Research on boron adsorption performance by pH–responsive nano dendritic polyurethanes

The selectivity and desorption capacity of adsorbent materials significantly impact adsorption capacity and recyclability. Developing resin-based boron adsorbents that simultaneously exhibit high specificity, large adsorption capacity, and excellent cycling performance remains a prevalent challenge for the extraction and removal of boron from aqueous systems. In this study, a series of polyurethane nanomaterials with dendritic structures and tertiary N as the pH-responsive branching center were designed and prepared. The particle size and surface morphology of the material were characterized using Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). The influence of two microstructure dynamic changes, namely “density” and “expansion”, triggered by pH, on its boron adsorption performance was systematically studied. The results showed that the material had excellent specific selectivity. By taking advantage of the protonation property of tertiary N and exploring the adsorption performance of the material under pH regulation, the adsorption capacity could reach up to 172 mg·g −1 , achieving a 28 % increase. Meanwhile, the response characteristic of enhanced hydrophilicity at low pH enabled the material to be restored to its initial state during the desorption process, thus having the ability to be reused multiple times. This research not only presented a high-performance boron adsorbent, but also showcased a new paradigm for designing next-generation adsorption materials through “intelligent response”, offering a brand-new approach for achieving efficient and precise control of the adsorption process.