Integrated fabric distillation-crystallizer for zero liquid discharge of hypersaline brines

Zero liquid discharge (ZLD) requires cost-effective brine crystallization processes capable of stable operation under hypersaline conditions. Here, we introduce a fabric distillation-crystallization (FDC) process that integrates a fabric distillation (FD) unit with a simple crystallizer to achieve stable salt crystallization using low-grade thermal energy. When treating NaCl feed solutions of 293 g l^-1, standalone FD failed due to salt deposition on the fabric, whereas FDC sustained continuous crystal production without visible scaling by decoupling evaporation from crystallization. Controlled FDC experiments showed that crystallizer operating conditions had minimal influence on crystallization rate, which instead scaled directly with water flux in the FD unit. Mechanistic analysis revealed that crystal growth, rather than nucleation, governed the overall kinetics, so crystallization rate was dictated by evaporation. These results indicate that robust and effective FDC systems can be constructed using inexpensive fabrics and a simple crystallizer, with performance improvements achieved by maximizing water flux in the FD stage. Overall, this study establishes FDC as a promising technology for ZLD and provides a mechanistic framework for tailoring crystallization performance across diverse brine treatment applications.