Poly(vinylidene fluoride) membrane with immobilized TiO2 for degradation of steroid hormone micropollutants in a photocatalytic membrane reactor

The lack of effective technologies to remove steroid hormones (SHs) from aquatic systems is a critical issue for both environment and public health. The performance of a flow-through photocatalytic membrane reactor (PMR) with TiO2 immobilized on a photostable poly(vinylidene fluoride) membrane (PVDF-TiO2) was evaluated in the context of SHs degradation at concentrations from 0.05 to 1000 mu g/L under UV exposure (365 nm). A comprehensive investigation into the membrane preparation approach, including varying the surface Ti content and distribution, and membrane pore size, was conducted to gain insights on the rate-limiting steps for the SHs degradation. Increasing surface Ti content from 4 % to 6.5 % enhanced the 17 beta-estradiol (E2) degradation from 46 +/- 12-81 +/- 6 %. Apparent degradation kinetics were independent of both TiO2 homogeneity and membrane pore size (0.1-0.45 mu m). With optimized conditions, E2 removal was higher than 96 % at environmentally relevant feed concentration (100 ng/L), a flux of 60 L/m2h, 25 mW/cm2, and 6.5 % Ti. These results indicated that the E2 degradation on the PVDF-TiO2 membrane was limited by the catalyst content and light penetration depth. Further exploration of novel TiO2 immobilization approach that can offer a larger catalyst content and light penetration is required to improve the micropollutant removal efficiency in PMR.

Automated summary

The lack of effective technologies to remove steroid hormones (SHs) from aquatic systems is a critical issue for both environment and public health. The performance of a flow-through photocatalytic membrane reactor (PMR) with TiO2 immobilized on a photostable poly(vinylidene fluoride) membrane (PVDF-TiO2) was evaluated. Increasing surface Ti content enhanced the degradation of 17 beta-estradiol (E2). The degradation kinetics were independent of both TiO2 homogeneity and membrane pore size.