Sustainable Activated Carbon Production from Water Filter Waste Carbon Cartridge: Insights into Adsorption Isotherms, Kinetics, And Mechanisms

In this study, an efficient, sustainable, and environmental waste upcycling approach was employed for the one-step preparation of a chemically activated adsorbent using water filter carbon cartridges (AC-WFCC). The simple chemical activation method provides a straightforward and scalable approach, contributing to both waste management and environmental remediation. AC-WFCC was thoroughly examined using XRD, BET, SEM, HR-TEM, FT-IR, and Raman spectroscopy to confirm its structural integrity and high surface area (922.18 m²·g^–1). It exhibited a maximum adsorption capacity of 306.22 mg·g^–1 for the removal of methyl orange (MO). The detailed investigational study on the effects of pH, adsorbent dose, contact time, and concentration on adsorption performance was carried out. The adsorption process follows the Redlich–Peterson adsorption isotherm model (R² = 0.988) and pseudo-second-order kinetics (R² = 0.999). The thermodynamic parameters ΔG, ΔH, and ΔS revealed the spontaneous and exothermic nature of the adsorption of MO by AC-WFCC. Further, a phytotoxicity study on Vigna Mungo seeds was performed, and it demonstrates the nontoxic behavior of AC-WFCC with 80 to 100% seed germination in treated dye solution. AC-WFCC was regenerated and reused for up to five successive cycles. Finally, the applicability of the adsorbent was checked towards diverse environmental pollutants with excellent efficacy.