Hybrid PAC-submerged membrane system for trace organics removal: I. Adsorption kinetics study of PAC in a bubbled solution

Part I of this study presents a theoretical method combined with experiments to determine the adsorption kinetics of powdered activated carbon (PAC) in the hybrid PAC-submerged membrane (SM) system with air bubbling for trace organics removal. The homogeneous surface diffusion model (HSDM) was applied to describe the kinetics of the adsorbate uptake. The differences between the model solutions and the corresponding experimental results were minimized by means of Levenberg–Marquardt algorithm so that two kinetic parameters D_S and k_f involved in HSDM were obtained simultaneously. The D_S was found to be 1.14 × 10⁻¹⁶ m²/s and the k_f value was correlated with the bubbling rate (Q_b) and carbon dosage (C_c), which are required in the modeling of the hybrid PAC-SM system presented in Part II of this study. The k_f was enhanced from 1.18 × 10⁻⁴ to 4.18 × 10⁻⁴ m/s when the bubbling intensity increased in the intermittent bubbling tests, suggesting that from energy consumption point of view, the high intensity intermittent bubbling is more efficient in improving the liquid film mass transfer than continuous bubbling with the same net bubbling rate.