KINETIC MODELLING FOR ADSORPTIVE REMOVAL OF ACETIC ACID FROM ITS AQUEOUS SOLUTION USING BIOSORBENTS FROM WASTE BAOBAB AND TAMARIND OF DHOFAR

Abstract

The adsorption kinetics of acetic acid from aqueous solution onto raw and activated baobab (RB, AB) and tamarind (RT, AT) biosorbents of Dhofar were systematically investigated to evaluate the influence of biosorbent activation on adsorption performance and mechanism. Experimental data were analyzed using linear forms of eight kinetic models, including pseudo-first order (PFO), pseudo-second order (PSO), Elovich (EV), Brouers-Sotolongo (BS), Weibull (WB), Hill (HL), intra-particle diffusion (IPD), and Boyd (BY) models. Model performance was assessed through comprehensive error analytical parameters, including sum of squared errors (SSE), mean squared sum of errors (MSSE), standard error (SE), average absolute relative deviation (AARD), determination coefficient (R²) and correlation coefficient (R), chi-square test (χ²), and bias (b) factor. Among the adsorption kinetic models, the PSO and BS models demonstrated superior agreement with experimental data for most biosorbents, as evidenced by lower SSE and AARD values, highlighting the dominant chemisorption and heterogeneous adsorption behavior. Diffusion models, such as the IPD and BY models, revealed that adsorption was partly controlled by both boundary layer effects and intra-particle diffusion, with diffusion playing a more significant role in raw biosorbents. Activation of the biosorbents enhanced adsorption capacity and modified the kinetics, suggesting increased availability of active sites and improved surface accessibility. These findings demonstrate that error analysis based on kinetic models provides a robust framework for evaluating adsorption performance and mechanism.