(736b) Bioinspired Green Chemistry to Design Sustainable and Scalable High Value Nanosilica

This presentation will demonstrate a new bioinspired methodology to advance green chemistry and engineering research for nanosilica and its sustainability manufacturing. Nanosilica is a technologically important material with applications in the composites, catalysis, drug delivery and separations sectors, with an estimated market value of $3.6 billion per annum. The high value silica exhibit well-defined particle sizes or mesoporosity for nanoparticles and for porous materials respectively. To achieve these attributes, current methods (e.g. templated silicas like MCM-41) require uneconomical synthesis with high energy purification (e.g. calcination), leading to wastefulness, thus preventing their industrial implementation.

Taking inspiration from biomineralisation, we have developed bioinspired synthesis. This green method (mild, one-pot and rapid synthesis in water, at room temperature and neutral pH) is sustainable when compared to traditional routes, yet offers excellent control over the properties of the materials and is economical [1, 2]. In this presentation, we will discuss new results on the discovery, design and manufacturing of green silica products. In particular, we will show how innovative approaches helped in reducing energy and resource consumption while simultaneously offering higher value products economically.

The first part of the presentation will focus on green products: the bioinspired synthesis of monodisperse silica nanoparticles of sizes between 9-300 nm and mesoporous silica with pores between 9-20 nm. We note that both syntheses occur at room temperature and neutral pH in water and within 10 minutes – this is a significant step-change compared to traditional Stöber or template syntheses.

The second part of the presentation will describe the green engineering advances made on the process: the discovery of room temperature purification of silica without the need for energy intensive calcination [3, 4]. This also allows for up to 96% recycling of the key feedstock and solvent. Process calculations indicate that our new method will reduce the carbon footprint of purification by 95-97% and reduce the resource usage by 95% through reuse, thus significantly reducing both the cost and wastefulness. The final part of the presentation will show how we have been able to scale-up to produce hundreds of grams per day of high value nanosilicas without the need for specialist equipment, with very low energy usage and low waste produced, thus demonstrating the sustainability and scalability of the new technique.

Taken together, this presentation will show how we have developed a greener, cheaper, and readily scalable method for production of bespoke nanosilica. This is a significant technological advance which is enabling sustainable and economical scale-up of these materials for commercial applications.

References

[1] S. V. Patwardhan, J. R. H. Manning and M. Chiacchia, Current Opinion in Green and Sustainable Chemistry, 2018, 12, 110-116.

[2] S. V. Patwardhan and S. S. Staniland, Green Nanomaterials, IoP Publishing, Bristol, 2019.

[3] J. R. H. Manning, T. Yip, A. Centi, M. Jorge and S. V. Patwardhan, ChemSusChem, 2017, 10, 1683-1691.

[4] J. R. H. Manning and S. V. Patwardhan, WO2017037460.