Özet:

In this study, the Response Surface Method statistically optimized Pb(II) adsorption on activated carbon prepared using corn husk. The full central composite design was the statistical method selected for optimization using adsorption capacity as a response factor. The quadratic model best explained the process. Adsorption parameters optimized were solution pH, contact time, temperature, and adsorbent dose. The respective optimum values were 4.5, 64 min, 50°C, and 0.4 g L-1. Adsorption isotherm and kinetics studies evaluated the data obtained at different temperatures using different isotherm and kinetics models. The non-linear curve fitting method determined the model with the best fit. Freundlich’s model best accommodated the isotherm data, whereas the pseudo-second-order kinetic model best modeled the kinetics data. Weber-Morris intraparticle diffusion model revealed the existence of multiple rate-controlling processes. The activation energy for the adsorption of Pb(II) ions was 30.17 kJ mol-1. The thermodynamics studies showed that the process was an entropy-driven endothermic process. Gibb’s free energy (ΔG) values were negative at the studied temperatures, and the spontaneity increased with the increase in temperature. The enthalpy (ΔH) and entropy change (ΔS) was 43.78 kJ mol-1 and 154.2 J mol K-1. The study concluded that the statistical method simplified the optimization of the adsorption process and produced an efficient adsorbent from corn husk.

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