Greener nanomaterials could transform the way our everyday objects are made

Tiny nanoparticles are at the cutting edge of materials science – with special properties that make them ideal for absorbing light from solar panels, cleaning wastewater and delivering medicines with precision.

Some nanoparticles come in the form of sheets or fibers. But nanomaterials all have one thing in common: their structure contains components whose dimensions are on the order of nanometers, more than 10,000 times smaller than the width of a human hair. Research shows that nanomaterials often perform better than the same materials manufactured on a larger scale. Their potential is enormous, but their manufacture may currently have harmful effects on the environment due to the use or production of hazardous chemicals.

I am one of many researchers studying how to create, manipulate and apply these materials sustainably to develop new technologies and improve existing ones. This provides benefits in many applications including aerospace, solar panels and electronics.

Silica nanomaterial is already all around you, but you probably don’t even realize it. Silica (SiO₂), a compound that contains both silicon and oxygen, is commonly found in rocks. It is one of the most mass-produced nanomaterials in the world, with an expected market of US$5 trillion (£3.8 trillion) by 2025.

It’s used to make things you encounter every day, like improving the strength of concrete or the durability of rubber tires, and it also improves the cleaning properties and consistency of toothpaste. Silica nanomaterials could have exciting, high-value applications, such as medicines and wastewater treatment.

While silica products can be great, the way they are made is often not ideal for the environment, or even economically feasible. Manufacturing is essential to the overall sustainability of products, but it is often invisible to consumers. As such, it is an aspect that most people consider much less than, for example, whether something will be recycled.

Manufacturing silica often requires energy-intensive processes or generates unpleasant waste that is difficult to dispose of safely. Trying to reduce the environmental footprint of existing processes is not enough. Developing new production methods is essential to ensure that new technologies, such as more advanced solar panels, can both help society and have less impact on the environment than traditional manufacturing.

I am part of the Green Nanomaterials Research Group at the University of Sheffield, where my colleagues and I are working hard to develop sustainable, scalable and cost-effective pathways to functional nanostructured materials. We address aspects from discovery to manufacturing, applications and commercialization, taking into account performance, scalability, environment and cost.

A greener approach to chemistry

Our goal is to make better nanomaterials for important applications, while considering the environmental impact at every stage of a nanomaterial’s life, from raw materials through product use and disposal and of any by-product. This approach is known as “green chemistry”, a concept developed in 1998 that has been used to develop strategies for greener pathways to nanomaterials.

Some algae, including these diatoms, naturally make silica to build cell walls and are being studied in the development of bio-inspired silica. Diana Will/Shutterstock

The silica nanomaterial is suitable for this green chemistry approach because it is already made in nature by plants and sponges as a structural support. What better teacher of green chemistry than learning from nature itself? My research group has created bio-inspired silica, a product that can be made at room temperature and under the mild conditions in which silica is produced naturally in biology.

Today, colleagues in my research group are scaling up the production of bioinspired silica, exploring its use in different applications, and fabricating different nanomaterials. During this time, I’m exploring how changing the conditions in which we produce silica can improve the properties, like surface area, that allow it to work better.

Green nanomaterials have enormous potential to advance critical technologies, and if green silica could be developed on a larger scale, the potential for substantial change in the delivery of medicines and renewable energy is vast.