Mechanism of simultaneous removal of aluminum and fluoride from aqueous solution by La/Mg/Si-activated carbon

Minhee Kim, Choe Earn Choong, Seunghun Hyun, Chang Min Park, Gooyong Lee

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

La/Mg/Si-activated carbon derived from palm shell has been a suitable material for removal of aluminum and fluoride from aqueous solution. In the study, the mechanism of simultaneous removal of aluminum and fluoride by La/Mg/Si-activated carbon (La/Mg/Si-AC) was investigated to understand its high efficiency. It was found that the removal of aluminum and fluoride by La/Mg/Si-AC was favored at lower pH compared to the point of zero charge of La/Mg/Si-AC and high temperature. Adsorption capacity of Al(OH)4- was about 10 times higher than that of F- due to the strong binding affinity of Al(OH)4- on protonated surface and competition between F- and OH- toward charged adsorption site. Kinetics results showed that the aluminum and fluoride adsorption were explained using the pseudo-second-order kinetic model and intra-particle diffusion model. Adsorption process of Al(OH)4- and F- was driven by the potential rate-limiting step involved in mass transport process occurred on the boundary diffusion layer of porous adsorbent surface. Electrostatic interaction between protonated surface of La/Mg/Si-AC and negatively charged ions (i.e., Al(OH)4- and F-) as well as ion-exchange between hydroxide and ionic metal species were important mechanisms in the process of aluminum and fluoride adsorption. Driving forces for adsorption of individual Al(OH)4- and F- were not entirely different. Identifying the dominant mechanism will be helpful in understanding the adsorption process and developing new adsorbent. Mechanism of simultaneous removal of aluminum and fluoride by lanthanum/magnesium/silica -activated carbon are predicted.

Original languageEnglish
Article number126580
JournalChemosphere
Volume253
DOIs
Publication statusPublished - 2020 Aug

Keywords

  • Adsorption mechanism
  • Aluminum
  • Fluoride
  • Lanthanum/magnesium/silica-activated carbon

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

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