Capture of Carbon Dioxide With Tetraethylenepentamine-Functionalized Industrial Carbon Nanotubes

Industrial carbon nanotubes (I-CNTs) is a low-cost substitute for commercially available multi-walled carbon nanotubes (CCNTs). In this work, I-CNTs were functionalized with tetraethylenepentamine (TEPA) for CO₂ capture. The performance of I-CNTs-TEPA was compared with that of CCNTs. It was found that I-CNTs-TEPA exhibited high CO₂ adsorption capacity similar to CCNTs-TEPA. The adsorption capacity of I-CNTs-TEPA was in the range of 2.145 to 3.088 mmol/g depending on adsorption temperatures. Both adsorption isotherms of I-CNTs-TEPA and the isosteric heat of different adsorption capacity were obtained from experiments. H₂O, SO₂ or NO has been found to have no significant impacts on the adsorption capacity of CO₂. I-CNTs-TEPA was further extruded to form granules (I-CNTs-TEPA-G) with a specific mold. The adsorption capacity of I-CNTs-TEPA and I-CNTs-TEPA-G remained almost the same after 5 cycles of adsorption/regeneration with adsorption conditions of 10 vol % CO₂, 500 ppm SO₂, 500 ppm NO, 100% relative humidity, and a temperature of 313 K. Having advantages such as low-cost, easiness in processing, high adsorption capacity, good poison resistance, and decent performance after recycling, I-CNTs-TEPA seems to be a promising adsorbent for CO₂ capture from flue gas.