Sustainable and eco-friendly removal of 2,4,6-tricholorophenol from water using an acid-activated bio-waste/graphene oxide composite

The presence of 2,4,6-trichlorophenol (TCP) in aquatic systems presents considerable environmental and health risk owing to its persistence, toxicity, and bio-accumulative characteristics. In this work, an acid-activated eggshell/graphene oxide (AAES/GO) composite as an innovative and sustainable adsorbent was synthesized and characterized for the effective removal of TCP from aqueous solutions. The composite was synthesized via phosphoric acid activation of eggshells for surface modification, then incorporating graphene oxide for surface reactivity and adsorption capability enhancement. The thorough physicochemical analysis utilizing FTIR, SEM, EDX, and XRD validated the effective alteration and enhanced textural qualities of the AAES/GO composite. Adsorption experiments revealed fast adsorption of TCP, with a 63% removal accomplished in 10 min. The adsorption kinetics adhered to the pseudo-second-order model (R² = 0.99), signifying a chemically regulated adsorption process. Isotherm analysis indicated that the Temkin model (R² = 0.92) most accurately characterized the adsorption behavior, emphasizing the significance of surface interactions. The composite demonstrated elevated effectiveness with optimal adsorption at pH 6.5. Regeneration investigations demonstrated that the material could be re-utilized for a maximum of three cycles before experiencing a substantial decline in efficiency. The results indicate that the AAES/GO composite is a cost-effective, environmentally sustainable, and efficient adsorbent, presenting a viable alternative for the removal of TCP from contaminated water systems.