Preparation of high-surface area activated carbons from Paulownia wood by ZnCl2 activation

In this study, an activated carbon with high-surface area was prepared from Paulownia (P. tomentose) wood by chemical activation with ZnCl2. The influences of carbonization temperature and impregnation ratio on the pore structure of the activated carbon were investigated. Activation temperatures and impregnation ratios were selected in the range of 400–700 °C and 0.5–4.0, respectively. Under the experimental conditions investigated, a carbonization temperature of 400 °C and impregnation ratio of 4.0 were found to be suitable for producing high-surface area activated carbon. It was shown that ZnCl2 works effectively as dehydration reagent below 500 °C. The obtained carbons were characterized by nitrogen adsorption–desorption isotherms at 77 K. The results showed that the surface area and micropore volume of activated carbons, which were determined by application of the Brunauer–Emmett–Teller (BET) and t-plot methods, were achieved as high as 2736 m2/g and 0.69 cm3/g, respectively. The chemically activated carbons were found to be mainly type I carbons. The microstructures of the char and activated carbons were also examined with scanning electron microscopy (SEM).