Theoretical and experimental study on the fluidity performance of hard-to-fluidize carbon nanotubes-based CO2 capture sorbents

Abstract

Carbon nanotubes-based materials have been identified as promising sorbents for efficient CO2 capture in fluidized beds, suffering from insufficient contact with CO2 for the high-level CO2 capture capacity. This study focuses on promoting the fluidizability of hard-to-fluidize pure and synthesized silica-coated amine-functionalized carbon nanotubes. The novel synthesized sorbent presents a superior sorption capacity of about 25 times higher than pure carbon nanotubes during 5 consecutive adsorption/regeneration cycles. The low-cost fluidizable-SiO2 nanoparticles are used as assistant material to improve the fluidity of carbon nanotubes-based sorbents. Results reveal that a minimum amount of 7.5 and 5 wt% SiO2 nanoparticles are required to achieve an agglomerate particulate fluidization behavior for pure and synthesized carbon nanotubes, respectively. Pure carbon nanotubes + 7.5 wt% SiO2 and synthesized carbon nanotubes + 5 wt% SiO2 indicates an agglomerate particulate fluidization characteristic, including the high-level bed expansion ratio, low minimum fluidization velocity (1.5 and 1.6 cms−1), high Richardson—Zaki n index (5.2 and 5.3 > 5), and low Π value (83.2 and 84.8 < 100, respectively). Chemical modification of carbon nanotubes causes not only enhanced CO2 uptake capacity but also decreases the required amount of silica additive to reach a homogeneous fluidization behavior for synthesized carbon nanotubes sorbent.

Exploring Spherical‐Shaped Catalysts: Synthesis and Characterization for Efficient Hydrogenation of para‐Nitrophenol

“…It is worth mentioning that the addition of ethylenediamine causes both asymmetric and symmetric stretching of NH 2 groups, which are seen at 3562 cm −1 and 3612 cm −1 caused an overlapping with OH stretching bands and make intense peaks in this region [27] . The C−H stretching band (CH 3 group) was observed at 2885 cm −1 [28] . Two significant peaks at 1705 cm −1 and 1643 cm −1 were indexed to the C=O stretching bond [29] .…”

“…[27] The CÀ H stretching band (CH 3 group) was observed at 2885 cm À 1 . [28] Two significant peaks at 1705 cm À 1 and 1643 cm À 1 were indexed to the C=O stretching bond. [29] Symmetric and antisymmetric strong vibrations of the COO À groups were seen at 1461 cm À 1 and 1504 cm À 1 , respectively.…”

Nitrate Removal Performance of Different Granular Adsorbents Using a Novel Fe-Exchanged Nanoporous Clinoptilolite

“…Recently, much attention has been paid to employing high-efficient adsorbents to enhance nitrate removal performance in water and wastewater. Proper absorbent selection is a vital factor in nitrate removal efficiency, reusability, and capability in its effectiveness under variable environmental conditions. − …”

The effect of different antifouling paints on biocide release rate and mechanical properties

“…Numerous studies have focused on examining the corrosive characteristics of PANI coatings proving that with the addition of nanoparticles (NPs) to the coatings, better anticorrosive properties will be gained due to the formation of the stable passive lm on the surface of the substrate. These nanoparticles include Fe 2 O 3 [26][27][28][29][30], CNT [31][32][33][34], ZnO, ZrO 2 [35][36][37][38], activated carbon [39,40], and TiO 2 [41][42][43][44][45][46][47][48]. Zinc oxide (ZnO), an inorganic material, has been used widely in many applications like photocatalysis [49], optic, heat transfer, and especially for antibacterial purposes [50][51][52][53].…”