Synthesis of graphene-based nanocomposites with superior doxycycline removal efficiency and antimicrobial studies.

[Display omitted] • Preparation of graphene (G) nanosheets up to the kg scale from waste electronic. • Preparation of binary Nb 2 O 5 @G and Ag@G nanocomposite-based photocatalysts. • The as-synthesized photocatalysts were used for degradation of doxycycline antibiotics. • Nb 2 O 5 @G photocatalyst showed high degradation (98.5%) for doxycycline in 120 min under visible light. • In addition, these nanocomposites showed good potential against E. coli bacterial strains. Herein, we report the successful preparation of high-quality graphene (G) nanosheets up to the kg scale using an electrochemical technique using graphite rods from scrap dry cell batteries. The as-prepared graphene was then decorated in-stiu with niobium oxide (Nb 2 O 5) and silver (Ag) nanoparticles to prepare Nb 2 O 5 @G and Ag@G nanocomposites. Powdered X-ray diffraction (p-XRD), Fourier-transform (FT-IR) infrared spectroscopy, UV–visible (UV–vis) spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM) were used to characterize the as-prepared nanocomposite material. This binary Nb 2 O 5 @G nanocomposite was subsequently used to degrade doxycycline antibiotic with an efficiency of 98.5 % in 120 min under visible light conditions. To determine the optimal scope of the as-prepared composite catalyst, degradation studies were performed at different pH values, photocatalyst doses and temperatures. Kinetics studies revealed that the processes followed pseudo-first-order kinetics. In addition, the as-synthesized graphene , Nb 2 O 5 @G and Ag@G nanocomposites were used for selective application against E. coli bacterial strains. Overall, Ag@G has shown good potential application prospects in the development of antibacterial materials in comparison with Nb 2 O 5 @G and pristine graphene. This study highlights the potential of as-prepared graphene-based nanocomposites for use in waste treatment and environmental bioremediation. [ABSTRACT FROM AUTHOR]