The analysis of chloroform vapor sorption at 35 degrees C in semicrystalline syndiotactic polystyrene samples shows remarkably different sorption isotherms, depending on the crystalline form of the samples. In particular, "emptied" clathrate ("emptied" delta form) samples are characterized by higher equilibrium sorption levels and the differences are particularly relevant for low vapor activities. Moreover, sorption kinetics detected at a vapor activity equal to 0.5 show that in the case of "emptied" delta form samples the sorption rate is much higher than for the other semicrystalline samples. The larger sorption equilibrium uptakes and sorption rates of the "emptied" delta form samples are essentially due to their ability to absorb chloroform, already for low activities, by clathration in the crystalline phase. The measured equilibrium uptakes and sorption kinetics suggest that "emptied" delta form samples of syndiotactic polystyrene could be suitable for removing polluting chlorinated compounds from vapor and liquid streams.