Photochemical and acoustic interactions of biochar with CO₂ and H₂O: Applications in power generation and CO₂ capture

Abstract

A critical literature review suggests that carbonaceous compounds react with (CO2 +H2O) 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 CO2 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 CO2 capture. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1054–1065, 2014

An overview of low‐temperature plasma surface modification of carbon materials for removal of pollutants from liquid and gas phases

“…The physical modification methods mainly include the heating method, [ 65‐68 ] microwave method, [ 69,70 ] and ultrasonic method. [ 71 ] It mainly changes the pore structure of CMs, such as SSA, pore volume, and pore size. In contrast, chemical modification mainly increases the active functional groups on the surface of CMs and improves its chemical adsorption capacity for pollutants.…”

Comparative study between physicochemical characterization of biochar and metal organic frameworks (MOFs) as gas adsorbents

“…The peak at 1600–1700 cm −1 was related to C=O stretching attributed to the carbonyl group while the aliphatic C‐H stretch vibration or C‐C chains at 3000–2700 cm −1 was detected in the biochar spectrum . The phenol functional group peak (O‐H) was observed (3300–3900 cm −1 ) . The FTIR spectra of biochars and MOF‐5 are almost identical, however, the C=O functional group peaks in biochars intensify more than MOF‐5.…”

Phosphorus Sorption Behavior of Torrefied Agricultural Byproducts under Sonicated Versus Non-Sonicated Conditions

“…Sonication resulted in a significant reduction in P sorption maxima for PF agrichar only, which can be attributed to the increase in surface area of contact as a result of sonication (W. Y. Chen et al, 2014) and increased exposure of soluble P containing sites, which contributed back into the solution and lowered S max . While both PF and HB can potentially act as P sinks due to higher total Ca content and relatively high S max values, it is critical to note that while wet sonication can increase CEC, it does not necessarily increase the P sorption capacity as demonstrated by PF agrichar.…”

“…Sonication has been widely used to enhance mixing and reduce mass-transfer limitation at the liquid/solid interface (W. Y. Chen et al, 2014) and could expose cluster of graphene and graphene oxide in biochar forming graphene and graphene oxide platelets resulting in net increase of surface area of contact (Stankovich et al, 2006). Sonication has been found to enhance release of P from activated sludge (Wang, Qiu, Lu, & Ying, 2010).…”