Comprehensive isotherm, kinetic, and thermodynamic study of phenol adsorption onto avocado seed nanomaterial

The novelty of this work lies in the development of a sustainable nanomaterial with an exceptionally high surface area and the comprehensive application of advanced nonlinear isotherm and kinetic modeling. Avocado seed nanomaterial (ASNM) was comprehensively characterized, particle size analysis revealed a uniform distribution of 155-160 nm, with BET surface areas of 2963.4 m²/g, confirming microporous character. SEM imaging revealed a rough morphology, while TEM confirmed nanodomains. Several nonlinear isotherm models were employed to evaluate the efficacy of adsorption. Henry, Langmuir, Freundlich, Temkin, Dubinin-Radushkevish, Jovanovic, Harkins-Jura, Frenkel-Halsey-Hill, Elovich, Sips, Toth, Khan, Liu, Jossens, Radke-Prausnitz, Redlich-Peterson, Hill, Baudu, and Fritz-Schlunder isotherms were used to test the equilibrium data. The model parameters were statistically analyzed using error functions, including the Residual Sum of Squares Error, Chi-square, Average Relative Error, Hybrid Fractional Error Function, Marquardt's Percent Standard Deviation, coefficient of determination, adjusted coefficient, and Root Mean Square Error. For isotherm model, Liu had a goodness of fit. Pseudo-first-order, pseudo-second-order, Elovich, Avrami, Weber-Morris, Linear Driving Force, Boyd's external diffusion, and Bangham models were used to examine the kinetic data. The Avrami and Bangham models provided the best fit for the sorption kinetics of phenol. Thermodynamic parameters confirmed that phenol adsorption was endothermic and spontaneous.