Removal of Lead Ions by Hydroxyapatite Prepared from the Egg Shell

Abstract

Carbonate hydroxyapatite (CHAP) was synthesized from domestic hen egg shells. The obtained CHAP was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy and investigated as metal adsorption for Pb 2+ from aqueous solutions. The effect of various parameters on the adsorption process such as contact time, solution pH, and temperature was studied to optimize the conditions for maximum adsorption. The results showed that the removal efficiency of Pb 2+ by carbonate hydroxyapatite calcined at 600°C (CHAPF) reached 99.78 %, with an initial Pb 2+ concentration of 200 mg · L -1 , pH ) 3, and a solid/liquid ratio of 1 g · L -1 . The equilibrium removal process of lead ions by CHAPF foam at pH ) 3 was well described by the Langmuir isotherm model, with a maximum adsorption capacity of 500 mg · g -1 at (25 and 35)°C. The removal mechanism of Pb 2+ by the CHAPF varies, depending on the initial concentration of lead in the aqueous solution: the dissolution of CHAPF and precipitation of hydropyromorphite (Pb 10 (PO 4 ) 6 (OH) 2 ) is dominant at low concentration [(20 to 200) mg · L -1 ], and the adsorption mechanism of Pb 2+ on the CHAPF surface and ion exchange reaction between Ca 2+ of hydroxyapatite and Pb 2+ in aqueous solution is dominant at high concentration [(500 to 700) mg · L -1 ]. The thermodynamics of the immobilization process indicates an exothermic sorption process of Pb 2+ .

Synthesis and characterization of hydroxyapatite nanoparticles impregnated on apple pomace to enhanced adsorption of Pb(II), Cd(II), and Ni(II) ions from aqueous solution

“…Nanoparticles (NPs) have high potential for the tertiary wastewater treatment technology because of their small size (1-100 nm), catalytic potential, highly reactive and large surface area, ease of separation, large number of active sites, and regeneration ability (Ali 2012). Hydoxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) is an ideal adsorbent because of its high sorption capacity for heavy metals, low water solubility, easy availability, low cost, and applicability under oxidizing and reducing conditions (Meski et al 2010;Ramesh et al 2012). Recently, Tang et al (2013) reported removal of Cr(VI) from aqueous solution using hydroxyapatite nanoparticles (HANPs) of different Ca/P ratios.…”

The adsorptive potential of chicken egg shells for the removal of oxalic acid from wastewater

“…From the first order rate equation the value of regression coefficient (R 2 ) is in between (0.91-0.99) which is closer to 1 and shows best agreement with literature. Energy of activation was calculated from Arrhenius straight line equation [27] which is as follows: ln (9) and are rate constants, is the activation energy, R is gas constant and T is absolute temperature. The activation energies calculated for acid adsorbed on raw and treated powder egg shells are given in Table 4.…”

“…Because of high cost and disposal problems, many of the conventional methods have not been applied at large scale in different industries. Adsorption has been found to be superior to other techniques in terms of low-cost, flexibility and simplicity of design, ease of operation and insensitivity to toxic pollutants [9] . In adsorption, different adsorbents used include activated carbon [10] , zeolite [11] , clays [12] , silica beads [13] , and polymeric acids [14] etc.…”

“…However, these egg shells can be used as an excellent adsorbent because of their porous nature; about 700 to 1,700 pores are present on the surface an egg shell [18,19] . The egg shells are also attractive as adsorbent due to their good mechanical properties and thermal stability [20] and already used as adsorbent for the removal of heavy metals [21] , phenolic compounds [22] , dyes [23] , and pesticides [24] .…”

Synthesis of alginate beads filled with nanohydroxyapatite: An efficient approach for fluoride sorption

“…9 Nowadays, the research studies have been focused on nanohydroxyapatite (n-HAp) because of its high surface area and reactivity. 10 However, the application of n-HAp in adsorption columns is limited because of its powder form, insufficient strength, and brittleness.…”