Fabrication of Ag/halloysite nanotubes/Fe₃O₄nanocatalyst and their catalytic performance in 4-nitrophenol reduction

Abstract

nanocatalyst was synthesized in our work. The structure of the as-prepared composite catalyst was that Fe 3 O 4 nanoparticles with the size of 5.0-8.0 nm were loaded in the internal hollow lumen of HNTs and Ag nanoparticles with a mean diameter of 20 nm were randomly deposited on the external surface of HNTs/ Fe 3 O 4 . The resultant Ag/HNTs/Fe 3 O 4 exhibited satisfied catalytic activity (with conversion of 100% in 38 min) to the reduction of 4-nitrophenol (4-NP) with sodium borohydride. The catalytic activity was markedly enhanced when the catalysts concentration was increased (the rate constant was gradually increased from 0.40 to 20.18 × 10 −3 s −1 ). Also, the advantage of the obtained magnetic composite catalyst in terms of their fast separation and simple reuse was identified through five successive catalytic and separation process cycles. It could be concluded that Ag/HNTs/Fe 3 O 4 showed satisfied catalytic activity, recoverability, and reusability, which showed great potential for practical application for water treatment.

Environmental implications and applications of engineered nanoscale magnetite and its hybrid nanocomposites: A review of recent literature

“…Ag/halloysite nanotubes/Fe3O4 (Ag/HNTs/Fe3O4) nanocatalyst has been synthesized in which Fe3O4 NPs (5-8 nm) are loaded in the internal hollow lumen of HNTs and Ag NP (20 nm) are randomly deposited on the external surface of HNTs/Fe3O4. The resultant Ag/HNTs/Fe3O4 exhibits excellent catalytic activity (with conversion of 100% in 38 min) to the reduction of 4-NP with NaBH4 [375]. MWCNTs-Fe3O4-Pd/Fe nanohybrids provide rapid adsorption, gradual dechlorination of 2,4-dichlorophenol, and final desorption of phenol.…”

Synthesis of Pectin/ Fe 3 O 4 / Bentonite nanocomposite hydrogel and investigation of heavy metal (Pb 2+ , Cu 2+ , and Cd 2+ ) adsorption properties from water

“…Pectin/ Fe3O4 and Pectin/ Fe3O4/ Bentonite cross the zero point at room temperature. The superparamagnetic properties of the synthesized nanocomposites can be observed by utilizing hysteresis loops [24,30,31]. Bio adsorbent exhibits superparamagnetic behavior due to its Sshaped form with no remanence (MR) and no coercivity (Hc) (Hc).…”