Adsorptive potential of synthesized sea urchin-based hydroxyapatite for Supranol yellow and nickel ion recovery from aqueous media: kinetics and thermodynamic studies

• Published in: Desalination and water treatment Vol. 252; pp. 348 - 360
• Main Authors: Medjdoub, Aicha, Nemchi, Fadila, Belayachi, Hanane, Bestani, Benaouda, Bourahla, Sarra, Belhakem, Mostefa, Benderdouche, Nouredine
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-03-2022
• Subjects: Paracentrotus lividus; Removal; Simulated-wastewater; Toxic pollutants; Removal; Toxic pollutants; Simulated-wastewater; Paracentrotus lividus
• ISSN: 1944-3986
• DOI: 10.5004/dwt.2022.28155

Locally affordable, eco-friendly and non-toxic biomaterial, sea urchin test (Paracentrotus lividus) as a precursor was converted in this investigation by simple and viable way into an efficient adsorbent for nickel ions and Supranol yellow dye removal from simulated wastewater. Powered urchin shell sea urchin test (SUT) and diammonium phosphate as sources of calcium and potassium, respectively, were used for hydroxyapatite synthesis by chemical precipitation route followed by calcination at 800°C. The resulting calcium phosphate based-adsorbent: hydroxyapatite urchin test (HAP-UT) was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller and pHzpc to appraise its physicochemical characteristics as well as the mechanism of both pollutants adsorption. Effect of conventional parameters on both pollutants uptakes such as equilibrium time, adsorbent dose, pH and temperature were also performed. Well known adsorption isotherms, namely Langmuir and Freundlich were used for data fitting to describe the adsorption equilibrium of both pollutants The raw material conversion to HAP-UT enhances the removal capacities from 58.48 to 666.67 mg g–1 at pH 2–3 and from 1.49 to 29.50 mg g–1 at pH 5–5.4 for Yellow supranol and nickel ions respectively. From the perspective of higher R2 values and the lower root mean square error values as an error indicator, Langmuir model is more representative for the experimental data predicting homogeneous surface coverage of the adsorbents. Thermodynamic analysis of the adsorption processes of both pollutants confirms their spontaneity and endothermicity. Adsorption mechanism found to obey to pseudo-second-order kinetic model. Obtained results showed that the synthetized hydroxyapatite from urchin shell as an adsorbent could prove to be very useful and efficient in removing toxic pollutants from industrial effluents.