Preparation of Functionalized Hydroxyapatite with Biopolymers as Efficient Adsorbents of Methylene Blue

In this study, we reported the synthesis of hydroxyapatite modified with biopolymers as λ-carrageenan and sodium alginate, which could be used as effective adsorbents of cationic dyes. Evidence of chemical modification was proved through chemical analysis, Fourier Trans-form Infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and specific surface area. The adsorption process was studied using methylene blue as representative cationic dye. The adsorbed quantity reached, at equilibrium, 142.85 mg/g and 98.23 mg/g using hydroxyapatite-sodium alginate and hydroxyapatite-(λ-carrageenan), respectively. However, it does not exceed 58.8 mg/g in the case of the unmodified hydroxyapatite. The adsorption of methylene blue using hybrid materials complied well with the pseudo-second-order suggesting a chemi-sorption. Freundlich and Langmuir isotherm described well the adsorption mechanism of the hydroxyapatite-(λ-carrageenan) and hydroxyapatite-sodium alginate, respectively. The high capacities of MB removal obtained in this study suggest the potential use of these materials in the treatment from wastewaters

Synthesis and characterization of alpha alumina-natural apatite based porous ceramic support for filtration application

The present study reported the synthesis of low-cost ceramic membrane supports. They were prepared by an extrusion method using alumina/natural apatite blends and further consolidated by heat treatment. The chemical composition, structure and particle size of the starting materials were analyzed. The effect of the natural apatite content, as sintering agent, on the microstructure, porosity, flexural strength and linear shrinkage of the prepared supports were studied as a function of sintering temperature. The microstructure exhibited that the sintering temperature decreased with the increment of the apatite content. The porosity and the pore size were controlled by the sintering temperature and the apatite amount added to the starting mixture. The mechanical strength and the linear shrinkage increased with increasing the apatite and the firing temperature. The sample selected for filtration displayed good porosity (45.38%) and pore size of 1.35 mu m giving a high perme-ability 959.64 h(-1) m(-2) bar(-1)

Bioactive composites of hydroxyapatite/polyvinylpyrrolidone for bone regeneration applications

<p>The implantation of bioactive composites for bone repair applications has recently gained the attention of many research groups. The present paper introduces a method for grafting of polyvinylpyrrolidone on the surface of hydroxyapatite (CaHAp) microcrystals by wet precipitation method to manufacture new composite scaffolds with suitability for bone tissue engineering. After grafting with the polymer, the degree of CaHAp crystallinity decreased, and its thermal behavior changed indicating a strong interaction between them. Homogenous clusters of CaHAp particles within the polymeric matrix were observed in combination with an increase in the roughness of the resulting structures. Bioactivity of the composites was tested using MTT assay; a higher viability of the seeded cells was observed relative to those cultured with CaHAp powder.</p