Novel mesoporous cupric oxide-based biomaterial: An efficient nanocatalyst toward catalytic reduction of emerging contaminants in the wastewater

The present study reports on catalytic reduction of emerging water contaminants under ambient conditions by employing green, cost-effective, sustainable, efficient, and easy-recoverable nanocatalyst. Initially, spherical nano-CuO particles with good distribution were bio-synthesized using agricultural wastes in a facile, simple, and low-energy consumption process. After the characterization, the catalytic performance of the bio-synthesized CuO particles was examined for removal of p-nitrophenol, Cr(VI), and methylene blue dye from aquatic systems. Nano-CuO particles successfully reduced 90–98% of pollutants in a short time (4 s–8 min). In the next attempt, to improve the stability, separation, and reusability of nano-CuO powder, and also, to prevent secondary contamination by powdery form, composite microbeads based on natural polymer substrate (Na-alginate) as a gelling agent and CaCl2 as a complexing agent were developed by dropping method. The reduction rate of pollutants was fast, and pollutants were removed in less than 25 min. Conversion percentages for Ca-alginate/CuO microbeads in removing pollutants were obtained at 90–98%. The catalytic degradation kinetics data were best fit to the pseudo-first-order model with good correlation coefficients (R2 > 98). Besides, the catalytic activity of the prepared nanocatalyst remained almost unaltered for 10 consecutive cycles. Easy fabrication, effortless separation, large-scale application, excellent performance, and durability make the nanocatalyst and the procedure sustainable and economical. [Display omitted] •Nano-CuO particles with good distribution were prepared from agricultural wastes.•Ca-alginate/CuO beads were used as efficient catalyst for pollutant removal.•90–98% of p-nitrophenol, Cr(VI), and methylene blue were removed in 25 min.•The results showed pseudo-first-order kinetic with good correlation coefficients.•Catalytic performance of nanocatalyst remained almost unaltered for 10 cycles.