Photothermal ZrN composite membranes for solar-driven water distillation

Many regions around the world, including the Arabian Peninsula, face a scarcity of freshwater resources and depend heavily on non-renewable energy sources for energy-intensive desalination processes, emphasizing the need for sustainable water treatment methods. To tackle this challenge, solar energy-driven membrane distillation is a promising and compatible solution for desalinating seawater. In this work, a solar-powered photothermal air gap membrane distillation (AGMD) system has been tested to treat brine by utilizing plasmonic-based composite membranes. Polyvinylidene fluoride (PVDF) membranes were prepared by incorporating low-cost zirconium nitride (ZrN) nanoparticles at varying concentrations to facilitate solar energy harvesting. ZrN-modified PVDF composite membranes significantly boost the solar absorption up to 75 % in the wavelength range of 250–800 nm, when compared to pristine PVDF membranes. The composite membranes with 56 % enhancement in porosity resulted in a permeate flux of 0.36 L m⁻² h⁻¹ and a rejection rate of ∼99 %. The developed photothermal water treatment system provides a highly effective and scalable solution for water treatment. Moreover, next-generation materials exhibiting photothermal effects have the potential to exploit solar renewable energy for decentralized off-grid desalination by converting sunlight into heat for a unique and favourable water-energy nexus.