The present work focuses on the role of nitrogen in the development of pores in activated carbon produced from lignin by K2CO3 activation, employing a fixed bed reactor under a high-purity He stream at temperatures of 500-900 degrees C. The specific surface area and pore volume obtained by activation of lignin alone are 230 m(2)/g and 0.13 cm(3)/g at 800 degrees C, and 540 m(2)/g and 0.31 cm(3)/g at 900 degrees C, respectively. Activation of a mixture of lignin and urea provides a significant increase in the surface area and volume, respectively reaching 3300-3400 m(2)/g and 2.0-2.3 cm(3)/g after holding at 800-900 degrees C for 1 h. Heating a lignin/urea/K2CO3 mixture leads to a significant decrease in the yield of released N-containing gases compared to the results for urea alone and a lignin/urea mixture, and most of the nitrogen in the urea is retained in the solid phase. X-ray photoelectron spectroscopy and X-ray diffraction analyses clearly show that part of the remaining nitrogen is present in heterocyclic structures (for example, pyridinic and pyrrolic nitrogen), and the rest is contained as KOCN at <= 600 degrees C and as KCN at >= 700 degrees C, such that the latter two compounds can be almost completely removed by water washing. The fate of nitrogen during heating of ligniniurea/K2CO3 and role of nitrogen in pore development in activated carbon are discussed on the basis of the results mentioned above. (C) 2016 Elsevier B.V. All rights reserved.