Cu (II)-phenolic complex incorporated hemodialysis membranes for efficient urea removal via enhanced adsorption strategy

The removal of urea poses a significant challenge in reclaiming waste dialysate, especially for portable dialysis. Here, we developed a novel Cu (II)-phenolic complex incorporated hemodialysis membrane through an adsorption-diffusion mechanism for efficient urea removal. The synergistic effect between the hemodialysis membrane and the adsorbent composed of tannic acid (TA), polyethyleneimine (PEI), and Fe (II)/Cu (II) bimetal ions exhibited enhanced coordination towards amine groups present in urea, resulting in rapid adsorption kinetics and high adsorption capacity via chemical interactions. Additionally, uniformly distributed Cu (II) sites on the membrane surface promoted the hemocompatibility by converting S-nitrosothiol to nitric oxide (NO), thereby inhibiting platelet activation. In simulated hemodialysis experiments, our adsorptive-diffusive membrane demonstrated high removal efficiency (∼90 %) for urea using 1 L dialysate compared to ∼10 % of pristine membrane. The incorporation of Cu (II)-phenolic complex into the hemodialysis membrane presents a novel approach for enhancing urea removal, thereby reducing dialysate consumption and simultaneously improving the hemocompatibility of the membrane.