In this work, an inexpensive and commercially available bentonite was modified by sulfuric acid and explored as the new type of support to immobilize tetraethylenepentamine (TEPA) for CO2 capture from flue gas. By applying sulfuric acid treatment, the textural properties, in particular, pore volume and surface area of bentonite, were significantly improved. Bentonite treated with 6 M sulfuric acid (Ben-H2SO4-6M) can reach a pore volume of 0.77 cc/g from that of the parent bentonite of 0.15 cc/g. With the maximum TEPA loading of 50 wt % onto the Ben-H2SO4-6M sorbent, the maximum CO2 breakthrough sorption capacity reached 130 mg of CO2/g of sorbent at 75 C under a dry condition. With an addition of moisture to the simulated flue gas, the CO2 sorption capacity can be further improved to 190 mg of CO2 at 18 vol% of moisture addition sorbent due to the bicarbonate formation under a wet condition. The TEPA/Ben-H2SO4-6M sorbents show a good regenerability and thermal stability below 130 C. The high CO2 sorption capacity, positive effect of moisture addition, and low capital cost of the raw bentonite materials imply that TEPA/Ben-H2SO4-6M could be a promising sorbent for cost-efficient CO2 capture from flue gas. The sulfuric acid treatment was demonstrated as an effective method for bentonite modification to immobilize TEPA for CO2 capture.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology