Reactive seeding growth of cobalt-doped MIL-88B(Fe) on Al2O3 membrane for phenol removal in a photocatalytic membrane reactor

In this study, cobalt-doped MIL-88B(Fe) (xCoMIL-88B(Fe)) was successfully synthesized and grown on an Al2O3 support. The cobalt doping of MIL-88(Fe) not only enhanced its visible-light absorption but also improved free electron–hole pair separation. On adding peroxymonosulfate (PMS), 5CoMIL-88B(Fe) powder demonstrated superior photocatalytic phenol removal than that without the PMS or catalyst. The reactive seeding growth of cobalt-doped MIL-88B(Fe) was employed to prepare a 5CoMIL-88B(Fe) membrane coupled with a filtration module to produce a photocatalytic membrane reactor (PMR). The permeate flux of the photocatalytic membrane reactor (PMR) was approximately 2900–4000 L m−2 h−1 bar−1 (LMH), which demonstrated over 90% phenol removal efficiency and exhibited high stability, reusability, recyclability, and high photocatalytic activity for phenol degradation over 10 cycles utilizing 5CoMIL-88B(Fe)@Al2O3 membrane with PMS. This is the first study to demonstrate a cobalt-doped MIL-88B(Fe) membrane through the reactive seeding method for a PMR system, which is an effective and sustainable process for wastewater treatment.