Photocatalysis mediated reactive dye degradation using statistical approach to protect water resources

In this study, the leaf extracts were used in co-precipitation methods to create superparamagnetic-reduced graphene composites. We also used Pennisetum glaucum panicle waste, a low-cost raw biomaterial, in place of commercial graphite to synthesise Graphene Oxide. The surface interaction of the magnetic nanoparticles over reduced Graphene Oxide sheets (rGO) potentially handles aggregation and enhanced photocatalytic electron transfer to facilitate strong dye degradation. The UV–visible peaks at 265 nm, 255 nm, 360 nm and 410 nm confirm the λmax shift due to composite formation; FT-IR reports the corresponding peaks for carboxylic, carbonyl, hydroxyl, epoxy and alkoxy functional groups. FE-SEM–EDX and XPS results demonstrate the iron nanoparticle distribution over the wrinkled rGO sheets. Particle size falls in the average range of 386.1 nm, and 229.9 nm for both our catalysts, with a zeta potential of − 33.3 mV and − 27.1 mV to render dispersion stability. VSM results with a magnetic hysteresis loop trend represent the superparamagnetic behaviour of our Photocatalysts. At pH 6, our composites demonstrated improved dye treatment up to 200 ppm in 2.5 h. The improved phyto-toxicity results for seed germination experiments and significant proof of the permitted range of physicochemical parameters were provided for the treated water. By using the two-way ANOVA, we verified the statistical significance with a p -value (> 0.05), and the composites were optimised using the RSM with CCD. Our findings thus open a new field for photocatalysts for wastewater treatment and their application for beneficial reuse to protect the environment from severe pollution. Graphical abstract