Harnessing the power of metal-organic frameworks to develop microplastic fouling resistant forward osmosis membranes

With the gradual increase of microplastics (MPs) in water and wastewater streams, it is imperative to investigate their removal using tertiary treatment systems to minimize and preferably prevent their entrance into aquatic environments. Forward osmosis (FO) is a non-pressurized membrane process with potential applications in MPs removal from wastewater. However, efficient application of FO systems relies on developing high-performance FO membranes with low fouling tendency. MPs are proven as emerging foulants in membrane systems, dimin-ishing their performance and lifetime and this highlights the need to consider MP fouling in developing sus-tainable membranes. The current study focuses on a novel modification of thin film composite (TFC) FO membranes by MIL-53(Fe) as a water-stable and hydrophilic metal-organic framework. Experimental results demonstrated that the optimized FO membrane (0.2 wt% MIL-53(Fe)) achieved a significantly higher water flux (90% increase) with a 23% less reverse salt flux. The modified membrane also had significantly less flux decline in fouling experiments and higher flux recovery after physical cleaning compared to the control membrane affirming its higher antifouling efficiency. MIL-53(Fe) integration in the FO substrate proved to be a practical method for developing high-performance TFC FO membranes with improved antifouling properties against MPs and organic foulants.

Automated summary

With the increase of microplastics in water and wastewater, it is necessary to study their removal using tertiary treatment systems to minimize and prevent their entrance into aquatic environments. Forward osmosis is a membrane process that shows potential in removing microplastics from wastewater, but it requires high-performance membranes with low fouling tendency. This study focuses on modifying thin film composite FO membranes with a water-stable and hydrophilic metal-organic framework, which shows improved antifouling properties against microplastics and organic foulants.