Dialysate Regeneration with Urea Selective Membrane Coupled to Photoelectrochemical Oxidation System

Abstract

AbstractPortable dialysis can meaningfully improve the health outcomes and life quality of end‐stage renal disease (ESRD) patients and reduce the economic burdens of dialysis related care. Current treatment sessions use 120 Kg of aqueous dialysate, thus key to realizing portability is the continuous regeneration of small volumes of spent dialysate. Urea is the single most abundant uremic waste. However, its removal is compromised from the interference of other uremic species. Osmotic membranes demonstrate high selectivity of urea over other uremic species in both reverse and forward osmosis (FO) modes. In FO mode, a urea mass transport coefficient of 1.2 µm s−1 is seen, corresponding to a diffusion coefficient of 1.2 × 10−9 cm2 s−1. By using a second stage dialyzer with a commercially available FO cartridge, daily urea removal rate of over 30 g, twice the daily generation rate, could be achieved at a dialysate flow rate of 400 mL min−1. Combined with an optimized urea photodecomposition device, selective removal of urea (0.32 mg cm−2 h−1) and excessive water (0.081 g cm−2 h−1) are achieved simultaneously thus scaling to 2000 cm2 electrode area for clinical needs of 15 g urea removal/day. No significant difference in the cytotoxicity between treated and untreated human spent dialysate is observed.