Simple fabrication of molecular sieving carbon for biogas upgrading via a temperature controlled carbonization of Phyllostachys pubescens

Abstract

In this study, molecular sieving carbons (MSCs) for biogas upgrading were successfully fabricated by a simple temperature controlled carbonization of moso bamboo (Phyllostachys pubescens) without energy consuming steps (i.e. char activation and pore modification). As the carbonization temperature increased from 600 to 900 °C, the specific surface area of bamboo charcoals increased and the pore size distribution of bamboo charcoal became narrower and closer to the dimensions of CH 4 (0.38 nm). Bamboo charcoals had a more disordered carbon stacking structure than commercial MSC and contained more surface oxides, which contribute to greater surface reactivity than commercial activated carbon. Bamboo charcoal carbonized at 900 °C had the highest CO 2 adsorption capacity (121.6 g kg −1), even higher than commercial MSC (102.88 g kg −1). Despite the poor kinetic CO 2 adsorption properties of bamboo charcoals compared to commercial MSC, synthetic biogas (60% CH 4 + 40% CO 2) was successfully upgaded to concentrated CH 4 (>90%) by small-scale pressure swing adsorption using bamboo charcoal. It is expected that bamboo charcoals can contribute to sustainable small-scale biogas upgrading.

Development of Biodegradable Flame-Retardant Bamboo Charcoal Composites, Part I: Thermal and Elemental Analyses

“…Note that these pores refer to the nanometre-sized interstitial spaces found within the pyrolyzed cell walls of the bamboo tissue, which give BC its excellent water purification and gas molecule adsorption properties [31,32]. Studies by Asada et al (2002), Wang et al (2008) and Seo et al (2016) [31][32][33] demonstrate how the specific surface area of bamboo charcoal can be increased with a reduced range of nano-pore sizes by adjusting the pyrolysis temperature between 400 and 1000 • C and in the atmosphere. These studies indicate optimum pyrolysis temperature and conditions varies according to the chemical compounds targeted for adsorption by the BC.…”

Molecular Sieving and Current Rectification Properties of Thin Organic Films

“…29 Molecular sieves can be realized using different materials, for example, vertically aligned mesoporous silica films, 30 porous covalent organic frameworks, 31 metallopolymeric films, 32 and graphene-based 33 or biological-based materials. 34 As stated before, the reduction of aryldiazonium salts yields dendritic multilayered films, that are, unorganized films. Hence, the intrinsic nature of these films is not suitable for molecular sieving.…”

“…The design of molecular sieves attracts attention of many research groups these days as they could find utility in applications such as water desalination, gas separation, or as membranes in fuel cells . Molecular sieves can be realized using different materials, for example, vertically aligned mesoporous silica films, porous covalent organic frameworks, metallopolymeric films, and graphene-based or biological-based materials . As stated before, the reduction of aryldiazonium salts yields dendritic multilayered films, that are, unorganized films.…”

Experimental Determination of the CH4 and CO2 Pure Gas Adsorption Isotherms on Different Activated Carbons

“…In a PSA biogas upgrading unit, biogas is put in contact with an adsorbent that selectively adsorbs and desorbs the carbon dioxide fraction. Many types of porous materials are used for the CH 4 /CO 2 separation, which includes carbon molecular sieves (CMS), , zeolites, , activated carbons, , and, more recently, metal organic frameworks (MOFs). , Although zeolites are the typically chosen adsorbent for the PSA biogas upgrading units, the use of activated carbons (ACs) presents important advantages such as a high surface area, developed pore volume, hydrophobic character, and, therefore, high resistance to water, lower cost, and low-energy requirements. , Nevertheless, activated carbons usually present low selectivity for carbon dioxide, restricting its use …”