Carbon dioxide and nitrogen adsorption on porous copolymers of divinylbenzene and acrylic acid

Porous copolymers of divinylbenzene (DVB) and acrylic acid (AA) having DVB:AA ratios of 6:4, 8:2 and 9:1 were prepared following a distillation-precipitation method, using toluene as the porogenic agent. The materials thus obtained, which showed specific surface area in the range of 380–600 m2 g−1 and pore volume in the range of 0.14–0.18 cm3 g−1, were investigated as possible adsorbents for CO2 capture from the flue gas of coal-fired power stations. For that purpose, the isosteric heat of adsorption (and CO2 adsorption capacity) was analysed from N2 and CO2 adsorption equilibrium isotherms obtained over a temperature range. For CO2, qst resulted to be in the range of 27–31 kJ mol−1 (the highest value corresponding to the 6:4 sample), while for N2 a value of qst ≈ 12 kJ mol−1 was obtained. Equilibrium adsorption capacity for CO2 (at ambient temperature and pressure) showed the value of about 1.35 mmol g−1. These results are discussed in the broader context of corresponding literature data for CO2 capture using protonic zeolites.