Amyloid-based carbon aerogels for water purification

Abstract

Water scarcity is a worldwide concern with various implications, such as widespread pollution with heavy metals and organic pollutants, resulting in global threats to the environment and human health, and calling for innovative remediation strategies. We show here that the capability of protein-based carbon aerogels for removing contaminants from water can be greatly improved by transforming proteins into amyloids before their hydrothermal carbonization. Amyloid fibrils were prepared from whey protein isolate, a by-product of the dairy industry, and upon addition to different carbohydrates, the ensued mixtures were used for carbon aerogels production. Furthermore, the generality of the approach for producing carbon aerogels was demonstrated using vegetable amyloids from soy protein. The carbon aerogels are able to adsorb Au(III), Pt(II), Fe(III), and Ag(I) with excellent removal efficiencies. Moreover, the amyloid whey lactose carbon aerogel has an adsorption capacity of 650.08 mg/g for Au(III), significantly higher than that of a carbon aerogel derived from monomer whey lactose. The reusability of the carbon aerogel is also proven over three continuous adsorption/regeneration cycles, with a stable performance in terms of removal efficiency indicating good long-term use. Taken together, the results demonstrate amyloid carbon aerogels’ capability as an efficient, sustainable, and inexpensive solution for water purification.