To investigate the effect of agitation time and feed concentration on percentage removal of phenol batch experiments were carried out at room temperature in the range of 100 to 700 mg/l of initial feed concentration and the results are shown in Fig. 2.Experimental conditions used were agitation speed of 200rpm, biosorbent dosage 0.15 g and pH 7.From figure it is observed that with increase in agitation time from 0 to 2 days, the percentage removal increased from 8% to 98%.Phenol adsorption from bulk liquid to biosorbent is high when the agitation time was increased. This leads to a higher adsorption of phenol on the biosorbent surface and it could reach an equilibrium beyond which percentage removal may not increase. In the present study equilibrium is reached at 4 days. The initial phenol concentration provides an important driving force to overcome all mass transfer limitations of phenol between the aqueous and sorbent phases. Therefore a higher opening phenol concentration will enrich the biosorption process. The increase in sorption capacity of bacterial strain with an increase in the initial phenol concentration might be due to a higher probability of collision between the phenol molecules and biosorbent. With increase in phenol concentration from 100 to 500 mg/L, the percentage removal reached 99% in 2 days. The equilibrium …show more content…
5. From the figure, it is observed that as the height of the liquid pool increased from 10 to 30 cm, the amount of phenol removed to the foam increases from 43.00603 to 76.13823 and enrichment ratio too increases from 2.93856 to 5.57488. This is due to the fact that as the height increases the residence time of the bubbles in the liquid pool increases. After a certain point, the adsorption of phenol onto bubbles could reach equilibrium, beyond which the percentage removal and enrichment ratio decreases to 15.57872 and 4.79045, respectively