Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants found in everything from consumer goods to fire retardants to cosmetics. Their most significant use is in military-grade firefighting foams that have been used for decades, causing widespread contamination of groundwater, drinking water wells, surface water, and soil. Firefighting drills performed at military bases and airports have led to high concentrations of PFAS near military bases, airports, and industrial manufacturing facilities (where PFAS are either used or produced), as well as in landfill leachate.

Nearly 1.3 billion tons of food — almost one-third of the world’s food supply — goes to waste each year. Producing and disposing of this much wasted food consumes 17.6 billion m3 of water and generates 193 million m.t. of greenhouse gases, according to the United Nations (UN) Food and Agriculture Organization (FAO) and the UN Environment Program. Novel food preservation technology could help feed every undernourished person on the planet and reduce the environmental impact of such waste.

Silicon is the dominant material for photovoltaic (PV) technologies due to its abundance, low cost, and good PV efficiency. Today, the most common way to produce polysilicon for PV applications is via the Siemens process, which consists of carbothermic reduction, synthesis, purification, and chemical vapor deposition of toxic explosive chlorosilanes. This process is inherently complex, difficult to scale, energy-intensive (~300 kWh/kg), and unsafe due to the presence of toxic, flammable, and dangerous chemicals such as silane (SiH4) and hydrochloric acid (HCl). In addition, because it emits a considerable amount of greenhouse gases (GHGs), the Siemens process is a “non-green” production method used for a “green” purpose.

Steel is the backbone of the modern world. The iron-based alloy is essential to construction, transportation, and many other activities tied to higher living standards. However, the iron and steel sector is a major source of carbon dioxide emissions, which are destabilizing the Earth’s climate.

Wildfires are one of the biggest environmental threats, burning millions of acres worldwide each year. Our ability to suppress wildland fires relies on the availability of water, and fire hose nozzles play an important role. As water travels from nozzle to fire, some of the water absorbs heat and evaporates, cooling the fuel mixture (e.g., thick brush and grass). Additionally, on conversion to steam, water expands 1,700 times, diluting the fuel vapors and inhibiting combustion. The percentage of water that absorbs heat and evaporates is called its evaporation efficiency. Therefore, it is critical to maximize the evaporation efficiency of the water stream.