Biodegradable and recyclable glass could help waste crisis

The widespread use of persistent, non-biodegradable glass that cannot be naturally eliminated can cause long-term environmental hazards and social burdens.

While glass is widely recycled, and can be recycled indefinitely unlike plastic, much of it still ends up in landfill when recyclers find it too difficult or expensive to separate the material out from other materials.

According to Recycle Across America, “More than 28 billion glass bottles and jars end up in landfills every year — that is the equivalent of filling up two Empire State Buildings every three weeks.”

To solve this problem, a research group led by professor Yan Xuehai from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences has developed a family of eco-friendly glass of biological origin fabricated from biologically derived amino acids or peptides.

Traditional glass, such as commercial inorganic glass and poly (methyl methacrylate) (PMMA) organic glass, is biologically incompatible and not readily degraded in nature. The development of biodegradable and biorecyclable glass is expected to have a minimal environmental footprint.

Unfortunately, manufacturing such eco-friendly glass of biological origin is very challenging because biomolecules possess poor thermal stability and decompose easily at the high temperatures typically used in glass manufacturing.

In this study, the researchers used chemically modified amino acids and peptides to fabricate biomolecular glass with biodegradability and biorecyclability features through the classic “heating-quenching” procedure.

The researchers tracked the glass-forming ability, glass-transition-related kinetic and thermodynamic parameters of the material, as well as glass performance in vitro and in vivo.

The biomolecular glass showed a unique combination of functional properties and eco-friendly features.

This included “excellent optical characteristics and mechanical properties”, the researchers said.

“The concept of biomolecular glass, beyond the commercially-used glasses or plastics, may underlie a green-life technology for a sustainable future,” said Xuehai. “However, the biomolecular glass is currently in the laboratory stage, and far from large-scale commercialisation.”