Single-Step Hydrothermal Synthesis of Biochar from H3 PO4-Activated Lettuce Waste for Efficient Adsorption of Cd(II) in Aqueous Solution

Quyun Chen, Tian C. Zhang, Like Ouyang, Shaojun Yuan

Research output: Contribution to journalArticlepeer-review

Abstract

Developing an ideal and cheap adsorbent for adsorbing heavy metals from aqueous solution has been urgently need. In this study, a novel, effective and low-cost method was developed to prepare the biochar from lettuce waste with H3 PO4 as an acidic activation agent at a low-temperature (circa 200 C) hydrothermal carbonization process. A batch adsorption experiment demonstrated that the biochar reaches the adsorption equilibrium within 30 min, and the optimal adsorption capacity of Cd(II) is 195.8 mg·g−1 at solution pH 6.0, which is significantly improved from circa 20.5 mg·g−1 of the original biochar without activator. The fitting results of the prepared biochar adsorption data conform to the pseudo-second-order kinetic model (PSO) and the Sips isotherm model, and the Cd(II) adsorption is a spontaneous and exothermic process. The hypothetical adsorption mechanism is mainly composed of ion exchange, electrostatic attraction, and surface complexation. This work offers a novel and low-temperature strategy to produce cheap and promising carbon-based adsorbents from organic vegetation wastes for removing heavy metals in aquatic environment efficiently.

Original languageEnglish (US)
Article number269
JournalMolecules
Volume27
Issue number1
DOIs
StatePublished - Jan 1 2022

Keywords

  • Adsorption mechanisms
  • Biochar
  • H PO activator
  • Hydrothermal carbonization
  • Lettuce waste

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemistry (miscellaneous)
  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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