Molecularly imprinted ZSM-5 zeolite for selective creatinine removal from dialysate: toward enhanced uremic toxin clearance

Abstract

Dialysate regeneration via uremic toxin removal remains to be studied. In this study, the removal of creatinine, one of the most water-soluble uremic toxins, using ZSM-5 zeolite as an adsorbent was investigated. The zeolite ZSM-5 was successfully synthesized (57%) with a mole ratio of 0.1 Na2O : 1 SiO : 0.0125 Al2O3 : 20H2O. Modification was performed using an imprinting technique with creatinine as the template to produce creatinine-imprinted ZSM-5 (IZ). Based on X-ray diffraction (XRD) characterization, the crystallinity of IZ was 67%. The successful imprinting of creatinine onto ZSM-5 was confirmed by comparing the FT-IR and surface area analysis characterization results with those of the synthesized ZSM-5. The FT-IR spectra of IZ and synthesized ZSM-5 exhibited similar patterns, indicating that the zeolite framework was preserved during the imprinting process. IZ exhibited shorter contact time and higher adsorption capacity than synthetic ZSM-5. The synthesized IZ was fabricated into a flat-sheet mixed matrix membrane (MMM) with cellulose acetate (CA) and acetone using a glass plate printing method with a composition of 30 CA : 0.1 zeolite : 100 acetone. The efficiency of creatinine adsorption by IZ in the powder form (84%) was greater than that of the MMM/IZ membranes (28.8%).