Synthesis and characterization of Ca-alginate/CuO bionanocomposite for removal of Reactive Yellow 145 dye: a green approach towards sustainability

The synthetic dyes have gained attention nowadays because of their adverse and toxic effects on the human health and their environment. In this study, a green polymer Ca-alginate/CuO bionanocomposite was synthesized from copper oxide nanoparticles which were applied for the remediation of Reactive Yellow 145. The bionanocomposite was prepared by using a simple and eco-friendly process, following the reduction of copper ions in the presence of Ca-alginate, followed by characterization using different analytical techniques including SEM–EDX, XRD, UV–vis and FTIR spectroscopy. Ca-alginate-based bionanocomposite was analyzed by UV–vis spectroscopy, showing a λ_max at 280 nm. Ca-alginate/CuO biopolymer was applied for the remediation of RY 145, and it was investigated using batch experiments following the optimization of experimental variables such as pH 6, 80 °C temperature, 0.04 mg/L initial dye concentration, 0.06 mg/L dose of catalyst and a 0.06 mg/L H₂O₂ concentration. The experimental results of COD and TOC were found to be 95.3% and 92.3% for RY 145. The bionanocomposite showed stability and high efficiency for degradation of dye up to four cycles of reusability. It was concluded that the Ca-alginate-based copper oxide bionanocomposite exhibited good photocatalytic adsorption capacity for the degradation of a toxic Reactive Yellow 145 dye, with a degradation efficiency of over 90% within 80 min under optimized conditions.