Efficient Pb²⁺ adsorption of biomorphic porous ZnO derived from legume straw

Abstract

Using legume straw as template, biomorphic porous ZnO (named ZnO‐B) was synthesized by impregnation and calcination methods. Different characterizations were used to analyze the as‐prepared samples, such as Thermal Gravimetric and Differential Thermal (TG‐DTA), powder X‐ray Diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscope (SEM), Energy dispersive X‐ray spectroscopy (EDX), and Transmission Electronic Microscope (TEM) methods. The adsorption properties of as‐synthesized samples for Pb2+ were studied. As a result, a baculiform structure with porous surface is formed by well‐crystallized ZnO grain self‐assembly on legume straw. The Brunauer–Emmett–Teller (BET) specific surface areas of ZnO‐B is larger than that of ZnO synthesized without template (expressed as ZnO‐A). The zeta potential isoelectric point of ZnO‐B is pHpzc = 5.31. The ZnO‐B showed the most outstanding performance adsorption properties for Pb2+ than ZnO‐A and ZnO‐C (commercial ZnO), removal efficiency was >97.65% and adsorption capacity was 78.73 mg/g. The adsorption equilibrium can be achieved within 20 min. Decrease of temperature would benefit the adsorption. The adsorption process followed the Pseudo‐second model, and the adsorption isotherm model accorded with the Freundlich isothermal model. The E values in Dubinin–Radushkevich (D–R) isotherm model indicated that the adsorption is chemisorption. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019

Green synthesis of nanostructured zinc oxide by Ocimum tenuiflorum extract: characterization, adsorption modeling, cytotoxic screening, and metal ions adsorption applications

“…This was followed by a rapid decline in adsorption due to fewer available sites for adsorption. The results imply that ZnO NPs have a high adsorption affinity for Pb 2+ , and hence is an efficient adsorbent for the elimination of this ion from aqueous solutions [40]. The data of the adsorption experiments were fitted to different isotherm and kinetic models.…”