Membrane scaling is a significant challenge in membrane distillation (MD). This study investigates the use of a 3D-printed carbon nanotube (CNT) spacer to mitigate calcium sulfate scaling during MD. Experiments using optical coherence tomography (OCT) and scanning electron microscopy (SEM) reveal a unique scaling mechanism with the CNT spacer, resulting in only a 37% flux reduction even at a high volume concentration factor (VCF). The study also develops a mechanistic model of MD-crystallization to explain the observed scaling mitigation, attributing it to enhanced flux, vaporization rate, and bubble formation, along with the CNT spacer's rough surface promoting detachment of initial nuclei.

Seongeom Jeong, Boram Gu, Sanghun Park, Kyunghwa Cho, Alicia Kyoungjin An, Sanghyun Jeong