimethylammonuim bromide (CTAB). The prepared lim-co-sty/Mag nanocomposites have been extensively characterized by FT-IR spectroscopy, X-ray diffraction (XRD), scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM). TEM analysis confirms the results obtained by XRD and clearly show that the obtained nanocomposites are partially exfoliated for the lower amount of clay (1% and 3% wt) and intercalated for higher amounts of clay (7% and 10% wt). Moreover, thermogravimetric analysis (TGA) indicated an enhancement of thermal stability of nanocomposites compared with the pure copolymer.
A new electrochemical sensor based on inactivated Escherichia coli (E. coli) was prepared for the determination of lead ions (Pb²⁺) in real samples. The biorecognition element was obtained by inactivation of the E. coli bacteria. The biosensing platform was constructed by mixing bovine serum albumin (BSA) with inactivated Escherichia coli (E. coli*) deposited on the surface of platinum (Pt) electrode modified with conductive poly(vinylidene fluoride) (PVDF)/multiwall carbon nanotubes (MWCNT)-gold nanoparticles MWCNTs-PVDF-AuNPs/E. coli*-BSA. The impedance characterization of the nanocomposite reveals performance improvements in the charge transfer process (Ret = 20 Ω) compared to the use of Pt bare electrode (Ret = 115 Ω). Moreover, the bioelectrochemical reaction between the released-enzymes from inactivated E. coli* and the inhibitor (Pb²⁺) was confirmed and successfully demonstrates the inhibition system. The electrochemical detection of Pb²⁺ was performed by square wave voltammetry (SWV) with a detection limit of 0.13 μg/l and a quantification limit of 0.43 μg/l. The sensor was applied to detect lead ions in real samples like waste-water and lipstick with an excellent selectivity against copper ions. The biosensor is highly sensitive (30.1 μA/ppb.cm²) with good stability and reliable reproducibility with a relative standard deviation (RSD = 0.23%) for monitoring lead ions and seems operational for monitoring other hazardous materials. Graphical Abstract
This research work describes the degradation of quinoline yellow (QY) in aqueous solutions by the heterogeneous Fenton and photo-Fenton processes in the presence of CuO/Fe2O3 photocatalyst. CuO/Fe2O3 derived from LDH structure was synthesized by the co-precipitation method. The physiochemical characteristics of CuO/Fe2O3 were described by XRD, TEM/SEM, BET surface area, and FTIR techniques. The effects of pH, H2O2 concentration, dye concentration, catalyst dose, reaction temperature, and reusability of catalyst on the QY decolorization efficiency were studied. The results indicated that a complete removal of QY was achieved within 150 min, when the H2O2 and QY concentrations were 27.6 mM and 100 mg/L, respectively. The rate constants for QY removal by the heterogeneous Fenton system were calculated, and the experimental data were found to fit the pseudo-first order model. Under optimal conditions, the rate constants were, respectively, 0.02032 and 0.01715 min⁻¹ for the photo-Fenton and Fenton systems; this means that the addition of light has not a noticeable effect.
Benzoxazine containing phthalonitrile, as one of the most advanced high performance thermosetting resin, has gained a lot of attention in the last decades. Indeed, the combination of the thermally activated ring-opening polymerization of the benzoxazine and the cyano addition reaction of the phthalonitrile allows the development of robust polymeric networks. Following this path, a renewable natural resource, vanillin, was used to develop a new benzoxazine containing phthalonitrile thermosetting system. The newly developed monomers present the advantage of a simple synthesis process along with an autocatalytic polymerization mechanism. The molecular structures of the synthesized monomers were characterized by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H NMR). Thermal properties were also characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Typically, the newly developed monomers showed excellent thermal stability with starting decomposition temperatures over 496.4 °C with a char yield at 800 °C of about 80.7%. The thermomechanical properties were investigated by dynamic mechanical analyzer (DMA) and the fractured surfaces were studied by scanning electron microscopy (SEM). Globally, the newly developed partially-bio polymer showed outstanding thermal resistance along with excellent thermomechanical properties.
