Insight into microwave-assisted synthesis of the chitosan-MOF composite: Pb(II) adsorption

Environ Sci Pollut Res Int. 2023 Jan;30(3):6216-6233. doi: 10.1007/s11356-022-22438-6. Epub 2022 Aug 22.

Abstract

Heavy metal contamination has increased over the globe, causing significant environmental issues owing to direct and indirect releases into water bodies. As a result, metal removal from water entities must be addressed soon. Various adsorbents such as MOFs and chitosan have demonstrated promising results in water treatment. The present study prepared a composite material (chitosan-UiO-66-glycidyl methacrylate MOF) by a microwave-assisted method. The structure and morphology of the chitosan-MOF composite were studied using FE-SEM, EDX, XRD, BET, FT-IR, and TGA techniques. In addition, the adsorption of Pb(II) from aqueous solution onto the chitosan-MOF composite was analyzed in a batch study concerning pH, contact time, initial metal ion concentration, and adsorbent dosage. The composite has a large surface area of 867 m2/g with a total pore volume of 0.51 cm3/g and thermal stability of up to 400 [Formula: see text]. Following an analysis of the adsorption isotherms, kinetics, and thermodynamics, the Langmuir model showed an excellent fit with the adsorption data (R2 = 0.99) and chi-squared (X2 = 3.609). The adsorption process was a spontaneous exothermic reaction and the pseudo-second-order rate equation fitted the kinetic profile well. Moreover, the composite is recyclable, retaining 83.45% of its removal effectiveness after 5 consecutive cycles, demonstrating it as a sustainable adsorbent for metal recovery. This study introduces a novel synthesized composite with enhanced recyclability and a higher potential for eliminating pollutants from industrial wastewater.

Keywords: Adsorption; Chitosan-MOF composite; Lead removal; Metal–organic framework; Nanocomposites.

MeSH terms

  • Adsorption
  • Chitosan* / chemistry
  • Hydrogen-Ion Concentration
  • Kinetics
  • Lead
  • Microwaves
  • Spectroscopy, Fourier Transform Infrared
  • Water Pollutants, Chemical* / analysis
  • Water Purification* / methods

Substances

  • Chitosan
  • Lead
  • Water Pollutants, Chemical