Synthesis of hydroxyapatite derived from agricultural waste and its applications as an adsorbent for heavy metal removal from wastewater

 The presence of heavy metals in aquatic systems can be harmful to living species. Heavy metals are not biodegradable, and their tendency to accumulate in living organisms often causes different, undesirable consequences. Therefore, removing these impurities from wastewater has become one of the key issue related to environmental protection [Babel and Kurniawan 2004].There are many methods developed to remove heavy metals from wastewater and adsorption is one of the most popular one. Despite of the diversity of these technologies there is still a need to develop methods that do not require a large financial input [Hegazi 2013, Renu et al. 2017].The most important features that determine materials used as adsorbent is their low cost, biocompatibility and environmental friendly nature and hydroxyapatite presents all of them. Moreover, hydroxyapatite particles are characterized by high specific surface area and simple method of synthesis. It is also reported that it can be obtained from agricultural waste based on calcium like eggshells [Akram et al. 2014].The aim of this paper is to show and compare different methods of hydroxyapatite synthesis using eggshells as a source of calcium and it sorption capacity due to different metal cations from aqueous solution.