July 19, 2024

New Recycling Method for Disposable Diapers Utilizes Ultraviolet Light

Disposable diapers are a major contributor to global waste due to their difficulty to recycle. However, a new process utilizing ultraviolet (UV) light has been developed to salvage the “superabsorber” polymer found in the liners of these diapers, even if they are soiled.

The liners of most disposable diapers are made from a polymer called sodium polyacrylate, which transforms from a dry state to a hydrogel as it absorbs liquid. Previous attempts at recycling this material involved immersing it in a strong acid and heating it to 80 ºC (176 ºF) for approximately 16 hours. Although effective, this method is time-consuming and requires a significant amount of energy, making it impractical for large-scale recycling.

To find a more efficient alternative, scientists from Germany’s Karlsruhe Institute of Technology conducted research. They wetted sodium polyacrylate diaper liners with water and exposed them to UV light from a 1,000-watt lamp at room temperature. Within just five minutes, the polymer gel dissolved into a liquid that was collected in a reservoir. Using existing processes, the liquified sodium polyacrylate was then transformed into an adhesive and a thickening agent for dyes.

According to Professor Pavel Levkin from Karlsruhe, the UV light breaks the chains that link the polymers. These chains become loose, turning into liquid fibers that can swim in water. The use of UV light in this method is approximately 200 times faster than using acids.

While the experiments used clean diaper liners, the scientists believe that the process should work equally well on used liners. Levkin states that this discovery presents a promising strategy for recycling superabsorbers, which will significantly reduce environmental pollution and contribute to a more sustainable use of polymers.

The research conducted by the Karlsruhe Institute of Technology was recently published in the journal Applied Materials and Surfaces. This breakthrough in recycling technology could have significant implications for reducing global waste caused by disposable diapers. By utilizing UV light to dissolve the superabsorber polymer, this method offers a faster and more efficient way of recycling diaper liners. As the global focus on sustainability grows, innovations like this will play a crucial role in achieving a more environmentally friendly future.


1. Source: Coherent Market Insights, Public sources, Desk research
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