Metal-Organic Frameworks with Enhanced Electret Capability for Selective Electrostatic Separation

Electrostatic separation plays a pivotal role in bioseparation, energy conversion, and water treatment. Electrostatic polarization is an effective approach for injecting and trapping quasi-permanent charges in electrets, facilitating electrostatic separation. However, it remains challenging to simultaneously enhance charge density and suppress charge dissipation, which are both critical for achieving stable and efficient separation. Herein, we incorporate defect-engineered zeolitic imidazolate frameworks (ZIFs) into the polymer matrix via electrostatic polarization to construct high-performance electrets. Their rigid and ordered frameworks, enriched with abundant functional groups, facilitate the stabilization of reoriented dipoles and the retention of increased charge traps with elevated escape energy barriers following the introduction of structural defects, thereby enhancing the charge density and retention. The resulting composite film with defective ZIF-8 retains 97.4% of its surface potential after 14 days and achieves an exceptional adsorption capability of 487.6 mg/g for electropositive low-density lipoprotein (LDL), with a high LDL/high-density lipoprotein (HDL) selectivity ratio of 63.5 in serum, surpassing those of previously reported materials while also demonstrating excellent biosafety. This defect-induced electret enhancement strategy offers insights into the design of advanced electrostatic adsorbents for applications, such as DNA purification, lithium extraction, and protein separation.