Recent Advances in Carbon-Based Adsorbents for Adsorptive Separation of Light Hydrocarbons

Abstract

Light hydrocarbons (LHs) separation is an important process in petrochemical industry. The current separation technology predominantly relies on cryogenic distillation, which results in considerable energy consumption. Adsorptive separation using porous solids has received widespread attention due to its lower energy footprint and higher efficiency. Thus, tremendous efforts have been devoted to the design and synthesis of high-performance porous solids. Among them, porous carbons display exceptional stability, tunable pore structure, and surface chemistry and thus represent a class of novel adsorbents upon achieving the matched pore structures for LHs separations. In this review, the modulation strategies toward advanced carbon-based adsorbents for LHs separation are firstly reviewed. Then, the relationships between separation performances and key structural parameters of carbon adsorbents are discussed by exemplifying specific separation cases. The research findings on the control of the pore structures as well as the quantification of the adsorption sites are highlighted. Finally, the challenges of carbonaceous adsorbents facing for LHs separation are given, which would motivate us to rationally design more efficient absorbents and separation processes in future.

Probing sub-5 Ångstrom micropores in carbon for precise light olefin/paraffin separation

“…However, the major barrier is the broadly distributed pore size of carbonaceous materials, ranging from sub-nanometer to micrometer scale, due to the random arrangement of carbonaceous nanodomains with uncontrollable defects 22 . Such broad pore size distributions (PSD) inevitably cause the co-adsorption of both olefins and paraffins, thus poor selectivity at a low uptake ratio 23,24 .…”

Influence of Structural Domain Evolution in Carbon Materials on the Selective Separation of Alkenes from Alkanes

“…Despite a few metal–organic frameworks (MOFs) exhibiting molecular-level sieving of C 3 H 6 from C 3 H 8 benefiting from the ultrafine tuning of the topology and highly ordered pore structures, their practical applications are still constrained by the relatively high preparation cost . Porous carbons have attracted great attention due to their wide availability, inherent structural stability, and abundant porosity. − Nevertheless, their broad pore size distributions inevitably induce the coadsorption of both C 3 H 6 and C 3 H 8 molecules, resulting in low separation selectivity. Conventional physical or chemical activation during the preparation of carbon materials has difficulty in fabricating uniform ultramicropores.…”

Progress in the Separation and Purification of Carbon Hydrocarbon Compounds Using MOFs and Molecular Sieves

“…They could be used to precisely identify tiny differences in structural properties, such as the polarity and unsaturation of low-carbon hydrocarbon molecules, which is now a widespread issue [16]. Because of their sturdy construction, simple preparation process, and low cost, molecular sieves are widely utilized in the petrochemical industry and they also exhibit outstanding performance in the separation of low-carbon hydrocarbons [17]. They each have their own set of advantages and disadvantages.…”