High thiabendazole fungicide uptake using Cellana tramoserica shells modified by copper: characterization, adsorption mechanism, and optimization using CCD-RSM approach

In this paper, Cellana tramoserica (CT) shells were modified by copper and used as an adsorbent to remove thiabendazole (TBZ) from aqueous media. The removal efficiency of TBZ onto CT shells and modified Cellana tramoserica (CT-Cu) shells was investigated by considering the following parameters: initial pesticide concentration, solution pH, agitation time, temperature, and adsorbent mass. The experimental results show that the pseudo-first-order and Langmuir models well describe the adsorption process. The maximum adsorption amount for CT and CT-Cu is 319.68 mg/g and 376.12 mg/g, respectively. CT-Cu showed higher TBZ removal efficiency than CT, explained by the ligand exchange between the water and the pesticide molecules in the metal coordination sphere. Response surface methodology combined with central composite design (RSM-CCD) was used to optimize the adsorption conditions. Optimized values were obtained at 5 for pH, 50 ppm, 120 min, and 20 mg of CT-Cu adsorbent. Under these optimal conditions, 91% of TBZ was removed by adsorption onto CT-Cu. Graphical abstract