Ultrasonic assisted hydrolysis of barley straw biowastes into construction of a novel hemicellulose-based adsorbent and its adsorption properties for Pb~(2+) ions from aqueous solutions

摘要

In this study, a chemical fractionation process using sulfuric acid was investigated to recover hemicellulose from barley straw under ultrasonic, and then, the extracted hemicellulose was mixed with sodium alginate to prepare the biosorbent with the gelation-solidification method. The prepared biosorbent was characterized by Field Emission Scanning Electron Microscope (FESEM), Energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC), and Brunauer-Emmett-Teller (BET) surface area analysis and used for efficient toxic lead removal from aqueous solutions. Different factors influencing adsorption, mechanisms, kinetics, isotherms, and thermodynamics were explored. The rate-controlling step in the early stages of adsorption was film diffusion that was determined by Boyd, Webber, and Dubinin-Radushkevich models. The maximum Pb2+ adsorption capacity was obtained 277.78 mg/g in pH 1/4 5, 0.4 g/L adsorbent dosage, 210 mg/L initial Pb2+ concentration, and 55 degrees C temperature and the removal efficiency was over 99%. Besides, after 5 reuse cycles, the high lead adsorptivity was observed. Due to the benefits of the prepared biosorbent such as high adsorption capacity, renewability, low-cost, and biodegradability, they can be effective adsorbents for the treatment of heavy metals wastewaters. (C) 2020 Elsevier Ltd. All rights reserved.