Fabrication and Characterization of Magnetic Hydroxyapatite Entrapped Agarose Composite Beads with High Adsorption Capacity for Heavy Metal Removal

Abstract

Magnetic hydroxyapatite entrapped agarose composite beads (M-HAP/Agar composite beads) have been successfully synthesized by emulsification of magnetic HAP nanoparticles with agarose suspension. In the process, the magnetic HAP nanoparticles served as the main resource for high adsorption performance, which were constructed by surface modification of Fe3O4 with N-(phosphonomethyl)­iminodiacetic acid (PM-IDA) and followed by coating with HAP. This strategy integrates the distinct advantages of large-size beads and magnetic response for easy recovery as well as nanoparticles for high adsorption capacity. The resulting M-HAP/Agar composite beads display large specific surface area (90 m2 g–1) and uniform spherical shape (150 μm). These magnetic hydroxyapatite nanoparticles in beads can provide more adsorption sites due to their suitable porous structure. As a result, the adsorbent exhibits excellent performance in adsorption of Pb2+, Co2+, and Cu2+, showing maximum binding capacities as high as 842.6, 105.1, and 71.6 mg g–1, respectively. All these results suggest that these magnetic nanoparticles entrapped in beads have a positive effect on improving the adsorption capacity. Moreover, the beads possess superparamagnetism and large size, allowing them to be easily recovered from solution. Therefore, this work provides a promising approach for the design and synthesis of multifunctional hydroxyapatite composite beads for highly efficient removal of heavy metals in the field of wastewater treatment.

Adsorption of Inositol Phosphate on Hydroxyapatite Powder with High Specific Surface Area

“…Therefore, the adsorption was of chemical nature, chelate bond between IP6 and HAp. In general, it is common for the HAp as an adsorbent to fit the Langmuir model [ 36 , 37 ].…”

Porous BMTTPA–CS–GO nanocomposite for the efficient removal of heavy metal ions from aqueous solutions

“…Therefore, it can be inferred that the adsorption of Hg 2+ , Cu 2+ , Pb 2+ and Cd 2+ on the BMTTPA–CS–GO nanocomposite is mainly attributed to the chemical interaction between BMTTPA–CS–GO and heavy metal ions. 61 …”

“…A new binding energy peak is found at 102 eV aer Hg 2+ adsorption, which can be attributed to Hg 4f photoelectron, indicating that Hg 2+ is adsorbed on BMTTPA-CS-GO. 61,62 The spectra of Hg 4f 5/2 and Hg 4f 7/2 photoelectrons measured aer adsorption of Hg 2+ by BMTTPA-CS-GO show clear binding energy shis compared to Hg 2+ (Fig. 6B), indicating that Hg 2+ combined with N and S atoms in BMTTPA-CS-GO to form a new complex.…”

Tunable Hydroxyapatite/Magnetite Nanohybrids with Preserved Magnetic Properties

“…[37] Recently, researchers have paid much attention to the design of composite nanostructures by mixing two or more components to synthesize a single nanosystem which delivers enhanced multifunctional properties. [38] Nanocomposites derived from magnetic HAp can be obtained by a variety of methods, including hydrothermal synthesis, [39] chemical precipitation, [40] emulsion synthesis, [41] template synthesis, [38] mechanochemical synthesis, [42] in addition to mixed synthesis methods. [43] In particular, co-precipitation has been realized as the simplest method that allows control of the stoichiometry of the starting reagents and the morphology and properties of the produced NPs.…”