Treatment of Cd²⁺ and Cu²⁺ Ions Using Modified Apatite Ore

Abstract

Apatite ore from Lao Cai (Vietnam) has large reserves and low prices. Its main component is fluorapatite. The purification and modification of apatite ore can produce a material that can be used as an absorbent for heavy metals with high efficiency. The molecular structure, phase component, specific surface area, element component, and morphology of modified apatite ore from Lao Cai province, Vietnam, were characterized by IR, XRD, BET, EDX, and SEM methods. The IR and XRD results show that the modified process transformed apatite ore from fluorapatite to nanohydroxyapatite. The specific surface area of modified apatite ore (100.79 m2/g) is much higher than the original ore (3.97 m2/g). The modified apatite ore was used to adsorb Cd2+ and Cu2+ ions in water. The effect of adsorbent mass, pH, contact time, and initial concentration of Cd2+ and Cu2+ on the adsorption efficiency and capacity was investigated. Besides, the isotherm adsorption model was determined using Freundlich and Langmuir theories.

Co2+ and Cr3+ ions removal from wastewater by using nanostructural hydroxyapatite

“…Modification of the apatite ore procedure: The apatite ore was modified following the procedure in the published article, the obtained material had a phase structure with a specific surface area of 100.79 m 2. g -1 and pHpzc of about 7.49. [11] Modified apatite ore was characterized by the zeta potential by the Dynamic Light Scattering method (DLS, SZ-100V2, Nanoparticle analyzer, Nanopartica, Horiba Scientific (Japan) in the charge range of -200 to 200 mV at 25 °C).…”

“…The adsorption method based on natural sorbents is used widely for its simplicity, low costs, and high efficiency. [10][11][12] Among many materials that are used for sorption like activated carbon, [13][14][15] carbon nanotubes, [13] clays, [13,16] zeolites, [13,14] bioadsorbents, [10,13] silica, [15,17] wood ash, [4] and apatite, [10][11][12][18][19][20][21][22][23][24] the hydroxyapatite have promising properties for the heavy metals removal from the wastewater. The hydroxyapatite (HAp) having the formula (Ca10(PO4)6(OH)2) can occur in different forms like the bare HAp, fluorapatite (Ca10(PO4)6F2), and chlorapatite (Ca10(PO4)6Cl2).…”

“…This mineral offers a large surface for removing many chemical compounds from aqueous media and biocompatibility, being non-toxic for living organisms. Due to its physico-chemical properties it is widely synthesized to be used for adsorption of many inorganic compounds like heavy metal ions such as Cu 2+ , [11,19] Zn 2+ , [19] Cd 2+ , [10,11] Co 2+ , Ni 2+ , Hg 2+ , [22,25] Cr 6+ , [21] Ag + , [18] Pb 2+ , [12,14] Fe 3+ and Cr 3+ . [3,22] Hydroxyapatite also has tremendous potential for the removal of anions like As 3-, [24] F − , [26,27] organic pollutants like phenol, [18,23] nitrobenzene, [28] and even antibiotics with high adsorption ability.…”

“…[29][30][31] Hydroxyapatite can be synthesized from chemical sources or obtained from natural sources such as animal bones; [12,25] however, it can also be easily prepared from the natural apatite ores. [11] An enormous abundance of apatite ore, even 2.55 billion tons of the apatite, making it a low-cost and promising source of hydroxyapatite for wastewater treatment, especially the water reservoirs polluted with cobalt and chromium ions was found in Lao Cai province, Vietnam. This approach is still relatively new with only a few studies done before.…”

“…This approach is still relatively new with only a few studies done before. [11,32] In this work, the nanostructural hydroxyapatite was obtained within the chemical modification of natural apatite ore gained in the Lao Cai province as a low cost, natural, and eco-friendly adsorbent material for heavy metals treatment. We present the effective removal of the Co 2+ and Cr 3+ ions from the wastewater by the application of the hydroxyapatite, obtained from the natural apatite ore.…”