Mathematical modeling for the evaluation of zinc removal efficiency on clay sorbent.

The adsorption characteristics of zinc ion from aqueous solution on the lateritic clay were investigated through batch and column mode of operation. The system variables were optimized to evaluate the maximum extent of zinc adsorption as well as for the purpose of modeling. A model equation correlating zinc adsorption with input concentration was described. The adsorption behavior can well be described by Freundlich isotherm model rather than Langmuir isotherm model. The favorable and spontaneous nature of adsorption was indicated from the thermodynamical parameters. The capacity was determined from isotherm parameters in batch mode and breakthrough parameters in column mode. The bed depth service time (BDST) model was utilized to predict column efficiency corresponding to different bed heights. Elution performance of retained zinc, using HNO(3) of definite composition, was examined from elution profile. Efficiency of the process was determined through repetitive operation cycles of retention and elution. Effectiveness of the process was judged through estimation of efficiency versus the cost of operation.