The interactions between a biologically active flavonoid, hesperidin (HESP) and two of the most known π- acceptors DDQ and TCNE were investigated leading to two new charge transfer complexes (CTC). UV-Visible spectrophotometry was used to follow the reactions in solution in methanol and ethanol as solvents. Infrared and NMR spectrophotometry was used to characterize the products formed in the solid state reactions. The)1:1(stoichiometry of formed charge transfer complexes (HESP-DDQ and HESP-TCNE) was confirmed by Molar ratio method and Benesi-Hildbrand equation was used to calculate the formation constants KCT and the molar extinction coefficient ɛCT of the formed CTC. CTC formed in the reaction of hesperidin with π-acceptors DDQ and TCNE showed high formation constants KCT. KCT values for both CTC formed in ethanol are higher than those formed in methanol and those found for the HESP-DDQ CTC were higher than those of HESP-TCNE. Our results suggest the formation of stable CT complexes of hesperidin with π-acceptors DDQ and TCNE.
Pure and 15% bismuth-doped cobalt spinel ferrites [CoFe2O4 (CFO) and Co0.85Bi0.15Fe2O4 (CBFO)] were synthesized by the auto-combustion method using glycine as the fuel agent. Both structural and morphological studies confirmed the nanosize criteria for both compounds with an increase in particle size when introducing bismuth ions. The insertion of non-magnetic ions in the A-site of CFO compound induced a decrease in the saturation magnetization due to the increase of the antiferromagnetic interactions. The biocompatibility of CFO and CBFO nanoparticles with two different human breast cancer cells (T47-D and MDA-MB-231) and one prostate cancer cell (PC3) was evaluated. The CBFO compound induced a higher cancer cell mortality with IC50 values of 61.12, 66.41 and 134.38 µM, for MDA-MB-231, T47-D and PC3 cancer cells, respectively. The cytotoxicity against normal human cells was found to be lower than 2% even for high CBFO particle concentrations. Accordingly, both prepared compounds could be considered as potential therapeutic agents against cancer cells.
Dehydroacetic acid (DHA) and derivatives are widely used in the synthesis of pharmacologically active heterocyclic compounds. In this study, two new series of pyranonicotinonitriles and chromene-3-carbonitriles have been synthesized under microwave irradiation using DHA synthons, as starting materials, through multicomponent reaction (MCR), involving domino Knoevenagel-Michael addition or one pot intramolecular cyclization. All the resulting heterocyclic compounds have been characterized by ¹H NMR and ¹³C NMR, 2D NMR (HSQC, HMBC) and mass spectroscopy. Mass peaks of the synthetized compounds correspond perfectly to molecular ions [M+H] or [M+Na]. Notably, ¹H-NMR spectra of all the compounds display a characteristic doublet at δH 6.07 ppm, which is assigned to the pyran-2-one heterocycle. Biological activities, such as the antioxidant DPPH radical scavenging and antibacterial/antifungal assays against ATCC strains have been evaluated in-vitro. Results showed that all compounds are capable to reduce DPPH with different IC50 values. The germs sensitivity towards the synthesized compounds is variable with Staphylococcus aureus being the most sensitive bacteria. Further docking simulations have been carried out targeting S. aureus penicillin binding proteins group (PBP2, PBP3 and PBP4) and thymidylate kinase (TMK) and the cell division Z ring protein (FtsZ) using AutoDock Vina software. The validity of docking results have been confirmed based on the best affinity scores and types of interactions. The molecular mechanisms of the synthesized heterocycles towards target proteins involved in S. aureus growth have been predicted through molecular docking studies.
