Conversion of waste polystyrene foam into sulfonated hyper-crosslinked polymeric adsorbents for cadmium removal in a fixed-bed column

• Published in: Chemical engineering research & design 2019-02, Vol.142, p.346-354
• Main Authors: Jia, Jizhen, Fu, Zhenyu, Wang, Lin, Huang, Zenan, Liu, Changkun
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Cadmium; Chemical reactions; Column adsorption; Computer simulation; Correlation coefficients; Crosslinking; Friedel-Crafts reaction; Industrial wastes; Ion adsorption; Ion concentration; Polystyrene resins; Selectivity; Simulation; Sulfonation; Waste expanded polystyrene; Wastewater
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2018.12.025

[Display omitted] •Waste expanded polystyrene foam was used to prepare the sulfonated adsorbents.•The prepared adsorbents were used for the first time in the column adsorption for Cd ions.•Thomas model was employed to fit the adsorption breakthrough curve.•The adsorption mechanisms were explained with different influencing factors. In this paper, the sulfonated hyper-crosslinked polystyrene (SHCP) adsorbents derived from the waste expanded polystyrene foam (WEPS) were prepared by the simple one-step Friedel–Crafts reaction and the subsequent sulfonation. The prepared SHCP adsorbents were used for the first time in the fixed-bed dynamic adsorption experiments for the removal of cadmium (Cd) ions. The maximum adsorption capacity of SHCP for Cd ion reached 0.7mmol/g at the pH of 7 at the temperature of 25°C. The influencing factors of the actual industrial wastewater including initial Cd ion concentration, height-to-diameter (H/d) ratio, ionic strength and co-existing ions on Cd ion adsorption breakthrough curve were examined in a fixed-bed column with the SHCP adsorbents. Furthermore, Thomas model was employed to fit the adsorption breakthrough curve and the simulated adsorption capacity ranged from 68.90 to 80.46mg/g, with the correlation coefficient higher than 0.97. It was found that the decrease of the ionic strength and the Cd ion initial concentration, as well as the increase of the H/d ratio would increase the adsorption capacity and the breakthrough point in the Cd ion column adsorption. In addition, the SHCP showed good Cd ion selectivity over Na ions in the column adsorption.