Structure–Activity Relationship of Lanthanide-Incorporated Nano-Hydroxyapatite for the Adsorption of Fluoride and Lead

Abstract

The growing demand for water purification provided the initial momentum to produce lanthanide-incorporated nano-hydroxyapatite (HAP) such as HAP·CeO2, HAP·CeO2·La­(OH)3 (2:1), and HAP·CeO2·La­(OH)3 (3:2). These materials open avenues to remove fluoride and lead ions from contaminated water bodies effectively. Composites of HAP containing CeO2 and La­(OH)3 were prepared using in situ wet precipitation of HAP, followed by the addition of Ce­(SO4)2 and La­(NO3)3 into the same reaction mixture. The resultant solids were tested for the removal of fluoride and lead ions from contaminated water. It was found that the composite HAP·CeO2 shows fluoride and lead ion removal capacities of 185 and 416 mg/g, respectively. The fluoride removal capacity of the composite was improved when La­(OH)3 was incorporated and it was observed that the composite HAP·CeO2·La­(OH)3 (3:2) has the highest recorded fluoride removal capacity of 625 mg/g. The materials were characterized using scanning electron microscopy–energy-dispersive X-ray (SEM-EDX) spectrometry, Fourier transform infrared (FT-IR) spectrometry, X-ray powder diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) surface area analysis. Analysis of results showed that Ce and La are incorporated in the HAP matrix. Results of kinetic and leaching analyses indicated a chemisorptive behavior during fluoride and lead ion adsorption by the composites; meanwhile, the thermodynamic profile shows a high degree of feasibility for fluoride and lead adsorption.

The blending effect of natural polysaccharides with nano-zirconia towards the removal of fluoride and arsenate from water

“…Data obtained from the batch adsorption studies were fitted to the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DR) adsorption isotherm models, as explained in previous work [39][40][41][42][43].…”

Nanomagnetite- and Nanotitania-Incorporated Polyacrylonitrile Nanofibers for Simultaneous Cd(II)- and As(V)-Ion Removal Applications

“…Figure 7 shows the effect of Ca(II) and Mg(II) in water on As(V) and Cd(II) removal efficiencies at pH 6−7. It is intuitive to believe that Mg(II) and Ca(II) would interact with the sorbent in the same way as Cd(II) (due to the positive charge), whereas the mechanism should be different for AsO 4 3− owing to its negative charge. Hence, it can be expected that the competitive adsorption of Ca(II) and Mg(II) would matter more for Cd(II) removal than for As(V) removal.…”

“…The engineering of advanced materials for water purification applications is an area of research that has been extensively explored. Conventional nonmembrane techniques for water purification include multistep coagulation, flocculation, sedimentation, filtration, ion exchange, ozone treatment, precipitation, adsorption, and disinfection. − These conventional methods have a number of drawbacks, which can be overcome by novel membrane-based technologies . Membrane systems give improved selectivity, high separation efficiency, high stability, and the possibility of different modes of separation such as adsorption and ion exchange .…”

Investigation of Hydroxyapatite-Entrenched Cerium Organic Frameworks Incorporating Biopolymeric Beads for Efficient Fluoride Removal

“…Recently, Fernando et al reported the biopolymer-based nanohydroxyapatite (n-HAp) material as removing fluoride, lead, cadmium, and arsenic from water . Wimalasiri et al developed the lanthanide-incorporated n-HAp composite for fluoride and lead adsorption . He et al developed the hydroxyapatite (HAp) nanowires for the fluoride adsorption from contaminated water .…”

“…31 Wimalasiri et al developed the lanthanide-incorporated n-HAp composite for fluoride and lead adsorption. 32 He et al developed the hydroxyapatite (HAp) nanowires for the fluoride adsorption from contaminated water. 33 Nagaraj et al prepared a mineralsubstituted HAp nanocomposites material via a hydrothermal method for fluoride adsorption.…”