Removal of a local antiseptic dye on two solid supports by adsorption: Remoção de um corante antisséptico local em dois suportes sólidos por adsorção

In this research, we studied the adsorption of an Eosin B (EB) dye is a local antiseptic, available in pharmacies in the form of an active preparation on the surface of activated carbon and natural clay. Activated carbon and natural clay were characterized using various physicochemical techniques to determine the crystalline structures of the two adsorbents by DRX, and the chemical bonds by FTIR analysis, and finally, to know the maximum absorbance λmax of the dye by UV-Visible analysis. The effects of various experimental parameters, such as the effect of adsorbent mass, the initial concentration of eosin B is 1.610-4 molL-1, the contact time is 24 hours, and the pH 7 ~ 9, were studied. The removal of the dye increases with the decrease of the initial concentration of Eosin B (EB) and the contact time of the solution. The percentage of Eosin B (EB) removal increases accordingly, which arrives at 80% for activated carbon and 92% for natural clay. Langmuir and Freundlich adsorption models were used for the adsorption equilibrium descriptions. The data was very well corrected with these models. Monolayer adsorption capacities were equal to 50 mgg-1 at pH 8.3 and 25°C. Adsorption measurements show that the adsorption process is very fast and physical in nature

Removal of a food dye on two solid supports by adsorption

Activated carbon and natural clay are extremely promising for the removal of dyes in a water solution. Natural clay and activated carbon were characterized using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) techniques, and the food dye was characterized by UV-Visible. The effects of various experimental parameters, such as initial carmine concentration, contact time, temperature and pH were studied. The removal of the dye increases with the decrease in the initial concentration of carmine and the contact time of the solution. The percentage of carmine removal increases accordingly, reaching 97% for activated carbon and 67% for natural clay. Langmuir and Freundlich adsorption models were used for the adsorption equilibrium descriptions. The data was very well corrected with these models. Monolayer adsorption capacities were equal to 31 mgg-1 at pH 8.0 and 27°C. Adsorption measurements show that the adsorption process is very fast and physical in nature. Thermodynamic parameters such as enthalpy ∆H°, ∆S° entropy and ∆G° free enthalpy were also evaluated to reveal the nature of adsorption. The results explain that the adsorption process is an exothermic, spontaneous physisorption

Synthèse et propriétés électrochimique du système La1-xMxAlO3 M :(Sr,Ca)

Dans ce travail nous aborderons l’étude de l’effet de la substitution du strontium sur les propriétés de l’oxyde mixte LaAlO3. Des composés La1-xSrx AlO3 (0 < x < 0.3) ont été obtenus par co-précipitation. La structure pérovskite de ces composés a été confirmée par spectroscopie infrarouge et par diffraction aux rayons X, l’analyse par B.E.T a montré que la surface spécifique possède une large distribution des diamètres des pores. Les clichés du microscope à balayage électronique M.E.B proclament l’agglomération. Des méthodes de mesures électrochimiques et catalytiques dévoilent que les électrodes La1-xSrx AlO3 (0 < x < 0.3) et les poudres La1-xSrx AlO3 (0<x 0.3) présentent une meilleure activité électrochimique vis-à- vis des réactions de réduction et de dégagement de l’oxygène et une excellente activité électrocatalytique vis-à–vis a la réaction d’oxydation du méthane

Structure, dielectric and piezoelectric properties of Pb[(Zr0.45,Ti0.5)(Mn0.5,Sb0.5)0.05]O3 ceramics

International audienceThis study describes structure, dielectric and piezoelectric properties of Pb[(Zr 0.45 ,Ti 0.5)(Mn 0.5 ,Sb 0.5) 0.05 ]O 3 (PZT-PMS) ceramics prepared by conventional mixed-oxide route and sintered at up to 1180°C. The prepared ceramics was characterized by X-ray diffraction and scanning electron microscopy. The piezoelectric constants, dielectric constant, Young's modulus and electromechanical factors were measured in broad temperature range. The results showed that the PZT-PMS ceramics is composed of tetragonal and rhombohedral phases and has the average grain size of about 1 µm. The Pb[(Zr 0.45 ,Ti 0.5)(Mn 0.5 ,Sb 0.5) 0.05 ]O 3 ceramics has excellent dielectric and piezoelectric properties for wide practical applications. Thus, planar coupling factor of 0.70, poled dielectric constant of 8215, the Curie temperature of 345°C and dielectric loss of 6% were attained in the PZT-PMS ceramics sintered at 1180°C