Preparation of ultramicro-, micro-, and supermicroporous carbon adsorbents by template procedure

Abstract

The new template procedure for preparing ultramicro-, micro-, and supermicroporous carbon adsorbents is proposed on the basis of the use of two polymers with different thermal stabilities as a template matrix and a carbonizable carbon source. The polymeric template matrix is removed by thermal decomposition in the low-temperature pyrolysis of the polymer mixture, whereas the second polymer component of a mixture is transformed into a carbonizate. The resultant monolithic carbonizate is the polymeric matrix replica and represents a molecular-sieve ultramicroporous carbon adsorbent, which adsorbs water vapor at 293 K and does not adsorb nitrogen vapor at 77 K. The activation of this carbonizate with water vapor leads to a series of micro-and supermicroporous carbon adsorbents with a broad range of the parameters of a pore structure: BET specific surface area S _BET is 610–2130 m²/g, micropore volume W ₀ is 0.20–0.69 cm³/g, micropore half-width x ₀ (slit model) is 0.20–0.70 nm, mesopore specific area S _me is 20–1000 m²/g, and characteristic adsorption energy E ₀ is 15.6–27.4 kJ/mol.