For effectively improving the physical defoaming efficiency in foam fractionation, a new foam breaker with synthetic sponge cylinders was developed and its defoaming mechanism was analyzed. Due to synthetic sponge's high water absorption ability, it resulted in a large pressure difference inside and outside the liquid film to rapidly collapse the foam. The defoaming efficiency was studied on the basis of the effects of the type and number of synthetic sponge cylinders, SDS concentration, volumetric liquid fraction and volumetric air flowrate. The results show that the synthetic sponge cylinder with 0.23 +/- 0.05 mm in mean pore diameter and 70.0 +/- 0.5% in mean porosity had the highest defaoming efficiency and a larger number of synthetic sponge cylinders resulted in a higher defoaming percentage. Under suitable conditions, defoaming percentage of the new foam breaker with 4 of the optimal synthetic sponge cylinders reached 100.0%. Furthermore, the synthetic sponge cylinders had much higher defoaming efficiency, lower equipment cost, lower energy consumption and simpler preparation than perforated plates and paddle agitator. So the foam breaker with synthetic sponge cylinders is highly promising in industrial defoaming. (C) 2016 Elsevier B.V. All rights reserved.