Calotropis gigantea-mediated Green Synthesis of rGO–TiO₂ Nanocomposite for Efficient Decolorization of Textile Dye Effluent
J. Environ. Nanotechnol., Volume 15, No 2 (June 2026) pp. 370-379
Abstract
In the present study, a reduced graphene oxide–titanium dioxide (rGO–TiO2) bio-nanocomposite (NC) was synthesized using the reducing potential of Calotropis gigantea leaf extract. The synthesized NC was subjected to multiple analytical techniques to assess its structural and morphological characteristics. XRD and FT-IR analyses confirmed that Calotropis gigantea leaf extract effectively reduced GO to rGO and facilitated the formation of the rGO–TiO₂ NC. SEM–EDX analysis revealed that the NC exhibited a layered sheet-like and microball-like morphology. The raw textile effluent used in this study was characterized. A comparative analysis was conducted to evaluate the color removal efficiency of the NC in textile wastewater effluent. The use of NC in combination with centrifugation resulted in the removal of 77% of the apparent color and 90% of the turbidity from the textile effluent. Treatment using NC coupled with gravitational sedimentation achieved 67% apparent color removal and 87% turbidity removal. Color removal efficiency improved by 29% when NC coupled with gravitational sedimentation was used, compared with the effluent treated in a commercial wastewater treatment plant. The present work demonstrates a novel, simple, and environmentally friendly method for producing rGO–based nanomaterials with potential applications in wastewater treatment.
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