MS17-P01 Removal of methylene blue by adsorption using modified hydroxyapatite by carrageenan biopolymer Mongi Debbabi (Laboratoire de Physico-chimie des Matériaux, Faculté des Sciences., Monastir, Tunisia) Hassen Agougui (Laboratoire de Physico-chimie des Matériaux, Faculté des Sciences., Monastir, Tunisia) Mahjoub Jablib (Textile Materials and Process Research Unit, ENIM, Monastir, Tunisia) Hatem Majdoub (Laboratoire des Interfaces et des Matériaux Avancés, Faculté des Sciences., Monastir, Tunisia)email: m.debbabi@yahoo.frThe application of hydroxyapatite modified by biopolymers for the immobilization of various pollutants has been considered as a promising pollution control technology. In this scope, hydroxyapatite-Lambda carrageenan CaHAp-(λ-Carr) hybrid materials were prepared by co-precipitation method with different content of the bio-polymer (0, 5, 10 and 20%). Synthesized materials were characterized using X-ray diffraction (XRD), Infrared spectroscopy (FT-IR), chemical analysis, Scanning Electron Microscopy (SEM), specific surface area (SS) and pHzpc measurement. The X-ray powder analysis showed that the cristallinity is affected by the presence of the biopolymer. The FT-IR spectra show the presence of (λ-Carr) and CaHAp characteristic vibrations in the resulting product. After grafting BET measurements yielded particle specific surface areas ranging from 93 to 260 m2 g−1 depending on the grafted biopolymer. The adsorption capacities of methylene blue (MB) were investigated with respect to the effect of adsorbent amount, pH value, contact time, adsorbent dose, temperature and initial dye concentration. The pseudo-second-order and Freundlich isotherm equations were found to describe the adsorption mechanism. The percentage of MB removal by CaHAp and CaHAp-(λ-Carr)10 were equal to 81.40 % and 95.63 %, respectively. The results indicate that the modified hydroxyapatite possessed good adsorption ability towards MB dye and can be used as a low cost adsorbent for dye removal from wastewater.
 
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Keywords: Hydroxyapatite, Biopolymer, Adsorption.