摘要
The regulation of the pyrolysis process is a key step in increasing the carbon sequestration capacity of biochar.The effect of K_(3)PO_(4)addition on the yield,chemical composition,characteristic functional groups,macromolecular skeleton,graphite crystallites,and stability of biochar was studied in this paper using two-dimensional infrared correlation spectroscopy(2D-PCIS),X-ray photoelectron spectroscopy,Raman spectrum,and other characterization methods combined with thermal/chemical oxidation analysis.It is discovered that adding K_(3)PO_(4)may effectively minimize the graphitization temperature range and increase biochar’s yield,aromaticity,H/C ratio,and proportion of refractory/recalcitrant organic carbon.The 2D-PCIS and Raman analysis revealed that K_(3)PO_(4)mostly promoted the dehydrogenation and polycondensation process of the aromatic rings in the char precursor,transforming the amorphous carbon structure of biochar into an ordered turbostratic microcrystalline structure.K_(3)PO_(4)enhanced biochar stability mostly at medium-high temperatures(350~750℃)by stimulating the transformation of unstable structures of biochar to stable carbon-containing structures or by inhibiting the interaction of its active sites with oxidants through the mineralization process.A 20%phosphorus addition increased biochar’s refractory index(R_(50))by roughly 11%,and it also boosted biochar’s oxidation resistance(H_(2)O_(2)or K_(2)CrO_(4))efficiency,reducing carbon oxidation loss by up to 7.31%.However,at higher temperatures(>750℃),the doping of phosphorus atoms into the carbon skeleton degraded the biochar structure’s stability.The results of this study suggest that using exogenous phosphorus-containing additives is an efficient way to improve the stability of biochar.
出处
《Biochar》
CSCD
2024年第1期693-708,共16页
生物炭(英文)
基金
funded by the National Natural Science Foundation of China(52306243,52125601)
the China Postdoctoral Science Foundation(2023M731182).
