# Amine-Functionalized Clays as Solid Sorbents: High-Pressure CO2 Sorption Testing and Characterization

## TL;DR

This study shows that amine-treated clays from Ecuador can capture significantly more CO2 than untreated clays, offering a promising method for reducing carbon emissions.

## Contribution

Amine-functionalized clays from Ecuador are shown to have up to 442.85% higher CO2 sorption capacity than raw clays.

## Key findings

- Amine-functionalized clays achieved a maximum CO2 sorption capacity of 3.125 mmol CO2/g.
- CO2 sorption capacity improved by up to 442.85% after amine functionalization.
- Characterization techniques confirmed structural and chemical changes post-functionalization.

## Abstract

In this work, the CO2 sorption capacity of
both raw
and amine-functionalized clays was investigated. For this purpose,
samples of clay-based materials intended for industrial and artisanal
applications were collected in the province of Imbabura, Ecuador.
These raw materials were functionalized with monoethanolamine (MEA)
and ethylenediamine (EDA) mixtures to enhance the affinity for carbon
dioxide. CO2 sorption testing was conducted in a high pressure,
nonstirred system with an initial pressure of 3550 kPa and room temperature
(25 °C). CO2 sorption capacity was quantified by monitoring
the pressure drop resulting from CO2 uptake. Comprehensive
characterization of the clay-based materials was carried out using
nitrogen physisorption analysis, X-ray diffraction (XRD), Fourier
transform infrared spectroscopy (FTIR), thermogravimetric analysis
(TGA), and X-ray fluorescence (XRF) to determine the textural properties,
crystalline phases, physicochemical properties, and functional groups
present in the samples. The results demonstrated that amine-functionalized
clays exhibited higher CO2 sorption capacity, with improvements
of up to 442.85% compared to raw materials. Notably, the amine-functionalized
clays intended for artisanal usage achieved a maximum capacity of
3.125 mmol CO2/g. These findings confirmed that amine functionalization
favors CO2 capture, offering a viable and scalable alternative
to mitigate the impacts of the rising atmospheric CO2 emissions.