Hierarchically structural polyacrylonitrile/MIL-101(Cr) nanofibrous membranes with super adsorption performance for indoxyl sulfate

Excess protein-bound uremic toxins (such as indoxyl sulfate [IS]) in the blood could aggravate chronic kidney disease and also predispose to serious cardiovascular disease. In this study, we constructed a novel IS adsorbent polyacrylonitrile/MIL-101(Cr) (PAN-M) nanofibrous membrane with high adsorption capacity and ultra-fast sorption rate for IS. The porous metal-organic framework MIL-101(Cr) were embedded in PAN nanofibers by electrospinning as an adsorbent for easy recovery. It was found that MIL-101(Cr) had a strong electrostatic effect on the SO3- of IS and could reach the adsorption equilibrium within 5 min. Notably, MIL-101(Cr) showed an extremely high adsorption capacity (similar to 170 mg/g) for IS. The MIL-101(Cr) loading of prepared PAN-M nanofibrous membrane was optimized at 60 wt% and the optimal PAN-M60 exhibited an appreciable IS adsorption capacity (103 mg/g). The removal of IS was enhanced from 35.4% to 62.5% during hemodialysis by using PAN-M60 as adsorbent immersed in dialysate. This efficient adsorption performance can greatly reduce the consumption of dialysate and may shorten the hemodialysis time. This work would provide a fresh perspective on the development of MOF-based adsorbents to improve hemodialysis therapies.