Fullerene (<scp>C₆₀</scp>)‐doped zinc‐aluminium layered double hydroxide/polyvinyl alcohol nanocomposites: Synthesis, characterization, and photodegradation of methylene blue from water solution

Abstract

Abstract Introduction Layered double hydroxides (LDHs) are widely studied anionite clays consisting of positively‐charged hydroxide nanosheets which is described by the general formula: [M(II) 1−x M(III) x (OH) 2 ][A n− ·mH 2 O], where M(II) and M(III) are the divalent (e.g., Mg 2+ , Zn 2+ , Ca 2+ , Co 2+ , Ni 2+ , etc.) and trivalent (e.g., Al 3+ , Fe 3+ , Cr 3+ , etc.) metal ions, A n− and H 2 O is the interlamellar anion (e.g., Cl¯, Br¯, NO 3 ¯, CO 3 2 ¯, SO 4 2 ¯, SeO 4 2 ¯) for charge‐neutralization and hydrated state, respectively. They have been widely used in different industry sectors, in materials science and research. Polymer/LDH nanocomposites have gained significant attention in recent years. Carbon‐based nanomaterials, like fullerene, carbon nanotubes (CNT), graphene and graphene oxide have attracted significant attention. Fullerene molecules (C 60 , C 70 ) are used as reinforcing material for polymers to improve their mechanical, thermal, optical, energy storage and charge transport properties. Objectives C 60 ‐doped ZnAl‐layered double hydroxide/polyvinyl alcohol nanocomposites were successfully synthesized and their photocatalytic activity for photodegradation of methylene blue (MB) synthetic dye was quantitatively analyzed by ultraviolet (UV) spectroscopy. The effect of C 60 on the optical, structural, morphological properties, and photocatalytic activity of LDHs was investigated, and the impact of C 60 /LDH mass ratio and aging time on the properties was also studied. Methods Fullerene‐doped ZnAl‐LDH/PVA nanocomposites were synthesized via urea hydrolysis and coprecipitation‐coformation method. First, 10 wt% PVA/water solution (40 mL) is added into the mixed solution containing 0.015 mol of Zn(NO 3 ) 2 ·6H 2 O and 0.005 mol of Al 2 (SO 4 ) 3 ·9H 2 O and titrated by 2 M of NaOH and 1 M of NaHCO 3 mixed base solution to adjust pH 9. The obtained white slurry was shaken very hard and aged for 1 year. The obtained samples were marked by the mass percentage of C 60 as 1% C 60 @LDH/PVA, 10% C 60 @LDH/PVA, 20% C 60 @LDH/PVA, and 60% C 60 @LDH/PVA. Results and Discussion The basal spacing of C 60 ‐doped ZnAl‐LDH was estimated to be 9.217 Å which is wide enough from the general LDH (~7.0 Å). The crystallite size of nanoparticles is 9.217 nm and ~6 nm by Scherrer's equation and Williamson–Hall method from the XRD data, respectively. Rice‐shaped 2D morphology was formed with 100 nm–2 μm width and 500 nm–10 μm in length by SEM. The maximal photodegradation efficiency was found with 20% of C 60 doping (PD% = 96.98) after 360 min, where the sorption efficiency with this compound is very high ( R % = 85.55). Conclusions In the presented work, the effect of C 60 on the optical, structural, morphological properties, and photocatalytic activity of LDHs was investigated, and the impact of C 60 /LDH mass ratio and aging time on the properties was also studied. For the identification of the photocatalytic activity of obtained C 60 /LDH nanocomposites, MB was used as a model pollutant and the efficiency of the Zn/Al LDH nanocomposite, with various quantities of fullerene, is also evaluated.

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