In a world that seems to be drowning in plastic bottles, recycling this waste into useful materials would help to reduce its environmental impact. KAUST researchers have now invented a way to turn plastic bottles into porous membranes that could be used as molecular filters in the chemical industry.
Roughly 40 percent of the chemical industry's energy used goes into separating and purifying chemicals in heat-intensive processes, such as distillation and crystallization. Using porous membranes to separate molecules from liquids could dramatically reduce that energy consumption. But most conventional membranes are not robust enough to withstand the sort of solvents used in industry, and alternative ceramic membranes tend to be very expensive.
The KAUST team turned instead to recycled poly(ethylene terephthalate) (PET). "PET is mechanically and chemically robust, making it useful for filtration and purification processes that require sterilization or cleaning with acids or bleach," says Bruno Pulido, Ph.D. student. In 2016, global production of PET reached 50 million tonnes, accounting for about 9 percent of total plastic production. Roughly 30 percent of PET is used in the food industry, including single-use plastic bottles. PET is typically "down-cycled" into lower-value products, such as clothing fabrics, so converting it into higher-value filtration membranes could provide a strong economic incentive to improve recycling rates. Read full article..