Adsorption performance of hydroxyapatite with different crystalline and porous structure towards metal ions in multicomponent solution. (December 2019)

• Record Type: Journal Article
• Authors: Ivanets, A.I.; Kitikova, N.V.; Shashkova, I.L.; Roshchina, M.Yu.; Srivastava, V.; Sillanpää, M.
• Is Part Of: Journal of water process engineering. Volume 32(2019)
• Publication Date: 2019-12
• Subjects: Hydroxyapatite -- Adsorption mechanism -- Metal ions -- Crystallisation inhibitors -- Water treatment; Water-supply engineering -- Periodicals; Saline water conversion -- Periodicals; Seawater -- Distillation -- Periodicals; Sanitary engineering -- Periodicals; Sewage -- Purification -- Periodicals; 627
• DOI: 10.1016/j.jwpe.2019.100963
• Languages: English
• ISSNs: 2214-7144

Abstract

Graphical abstract: Highlights: The prepared HA had high efficiency in multicomponent solution purification. Using low doses of inhibitors had a positive effect on HA adsorption characteristics. The effect of crystalline and porous structure on HA efficiency was studied. For all adsorbents, residual metal ion concentration was lower MCL. A mechanism of metal ion adsorption on HA with different structures was proposed. Abstract: Hydroxyapatite (HA) is a well-known and widely used efficient adsorbent for toxic metal ion and radionuclide removal from wastewater. However, the relationship between the structural parameters of HA and its adsorption characteristics (capacity, selectivity, kinetic parameters) requires in-depth study. In this study, HA with different crystalline and porous structures was obtained using crystallisation inhibitors of different natures, and their adsorption properties in a multicomponent solution (Cd 2+, Co 2+, Cu 2+, Fe 3+, Ni 2+, Pb 2+ and Zn 2+ ) was investigated. Using low doses of inhibitors (Mg 2+ ions and hydroxyethylenediphosphonic acid) had a positive effect on HA adsorption characteristics, due to their low degree of crystallinity (amorphous calcium phosphate) and a well-developed porous structure (ABET up to 200-240 m 2 g −1 ). The adsorption capacity of the HA samples in relation to the Cd 2+, Cu 2+, Fe 3+, Pb 2+, Zn 2+ ions and their simultaneous presence in the solution varied from 0.13 to 1.28 mmol g −1 . The achieved residual concentration of Pb 2+, Zn 2+ and Cu 2+ ions was below the maximum concentration limit, and the ions of Fe 3+ were almost equal to zero. The highest adsorption of Co 2+ and Ni 2+ ions was observed for HA obtained in the presence of Mg 2+ . HA prepared with HEPD has been shown to have the highest efficiency towards Cd 2+, Cu 2+, Fe 3+, Pb 2+, Zn 2+ ions. The adsorption kinetic data fitted well with the pseudo-second-order model. It was shown that, depending on the composition and structural characteristics of the prepared HA, ion-exchange and dissolution-precipitation were the two main mechanisms in their interaction with metal ions.