Photochemical and acoustic interactions of biochar with CO 2 and H 2 O: Applications in power generation and CO 2 capture

A critical literature review suggests that carbonaceous compounds react with (CO 2 +H 2 O) mixture through thermal, photochemical, and sonochemical/sonophysical routes. A biochar was selected for studying these effects at 60°C and 1 atm for its potential benefits on power generation and CO 2 capture. All treatments remove sizable minerals (K, Na, and Si) detrimental in power generation, and introduce carbon (up to 16% of original carbon in biochar) into the biochar matrix. Most treatments show increased hydrogen (up to 24%). Treatments lead to notable increased heating value of biochar (up to 50%). Treated biochars show increase (up to 19 fold) in internal surface area. The ultrasound energy output is a fraction of the increased heating value. Thus, pretreatment is potentially attractive for increasing the energy efficiency in combustion and gasification. Moreover, better understandings of the salient reactions of these processes will be advantageous for the development of advanced adsorbents for CO 2 capture.