In the present work, attempts have been made to prepare a scintillating nanoparticles composite films of Ce3+ doped Y3Al5O12 (YAG:Ce) embedded in polystyrene polymer (PS). YAG:Ce phosphor is previously synthesized using sol–gel method. YAG:Ce‐PS composite films of 250±30 μm thickness were prepared by solvent casting procedure with different PS/solvent concentration and different mass ratio between nanoparticles YAG:Ce and polystyrene PS. X‐ray diffraction analysis confirmed that YAG:Ce powders were successfully prepared. Using TGA thermogravimetric analysis and DSC differential scanning calorimetry, we found that the glass transition temperature Tg and thermal degradation are shifted to higher temperatures for composites films relative to pure PS. PL photoluminescence shows yellow emission of the Ce3+ doped YAG phosphors, which are attributed to 5d → 4f transition of Ce3+ ion and the intensity of the emissions change with the mass ratio of the YAG:Ce nanoparticles incorporated in the polymer and with the concentration of the polymer solution.
This paper reports the hemi-synthesis of a new thiazole derivatives from 3-allylrhodanine under green chemical conditions (solvent free and ambient temperature). Two targeted molecules: perillaldehyde and cuminaldehyde from essential oils of Ammodaucus leucotrichus Coss. & Dur. and Cuminum cyminum L. were used. Thiazole derivatives (HRP11, 12) were obtained and characterized by FTIR, 1H NMR, 13C NMR, 2D NMR. In addition, stereochemistry of HRP11, 12 was characterized by using 2D NMR and their structural stability was confirmed by DFT calculation. Furthermore, the new products were screened for their in vitro biological activity and in silico interaction with TNF-α by using molecular docking study. A moderate antioxidant activity was found for the two obtained products evaluated by DPPH and ABTS radical scavenging techniques. Against all odds, HRP12 revealed an interesting antibacterial activity against Escherichia coli, Citrobacter freundii, and Salmonella typhimurium. Thereby, a molecular fluorescence spectroscopy was carried out to compare the fluorescence of gentamicin and that of HRP11, 12. Molecular docking performed on the Tumor Necrosis Factor (TNF-α) demonstrated sensitivity towards the thiazole derivatives obtained.
A novel potentially biologically active oxazaphosphinane derivatives was synthesized by facile synthetic approaches from the combination of hydroxyaniline, aldehyde and triethylphosphite. The crystal structure of compound 1b has been determined. Single crystals belong to the triclinic system with p -1 space. The relative in vitro antitumor activity against human cell lines (PRI, K562 and JURKAT) of these derivatives in comparison to chlorombucil is reported. All synthesized compound showed excellent activity with IC50 value of 0.014-0.035 mM. The binding energy of the Epidermal growth factor receptor (EGFR)-oxazaphosphinane complex and the calculated inhibition constant using docking simulation showed that all molecules has the ability to inhibit EGFR therapeutic target. In addition, DFT calculation has been used to analyze the electronic and geometric characteristics.
A new series of novel -aminophosphonate derivatives have been synthesized by new rapid and convenient approach, based on the stepwise one pot reaction of 2-hydroxyaniline, aromatic aldehydes and triethyl phosphite. The structure of all compounds have been identified by appropriate spectroscopic methods; such as FTIR, 1H, 13C, 31P NMR and ESI-MS. The crystal structure of diethyl-(2-fluorophenyl)-(2-hydroxy-4-methylphenyl)aminophosphonate has been determined, this crystal belongs to the P-1 space group. In vitro antifungal activity of the synthesized compounds were tested against wheat fusarium (Fusarium oxysporum) and compared with standard antifungal drug Chlorpyriphos EC to explore their potential antifungal activity. We also measured the antioxidant activity of these molecules, compared with vitamin C as standard antioxidant.
