Removal of carbaryl insecticide from aqueous solution using eggshell powder: a modeling study

A batch study was done for exploring the performance of eggshell powder (EGP) for adsorptive removal of carbaryl from aqueous solution. In the experiment, the operating factors were initial carbaryl concentration (5-20mgL(-1)), solution pH (2-10), adsorbent dose (0.01-0.1g/100ml) and contact time (10-60min). For optimization, evaluation of the effects and interactions of the operating factors response surface modeling was applied and the influence of the factors was checked through a two-level four factor Box-Behnken design (BBD) model. The predicted data had shown good agreement (R-2=0.9985) with experimental data. Furthermore, the adsorption data were best fitted with Freundlich isotherm and pseudo-second-order kinetics. Thermodynamic parameters revealed that the adsorption of process was spontaneous and endothermic. Finally it can be concluded that the EGP can be used as an alternative adsorbent for the removal of carbaryl from aqueous medium.