Design of chitosan/boehmite biocomposite for the removal of anionic and nonionic dyes from aqueous solutions: Adsorption isotherms, kinetics, and thermodynamics studies

Int J Biol Macromol. 2024 Feb;259(Pt 2):129219. doi: 10.1016/j.ijbiomac.2024.129219. Epub 2024 Jan 4.

Abstract

This study introduces a chitosan/boehmite biocomposite as an efficient adsorbent for removing anionic Congo Red (CR) and non-ionic Bromothymol Blue (BTB) from water. Boehmite nanoparticles were synthesized using the Sol-gel method and then attached to chitosan particles using sodium tripolyphosphate through co-precipitation method. Characterized through FTIR, FE-SEM, BET, and XRD, the biosorbent displayed structural integrity with optimized pH conditions of 3 for CR and 4 for BTB, achieving over 90 % adsorption within 30 min. Pseudo second order kinetics model and Langmuir isotherm revealed monolayer sorption with capacities of 64.93 mg/g for CR and 90.90 mg/g for BTB. Thermodynamics indicated a spontaneous and exothermic process, with physisorption as the primary mechanism. The biosorbent demonstrated excellent performance and recyclability over five cycles, highlighting its potential for eco-friendly dye removal in contaminated waters.

Keywords: Adsorption; Bromothymol blue; Chitosan/boehmite; Congo Red.

MeSH terms

  • Adsorption
  • Aluminum Hydroxide*
  • Aluminum Oxide*
  • Chitosan* / chemistry
  • Coloring Agents / chemistry
  • Congo Red
  • Hydrogen-Ion Concentration
  • Kinetics
  • Thermodynamics
  • Water
  • Water Pollutants, Chemical* / chemistry

Substances

  • Coloring Agents
  • Chitosan
  • aluminum oxide hydroxide
  • Water Pollutants, Chemical
  • Congo Red
  • Water
  • Aluminum Hydroxide
  • Aluminum Oxide