New insights into the interactions between Pb(II) and fruit waste biosorbent

Qian Wang*, Yunlong Wang, Junjie Tang, Zi Yang, Li Zhang, Xiaowu Huang

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Fruit waste is a sustainable biosorbent for heavy metal removal from wastewater. Elucidation of adsorption mechanism is imperative for the process control and development of effective adsorbents. In this study, watermelon rind (WR) exhibited selective and efficient Pb(II) adsorption with a maximum uptake of 230.5 mg/g at pH 5.0. The WR-packed bed column showed high Pb(II) uptake and robust durability over 10 adsorption-desorption cycles with long breakthrough time of 8–13 h (89–144 bed volume), and 95% of sequestered Pb(II) was rapidly desorbed in 1–2 h by 0.05 M HCl. Spectroscopic characterization by FTIR and XPS identified hydroxyl, carboxyl, amine, and ether groups as the binding sites for Pb(II) via the binding force of complexation. Physicochemical analysis showed that ion exchange with Mg2+ and Ca2+ accounted for 19% of Pb(II) adsorption by WR; electrostatic attraction and microprecipitation jointly contributed. Quantum chemistry simulation verified the interactions between Pb(II) and binding sites and revealed carboxyl was the preferential functional group. The findings corroborate the applicability of WR in scale-up Pb(II) removal/recovery from wastewater and elaborate the mechanisms of Pb(II) adsorption by the WR biosorbent. This also provides insights into the behavior of heavy metals in other liquid/solid interfaces.

Original languageEnglish
Article number135048
JournalChemosphere
Volume303
Issue number1
Number of pages10
ISSN0045-6535
DOIs
Publication statusPublished - Sep 2022

Keywords

  • Adsorption mechanism
  • Circular economy
  • Column study
  • Fruit waste
  • Heavy metal
  • Water Pollutants, Chemical/analysis
  • Fruit/chemistry
  • Adsorption
  • Metals, Heavy/analysis
  • Kinetics
  • Lead/analysis
  • Hydrogen-Ion Concentration
  • Waste Water/chemistry

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