Autohydrolysis treatment of bamboo and potassium oxalate (K2C2O4) activation of bamboo product for CO2 capture utilization

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Typically, the hydroxide agents, such as sodium hydroxide and potassium hydroxide, which have corrosive properties, are used in the carbon activation process. In this study, potassium oxalate (K2C2O4), a less toxic and non-corrosive activating reagent, was used to synthesize activated carbon from the solid residue after autohydrolysis treatment. The effect of the autohydrolysis treatment and the ratio of the K2C2O4/solid residue are presented in this study. Moreover, the comparison between the activated carbon from bamboo and biochar from the solid residue are also reported. The resulting activated carbon from the solid residue exhibited a high surface area of up to 1432 m2·g−1 and a total pore volume of up to 0.88 cm3·g−1. The autohydrolysis treatment enhanced the microporosity properties compared to those without pretreatment of the activated carbon. The microporosity of the activated carbon from the solid residue was dominated by the pore width at 0.7 nm, which is excellent for CO2 storage. At 25 °C and 1.013 × 105 Pa, the CO2 captured reached up to 4.1 mmol·g−1. On the other hand, the ratio between K2C2O4 and the solid residue has not played a critical role in determining the porosity properties. The ratio of the K2C2O4/solid residue of 2 could help the carbon material reach a highly microporous textural property that produces a high carbon capture capacity. Our finding proved the benefit of using the solid residue from the autohydrolysis treatment as a precursor material and offering a more friendly and sustainable activation carbon process.