Lead and cadmium removal by adsorption process using hydroxyapatite porous materials

Abstract

This contribution is a comparison study between synthetic hydroxyapatite (Sy-HAP) and commercial hydroxyapatite (C-HAP) for the removal of Pb2+ and Cd2+ ions present in wastewater from industrial effluents. The obtained results show that the equilibrium time required for complete adsorption of Pb2+ and Cd2+ ions on C-HAP and Sy-HAP is 15 min for both. The obtained removal efficiencies for Sy-HAP are 95.52% and 90.91% for Pb2+ and Cd2+ ions, respectively. Whereas, C-Hap presents lower removal efficiencies of 86.53% and 81.43% for Pb2+ and Cd2+ ions, respectively. Maximum adsorption was observed at pH 5; at lower pH levels adsorption was less. The experimental kinetic data fitted with the second order kinetic model. Thermodynamically, the adsorption process was endothermic and spontaneous in nature. Isotherm adsorption studies indicated that Langmuir, Freundlich and Temkin are the most valid models to describe and evaluate the adsorption process. The EDX results also confirmed the presence of lead and cadmium in adsorbents after adsorption. Finally, the HAP porous materials possess great potential for the removal of Pb2+ and Cd2+ ions from aqueous solutions and wastewater from industrial effluents.

Characterization of the Physical, Chemical, and Adsorption Properties of Coal-Fly-Ash–Hydroxyapatite Composites

“…The pH PZC of CFA was found to be 8.1 [66], 10.70 [76], and 12.17 [77], depending on its origin and composition. The pH PZC of HAp occurs in a wide range, including 3.0 [78], 4.6 and 5.8 [33], 6.22-6.64 [79], and 7.9 [80], and strongly depends on the synthesis conditions and precursor types. However, the pH PZC of CFA is in the alkaline region, whereas the pH PZC of HAp is in the acidic region, and the pH PZC of CFA-HAp1-4 is a result of the properties of both materials.…”

“…A review of the literature shows that these are very diverse materials, including chelating resins [21], low-cost waste-plant materials [22][23][24], nano-activated carbon [16], graphene oxide [2], nanocellulose/functionalized nanocellulose [25], clays and diatomaceous earth [26], fly ash [27], and zeolites [28]. Another group of highly effective dye-removing and heavymetal-removing [29][30][31] adsorbents [32][33][34] includes hydroxyapatites of natural and synthetic origin.…”

“…Various raw materials are used to produce HAps, and the possibility of using waste materials has been frequently explored. Biomaterials like oyster shells [32], eggshells [31], and bovine bones [33] have been successfully used as calcium substrates for synthesis using co-precipitation or hydrothermal methods. Power-plant byproducts-e.g., blast furnace slag [35,42] and steel slag [43]-are also good calcium substrates for the hydrothermal method.…”

Preparation, characterization and application of the nanocomposite PCL-PEG-PCL / Bentonite-TBHSA to the removal of methylene blue (MB) dye: Adsorption, Kinetics, and Isotherm studies

“…The Langmuir isotherm model is the most widely used to present liquid -solid adsorption which assumes monolayer adsorption, Whereas, Freundlich model is empirical which assumes the heterogeneous adsorption on the surfac [51,52] . However, Temkin model assumes that the decrease in heat of absorption with recovery rate is linear rather than logarithmic [42,51,35].…”

Adsorptive removal of Pb(II) and Cd(II) ions from aqueous solution onto modified Hiswa iron-kaolin clay: Equilibrium and thermodynamic aspects

“…Nowadays, nanomaterials have provided a promising technique for removal of toxic heavy metal ions from water, aqueous solutions and industrial wastewater, due to its low cost-effective, high efficiency, and simple to operate. Different natural minerals and the composites are studied such as montmorillonite (Barbier et al, 2000), zeollitic tuff (Budianta et al, 2020), bentonite (Mohajeri et al, 2018), expanded perlite (Torab-Mostaedi et al, 2010), natural zeolite (Panayotova, M., Velikov, B., 2002), natural diatomite (ElSayed, 2018), natural clay (Bedelean et al, 2009), activated alumina (Naiya et al, 2009), activated phosphate rock (Elouaer et al, 2008 ), ball clay (Rao and Kashifuddin, 2016), hydroxyapatite porous materials (Ramdani et al, 2020), manganoxide minerals (Sónmezay et al, 2012), natural phosphate (Yaacoubia et al, 2014), natural calcite (Yavuz et al, 2007), Sepiolite (Padilla et al, 2011), polyvinyl www.bosaljournals/chemint/ editorci@bosaljournals.com alcohol-modified kaolinite clay (Unuabonah et al, 2008), hydroxyapatite/chitosan composites (Park et al, 2015), polyphosphate-modified kaolinite clay (Amer et al, 2010), alkaline modification of kaolin (David et al, 2020), Nano kaolinite (Alasadi et al, 2019) unmodified and modified kaolinite clay (Al-Essa and Khalili, 2018;Abukhadra et al, 2019), magnetic core-zeolitic shell nanocomposites (Padervand and Gholami, 2013), natural mixture of kaolinite-albite-montmorillonite-illite clay (Eba et al, 2011), kaolinite and montmorillonite surfaces (Gupta and Bhattacharyya, 2008), Al( 13)-pillared acid-activated montmorillonite (Yan et al, 2008). hydroxyapatite/alginate/gelatin nanocomposites (Sangeetha et al, 2018), Iron nanocomposite and modified by Fe-S nanoparticles (Shahryari et al, 2019), thiol-lignocellulos...…”