Kinetics, equilibrium, statistical surface modeling and cost analysis of paraquat removal from aqueous solution using carbonated jujube seed.

This paper reports the removal of paraquat from an aqueous solution using prepared carbonated jujube seed (JS/HSO-700). JS/HSO-700 was characterized by XPS, TGA, FTIR, N2 physisorption, SEM, and Raman techniques. FTIR revealed the presence of active species on the JS/HSO-700 surface. The removal rate of paraquat was investigated as a function of multiple operational factors such as contact time, adsorbent dose and solution pH. Adsorption mechanism was fully investigated based on FTIR, Raman, and BET analyses before and after adsorption. Response surface methodology modeling using central composite design was performed to statistically optimize the adsorption conditions. The experimental paraquat removal efficiency was found to be 96.7 ± 2.02%, whereas the predicted value of the model was 94.31 ± 4.43%, showing that the predicted model values are in good agreement with the experimental value. Finally, cost analysis was performed to confirm the cost of the adsorbent based on energy consumption and reagent costs.