Protein nanofibrils for next generation sustainable water purification

Water scarcity is rapidly spreading across the planet, threatening the population across the five continents and calling for global sustainable solutions. Water reclamation is the most ecological approach for supplying clean drinking water. However, current water purification technologies are seldom sustainable, due to high-energy consumption and negative environmental footprint. Here, we review the cutting-edge technologies based on protein nanofibrils as water purification agents and we highlight the benefits of this green, efficient and affordable solution to alleviate the global water crisis. We discuss the different protein nanofibrils agents available and analyze them in terms of performance, range of applicability and sustainability. We underline the unique opportunity of designing protein nanofibrils for efficient water purification starting from food waste, as well as cattle, agricultural or dairy industry byproducts, allowing simultaneous environmental, economic and social benefits and we present a case analysis, including a detailed life cycle assessment, to establish their sustainable footprint against other common natural-based adsorbents, anticipating a bright future for this water purification approach.


Environmental
Material eco-compatibility and life cycle Protein nanofibrils are natural-based, unlike synthetic materials such as plastics and polymers. They are entirely biodegradable and environmentally friendly.

Secondary pollution
There is no release of potentially harmful chemical substances from the nanofibrils water purification agents. Unlike degradation technologies, there is no metabolite generation, which could cause secondary pollution.
Potential to recover valuable heavy metals Protein nanofibrils offer the possibility to reduce and recover the adsorbed contaminants such as heavy and precious metals, increasing their value as a sustainable water purification agent.

Waste and byproduct use and management
In many cases, the source of protein nanofibrils can be from industrial and agricultural waste and byproducts. Waste management by utilizing it and minimizing its disposal in environment is a key advantage of water purification by protein nanofibrils.

Carbon footprint
Differently from other energy-intensive technologies, protein nanofibrils water purification agents can operate under gravity-driven filtration, minimizing the energy consumption and CO 2 emission.

Treatment efficiency
Protein nanofibrils water purification agents have excellent removal efficiencies for a broad-spectrum of contaminants such as heavy metals, metalloids, radioactive wastes, pesticides, dyes, pharmaceuticals and phenolic compounds. Compared to the typical water treatment techniques, they offer faster binding and higher flux rates.

Product stability and reliability
Protein nanofibrils water purification agents are reliable and stable during the long-term operation and under different effluent conditions. In some cases (e.g. membranes and aerogels) they can be easily regenerated and reused in the process without significant changes in performance.

Safety
Thanks to their natural origin, protein nanofibrils are non-toxic and minimize health and safety risks regarding their application.

Ease of implementation and scale-up
Protein nanofibrils are suitable for a multitude of plant facilities, including membranes, cartridges, adsorption columns, granular sedimentation ponds, etc., from industrial to household levels due to their design flexibility, ease of operation and low maintenance needs.

Compatibility with other technologies
Protein nanofibrils water purification agents can be easily combined and integrated with other techniques to optimize the water purification process in sequential step treatments.

Cost of production and operation
Due to their origin and provenance, protein nanofibrils can be extremely affordable. The purification process from waste and byproduct sources can be carried out very inexpensively. Operating costs are minimal, and require virtually no energy, for example, by vacuum filtration and/or gravity driving forces.

Impact on economy
Protein nanofibrils technologies add value within the economy by elevating a waste product from industry to a high commodity product and technological material for water purification.

Public acceptance
The possibility to purify water by reducing food waste at a virtually zero CO2 emission and zero energy consumption make protein nanofibrils an outstanding technology from public acceptance perspective, with an extremely low environmental footprint and exceptional performance.

Improvement of public health and life quality
By globally providing clean water via a natural, simple and cheap approach, protein nanofibrils have a bright future ahead and could play a pivotal role in clean water supplying worldwide. Clean water consumption improves public health and the quality of life in general.

Sustainable Development Goals (UN)
Water purification using protein nanofibrils meets several of the sustainable development goals set by the United Nations for the 2030 agenda.