Nanomaterial Design for Solar-Driven Interfacial Evaporation in Microplastic Wastewater Treatment: Capture, Upcycling, and Environmental Assessment

Micro- and nanoplastics have emerged as persistent contaminants in aquatic systems, and conventional treatment rarely unites removal with water reuse and resource recovery. Solar-driven interfacial water evaporation (SDIWE) addresses this through nanomaterial design. Photothermal carbon nanostructures and two-dimensional materials localize solar heat at the air–water interface to drive clean-water production without external energy, while hierarchical nanopores and engineered nanocatalysts capture and partly upcycle the retained microplastics. This review organizes the field around a ternary framework of mass transfer and capture, energy conversion, and structure and operation, and it examines how nanomaterial design, including gradient nanopore sieving, nanofluidic thermal management, single-atom nanocatalysis for plastic upcycling, and antibacterial or salt-resistant nanocoatings, governs treatment performance and operational stability. A streamlined life-cycle assessment is further applied to benchmark representative nanomaterial-based evaporator systems, linking materials design to environmental sustainability. Three gaps are identified: standardized evaluation, validation in real water matrices, and product and nanoparticle toxicity screening. The review provides a nanomaterials-focused reference for the design and engineering translation of solar-driven microplastic wastewater treatment.