Engineering nanocomposite of graphene quantum dots/carbon foam/alginate/zinc oxide beads for efficacious removal of lead and methylene.

[Display omitted] • Engineering nanocomposite of GQDs/carbon foam/sodium alginate/zinc oxide beads. • Homogeneous spherical particles of nanocomposite with 20 nm average particle size. • Effective removal of lead ion and methylene blue dye at pH 6 and 7, respectively. • Endothermic and spontaneous adsorption reactions of the two pollutants. • Excellent removal of lead ion (100%) and MB (92.2%) from real water. The excessive industrial applications of methylene blue dye and lead ions with their high resistance to biodegradation in water systems have led to their detection in water effluents as pollutants of major concern and therefore they must be removed by efficient techniques. Carbonaceous based materials as carbon foam (C-Foam) and graphene quantum dots (GQDs) with sodium alginate are important reactive adsorbents in water treatment. Therefore, a novel nanocomposite was assembled via crosslinking of zinc oxide with carbon foam, GQDs and alginate to fabricate ZnO/C-Foam/GQDs/Alginate. This nanocomposite exhibited homogeneous and spherical particles with 20 nm average size. ZnO/C-Foam/GQDs/Alginate is designed to remove Pb^(II) and methylene blue (MB) pollutants. The collected results referred to the optimum pH 6 and 7 for Pb^(II) and MB, respectively. The computed thermodynamic parameters revealed endothermic and spontaneous reactions by the two pollutants providing ΔGo from −8.06 to −13.67 kJ/mol for lead ion and from −6.23 to −8.19 kJ/mol for MB dye. The interfering species exhibited almost insignificant impact. ZnO/C-Foam/GQDs/Alginate nanocomposite confirmed successful reusability for five successive regeneration cycles. Finally, ZnO/C-Foam/GQDs/Alginate nanocomposite provided excellent removal trends for Pb^(II) and MB pollutants from real water samples with100% and 92.2 % removal, respectively. [ABSTRACT FROM AUTHOR]