Synthesis and physicochemical evaluation of hydroxyapatite gel biosorbent for toxic Pb(II) removal from wastewater

Abstract

The agglomeration of hydroxyapatite (HAp) nanoparticles is the main challenge when it used as an adsorbent for removing toxic trace elements from aqueous solutions. In the present study, HAp gel was synthesized and evaluated as a potential bioadsorbent for treatment and sorption Pb(II) from polluted water. HAp gel was prepared by co-precipitation method and its physicochemical ability to remedy Pb(II) was tested by batch experiments under changing initial parameters such as pH and contact time. XRD, FTIR, and TEM techniques were used to characterize HAp gel, and ICP technique evaluated its physicochemical property to adsorb and remove Pb(II) from aqueous solutions. The adsorption equilibrium of Pb(II) on HAp gel was analyzed at room temperature using conventional Freundlich and Langmuir adsorption isotherm models. The synthetic HAp gel showed a pure nanocrystalline phase and well-dispersed nanorods. The HAp gel exhibited high sorption capacity at 344.8 mg/g for Pb(II) removal at a short equilibrium contact time of 10 min. The synthetic HAp gel is a promising efficient bioadsorbent to alleviate the problems accompanied conventional dried HAp agglomerates in particular for industrial and environmental applications that need an economic and eco-friendly non-agglomerated adsorbent.