Unravel the potential of zinc oxide nanoparticle-carbonized sawdust matrix for removal of lead (II) ions from aqueous solution

Zinc oxide nanoparticles (ZnOnp) are molecular nanoparticles synthesized by a chemical precipitation method fromzinc nitrate tetrahydrate and sodiumhydroxide. Carbonized sawdust (CSD) was prepared from sawdust obtained from a local wood mill. The matrix of both provides a better material as an adsorbent. The present study applied the functionality of ZnOnp, CSD, and ZnOnp-CSD matrix as adsorbent materials for the removal of Pb (II) ions from aqueous solution. The method of batch process was employed to investigate the potential of the adsorbents. The influence of pH, contact time, initial concentration of adsorbate, the dosage of adsorbents, and the temperature of adsorbate-adsorbent mixture on the adsorption capacity were revealed. The adsorption isotherm studies indicate that both Freundlich and Langmuir isotherms were suitable to express the experimental data obtained with theoretical maximum adsorption capacities (q(m)) of 70.42, 87.72, and 92.59 mg.g(-1) for the adsorption of Pb (II) ions onto ZnOnp, CSD, and ZnOnp-CSD matrix, respectively. The separation factors (R-L) calculated showed that the use of the adsorbents for the removal of Pb (II) ions is a feasible process with R-L < 1. The thermodynamic parameters obtained revealed that the processes are endothermic, feasible, and spontaneous in nature at 25-50 degrees C. Evaluation of the kineticmodel elected that the processes agreed betterwith pseudo-second order where the values of rate constant (k(2)) obtained for the adsorption of Pb (II) ions onto ZnOnp, CSD, and ZnOnp-CSD matrix are 0.00149, 0.00188, and 0.00315 g.mg(-1).min(-1), respectively. The reusability potential examined for four cycles indicated that the adsorbents have better potential and economic value of reuse and the ZnOnp-CSD matrix indicates improved adsorbent material to remove Pb (II) ions from aqueous solution. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.