Study on adsorption characteristics of sepia melanin adsorbing Pb2+

Sepia melanin was used as adsorbent for absorbing Pb2+ from water. The influences of Pb2+ initial concenration, pH value, adsorbing temperature, adsorbing time and sepia melanin contents on the adsorption effect of sepia melanin onto Pb2+ were discussed. The results indicated that when pH value was 4⁵, the Pb2+ absorbing amount reached the highest. The temperature almost didn't affect the adsorption. The absorbing rate decreased against the increase of Pb2+ initial concenration, while it increased with the increasing of adsorbing time and sepia melanin contents until it reached saturation adsorption. Adsorption process of Pb2+ by sepia melanin was in accordance with the Langmuir models and pseudo-second-order reaction equation and obeyed to the rule of single element layer.