Investigating Microcystin-LR adsorption mechanisms on mesoporous carbon, mesoporous silica, and their amino-functionalized form: Surface chemistry, pore structures, and molecular characteristics

Jeong Ann Park, Jin Kyu Kang, Sung Mok Jung, Jae Woo Choi, Sang Hyup Lee, Viviane Yargeau, Song Bae Kim

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Microcystin-LR (MC-LR) is the most common cyanotoxin released from algal-blooms. The study investigated the MC-LR adsorption mechanisms by comparing adsorption performance of protonated mesoporous carbon/silica (MC-H, MS-H) and their amino-functionalized forms (MC-NH2 and MS-NH2) considering surface chemistry and pore characteristics. The maximum MC-LR adsorption capacity (Langmuir model) of MC-H (37.87 mg/g) was the highest followed by MC-NH2 (29.25 mg/g) and MS-NH2 (23.03 mg/g), because pore structure is partly damaged during amino-functionalization. However, MC-NH2 (k2 = 0.042 g/mg/min) reacted faster with MC-LR than MC-H during early-stage adsorption due to enhancing electrostatic interactions. Intra-particle diffusion model fit indicated Kp,1 of MC-H (2.11 mg/g/min1/2) was greater than MC-NH2 due to its greater surface area and pore volume. Also, large mesopore diameters are favorable to MC-LR adsorption by pore diffusion. The effect of adsorbate molecular size on adsorption trend against MC-H, MC-NH2 and MS-NH2 was determined by kinetic experiments using two dyes, reactive blue and acid orange: MS-NH2 achieved the highest adsorption for both dyes due to the large number of amino groups on its surface (41.2 NH2/nm2). Overall, it was demonstrated that adsorption of MC-LR on mesoporous materials is governed by (meso-)pore diffusion and π – π (and hydrophobic) interactions induced by carbon materials; in addition, positively-charged grafted amino groups enhance initial MC-LR adsorption rate.

Original languageEnglish
Article number125811
JournalChemosphere
Volume247
DOIs
Publication statusPublished - 2020 May

Keywords

  • Amino-functionalization
  • Mesoporous carbon
  • Mesoporous silica
  • Microcystin-LR
  • Molecular characteristics
  • Pore diffusion

ASJC Scopus subject areas

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

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