Ultra-selective uranium separation by in-situ formation of π-f conjugated 2D uranium-organic framework

Abstract

With the rapid development of nuclear energy, problems with uranium supply chain and nuclear waste accumulation have motivated researchers to improve uranium separation methods. Here we show a paradigm for such goal based on the in-situ formation of π-f conjugated two-dimensional uranium-organic framework. After screening five π-conjugated organic ligands, we find that 1,3,5-triformylphloroglucinol would be the best one to construct uranium-organic framework, thus resulting in 100% uranium removal from both high and low concentration with the residual concentration far below the WHO drinking water standard (15 ppb), and 97% uranium capture from natural seawater (3.3 ppb) with a record uptake efficiency of 0.64 mg·g⁻¹·d⁻¹. We also find that 1,3,5-triformylphloroglucinol can overcome the ion-interference issue such as the presence of massive interference ions or a 21-ions mixed solution. Our finds confirm the superiority of our separation approach over established ones, and will provide a fundamental molecule design for separation upon metal-organic framework chemistry.

Methodologies to achieve efficient and selective uranium separation originating from nuclear waste are desirable. Here the authors report the in-situ formation of π-f conjugated 2D uranium-organic framework for uranium separation, leading to superior performance in uranium uptake and outstanding uranium generation efficiency from seawater.