Synthesis, characterization of hydroxyapatite‐lambda carrageenan, and evaluation of its performance for the adsorption of methylene blue from aqueous suspension

Abstract

The present work describes the synthesis of hydroxyapatite-lambda carrageenan CaHAp-(k-Carr) using an aqueous coprecipitation method. The characterization of the prepared hybrid compounds was achieved using chemical analysis, Fourier Transform Infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and specific surface area. The results gleaned from X-ray powder analysis proved the presence of (k-Carr) and revealed that the increase of its concentration leads to the decrease of the CaHAp crystallinity. Fourier transform Infrared spectra show the presence of (k-Carr) and CaHAp characteristic vibrations in the resulting product. Scanning electron microscopy analyses reveal that the morphology of particles was changed by grafting and they are characterized by aggregates of different sizes and irregular shapes. After grafting BET measurements yielded particle specific surface areas ranging from 93 to 260 m 2 g 21 depending on the grafted biopolymer. The prepared products were, further, applied for the adsorption of methylene blue (a cationic dye) from aqueous suspension. The adsorption capacity was determined with respect to pH value, the initial dye concentration, time contact, and temperature. The kinetic, thermodynamic, and adsorption isotherm models were assessed for the description of the dye adsorption process. The experimental resulting data show that the prepared hybrid compound CaHAp-(k-Carr) is an efficient adsorbent for the removal of dyes.

Electrospun polyacrylonitrile/hydroxyapatite composite nanofibrous membranes for the removal of lead ions from aqueous solutions

“…The absorption peaks at 1377 cm −1 can be assigned to CO 3 2− , which are the result of the absorption of CO 2 from the air during the HAP preparation process. 43…”

“…The absorption peaks at 1377 cm À1 can be assigned to CO 3 2À , which are the result of the absorption of CO 2 from the air during the HAP preparation process. 43 The spectrum in Fig. 3(b) shows that all the characteristic peaks of PAN in Fig.…”

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“…From Figure b, the pH pzc value was found to be around 5.4. Also, the adsorbent surface was positive when pH pzc > pH and negative for pH pzc < pH (Agougui, ). In addition, when the pH pzc is equivalent to pH solution, adsorbent surface group charge is impartial and electrostatic force is insignificant between NCS/SA and Pb(II) (Ganesan, Kamaraj, & Vasudevan, ).…”

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“…[43] Antiviral activity for herpesvirus types 1 and 3 have been reported for LC, which also absorbs methylene blue dye in aqueous solutions. [44][45][46] Other seaweeds also produce sulfated polysaccharides with potentially useful biological properties. Fucose-containing sulfated polysaccharides and other sulfated polymers present in brown algal cell walls have a broad range of biological properties such as anti-infectious and anticancer actions, regulation of the immune response, promotion of hemostasis and anti-inflammatory responses, antioxidant activity, and free radical scavenging activity.…”