Removal of lead from aqueous solution using superparamagnetic palygorskite nanocomposite:Material characterization and regeneration studies

Rusmin, Ruhaida and Sarkar, Binoy and Tsuzuki, Takuya and Kawashima, Nobuyuki and Naidu, Ravi (2017) Removal of lead from aqueous solution using superparamagnetic palygorskite nanocomposite:Material characterization and regeneration studies. Chemosphere, 186. pp. 1006-1015. ISSN 0045-6535

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Abstract

A palygorskite-iron oxide nanocomposite (Pal-IO) was synthesized in situ by embedding magnetite into the palygorskite structure through co-precipitation method. The physico-chemical characteristics of Pal-IO and their pristine components were examined through various spectroscopic and micro-analytical techniques. Batch adsorption experiments were conducted to evaluate the performance of Pal-IO in removing Pb(II) from aqueous solution. The surface morphology, magnetic recyclability and adsorption efficiency of regenerated Pal-IO using desorbing agents HCl (Pal-IO-HCl) and ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) (Pal-IO-EDTA) were compared. The nanocomposite showed a superparamagnetic property (magnetic susceptibility: 20.2 emu g−1) with higher specific surface area (99.8 m2 g−1) than the pristine palygorskite (49.4 m2 g−1) and iron oxide (72.6 m2 g−1). Pal-IO showed a maximum Pb(II) adsorption capacity of 26.6 mg g−1 (experimental condition: 5 g L−1 adsorbent loading, 150 agitations min−1, initial Pb(II) concentration from 20 to 500 mg L−1, at 25 °C) with easy separation of the spent adsorbent. The adsorption data best fitted to the Langmuir isotherm model (R2 = 0.9995) and pseudo-second order kinetic model (R2 = 0.9945). Pb(II) desorption using EDTA as the complexing agent produced no disaggregation of Pal-IO crystal bundles, and was able to preserve the composite's magnetic recyclability. Pal-IO-EDTA exhibited almost 64% removal capacity after three cycles of regeneration and preserved the nanocomposite's structural integrity and magnetic properties (15.6 emu g−1). The nanocomposite holds advantages as a sustainable material (easily separable and recyclable) for potential application in purifying heavy metal contaminated wastewaters.

Item Type:
Journal Article
Journal or Publication Title:
Chemosphere
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2300/2307
Subjects:
ID Code:
140609
Deposited By:
Deposited On:
22 Jan 2020 11:40
Refereed?:
Yes
Published?:
Published
Last Modified:
16 Sep 2020 06:07