Desinta Dwi Ristiana, Lathifah Puji Hastuti, Saptarini, Khansa Adinda Shafira, Aida Udkhiyah, Dinda Quratul Aini Irianto
In this study, Cu2O, CdS, and Cu2O decorated with CdS nanorods were successfully synthesized and applied for the adsorption of crystal violet (CV) dye. Cu2O had a cauliflower-like shape, while CdS underwent a phase transition from cubic to the hexagonal structure, forming nanorods anchored to the Cu2O surface. The Cu2O/CdS composite achieved the highest removal efficiency with 65% CV removal. Kinetic analysis revealed that the adsorption of CV onto CdS and Cu2O/CdS followed the pseudo-second order model, with a rate constant (k2) of 0.0268 g mg⁻1 min⁻1, indicating that chemisorption is the dominant mechanism. Equilibrium data were evaluated using the Langmuir and Freundlich isotherms, with the Freundlich model providing a superior fit (R2 = 0.9522) and Freundlich constants of 17.969 mg g⁻1 and 19.5865 mg g⁻1 for CdS and Cu2O/CdS, respectively, suggesting heterogeneous multilayer adsorption as the governing mechanism. The enhanced performance of the Cu2O/CdS composite is attributed to the hierarchical morphological structure of Cu2O and the hexagonal structure of CdS. Overall, the results demonstrate that Cu2O/CdS is a promising adsorbent for removing dye from aqueous systems, offering high adsorption capacity, favorable kinetics, and heterogeneous adsorption behavior. © The Author(s), under exclusive licence to Springer Nature B.V. 2026.
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Brawijaya University, Malang, 65145, Indonesia; Graduate School, Universitas Padjadjaran, Bandung, 40132, Indonesia
