Adsorption of Pb(II) and Cd(II) ions onto modified biogenic slaughterhouse waste: equilibrium and kinetic analysis

• Published in: International journal of environmental analytical chemistry Vol. 102; no. 16; pp. 4344 - 4363
• Main Authors: Ngueagni, P. Tsopbou, Kumar, P. Senthil, Woumfo, E. Djoufac, Prasanth, S. M.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 16.12.2022; Taylor & Francis LLC
• Subjects: Abattoirs; Adsorbents; Adsorption; adsorption isotherms; Biocompatibility; Cadmium; Cd(II); Chemical properties; Chemicophysical properties; Chemisorption; Cost analysis; Desorption; Electron microscopy; Equilibrium; Heavy metals; Isotherms; Lead; Mathematical models; Mesoporous Hydroxyapatites; Optimization; Parameters; Pb(II); pH effects; Physicochemical processes; Physicochemical properties; Porosity; Process parameters; regeneration; Removal; Scanning electron microscopy; Slaughtering; Uptake; Zinc
• ISSN: 0306-7319; 1029-0397
• DOI: 10.1080/03067319.2020.1784409

Hydroxyapatites are biocompatible and noteworthy low-cost adsorbent directly produced by calcinatedbiogenic materials with different structures and physico-chemical properties. In this study, adsorption of Pb(II) and Cd(II) onto mesoporous and macroporous hydroxyapatites thermally extracted from cattle horn core was investigated in batch method. The obtained hydroxyapatites were characterised by scanning electron microscopy, the porosity was investigated via nitrogen adsorption-desorption, and elemental map has revealed their surface composition. A decrease of porosity of 0.4272, 0.3671, and 0.0052 cm 3  g −1 for P 400 , P 600 and P 1100 , respectively, and a homogeneous distribution of Ca, P, O, C, Zn and Mg have been observed. Optimisation parameters such as adsorbent dosage, pH, initial concentration, contact time, and temperature were then evaluated to reach the maximum adsorption capacity. Hydroxyapatites obtained at lower temperature have shown a higher affinity for Pb(II) removal rather than Cd(II). Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms were used to describe the equilibrium data. Equilibrium was best described by Langmuir isotherm model, with maximum estimated adsorption capacities of 256.41 and105.26 mg/g for Pb(II) and Cd(II), respectively, for P 400 . Maximum removal efficiency at pH 6 was observed, concomitant with a fast adsorption equilibrium attended at around 45 min. Furthermore, Lagergen pseudo-second-order model exhibited the best correlation with the adsorption data, suggesting chemisorption as the rate-limiting step of the process. Thermodynamically, overall parameters revealed an exothermic, spontaneous, feasible, and favourable uptake of the aforementioned heavy metal at a lower temperature in nature. Adsorption/desorption up to four cycles has been obtained with a regeneration above 96% for each adsorbent. These findings concluded that hydroxyapatites from slaughterhouse waste are an eco-friendly, promising and potentially reused adsorbent for the removal of heavy metal in practical purposes.