Title : Removal of phenol from wastewater in fixed-bed column using low cost natural bio adsorbent neem leaves
The research aims to carry out the fixed-bed column study of phenol removal from wastewater by low-cost natural bioadsorbent neem leaves. The neem leaves were characterized by SEM, XRD, FTIR and BET analyzers. The optimum pH of the phenol solution was determined by batch experiments. The column experiments for determination of phenol removal efficiency by neem leaves were performed at optimum pH 3 at different bed height (8.5-13.5 cm), flow rate (10-30 ml/min) and initial phenol concentration (100-300 mg/L). The experiments showed that the breakthrough and exhaustion times increased with the rise of bed height, but decreased with the rise of flow rate and phenol concentration. The adsorption mechanism involved the interactions between the cellulose, hemicelluloses and lignin materials of the adsorbent and phenol molecules through n- π, π-π and H-bonding. The kinetic study with the experimental results showed that the Yen et al. model (r2 = 0.9911, KY = 0.63711 ml/mg.min, qY = 6165 mg/gm) was fitted best. The scale-up design was performed using the best fitted kinetic model. Desorption of phenol from used adsorbent with ethanol solution (30% v/v) indicated 60.10% regeneration efficiency. The safe disposal of used adsorbent was studied by incineration. The multiple linear regressions (MLR) and artificial neural networks (ANN) showed that the experimental results could be used with successful predictions. The research thus concludes that the neem leaves are the effective low-cost natural bio-adsorbent for phenol removal and therefore can be successfully applied to many small and medium scale industries, especially in the third world countries.