In this paper, TCO (Transparent Conductive Oxide) incorporating ultrathin Ag intermediate film is proposed as a new buffer layer to enhance the efficiency of CIGS thin-film solar cells (TFSCs).In this regard, versatile multilayer thin-films based on ZnO/Ag/ZnO and ITO/Ag/ITO structures were deposited on glass using RF magnetron sputtering technique to determine the optoelectronic parameters of the multilayer structures. The elaborated samples were then characterized using SEM, EDS, XRD, and UV–Visible absorption spectroscopy techniques to investigate the structure morphological, optical, and electronic properties. The deposited multilayer thin-films showed amorphous-like structure and exhibited a broadband absorbance over the visible and even NIR spectrum ranges, indicating its potential application as alternative buffer layers for thin-film solar cells. In this context, TCO/Ag/TCO/CIGS solar cells have been numerically investigated using the deposited multilayer optoelectronic properties. It was revealed that the estimated efficiency of the ZnO/Ag/ZnO/CIGS-based solar cell could reach 18.5% with an open circuit voltage of 0.7 V and a short-circuit current density of 34.8 mA/cm². The performances exhibited by the investigated solar cell demonstrated that ZnO/Ag/ZnO multilayer can be used as an alternative to the conventional CdS buffer layer for developing high-performance non-toxic CIGS solar cells.
In the current paper, the new molecule (E)-3-(2-Ethoxyphenyl) -5-(3-(2methoxyphenyl) -4 methylthiazol-2(3H) -ylidene) -2-thioxothiazolidin-4-one (EMTh2) was synthesized and characterized using FT-IR, UV-Vis, NMR, and X-ray diffraction experimental techniques. The experimental structure was determined from single-crystal X-ray diffraction data at low temperature (173K). The compound crystallizes in the monoclinic system and space group P21/c with cell parameters: a=11.1100(5) Å, b=13.0597(6) Å, c=15.2343(7) Å, β=103.480(5)°, Z=4. R= 0.0512 was the final value for 4372 observed reflections. The two thiazol rings are coplanar, while the ethoxyphenyl and methoxy phenyl rings are essentially perpendicular to these rings with dihedral angle values of 107.2° for C4-N2-C8-C13 and 101.7° for C3-1-C15-C20. All theoretical calculations are performed using DFT with B3LYP functional and 6-31G(d,p) basis set. Both theoretical and experimental molecular structures were investigated and compared to one another. Furthermore, Hirshfeld surface analysis was performed to display surface contours and 2D-fingerprint plots were used to obtain contributions of the most important intermolecular interactions. The theoretical UV-Vis spectrum was computed in chloroform as a solvent using the TD-DFT method. ¹H and ¹³C-NMR chemical shifts were calculated using the GIAO approximation and the results were compared to the experimental ones. In addition, natural bond orbital (NBO), global reactivity parameters, MPA and NPA atomic charges, molecular electrostatic potential, Fukui functions were estimated using the same level of theory. The interactions between the investigated molecule and DNA bases (mainly adenine, cytosine, guanine, and thymine) were explored using the electrophilicity-based charge transfer method.
Vector-borne diseases represent a real threats worldwide, in reason of the lack of vaccine and cure for some diseases. Among arthropod vectors, mosquitoes are described to be the most dangerous animal on earth, resulting in an estimated 725,000 deaths per year due to their borne diseases. Geographical position of Algeria makes this country a high risk area for emerging and re-emerging diseases, such as dengue coming from north (Europe) and malaria from south (Africa). To prevent these threats, rapid and continuous surveillance of mosquito vectors is essential. For this purpose we aimed in this study to create a mosquito vectors locale database using MALDI-TOF mass spectrometry technology for rapid identification of these arthropods. This methodology was validated by testing 211 mosquitoes, including four species (Aedes albopictus, Culex pipiens, Culex quinquefasciatus, and Culiseta longiareolata), in two northern wilayahs of Algeria (Algiers and Bejaia). Species determination by MALDI TOF MS was highly concordant with reference phenotypic and genetic methods. Using this MALDI-TOF MS tool will allow better surveillance of mosquito species able to transmit mosquito borne diseases in Algeria.
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