Next-generation tech turns face mask waste into hydrogen

This research, led by a team of international scientists, not only offers a sustainable solution to the face-mask waste problem, but also demonstrates significant economic and environmental benefits.

Since the outbreak of COVID-19, face masks have become a daily necessity, leading to a massive amount of waste.

Improper disposal of these masks poses ecological threats, including virus spread and microplastic pollution. 

Traditional treatment methods like high-temperature incineration and landfilling are costly and environmentally
unfriendly.

The researchers proposed an economic-environmental hybrid pre-assessment method. This method, based on a coupling model, takes into account technical design, systemic economic factors, and life-cycle environmental analysis. 

By using process simulation software like Aspen Plus, key data for industrial-scale technologies were predicted, helping to overcome the challenge of lacking techno-economic data in the research and development stage.

In the catalyst selection process, the team compared two widely recognised catalysts: Fe/Al2O3 and FeNi/Al2O3, as well
as two reaction methods: conventional heating and microwave-assisted heating. 

The results showed that the bimetal catalyst FeNi/Al2O3 exhibited higher catalytic activity and better stability. 

Specifically, the FeNi-MW (microwave-assisted catalysis with FeNi/Al2O3) had the highest catalytic activity for converting face masks into CNTs and hydrogen, with high yields of 38.49wt% and 0.715m3/kg respectively.

From an economic perspective, the study found that when the price of CNTs exceeds 1.49×104 USD/t, microwave-assisted pyrolysis is the optimal choice
due to its superior environmental performance and economic benefits. 

It can reduce the life cycle greenhouse gas emissions, eutrophication potential, and human toxicity, while also increasing the system revenue.

On the other hand, conventional heating pyrolysis with the FeNi/Al2O3 catalyst may be more economical in some cases because of its good stability over 43 reaction regeneration cycles.

This innovative technology has multiple advantages. It aligns with the principles of a circular economy by effectively recycling
waste. 

From an atomic economy perspective, it separates the C and H elements in face masks to produce high-value products without the need for additional methane or propylene as in conventional CVD methods for preparing CNTs.

The research not only provides a promising solution for the treatment of face-mask waste but also offers insights into the development of sustainable technologies for plastic waste management. 

As the market for CNTs grows and pyrolysis technology matures, this approach could play an increasingly important role in promoting environmental sustainability and economic development.