Synthesis of carbon monoliths with a tailored hierarchical pore structure for selective CO2 capture

Abstract

Carbon monolithic adsorbents exhibiting a hierarchical pore structure are produced via a synthesis route based on the stabilization of liquid foams followed by a carbonization step. The macro-microporous structure is achieved by the incorporation of microporous, biomass-derived activated carbon particles in the liquid foam enclosed by a cationic surfactant as stabilizer. This method yields crack-free monoliths (solid foams) with a compressive strength of the order of 20 kPa. The microstructure and the textural properties of the final solid foams have been investigated by means of Scanning Electron Microscopy (SEM) and gas adsorption. The behavior as selective CO 2 adsorbents at 25 ºC has been evaluated using breakthrough experiments under simulated post-combustion conditions (16 % V/V CO 2 /N 2), resulting in a selectivity factor of 13 over N 2. The hierarchical pore structure of the monoliths allows a rapid transport of the gas mixture through the macropores with no appreciable pressure drop, retaining more than 90% of the adsorption capacity ( 0.868 mmol/g) after several adsorption/desorption cycles. Moreover, the monolith has shown a CO 2 uptake capacity of 2.62 mmol/g under static condition at 1 bar and 25 ºC. This study provides guidelines for the design of carbon-based foams decorated with carbon particles, which have morphological and textural properties that can be carefully selected for any gas-selective capture application.

Manufacture of Carbon Materials with High Nitrogen Content

“…For the study of porosity, the Quantachrome device (Quadrawin, Boynton Beach, Florida, USA has been used. The study has been carried out by adsorption-desorption of nitrogen at 77 K and carbon dioxide at 273 K. The surface area is determined from the branch of adsorption of the nitrogen isotherm applying the BET equation, for the analysis a minimum of 5 points have been used, and in all cases the C is positive [ 20 ]. Samples were outgassed at 150 °C for 4 h prior to the adsorption measurements.…”

Preparation of Carbon-Silicon Doping Composite Adsorbent Material for Removal of VOCs

“…The saturated adsorption state was considered when the outlet concentration held constant. The uptake of p-xylene by composite adsorption material from gaseous mixture [7,14] at each time, Qt (mg/g), was determined as follows: Qt=1w[FAMC0(normalt−∫0tCtC0dt)],…”

“…Many different methods have been proposed and developed to treat the VOCs, including absorption, combustion disposal, catalytic oxidation, and membrane separation [4,5,6]. The fixed-bed adsorption is a promising method [7], which could be used individually or combined together with other methods to fully separate the VOCs from the off-gases, allowing the off-gases to be discharged cleanly [8]. In addition, the adsorption process could recover the VOCs through an adsorption-desorption cyclic process [9,10].…”

Advances in Post‐Combustion CO2Capture by Physical Adsorption: From Materials Innovation to Separation Practice

“…Instead of block copolymers, Zabiegaj et al [46] . employed liquid foam stabilized by solid particles as a template to synthesize monolithic carbons.…”