Polyacrylonitrile (PAN) hollow fibers were pretreated with ammonium dibasic phosphate and then further oxidized in air, carbonized in nitrogen, and activated with carbon dioxide. The effects of carbonization temperature of PAN hollow fiber precursor on the microstructure, specific surface, pore-size distribution, and adsorption properties of PAN-based carbon hollow fiber (PAN-CHF) and PAN-based activated carbon hollow fibers (PAN-ACHF) were studied in this work. After the activation process, the surface area of the PAN-ACHF increased very remarkably, reaching 900 m(2) g(-1) when carbonization is 1000 degrees C, and the adsorption ratios to creatinine and VB12 of ACHF were much higher than those of CHF, especially to VB12. The different adsorption ratios to two adsorbates including creatinine and VB12 reflect the number of micropores and mesopores in PAN-ACHF. The dominant pore sizes of mesopores in PAN-ACHF are from 2 to 5 nm. (C) 2005 Wiley Periodicals, Inc.