Activated Carbon from Palm Date Seeds for CO2 Capture

Abstract

The process of carbon dioxide capture and storage is seen as a critical strategy to mitigate the so-called greenhouse effect and the planetary climate changes associated with it. In this study, we investigated the CO₂ adsorption capacity of various microporous carbon materials originating from palm date seeds (PDS) using green chemistry synthesis. The PDS was used as a precursor for the hydrochar and activated carbon (AC). Typically, by using the hydrothermal carbonization (HTC) process, we obtained a powder that was then subjected to an activation step using KOH, H₃PO₄ or CO₂, thereby producing the activated HTC-PDS samples. Beyond their morphological and textural characteristics, we investigated the chemical composition and lattice ordering. Most PDS-derived powders have a high surface area (>1000 m² g^-1) and large micropore volume (>0.5 cm³ g^-1). However, the defining characteristic for the maximal CO₂ uptake (5.44 mmol g^-1, by one of the alkaline activated samples) was the lattice restructuring that occurred. This work highlights the need to conduct structural and elemental analysis of carbon powders used as gas adsorbents and activated with chemicals that can produce graphite intercalation compounds.

Keywords: CO2 capture; activation; adsorption; hydrothermal carbonization; palm date seeds.

Figure 1

SEM images of the (a) HTC-PDS and (b–f) the corresponding activated materials.

Figure 2

Raman spectra for the HTC-PDS and the respective activated carbon materials.

Figure 3

(a) N₂ sorption isotherms and (b) the pore size distributions of the HTC-PDS and respective activated materials. The measurements were performed at −196 °C with N₂.

Figure 4

Pure component CO₂ adsorption isotherms, measured at 25 °C and up to 1 bar, of the activated HTC-PDS powders.