Green and High Mechanical Properties of Corn Straw Solar Evaporator for Efficient Wastewater Treatment

The development of solar-driven evaporators with high efficiency, low cost, and environmental friendliness is very important for wastewater treatment. Here, a green and biodegradable solar evaporator based on natural corn straw was fabricated by uniformly coating the upper surface of straws with carbon nanotubes via the drop-casting method. The evaporator is endowed with good structural stability, excellent light absorption performance (88–95%) and a fast evaporation rate (∼1.52 kg·m–2·h–1). The mechanically robust evaporator shows significant purification capabilities for simulated wastewater containing heavy metal ions (e.g., Cu2+, Fe3+, Cr6+) with a removal rate of 99.2% even in an acidic environment due to its hierarchical porous structure and surface photothermal conversion performance. This work provides a strategy for the high-value resource utilization of agricultural waste and offers a concept for the development of low-cost, biodegradable solar-powered water purification devices.