Cellulose-rich photothermal wood aerogels via partially delignification-reactive black dyeing for interface evaporation of dye wastewater.

Conventional dye wastewater treatment methods, like adsorption and degradation, have limitations such as restricted applicability, secondary pollution, and residue issues. Developing efficient, eco-friendly, and universal decolorization materials is crucial for treating complex dye wastewater. In this study, black-dyed cellulose-rich wood aerogels were used to construct a 3D flower-shaped solar evaporator for purifying dye wastewater. The synergistic effect of the black dye's photothermal conversion and the 3D structure design improved evaporation efficiency. The solar evaporators effectively removed various dyes, including reactive, reducing, disperse, cationic, and acid dyes. The photothermal aerogels exhibited an evaporation rate of 1.89 kg·m·h, leaving no residual dyes or other dyeing auxiliaries such as salts, surfactants, and heavy metal ions in the evaporated water. The purified water has a chroma of 0, pH between 7 and 9, sodium ion removal rate of 99.9 %, and no residual chromium ions, meeting the direct discharge standard. Benefiting from their simple construction process and excellent characteristics such as high efficiency, environmental friendliness, universality, and recyclability, the as-prepared photothermal wood aerogels exhibit potential applications in fields of dye, heavy metals, protein, etc. wastewater purification.