Phenol Adsorption on Commercial Palm Shell Activated Carbon: A Framework for Resolving Multi-Model Paradoxes Through Objective Selection and Mechanistic Reconciliation
International Journal of Chemical Kinetics, vol.58, no.8, pp.447-456, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 58 Issue: 8
- Publication Date: 2026
- Doi Number: 10.1002/kin.70058
- Journal Name: International Journal of Chemical Kinetics
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex
- Page Numbers: pp.447-456
- Keywords: adsorption mechanism, AIC criterion, data interpretation, fractal diffusion, model selection, surface heterogeneity
- Süleyman Demirel University Affiliated: Yes
Abstract
Conventional adsorption studies frequently encounter a methodological paradox where multiple kinetic and isotherm models provide statistically valid fits while suggesting contradictory physical mechanisms. This study presents a systematic framework to resolve such contradictions and derive a unified mechanistic understanding. Using phenol adsorption on palm shell activated carbon as a case study, we demonstrate a pathway that moves beyond routine model cataloging. The framework integrates: (1) Objective model discrimination using Akaike (AIC) and Bayesian (BIC) Information Criteria, which decisively identified the Pseudo-Second Order model (R2 = 0.9992, AICc = −648.2) over the misleadingly high-R2 Pseudo-First Order model, establishing chemisorption as rate-limiting; (2) Paradox resolution through the Sips isotherm model, which reconciles excellent Langmuir and Freundlich fits by quantifying surface heterogeneity (ns = 0.3215 at 25°C) while accounting for high-affinity sites; and (3) Advanced diffusion diagnostics via fractal analysis, revealing concentration-dependent sub-diffusive transport (fractal exponent a decreasing from 0.916 to 0.726). Thermodynamics confirmed strong chemisorption (ΔH° = −68.1 to −104.5 kJ/mol). This work provides a criterial protocol for transforming conflicting adsorption model outputs into coherent, evidence-based mechanisms applicable across diverse adsorbent systems.