Preparation and evaluation of activated carbon-based desulfurization adsorbent by one-step method at low temperature

Activated carbon was prepared by one-step method at low temperature using sawdust as material. Effect of preparation and adsorption conditions among liquid-solid and gas-solid on desulfurization performance was discussed. The results show that the optimum preparation conditions are as follows:mass ratio of 1:1 for impregnation liquid (with HNO₃ mass fraction of 30%) and sawdust, NiO loading of 5% on surface of adsorbent, impregnation time of 24 h under room temperature and calcination time of 3 h under 400℃. Under adsorbent mass/DBT volume of 0.2 g/10 mL, liquid-solid adsorption temperature of 40℃ and adsorption time of 5 h, desulfurization efficiency can reach 28.36%. After continuous adsorption 4 times saturated adsorption sulfur capacity is up to 2.34 mgS/g. Under gas-solid adsorption temperature of 250℃ and adsorption velocity of 6.3 h^-1, adsorption sulfur capacity can reach 2.37 mgS/g. The effect of high temperature gas-solid adsorption desulfurization on adsorbent indicates that BET specific surface area, total pore volume and micropore volume of adsorbent have been improved obviously, which show that the gas-solid adsorption desulfurization process has realized the reaming activation of activated carbon simultaneously. The regeneration experiment of toluene solvent shows that the regeneration performance can reach more than 90% after 5 times cycle.