Photocatalytic Ti-organic hybrid membranes for ultrafast organic micropollutants degradation

Water pollution induced by organic micropollutants (OMPs) poses a severe threat to human health and ecosystems. Catalytic membranes with photocatalysts immobilized either on the surface or within the bulk structure represent a promising strategy for OMPs degradation. However, the effective collision between OMPs and catalytically active sites is inherently limited, significantly reducing the degradation efficiency. To address this challenge, we fabricate a titanium (Ti)-organic hybrid nanofiltration membrane, in which Ti-oxygen clusters, acting as core photocatalytic sites, are bridged by rigid organic linkers to construct a nanoporous architecture. This design yields a photocatalytic membrane featuring fully exposed active sites within the open, accessible channels. As OMPs pass through the molecular-sized channels, each molecule is ensured to contact the catalytic sites, thereby boosting OMPs degradation. Taking tetracycline (TC) as a model OMP, this photocatalytic membrane achieves nearly 100% degradation at a high flux of 90 L m −2  h −1 , with a degradation rate as high a 9.9 × 10 −6  mol m −2  min −1 . This rate is one to three orders of magnitude higher than that of the photocatalytic membranes reported to date, and the membrane can simultaneously maintain stable operation for an extended period. This work establishes a new paradigm for the rational design of catalytic membranes.