Nano/submicrometer-emulsion oily wastewater treatment inspired by plant transpiration

Oily wastewater treatment has attracted considerable attention because the wastewater poses a serious threat to the safety of drinking water, the ecological environment, and human health. Although significant progress has been made with regard to the development of superwettable separation membranes, there is a need for addressing the challenges that arise with the treatment of nano/submicrometer-emulsion oily water, oily seawater, and acid-base-corrosion oily wastewater. Herein, inspired by plant transpiration, a solar-driven device is developed that is based on wood, poly(vinyl alcohol), and hydroxylated multiwalled carbon nanotubes; this device demonstrates a purification efficiency of up to 99.7% toward various nano/submicrometer-emulsion oily wastewaters. Remarkably, owing to the outstanding desalination capacity and robust acid-alkali tolerance, the prepared device achieved a one-step production of fresh water from oily seawater and acid-base-corrosion oily water. Therefore, the development of this device provides a method for treating oily wastewater to produce fresh water.