Adsorptive removal of Pb(II) ions from aqueous solutions by thiourea-functionalized magnetic ZnO/nanocellulose composite: Optimization by response surface methodology (RSM).

Removal of pollutants by bio-superadsorbent is currently in the limelight due to their low cost and biocompatibility with the environment. In this research, the thiourea-modified magnetic ZnO/nanocellulose composite (TZFNC) with high adsorption capacity and separation efficiency for Pb(II) was prepared successfully, and its physicochemical properties were characterized via XRD, SEM, TEM, AFM, BET, FTIR, XPS, EDAX, Zeta-potential and VSM, respectively. Response surface methodology (RSM) has been applied in order to study the influence of operational parameters (pH, lead ions concentration, adsorbent dosage and contact time) on the removal efficiency of lead ions with TZFNC as a novel adsorbent. The results indicated that the efficiency of Pb(II) removal is 99.99% under the optimum conditions of experimental factors (pH = 6.5, the amount of adsorbent = 40 mg, Pb(II) concentration = 60 mg L-1, and contact time = 14.5 min). The equilibrium, and kinetic studies suggested that the adsorption process followed the Langmuir isotherm and Pseudo-Second-Order model. Thermodynamic data showed that the sorption process was feasible, spontaneous, and endothermic. The maximum adsorption capacity was found to be 554.4 mg/g. The good adsorption performance, recyclability and easy magnetic separation ability made sure that the TZFNC has great potential for purification of Pb(II) contaminated wastewater.