Study on preparation and desulfurization characteristics of biomass activated carbon by microwave heating CO2 activation method

Taking soybean straw rich in nitrogen-containing functional groups as the raw material precursor, combined with the special advantages of microwave heating, microwave heating technology is applied to the pyrolysis and activation process of soybean straw. The pyrolysis solid product is used as the activation raw material, and CO₂ is used as the activator to study the preparation of activated carbon, in order to prepare the biomass activated carbon with high desulfurization performance. First, the optimal activation level was obtained by orthogonal experimental design and range analysis. Then, the effects of microwave power, CO₂ flow rate and activation time on the yield, pore structure and desulfurization performance of activated carbon were investigated by single factor experiment. The optimal activation conditions were selected by comparative analysis: microwave power 900 W, CO₂ flow rate 0.10 L/min, activation time 20 min. Under these conditions, the yield of activated carbon is 76.3%(mass), the SO₂ adsorbance quantity is 112.56 mg/g, specific surface area is 466.28 m²/g. Compared with pyrolytic carbon, activated carbon has larger specific surface area and more abundant pores and significantly improved desulfurization performance.