Regeneration and reuse of microbial extracellular polymers immobilised on a bed column for heavy metal recovery

Victor Ajao*, Kang Nam, Paraschos Chatzopoulos, Evan Spruijt, Harry Bruning, Huub Rijnaarts, Hardy Temmink

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Scopus)

Abstract

Microbial extracellular polymeric substances (EPS) have gained increasing attention for various water treatment applications. In this study, EPS produced from nitrogen-limited glycerol/ethanol-rich wastewater were used to recover Cu2+ and Pb2+ from aqueous solutions. Continuous flow-through tests were conducted on a column packed with silica gel coated with polyethyleneimine, to which EPS were irreversibly attached as shown by optical reflectometry. These immobilised EPS excellently adsorbed Cu2+ and Pb2+, with 99.9% of influent metal adsorbed before the breakthrough points. Metal desorption was achieved with 0.1M HCl, with an average recovery of 86% for Cu2+ and 90% recovery for Pb2+. For the first time, we successfully showed the possibility to regenerate and reuse the immobilised EPS for five adsorption-desorption cycles (using Cu2+ as an example) with no reduction in the adsorbed amount at the breakthrough point (qbp). Based on the mass balance of the associated metal ions participating in the adsorption process, ion exchange was identified as the major mechanism responsible for Cu2+ and Pb2+ adsorption by EPS. The results demonstrate the potential of wastewater-produced EPS as an attractive and perhaps, cost-effective biosorbent for heavy metal removal (to trace effluent concentrations) and recovery (86–99%).

Original languageEnglish
Article number115472
JournalWater Research
Volume171
DOIs
Publication statusPublished - 15 Mar 2020

Keywords

  • Biosorption
  • Column
  • Extracellular polymeric substances
  • Ion exchange mechanism
  • Metal adsorption

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