In
the current study, a new type of composite adsorbent was synthesized
by amine modification of binder-containing zeolite 4A bodies and its
potential application in the post-combustion CO2 capture
was evaluated. A wide range of aliphatic straight chain amines such
as propylamine (PA), butylamine (BA), pentylamine (PEA), and their
respective branched chain amines, iso-propylamine
(IPA), iso-butylamine (IBA), and iso-pentylamine (IPEA), were used in a smaller fraction to modify binder-containing
zeolite 4A bodies. The synthesized materials were characterized by
various spectro-analytical techniques to elucidate the effect of amine
modification on physicochemical properties of binder-containing zeolite
4A bodies and its reactivity for CO2 capture. Among all
of the studied hybrid adsorbents, the iso-butylamine-modified
binder-containing zeolite 4A bodies (IBA-Z4A) exhibited excellent
CO2 adsorption performance with a maximum adsorption capacity
of 2.56 mmol g–1 at 25 °C and 1 bar of pressure.
Notably, IBA-Z4A also demonstrated excellent purity (98%) and remarkably
high CO2/N2 selectivity (335) as compared to
the pristine binder-containing zeolite 4A bodies (24). Such enhanced
CO2 adsorption capacity and high CO2/N2 selectivity values for IBA-Z4A can be attributed to the symbiotic
interactions between CO2 and amines governed by the basicity,
electron density at the N atom of amines, and the steric effect of
adsorbing molecules (CO2 and N2) at the adsorbent
surface. Notably, IBA-Z4A also displayed a marginal isosteric heat
of adsorption for CO2 (51 kJ mol–1) along
with the encouraging thermochemical cyclic stability over five consecutive
CO2 adsorption–desorption cycles at 25 °C and
1 bar, believed to be the best suited for post-combustion CO2 capture.
The current study reports the utilization of tetraethylenepentamine
(TEPA)-modified hierarchical silica particles having bimodal meso/macroporosity
for CO2 capture under simulated direct air capture (DAC)
conditions (400 ppm CO2 in He). Results infer a typical
relation between TEPA loading and CO2 capture, where TEPA-impregnated
HS (HS-TEPA-70) exhibits exceptionally high CO2 uptake
(5.20 mmol/g), shorter adsorption half time (110 min), and excellent
amine efficiency (0.32 mmol of CO2/mmol of N) with moderate
CO2/N2 selectivity at 30 °C under DAC conditions.
HS-TEPA-70 also showed appreciable CO2 adsorption performance
(5.88 mmol/g) under humid conditions (50 ± 3% RH) with 400 ppm
CO2 in He at 30 °C. TEPA-impregnated HS even displays
better thermal stability up to 10 consecutive adsorption–desorption
cycles with minimal amine leaching and moderate CO2 regeneration
energy. Moreover, the pelletized form of HS-TEPA-70 also demonstrates
better CO2 adsorption performance (3.34 mmol/g), which
makes it a promising candidate for CO2 capture from ambient
air by temperature swing adsorption.
To understand critical problems associated with solid waste and its consequences for the environment, a laboratory experiment is presented on the synthesis of aluminum-based metal−organic framework (MOF) MIL-53(Al) from household waste (PET bottles and aluminum foil/can), for undergraduate students of chemistry. This work is designed to teach students the research methodology and basic understanding of MOFs and their application in carbon capture and storage (CCS). Students also learnt several instrumentation techniques such as UV−vis spectroscopy, powder X-ray diffraction (P-XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and gas sorption to characterize the physicochemical properties of . The facile production of MIL-53(Al) enabled the students to investigate its applicability in CO 2 sorption. The calculations of essential parameters such as CO 2 over N 2 selectivity and the use of statistical tools in data processing are also explained to the students. In the end, the instructor presented his/her feedback by evaluating the answer sheets (pre-and postlab work) and by demonstrating the overall lab work through a model presentation.
Direct Air Capture (DAC) emerges as a new technology that can contribute to “negative carbon emission.” Recent progress in surface chemistry and material synthesis has allowed a new generation of...
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