Effects of manufacturing conditions on the adsorption capacity of heavy metal ions by Makino bamboo charcoal

The objective of this study was to investigate the effects of manufacturing conditions on the adsorption capacity of heavy metal ions by Makino bamboo charcoal. Results show that the specific surface area and iodine number of bamboo charcoal activated at 900 °C were larger than those of bamboo charcoal activated at 800 °C. The specific surface area of bamboo charcoal activated at 800 °C by carbon dioxide was larger than that of charcoal activated by steam. However, a contrary result was observed when the activation temperature was 900 °C. The total volume and proportion of micropores in bamboo charcoal activated by carbon dioxide were greater than those in the other sample groups. However, the total volume and bulk volume of meso- and macropores, and average pore diameter for bamboo charcoal activated by steam were greater than those in the other sample groups. Using 5 g bamboo charcoal (10–30 mesh) with a soaking time of 24 h, a better adsorption effect on Pb2+ (100%), Cu2+ (100%), and Cr3+ (88–98%) was found. However, medium frequencies were observed for the adsorption of Cd2+ (40–80%) and Ni2+ (20–60%). Very limited adsorption of As5+ was detected in this study. For the same charcoal grain sizes, the adsorption capacity of 0.5 g of charcoal was better than that of 0.1 g. The improved adsorption effect of the sample group activated by steam was compared with the sample group activated by carbon dioxide.