Plasmonic titanium nitride-based membranes for solar-driven domestic wastewater distillation treatment

Membrane separation processes have emerged as efficient wastewater treatment technologies due to their reduced footprint, sustainability, cost-effectiveness, ease of operation, high filtration selectivity, and compliance with end-user requirements. Especially solar-driven membrane distillation, known for its low energy requirements and high pollutant rejection rates, has gained prominence as a potential wastewater treatment process that does not need external thermal energy input for water treatment. Herein, we demonstrate plasmonic titanium nitride nanoparticle-incorporated polymeric membranes for the solar-driven membrane distillation of domestic laundry wastewater, specifically focusing on SDBS (sodium dodecylbenzene sulfonate) surfactant removal. Under solar illumination, the plasmonic element within the polymeric matrix enables a localized heating effect driven by photothermal conversion in the proximity of the surface of distillation membranes, thereby producing a vapor pressure enough for water distillation across the hydrophobic membranes. The fabricated photothermal mixed matrix membranes showed incremental distillation flux and derived energy efficiency with the loading of titanium nitride nanoparticles under light illumination, reaching up to 0.47 kg/m2h and 29.79 %, respectively. The rejection rate against SDBS achieved up to 99 %. We also verified that its distinctive surface photothermal heating effect is associated with enhanced plasmonic absorption, surface thermal conductivity, and improved interfacial heat transfer of the membranes in the presence of plasmonic elements. The photothermal membranes proved that the permeate produced by photothermal distillation of real laundry wastewater fulfilled all required parameters for safe use as irrigation water, demonstrating its practical feasibility and viability of solar-driven distillation for domestic wastewater treatment and reuse.