ABSTRACT This study systematically investigates the adsorption and diffusion‐based kinetics of Ni(II) uptake onto N‐(((2‐((2‐aminoethyl)amino)ethyl)amino)methyl)‐4‐sulfamoylbenzamide‐impregnated hydrous zirconium oxide (AESB/HZO) within the temperature range of 303–333 K. Fractal‐like pseudo‐second‐order (FPSO) and fractal‐like pseudo‐first‐order (FPFO) models were employed to elucidate the adsorption mechanism, with FPSO demonstrating superior correlation (R 2 > 0.9995), confirming a chemisorptive rate‐controlling process. The Elovich model (R 2 > 0.9952) further validated surface heterogeneity in adsorption kinetics. Diffusion‐based models revealed that Ni(II) ions were initially transported to the external surface via external mass transfer (Mathews‐Weber and Furusawa‐Smith models), followed by intraparticle diffusion as the primary rate‐limiting step (Fick's law, R 2 > 0.9958). The Urano and Tachikawa model reinforced this, whereas the Boyd film diffusion model (R 2 100) confirmed intraparticle diffusion dominance, while the Bangham pore diffusion model indicated significant pore diffusion contributions. The dual exponential model indicated that both external mass transport and internal pore diffusion contributed to the overall adsorption process. Statistical physics models provided deeper adsorption insights, with Model 2 yielding the best fit (R 2 > 0.999, 𝜒 2 0) with reduced randomness (ΔS < 0), emphasizing structured Ni(II) uptake. This mechanistic understanding facilitates the optimization of AESB/HZO for efficient Ni(II) removal in environmental applications.
Nasir et al. (Fri,) studied this question.