CO2 and CH4 Adsorption Behavior of Biomass-Based Activated Carbons

Deneb Peredo-Mancilla,David Bessieres,Cecile Hort,Mejdi Jeguirim,Imen Ghouma,Camelia Matei Ghimbeu

doi:10.3390/en11113136

Abstract

The aim of the present work is to study the effect of different activation methods for the production of a biomass-based activated carbon on the CO 2 and CH 4 adsorption. The influence of the activation method on the adsorption uptake was studied using three activated carbons obtained by different activation methods (H 3 PO 4 chemical activation and H 2 O and CO 2 physical activation) of olive stones. Methane and carbon dioxide pure gas adsorption experiments were carried out at two working temperatures (303.15 and 323.15 K). The influence of the activation method on the adsorption uptake was studied in terms of both textural properties and surface chemistry. For the three adsorbents, the CO 2 adsorption was more important than that of CH 4 . The chemically-activated carbon presented a higher specific surface area and micropore volume, which led to a higher adsorption capacity of both CO 2 and CH 4 . For methane adsorption, the presence of mesopores facilitated the diffusion of the gas molecules into the micropores. In the case of carbon dioxide adsorption, the presence of more oxygen groups on the water vapor-activated carbon enhanced its adsorption capacity.

Highlights

As part of the efforts being made to fight climate change, governments of 195 countries signed the Paris Agreement, in which they agreed to keep the increase of the global average temperature well below 2 ◦ C from the preindustrial temperatures [1]
Three activated carbons produced from olive stones by CO2 physical activation, H2 O physical activation and H3 PO4 chemical activation were employed
The activated carbon obtained by chemical activation with phosphoric acid of the precursor material presents a higher surface area, total pore volume and micropore volume, which led to a higher adsorption capacity for both methane and carbon dioxide

Summary

Introduction

As part of the efforts being made to fight climate change, governments of 195 countries signed the Paris Agreement, in which they agreed to keep the increase of the global average temperature well below 2 ◦ C from the preindustrial temperatures [1]. 20-20-20 goal: 20% increase of energy efficiency, 20% reduction of greenhouse gas (GHG) emissions and 20% of EU energy from renewables by 2020. Biogas is a gaseous mixture produced when organic matter is degraded by micro-organisms under anaerobic conditions in a process known as anaerobic digestion (AD); its main components are methane (CH4 ) in a concentration of 50–70 vol% and carbon dioxide (CO2 ) ranging from 30–45 vol% Collected biogas can be directly burned to produce electricity with an efficiency of roughly 38% [3]. The energy density of biogas can be increased by an upgrading process in which the non-combustible gas (CO2 ) and other impurities are separated to produce biomethane, a highly-purified methane stream (around 98% purity), which can function as a vehicle fuel or can be injected into the natural gas grid.

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