The influence of polyethyleneimine type and molecular weight on the CO2 capture performance of PEI-nano silica adsorbents

Kaimin Li, Jianguo Jiang*, Feng Yan, Sicong Tian, Xuejing Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

79 Citations (Scopus)

Abstract

Amine-silica adsorbents are considered alternatives to aqueous solutions of amines, which have been traditionally used to capture carbon dioxide (CO 2) from flue gas. Among amine-silica adsorbents, polyethyleneimine (PEI)-silica is particularly effective at capturing CO 2 from flue gas due to its high thermal stability. In this study, we investigated the influence of PEI type (i.e. branched vs. linear) and molecular weight on the CO 2 capture performance of PEI-silica adsorbents. PEI molecular weight influenced the thermal stability of PEI-silica adsorbents; however, when the molecular weight was ≥1200Da the increase in stability was negligible in the temperature range of 25-160°C. Branched PEIs (BPEIs) achieved higher CO 2 saturated sorption capacities compared to linear PEIs (LPEIs); however, LPEIs were more stable than BPEIs during CO 2 sorption-desorption cycling. PEI molecular weight also influenced the CO 2 saturated sorption capacity; CO 2 saturated sorption capacity decreased as PEI molecular weight increased, and among the adsorbents tested in this study BPEI/800-silica had the highest CO 2 saturated sorption capacity (202mg CO 2/g adsorbent). Both PEI type and molecular weight exhibited influence on the sorption or desorption heat of PEI-silica adsorbents. The CO 2 regeneration heat was much lower than that of MEA solution for all PEI-silica adsorbents tested in this study.

Original languageEnglish
Pages (from-to)750-755
Number of pages6
JournalApplied Energy
Volume136
DOIs
Publication statusPublished - 31 Dec 2014
Externally publishedYes

Keywords

  • Carbon capture
  • Polyethyleneimine
  • CO2 adsorbent
  • Nano silica
  • CARBON-DIOXIDE
  • POSTCOMBUSTION CAPTURE
  • AMINE SORBENTS
  • HIGH-CAPACITY
  • ADSORPTION
  • SBA-15
  • DESORPTION
  • KINETICS
  • TEMPERATURES
  • ZEOLITES

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