Toward sustainable hydrogen storage and carbon dioxide capture in post-combustion conditions

Abstract

This work addresses two environmental issues of major concern: hydrogen storage for hydrogen economy implementation and CO2 capture to reduce greenhouse gas emissions. For these purposes, two granular activated carbons were synthesized through chemical activation of olive stones by means of potassium derivatives (KOH and K2CO3).The storage or capture technique is pure physical adsorption on the porous framework of carbon materials. The porosity characterizations reveal typical ultramicroporous carbons with average pore sizes of about 0.53 and 0.69 nm for K2CO3 and KOH-activated carbons, respectively. The volumetric measurements of cryogenic hydrogen adsorption show monolayer process. At subatmospheric pressures the narrower micropores show stronger binding energy to hydrogen molecules. Consequently, K2CO3-activated carbon outperforms the other sample at pressures lower or equal to 100 Torr. However, at higher pressures this porosity range saturates and KOH-activated carbon exhibits a H2 storage capacity of 3wt%, 70% of which is achievable at only 1 bar. This result is interesting especially for stationary applications wherein volume is not a limitation. CO2 shows a similar behavior than H2 when it was adsorbed purely at 0°C, and AC_KOH retains its excellence with a capacity of 5.6 mmol g-1 at 1 bar. Finally, the two carbons were tested as CO2 adsorbents in conditions representative of post combustion capture applications (10% CO2 at atmospheric pressure and at 50°C). Both carbons show 2 fast adsorption-desorption kinetics, perfectly described by pseudo-first order model. At these conditions, it was proven that only narrow micropores are essential for CO2 adsorption.

The Effect of Rotation on Gas Storage in Nanoporous Materials

“…Cellulosic AC doped with Cu 48 25 15 [22] Carbon foam 15.2 0 5 [23] Chemically activated AC from olive stone 10 50 1 [9] Modified AC from fir bark 7l 0 1 [24] AC Norit RX * 2.5 30 5 [25] AC from black locust activated with KOH 5.05 25 1 [26] AC doped with N,S and activated with potassium salts 3.04-3.99 25 1 [27] The asterisk (*) denotes the material used in this study.…”

“…Among them are (a) carbon capture and sequestration (CCS) and (b) carbon capture and storage (CCS). Classical CO 2 capture techniques are carried out at the point of production and include (i) pre-combustion or stream purification [3] and (ii) post-combustion CO 2 capture [9]. However, due to the severe problem of climate change, direct capture of CO 2 from the atmosphere (direct air capture-DAC) is also highly desirable [10].…”

Highly Efficient Multisubstrate Agricultural Waste-Derived Activated Carbon for Enhanced CO2 Capture

“…Several researchers have investigated CO 2 capture using commercial activated carbon or modified commercial AC derived from coal, pitch, and other fossil fuel-derived compounds. , However, the high cost of current commercial activated carbon and a limited reservoir of fossils highly hinder the economic viability of its wide application. In recent years, the use of various single-substrate-based renewable elemental carbon sources such as Douglas, coffee husk, white wood, bagasse and rice husk, wheat flour, peanut shells, Olive stones, coffee residue, etc. have been proposed for preparing activated carbon for CO 2 capture.…”

Activated Carbons from Hydrothermal Carbonization and Chemical Activation of Olive Stones: Application in Sulfamethoxazole Adsorption

“…Olive stones are being widely used as fuel in southern Europe, especially in Croatia, Greece, Italy, Portugal, Slovenia, Spain and Turkey [28,29]. Recently, different alternatives have emerged to give value to this by-product as the production of catalysts [30], food supplements [31] and adsorbents for CO 2 removal [32,33], heavy metals [34,35], textile dyes [36] and pharmaceuticals [37,38]. Several preparation methods have been carried out to transform olive stones into a good adsorbent material.…”