Recyclable nanocomposites for environmental remediation

8 Aug 2016. NUS scientists have developed multi-component nanocomposites which function as efficient visible-light photocatalysts with excellent magnetic recoverability.

There is rapidly growing demand for materials with high efficiency, good reusability, and low cost to reduce pollutants from wastewater. Despite much research efforts towards addressing these requirements, it remains a challenge to have a material which is able to address all these needs.

A team of scientists led by Prof CHEN Wei from the Department of Chemistry and Physics in NUS has fabricated multi-component nanocomposites comprising a magnetite core encased within an outer silver-decorated anatase (a mineral form of titanium dioxide) shell. These nanocomposites exhibit improved efficiency in the photocatalytic degradation of Rhodamine B (RhB) at room temperature under visible light and solar light irradiation. RhB is a chemical compound which is often used as a tracer dye in water to determine the flow rate and direction. These nanostructured photocatalysts are magnetic in nature and can be collected and separated easily by applying an external magnetic field. Experimental results have shown that they can be reused for up to eight times while maintaining their photocatalytic efficiency. The enhanced photocatalytic activity, good chemical stability and low fabrication cost, in combination with the ability for magnetic recyclability, makes this a promising material for environmental remediation.

This study provides a basis for the design of highly efficient and recyclable multi-component photocatalysts. Moving forward, the research team intends to develop new nanostructured photocatalysts that can potentially be used to treat other organic pollutants.

Figure shows the photocatalytic degradation of RhB at room temperature under visible light and solar light irradiation and the separation-recovery process.

Reference

Wang YY, Pan F, Dong WH, Xu LL, Wu K, Xu GQ, Chen Wei, “Recyclable silver-decorated magnetic titania nanocomposite with enhanced visible-light photocatalytic activity”.Applied Catalysis B Environmental 189(2016):192-198.