Advancements in Hypersaline Wastewater Treatment: The Promise of Quasi‐Liquid Surfaces to Reduce Salt Scaling

Zero Liquid Discharge (ZLD) in desalination aims to eliminate liquid waste while producing salt byproducts and clean water, but current membrane‐based systems are energy‐intensive and inefficient. Evaporation‐based ZLD can treat saline wastewater. However, salt accumulation on evaporation surfaces disrupts its performance. This study introduces a Quasi‐Liquid Surface (QLS), an engineered surface featuring covalently grafted polymer brush layer to reduce salt scaling in ZLD systems. Evaporation dynamics of brine droplets on QLS were studied under various solar illumination (0.34–1.1 kW m − 2 ) and initial salt concentrations. The QLS, with its ultra‐low contact angle hysteresis, promoted compact centrally located crystals with smaller projected areas, whereas spin coated Polydimethylsiloxane (PDMS) exhibited ring‐shaped deposition. Adhesion tests revealed that QLS reduced salt adhesion to 0.4 mN mg − 1 compared to 40 mN mg − 1 on PDMS. This reduction results from its ultra‐smooth, ultra‐slippery surface and de‐wetting (retraction of thin residual film) during the final evaporation stage, minimizing the true contact area between the crystal and substrate. As a result, the crystals can be blown off easily under gentle airflow, leaving a clean surface ready for continuous desalination. This study basically highlights the potential of the QLS in sustainable hypersaline wastewater management, advancing environmental sustainability and water resource preservation.