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Hollow Polyaniline Microsphere/Fe 3 O 4 Nanocomposite as an Effective Adsorbent for Removal of Arsenic from Water.

Research paper by Soumi S Dutta, Kunal K Manna, Suneel Kumar SK Srivastava, Ashok Kumar AK Gupta, Manoj Kumar MK Yadav

Indexed on: 20 Mar '20Published on: 20 Mar '20Published in: Scientific Reports



Abstract

Polyaniline hollow microsphere (PNHM)/FeO magnetic nanocomposites have been synthesized by a novel strategy and characterized. Subsequently, PNHM/FeO-40 (FeO content: 40 wt.%) was used as an adsorbent for the removal of arsenic (As) from the contaminated water. Our investigations showed 98-99% removal of As(III) and As(V) in the presence of PNHM/FeO-40 following pseudo-second-order kinetics (R > 0.97) and equilibrium isotherm data fitting well with Freundlich isotherm (R > 0.98). The maximum adsorption capacity of As(III) and As(V) correspond to 28.27 and 83.08 mg g, respectively. A probable adsorption mechanism based on X-ray photoelectron spectroscopy analysis was also proposed involving monodentate-mononuclear/bidentate-binuclear As-Fe complex formation via legend exchange. In contrast to NO and SO ions, the presence of PO and CO co-ions in contaminated water showed decrease in the adsorption capacity of As(III) due to the competitive adsorption. The regeneration and reusability studies of spent PNHM/FeO-40 adsorbent showed ~83% of As(III) removal in the third adsorption cycle. PNHM/FeO-40 was also found to be very effective in the removal of arsenic (<10 μg L) from naturally arsenic-contaminated groundwater sample.