K Shakitha, V N Meena Devi
Biomass-derived activated carbon is widely recognized as an eco-friendly and sustainable adsorbent for wastewater treatment. In this study, activated carbon was synthesized from the aerial parts of Cyanthillium cinereum through phosphoric acid activation followed by controlled carbonization. The prepared CC-AC was characterized using XRD, FTIR, SEM, EDX, BET, and zeta-potential analyses, confirming its amorphous structure, oxygen-containing surface functionalities, well-developed porous characteristics, and pH-dependent surface charge behavior. The adsorption performance of CC-AC was evaluated for the removal of Methylene Blue and Eosin Yellow under different conditions such as pH, contact time, adsorbent dosage, and initial dye concentration. The results showed high removal efficiencies of 90% for Methylene Blue and 83% for Eosin Yellow. Adsorption kinetics were best described mathematically by the pseudo-second-order model, while intraparticle-diffusion and Boyd analyses indicated the involvement of multiple mass-transfer steps. Equilibrium data were best described by the Langmuir model, indicating predominant Langmuir-type equilibrium behavior. The findings demonstrate that Cyanthillium cinereum-derived activated carbon is a cost-effective and sustainable adsorbent for dye-contaminated wastewater treatment.