Adsorptive removal of cationic methylene blue and anionic Congo red dyes using wet-torrefied microalgal biochar: Equilibrium, kinetic and mechanism modeling

Kai Ling Yu, Xin Jiat Lee, Hwai Chyuan Ong, Wei-Hsin Chen*, Jo-Shu Chang, Chih-Sheng Lin, Pau Loke Show, Tau Chuan Ling

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

This study aims to investigate the adsorption behavior of cationic and anionic dyes of methylene blue (MB) and Congo red (CR) onto wet-torrefied Chlorella sp. microalgal biochar respectively, as an approach to generate a waste-derived and low-cost adsorbent. The wet-torrefied microalgal biochar possessed microporous properties with pore diameter less than 2 nm. The optimum adsorbent dosage of wet-torrefied microalgal biochar for MB and CR dyes removal were determined at 1 g/L and 2 g/L, respectively, with their natural pHs as the optimum adsorption pHs. The determined equilibrium contact times for MB and CR were 120 h and 4 h, respectively. Based on the equilibrium modeling, the results revealed that Langmuir isotherm showed the best model fit, based on the highest R-2 coefficient, for both the adsorption processes of MB and CR using the wet-torrefied microalgal biochar, indicating that the monolayer adsorption was the dominant process. From the modeling, the maximum adsorption capacities for MB and CR were 113.00 mg/g and 164.35 mg/g, respectively. The kinetic modeling indicated the adsorption rate and mechanism of the dyes adsorption processes, which could be crucial for future modeling and application of wet-torrefied microalgal biochar. From the results, it suggests that the valorization of microalgae by utilizing wet-torrefied microalgal biochar as the effective adsorbent for the removal of toxic dyes with an approach of microalgal biorefinery and value-added application to the environment is feasible. (C) 2020 Elsevier Ltd. All rights reserved.

Original languageEnglish
Article number115986
Number of pages12
JournalEnvironmental pollution
Volume272
DOIs
StatePublished - 1 Mar 2021

Keywords

  • Microalgae
  • Biochar
  • Dye adsorption
  • Wet torrefaction
  • Environmental sustainability
  • Equilibrium and kinetic modeling

Fingerprint

Dive into the research topics of 'Adsorptive removal of cationic methylene blue and anionic Congo red dyes using wet-torrefied microalgal biochar: Equilibrium, kinetic and mechanism modeling'. Together they form a unique fingerprint.

Cite this