VALORISATION DES PELURES DE POMMES DE TERRE POUR LE TRAITEMENT D’UNE SOLUTION AQUEUSE CONTENANT UN COLORANT TEXTILE (REACTIVE BLUE 72)

Les pelures de pomme de terre étudiées dans le cadre de ce travail constituent des ressources abondantes et localement disponibles à faible coût. Cette étude a pour objectif d’illustrer la valorisation de ces déchets et leur utilisation pour le traitement d’effluents chargés en colorants textiles (Réactive blue72 noté BT). L'effet de quelques paramètres expérimentaux (pH, concentration initiale du colorant, taille des particules ainsi que le temps de contact) a été étudié en utilisant une technique d'adsorption en batch réalisée dans un agitateur va- et-vient. L’adsorption obéit à l’isotherme de Freundlich ainsi qu’à l’isotherme de Langmuir type I (R2= 0,94) avec une capacité maximale d’adsorption égale à 76,92mg.g-1. La cinétique est de pseudo- deuxième ordre (R2= 0,999). La valeur positive de ΔH0 (6,82 KJ.mole-1) montre que l’adsorption est endothermique, celle de l’entropie ΔS0 (44,01 J.mole-1.K-1) reflète une augmentation aléatoire du désordre sur l’interface solide/solution durant l’adsorption. Les valeurs négatives de ΔG0 montrent que l’adsorption est physique. 

Reaction of calcium phosphate with textile dyes for purification of wastewaters

International audienceWhen unsintered hydroxyapatite (HA) is dissolved in acidic solution (pH less than 3), the calcium salt dissolves readily and may be re-precipitated at neutral pH values by neutralization with base. Maturation of this precipitate eventually leads to the neo-formation of calcium phosphates similar to HA. HA is a stable solid under neutral or basic conditions and has interesting adsorption properties. Particularly, textile dyes can be adsorbed on HA particles. Thermal treatment below 800 degrees C degrades adsorbed organic matter and generates mineral HA. Such HA can be recovered and reused by re-dissolution in acidic water. We have experimented with such recycled HA the co-precipitation of textile dyes and found that HA can be reused several times. For most textile dyes, a very high level of color removal was observed (above 98%), with a small loss of HA during the recycling process (12%). This makes the treatment of textile dye polluted waters by HA co-precipitation feasible and sustainable

Hydroxylapatite and alizarinsulfonate as a model for depollution of textile dyes

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Phytic acid-doped poly-N-phenylglycine potato peels for removal of anionic dyes: investigation of adsorption parameters

International audienceIn this work, we report on enhanced adsorption of anionic dyes, Reactive blue 49 (RB 49) and Direct Blue 199 (DB 199), using a phytic acid-doped poly-N-phenylglycine@potato peel (PA-PPG@PP) nanocomposite material. The PA-PPG@PP was prepared using a radical polymerization process by varying the amount of potato peel powder (PP) in the composite material. The surface structure and composition were examined by zeta potential, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis. The influence of different operating conditions such as adsorbent dose, initial dye concentration, contact time, pH and ionic strength on the removal efficiency of PA-PPG@PP2 was assessed to achieve the optimum conditions for RB 49 dye adsorption. Adsorption equilibrium data were well-described by the Langmuir model and the maximum adsorption capacities of PA-PPG@PP2 for RB 49 and DB 199 at 298 K and pH = 6.5 were 216 and 1148 mg g−1, respectively. The maximum adsorption capacity of RB 49 dye on the PA-PPG@PP2 surface was achieved at 318 K (285 mg g−1). The adsorption process was described by the pseudo-second-order kinetics model (R2 > 0.999). The thermodynamic study proved that the adsorption processes were endothermic and favorable. The dye molecules were adsorbed on the composite material surface mainly through hydrophobic and electrostatic interactions, as well as hydrogen bonding. Additionally, our experimental results suggested that the hydrophobic interactions increased upon increasing ionic strength, while the electrostatic interactions decreased upon elevating the ionic strength of the solution. The findings in this work revealed the potential of biomass powder, potato peels, in adsorption processes upon hybridization with a biocompatible organic polymer, poly-N-phenylglycine