Mokhtar Boutahala

Adsorption removal of tartrazine by chitosan/polyaniline composite: Kinetics and equilibrium studies

The present work focused on the performance of chitosan/polyaniline (Cht-PANI) composite for removing tartrazine dye from aqueous solutions. The adsorbent was characterized using SEM, XRD, FTIR, and TGA/DTA techniques. The effects of pH, initial dye concentration, contact time, and temperature on azo dye removal were studied. The kinetics and isotherm of tartrazine removal follow pseudo-second-order kinetics and the Freundlich isotherm, respectively. The Langmiur isotherm model exhibted a maximum adsorption capacity of 584.0 mg/g. The thermodynamic parameters were calculated and the negative values of ΔG° and positive value of ΔH° indicate that the adsorption processes are spontaneous and endothermic in nature. In addition, the resulting adsorbent reusability was demonstrated over four cycles, indicating that the Cht-PANI is a very promising adsorbent for removal of toxic pollutants from aqueous solutions.

Les Polysaccharides Cellulosiques et Leurs Applications dans le Domaine de la Sante : Exemple de la Preparation des Pansements Cicatrisants = Cellulose Polysaccharides and Their Applications in the Field of Health : Example of the Preparation of the Healing Dressing

Dans le present travail, differents biofilms a base de la gelatine associee a la cellulose, la carboxymethylcellulose, et la methylcellulose sont prepares. Il est observe que la reticulation en presence du glutaraldehyde apporte une meilleure propriete mecanique tout en augmentant la resistance thermique, et une diminution de l’hydrosolubilite de biopolymer utilise. Ces biofilms sont aussi modifies par l’addition du glycerol ce qui entraine une diminution de la fragilite et du retrait. Le test de gonflement montre que l’association de la carboxymethylcellulose a la gelatine presente des proprietes d’absorption importantes, ce qui fait un bon candidat pour absorber les exsudats afin de preserver les berges de la plaie et la peau peri-lesionnelle. Toutefois, l’etude en fonction de la temperature montre qu’a temperature ambiante, les taux de gonflement (Gmax) correspondants sont inferieurs a ceux obtenus a 37°C (temperature du corps humain). Le dosage par spectrophotometrie UV-vis indique qu’il existe une liberation considerable de constituant(s) de biofilms a 37°C, ce qui permettre une meilleure cicatrisation en maintenant un milieu humide favorable sur le lit de la plaie.

Synthesis and characterization of ZnAl-layered double hydroxide and organo-K10 montmorillonite for the removal of diclofenac from aqueous solution

Two prepared adsorbents, namely, calcined ZnAl-layered double hydroxide and K10 montmorillonite intercalated with cetyltrimethyl-ammonium bromide cations are used in diclofenac sodium adsorption under the batch reactor operations. The pseudo-second-order model describes better the results of the kinetics. Fitting parameters revealed that the rate of adsorption increased with the increase in diclofenac sodium concentration and decrease in background electrolyte concentration and temperature, while the solution pH did not have a significant effect. The maximum adsorption capacities of diclofenac obtained by Langmuir model are found to be 55.46 and 737.02 mg/g for K10 montmorillonite intercalated with cetyltrimethyl-ammonium bromide cations and ZnAl-C LDH, respectively. The results of adsorption–desorption cycles revealed that ZnAl-C LDH and K10 montmorillonite intercalated with cetyltrimethyl-ammonium bromide cations have an excellent potential to be used as an economical adsorbent for the removal of diclofenac sodium from water.