Batch Equilibrium and Effects of Ionic Strength on Kinetic Study of Adsorption of Phenacetin from Aqueous Solution Using Activated Carbon Derived from a Mixture of Ayous Sawdust and Cucurbitaceae Peelings

The present study is based on the adsorption of phenacetin on activated carbon prepared from ayous sawdust, Cucurbitaceae peelings and the mixture of the two materials using the batch technique. EDX analysis of the activated carbons showed that each one of them was constituted of carbon and oxygen. The mixture of ayous sawdust and Cucurbitaceae peelings did not show an increase in the percentage of carbon. SEM analysis showed that the mixture showed a change in the nature of pore present in activated carbons. The FT-IR analysis shows after adsorption one peak around 2200 cm-1 and the larger peaks near 1100 cm-1 are the proof that both activated carbons have adsorbed phenacetin. Adsorption was carried out by variation of the pH, contact time, ionic strength and initial concentration. The equilibrium time was achieved within 2 hours for both activated carbons. The maximum adsorption occurred at pH 2 for all the activated carbons. The adsorbent/adsorbate equilibrium was well described by the pseudo-second-order kinetic model and Langmuir’s adsorption model. The ionic strength was investigated using KCl, MgCl2 and CaCl2. The result showed that CaCl2 was the best salt in term of increasing the adsorbed quantities. Using the pseudo-second-order and Elovich kinetic models, it was also observed that CaCl2 increased the initial rate of adsorption while MgCl2 increased the desorption rate constant. This can be attributed to the adsorbed calcium phenacetin complex that is more stable than the magnesium and potassium phenacetin complex. Multi-linearity observed in Weber and Morris diffusion model, implying that more than one mechanism affected the adsorption process and the intraparticle diffusion is not the only process that can control the kinetics of adsorption. We have also found that the mixture of the precursors favor the mass transfer from the solution to the adsorption site inside the activated carbons and their fixation.