Functional PVDF ultrafiltration membrane for Tetrabromobisphenol-A (TBBPA) removal with high water recovery

Tetrabromobisphenol-A (TBBPA) is one of the most important brominated flame retardants (BFRs), accounting for 60% of the total commercial BFR market. Increasing amounts of TBBPA and byproducts are released to the aquatic environment due to their extensive utilization in various sectors. However, research on the treatment of TBBPA contaminated wastewater using membrane filtration is still lacked. Herein, a PVDF10-PAA-ZrO₂ membrane was successfully developed and applied for the treatment of high-concentration TBBPA wastewater with super-high water recovery. The membrane was obtained through surface functionalization with nano-ZrO₂ from commercial PVDF ultrafiltration (UF) membrane. Compared to the commercial PVDF membrane, the developed membrane exhibited 4 times of permeate flux which was up to 200 L/m² min with comparable TBBPA rejection rate. Furthermore, the mechanisms of membrane development and TBBPA rejection were explored through synchrotron-based ATR-FTIR and X-ray analyses. It was revealed that ZrO₂ NPs were immobilized into membrane surface through binding with PAA layer, where the O of the carboxyl group combined with the Zr⁴⁺ on the ZrO₂ NP surface to form C-O-Zr bond through monodentate and bridging-bidentate modes. The sieving function of membrane could be the main mechanism of TBBPA removal. This research demonstrated a practical route and solid insight toward the development of highly efficient membrane for TBBPA removal. The proposed PVDF10-PAA-ZrO₂ membrane can also be promising for other industrial separation and purification applications.