Preparation of biomass activated carbon by steam activation

Biomass activated carbon prepared from rice hulls, peanut shell and corn cob by steam activation were studied. The reaction mechanism of the yield of activated carbon (Cyield) is discussed. Experimental results show that the effects of activation temperature, activation time and flowrate of steam on the adsorption properties were investigated by comparing the yield of Cyield, methylene blue (MB) adsorption. The yield of Cyield decreases and adsorption performance increases first and then decreases with the increase of activation time and activation temperature. The yield of Cyield decreases firstly and then increases with the increase of flowrate of steam. Adsorption performance increases firstly and then decreases with the increase of flowrate of steam. Corn cob is the best raw material for Cyield, The optimum activated conditions are activation temperature 800C, activation time 90 min and the flowrate of steam 15 mL/h. Under these conditions the activated carbon yield, the methylene blue adsorption, the specific surface area and the average pore size are 26.18%, 150 mL/g, 924.48 m2/g and 2.4 mm respectively.