Modification of CaCO3 and CaCO3 pin-coated cellulose paper under supercritical carbon dioxide–ethanol mixture for enhanced NO2 capture

Nemanja Barac*, Ernest Barcelo, Dusica Stojanovic, Stoja Milovanovic, Petar Uskokovic, Patrick Gane, Katarina Dimic-Misic, Monireh Imani, Djordje Janackovic

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

In this work, we examine two modifications of fine-ground calcium carbonate material (GCC) in order to enhanced sorption of NO2 and subsequent reaction properties toward NO2/NO3 formation by firstly exposing the GCC to supercritical (sc) CO2 in order to increase particle surface area, a choice specifically made to avoid altering the surface chemistry, and secondly considering the potential advantage of using a surface coupling agent toward NO2. The modification by the coupling agent amino silane (AMEO silane) was applied in a supercritical CO2–ethanol mixture. The samples were characterised before and after modification by field emission scanning electron microscopy (FESEM), specific surface area determination (BET nitrogen adsorption), ATR-FTIR spectroscopy and ion chromatography to reveal the effects of the surface modification(s) on the morphology, surface textural properties and sorption versus reaction properties with NO2. The performance of the treated sorbents for NO2 capture was evaluated at room temperature. Results show that reactivity of NO2 with GCC was observed to increase as a function of increased surface area resulting from scCO2 exposure, but that the presence of AMEO silane on the surface, while enhancing initial adsorption of NO2 was seen subsequently to act to block reactivity. Thus, judicious use of coupling agent can provide desired rapid initial adsorption of the gas, but the goal of long-term CaCO3-consuming reactivity, so as to prolong the uptake of NO2 beyond surface saturation alone, is achieved by increasing surface area while retaining chemical-free exposed CaCO3 surface.

Original languageEnglish
Number of pages11
JournalEnvironmental Science and Pollution Research
Early online date21 Sep 2021
DOIs
Publication statusE-pub ahead of print - 21 Sep 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • AMEO silane
  • Calcium carbonate
  • NO mitigation
  • Supercritical CO
  • Surface modification

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