Removal of Cd2+ from aqueous solutions by hydroxyapatite

“…More recently, hydroxyapatite, has been proposed as a inexpensive but efficient adsorbent for removal/remediation of soils polluted by Pb (Hashimoto et al, 2009;Slobodan, 2009), Zn and Cd (Chen et al, 2007;Zhu et al, 2008) and Cu-, Znpolluted wastewater (Qian et al, 2008;Wang et al, 2009). Besides phosphates, activated carbons are considered also an efficient treatment for the removal of many organic compounds and metals from both liquid and gas phases (Cheung et al, 2002;Danny et al, 2004;Xiao and Thomas, 2004;Chen et al, 2006), but expensive.…”

mentioning

confidence: 99%

Adsorption of aqueous Cd2+, Pb2+, Cu2+ ions by nano-hydroxyapatite: Single- and multi-metal competitive adsorption study

Chen

et al. 2010

Geochem. J.

161

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Being an inexpensive but efficient adsorbent, hydroxyapatite is extensively used for decontaminating wastewater and soils polluted by heavy metals. However, its solubility and grain size can affect its remediation effectiveness. This study investigated the ability of nano-hydroxyapatite (nano-HAP) to adsorb aqueous Cd, Pb and Cu ions from single-metal and multi-metal ions reaction systems. Langmuir and Freundlich isotherm equations were employed to study the sorption constants. Based on the sum of squares errors (SSE), results showed that the Langmuir isotherm better fits sorption data than the Freundlich equation. The sorption affinity of nano-HAP for Pb(II) is always higher than that for Cu(II) and for Cd(II); the sorption maxima for the Cd, Pb and Cu follow the order Pb 2+ > Cu 2+ > Cd 2+ . This could be inversely proportional to the hydrated ionic radii as Pb 2+ (4.01 Å) > Cu 2+ (4.19 Å) > Cd 2+ (4.26 Å). The measured selectivity coefficients in multi-metal (Cd-Pb-Cu) reaction systems shows that Pb has the highest sorption selectivity on nano-HAP among the metals investigated. This sorption selectivity coincided well with the sorption affinity order in mono-metal reaction systems. The pH of the solution is an important parameter in controlling Cd, Pb and Cu ions sorption on nano-HAP. Indeed, the nano-HAP sorption capacity increases with increasing pH up to a value of 6.25. This implies that the removal of metals from the solution is recommended for pH ≈ 6.25 or below, during remediation using nano-HAP as a sorbent.

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“…8b, there was no significant change in adsorption removal efficiency by using different dose of adsorbent. However, increment of HAp/ NaP amount provides greater sorption sites while a large amount of the adsorbent effectively reduces the unsaturation of such sites of per unit mass, resulting in the great reduction in per unit mass adsorption at higher HAp/NaP amount [41]. Thus, the dose of 2 g/L, which gave maximum metal ion removal, was taken into consideration for further experiments.…”

Section: Effect Of Phmentioning

confidence: 99%

Removal of heavy metals and bacteria from aqueous solution by novel hydroxyapatite/zeolite nanocomposite, preparation, and characterization

2016

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In this study, a HAp/NaP nanocomposite was prepared by adding a synthesized nano-hydroxyapatite to zeolite NaP gel in the hydrothermal condition and used for the removal of lead(II) and cadmium(II) ions from aqueous solution. HAp/zeolite nanocomposite was then characterized by Fourier transform infrared spectroscopy, X-ray diffraction and Rietveld method, scanning electron microscope, energy-dispersive X-ray analysis, and surface area and thermal analyses. Results suggested that the nanocomposite crystals of HAp were dispersed onto the zeolite external surface and/or encapsulated within the zeolite channels and pores. The potential of the composite in adsorption of heavy metals was investigated by using batch experiment. The metal concentration in the equilibrium Ce (mg/g) after adsorption with nanocomposite of HAp/NaP was analyzed using flame atomic adsorption spectrometry. The adsorption experiments were carried out at pH of 3–9. The influences of contact time, initial concentration, dose, and temperature on the adsorption of lead and cadmium ions were also studied. Results show that these nanocomposites have further adsorption related to NaP and HAp. They have great potential (about 95 %) for Pb(II) and Cd(II) adsorption at room temperature. The equilibrium process was described by Frendlich, Langmuir, Temkin, and Dubinin–Radushkevich (D-R) models. The kinetics data were successfully fitted by a pseudo-second-order model. The in vitro antibacterial activity of these composites was evaluated against Bacillus subtilis (as Gram-positive bacteria) and Pseudomonas aeruginosa (as Gram-negative bacteria) and compared with standard drugs that show inhibition on bacterial growth

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Removal of Cd2+ from aqueous solutions by hydroxyapatite

Cited by 113 publications

References 22 publications

Adsorption of Cd (II) and Zn (II) from aqueous solutions using magnetic hydroxyapatite nanoparticles as adsorbents

Adsorption of Cd (II) and Zn (II) from aqueous solutions using magnetic hydroxyapatite nanoparticles as adsorbents

Adsorption of aqueous Cd2+, Pb2+, Cu2+ ions by nano-hydroxyapatite: Single- and multi-metal competitive adsorption study

Removal of heavy metals and bacteria from aqueous solution by novel hydroxyapatite/zeolite nanocomposite, preparation, and characterization

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