Effect of heat treatment on bioelectronic coordinates and antibacterial activities of natural and synthetic clays

Our work consists in studying the effect of the thermal treatment at 900°C of three clays “two anionic clays of synthesis ' Double lamellar hydroxide' Zn3Al-CO3 and Mg3Al-CO3, and another natural cationic: Ghassoul (Gh)”, on their antibacterial and bioelectronic power. Their chemical characteristics such as pH at zero charge point (pHzcp), redox potential (Eh), index of oxidizing/reducing power (rH2), and electrochemical potential to dissipate energy (W), as well as the type of oxide formed as a result of this treatment; were also determined. The materials were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and scanning electron microscopy (SEM). Antibacterial activity was tested for four bacteria: two Gram positive (Staphylococcus aureus, Enterococcus faecalis) and two Gram negative (Escherichia coli, Salmonella spp). The antibacterial power of the three clays was evaluated by their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), using the microtiter plate technique. The results showed that the pHzcp, rH2, W and antibacterial power of the two lamellar double hydroxides increased as a result of heat treatment. While the test on the heat treated cationic clay showed an opposite result. It thus appears that the changes in the physicochemical and electrochemical characteristics of the clays following their calcination at 900°C; are at the origin of the change in their antibacterial powe

Removing polyphenols contained in olive mill wastewater by membrane based on natural clay and Hydrotalcite Mg-Al

The purpose of this work is to study the performance of a membrane based on Ghassoul and Hydrotalcite (GHTM) in the retention of polyphenols (organic pollutants). This membrane was elaborated and characterized in our laboratory and was used in the filtration of olive mill wastewaters (OMW) of semi-modern unit of the olives. The choice of these materials depends essentially on their interesting properties (low cost, abundantly in nature and the ease of the preparation).The diluted OMW (40%, 60% and 80%) were very acidic with a pH between 5.29-5.64 and had a high concentration of polyphenols from 30-60mg/L. However, after treatment the permeate revealed a significant decrease in polyphenols of61% and a complete disappearance of brown coloration for 80% OMW.The results show that the membrane developed is efficient to remove the polyphenols and reduce the turbidity, COD and BOD5 of OMW

Solvent-free aldol condensation of furfural and acetone on calcined Mg-Al hydrotalcites

Une série de matériaux de type hydrotalcite Mg X Al-CO 3 , où X correspond au rapport molaire nominal Mg / Al (X: 2, 2,5, 3 et 3,5), ont été préparés et caractérisés par fluorescence X (XRF ), X - diffraction des rayons (XRD), spectroscopie infrarouge (FT-IR) et analyse thermique (TG-DTA). L'oxyde mixte (Mg X Al-O) avec un rapport Mg / Al de 3,5 dérivé de l'hydrotalcite calcinée à 450 ° C s'est avéré être le catalyseur optimal qui peut donner la basicité la plus élevée et la plus grande activité catalytique pour la condensation aldolique sans solvant du furfural et de l'acétone.L'activité des hydrotalcites de Mg-Al calciné pour cette réaction était corrélée à leur basicité telle que déterminée par l'adsorption de phénol. La meilleure conversion du furfural et la sélectivité du furfural-acétone (FA) ont été obtenues à 90 ° C après 2 heures sur le Mg 3,5 Al-O avec 98% de conversion et une sélectivité de 78% en (FA). L'activation pour la condensation d'aldol entre le furfural et l'acétone s'est avérée être de 24,8 KJ / mol en catalyze hétérogène avec des hydrotalcites de Mg-Al calciné par rapport à la valeur augmentée en catalyze homogène avec NaOH qui était de 55,8 KJ / mol

Synthèse et caractérisation d'hydrotalcites Mg-Al. Application à l'éldolisation de l'acétone

Hydrotalcites were prepared with various Mg/Al ratios. The influence of pH and alkaline solution of the precipitation were examined. The compounds are well cristallized when the precipitation is done with NaOH + Na2CO3 alkaline solutions at pH near 10. These samples contain Cl- and (CO3)2- compensating anions in the interlayer space. In all cases well defined hydrotalcites phases are obtained. By exchange reactions of the synthetized samples with Na2CO3 the Cl- anions are totally removed. The production of diacetone alcohol by aldol condensation of acetone is an important industrial reaction using soda or potash as catalysts. The substitution of liquid base catalysts by solid catalysts is desirable to preserve environment. In this goal the basicity of Mg-Al hydrotalcites have been tested in the condensation reaction of acetone. It is also evidenced that for the activation temperature higher 400 °C the catalytic activity of these materials increases with the content of (CO3)2- and the Mg/Al ratio

Elaboration and characterization of a natural bentonite-poly(ethylene glycol) composite: Development of an exact theoretical study in function of the polymer-density

The first aim of this work was a systematic experimental and theoretical study of the basal-spacing and characteristics of X-rays diffraction-peaks (positions, intensities, crystallites size...), versus the polymer-density, for a natural bentonite-poly(ethylene glycol) composite. The natural bentonite was extracted from a deposit located in Eastern Rif chain of Morocco (near Nador-city). The basal distance and diffraction-peaks characteristics were measured using X-Rays Diffraction (XRD) method, first, for raw bentonite, and second, for bentonite-poly(ethylene glycol) composites. In particular, measurements reveal the existence of a series of montmorillonite-phases (crystallites) of different sizes within the composites. Afterwards, we have developed a powerful theoretical approach based on Renormalization Theory, and obtain exact scaling relations for the physical quantities of interest. We have compared our theoretical predictions with our experimental data dealt with the considered natural bentonite-poly(ethylene glycol) composites, and found that theory and experiment are in good agreement. Also, as a complementary experimental study, we achieved a detailed analysis of pure PEG, natural bentonite and Bentonite-PEG composites using the so-called Fourier Transform Infrared Spectroscopy (FTIR) tool. A comparison between these complexes show that the polymer-density affects drastically the stretching and bending vibration modes