Facile pyrrole oxidative polymerization with ionic liquid to modify ceramic membrane for sustainable fouling control

Ceramic membrane bioreactor (CMBR) is an attractive alternative for wastewater treatment, although still subjects to fouling problem. This study facilely modified CM by oxidative polymerization of pyrrole with ionic liquid, to greatly enhance its conductivity and hydrophilic, and to sustainably mitigate fouling in an electric CMBR. Highly conductive ceramic membrane, BVIMBF4-CM, was facile obtained involving an ionic liquid 1-vinyl-3-butylimidazolium tetrafluoroborate (BVIMBF4) on the base CM (Base-CM). After simple modification, the electrical resistance of CM was reduced significantly from 1017 Omega/sq to 349 Omega/sq, while its water contact angle decreased from 44.0 degrees to 30.5 degrees. With the assistant of minute electric field, BVIMBF4-CM exhibited a high rejection efficiency of over 85% Cu2+, 65% Ni2+ and 93% bovine serum albumin (BSA). The interaction energy analysis verified BVIMBF4-CM itself prevent BSA from the membrane surface by the positive total interfacial energy. Meanwhile, the electrophoretic force provided by electric field enhanced the removal efficiency and antifouling capability of the BVIMBF4-CM. By using this modified CM to form an E-CMBR, a comparable removal efficiency as the CMBR could be stably obtained, which especially demonstrated significantly anti-fouling performance, as fouling rate decreased by 31.4-43.5%, and the total membrane resistance was only 60.8% of the Base-CM, under a minute electric field of 0.8 V/m. Enhanced hydrophilicity and conductivity of the BVIMBF4-CM take major responsible for this stable fouling alleviation in the E-CMBR. The new and facile method for CM modification proposed herein can serve as a reliable effort towards the application of antifouling E-CMBR system in wastewater treatment.

Automated summary

This study modified ceramic membrane through oxidative polymerization to enhance its conductivity and hydrophilicity, effectively reducing fouling in an electric CMBR system. The modified BVIMBF4-CM showed high rejection efficiency for various substances and demonstrated improved antifouling capability under the influence of an electric field. The new modification method proposed in this study has the potential to be a reliable solution for implementing antifouling E-CMBR systems in wastewater treatment.