The contact time defined as the tim

The contact time defined as the time of immersing the
biosorbents in the metal ion solution. The influence of biosorbents
toward the immersion time is determined by the stability of the
metal complex formed during the adsorption process between the
metal ions and the biosorbents. Highly stable metal/biosorbent
complexes associated by high metal adsorption efficiency, while
low stable metal/biosorbent complexes dissociated in the medium,
and consequently decreases the adsorption efficiency by time.