BACKGROUND: A simple and effective method with environmental and economic benefits has been developed to produce spherical lignin and spheroidal microporous/mesoporous activated carbon from pulping black liquor. RESULTS: Spherical lignin with regular size of about 100 nm was obtained at 90 degrees C after 8 h treatment at pH 2. Pyrolysis of spherical lignin was impregnated with H(3)PO(4) producing spheroidal microporous/mesoporous activated carbon with high apparent Brunauer-Emmett-Teller (BET) surface area of 1972 m(2) g(-1) and high carbon content of 68.0 wt% at 700 degrees C with impregnation ratio of 1:7. CONCLUSION: The process was inexpensive, sustainable, environment-friendly and suitable for large-scale production. (C) 2011 Society of Chemical Industry