Photoconverting waste amphiphiles at the mild air–water interface into easily separable value-added products

Abstract

The traditional conversion of organic wastes into value-added products encounters bottlenecks such as the use of expensive, toxic solvents and cumbersome post-treatment of the separated products. To overcome these bottlenecks, the in situ air–water interface is employed to convert four waste surfactants into easily separable value-added products upon photoirradiation under ambient conditions. The results show that four representative amphiphiles with different functional groups can be directly transformed into automatically separated hydrocarbons and fluorescent nanoparticles (FNs) in the gas and solid phases respectively. Such an excellent separation performance is attributed to the fact that the Henry's law constant and dipole moment of the products are significantly reduced relative to those of their parents and the unique two-dimensional (2D) interface further accelerates their separation. In particular, the optimal selectivity of olefins is up to 99%, and the fluorescence quantum yield of FNs can reach as high as 44.35%. Combined with theoretical calculations, the referred mechanism and influences of functional groups on the resource transformation pathway and products are revealed in depth. This work provides important theoretical guidance for efficient, green and economical waste-to-resource conversion.