Bed Lab Report

3. RESULTS AND DISCUSSIONS

3.1 Effect of operating Conditions

3.1.1 Effect of bed height
The effect of bed height on fixed bed adsorption at different bed height of 7.5, 13.5 and 27.5 cm is shown in following figure.

Fig. 1. Effect of bed height on breakthrough curve for phenol adsorption. (Amount of CFA= 5, 10 and 20 grams, Bed Height = 7.5, 13.5 and 27.5 cm, Influent flow rate = 0.375 ml/ min, Initial concentration (C0) = 1039.9 mg/lit)

It is observed that as the bed height increases, breakpoint time also increases. This shows that at the smaller bed height the effluent adsorbate concentration ratio increases more rapidly than for a higher bed height. Additionally the bed is saturated in less time for smaller bed height than the bigger

Fig. 5. Combined breakthrough curve for phenol adsorption. (Bed Height = 7.5 cm, amount of CFA= 5 grams, Influent flow rate = 60.0 ml/ hr, Initial concentration (C0) = 1039.9, 651.2, 292.7 & 70.0 mg/l)

Fig. 6. Combined breakthrough curve for phenol adsorption. (Bed Height = 13.5 cm, Amount of CFA= 10 grams, Influent flow rate = 60.0 ml/ hr, Initial concentration (C0) = 1039.9, 651.2, 292.7 & 70.0 mg/l)

Fig. 7. Combined breakthrough curve for phenol adsorption. (Bed Height = 27.5 cm, Amount of CFA= 20 grams, Influent flow rate = 60.0 ml/ hr, Initial concentration (C0) = 1039.9, 651.2, 292.7 & 70.0 mg/l)

It was observed from the figures 5, 6 and 7 that as the initial phenol concentration increases, the break point time decreases. For large phenol concentration, steeper breakthrough curves are found, because of the lower mass-transfer flux from the bulk solution to the particle surface due to the weaker driving force. In addition at higher concentration, the isotherm gradient is lower, resulting in higher driving force along the adsorbent