Photo-initiated dispersion polymerization, a photochemical method for preparing poly (styrene-co-maleic anhydride) microspheres, is introduced for the first time in this paper. Ultraviolet lamp, ethanol/water mixture, 2,2-azobisisobutyronitrile, and poly (vinylpyrrolidone) were respectively used as the light source, green solvent, initiator, and stabilizer in the preparation. After careful study of the influencing factors, formations, sizes and size distributions of the microspheres were found to systematically vary with light intensity and amount of reagents used. Under the optimal conditions, microspheres with the narrowest size distribution and sizes smaller than 1 mu m were obtained. Based on the functional groups contributed by the MAH, an important application of the prepared microspheres in Ni2+ adsorption was explored. Adsorption capacities were controlled by the MAH amount added in the microsphere preparation. (C) 2013 Elsevier B.V. All rights reserved.