Waste biomass and dye wastewater pollution have been the serious environmental problems. The interfacial solar-steam generation technology is an effective and sustainable method for the water purification. However, the complex preparation process, high economic cost and probably secondary environmental pollution of traditional photo-thermal materials restricted their practical large-scale application. Herein, the biochar cakes (BCs) deriving from waste biomass were prepared, and the granular and schistose MgO coatings were dressed on the surface of carbonized fiber to improve their hydrophilicity. The BCs with high solar absorbance and super-hydrophilicity were applied in the photo-thermal purification of dye wastewater with solar energy. The highest evaporation rate of dye wastewater with BCs reached 2.27 kg m⁻² h⁻¹, and the corresponding conversion efficiency of solar to steam generation was 78.98% under the simulated solar irradiation (1846.0 w/m²). The collected clean water from the solar-steam evaporators reached the emission standards of EU Water Framework Directive (91/271/EEC). Considering the simple and economical preparation method, this process made the practical large-scale application of photo-thermal BCs on dye wastewater treatment a reality, and also provided a cost-effective management strategy for the waste biomass.

废生物质和染料废水的污染一直是严重的环境问题。界面太阳蒸汽产生技术是一种有效且可持续的净水方法。然而，传统光热材料的制备过程复杂，经济成本高以及可能造成的二次环境污染限制了其实际的大规模应用。在此，制备了源自废物生物质的生物炭饼（BC），并将颗粒状和片状的MgO涂层覆盖在碳化纤维的表面，以提高其亲水性。高吸光度和超亲水性的BCs被用于太阳能染料废水的光热净化。含BC的染料废水的最高蒸发速率达到2.27 kg m ^-2h ^-1，在模拟太阳辐射下（1846.0 w / m ²），太阳向蒸汽的转化效率为78.98％。从太阳能蒸汽蒸发器收集的清洁水达到了欧盟水框架指令（91/271 / EEC）的排放标准。考虑到简单，经济的制备方法，该工艺使得光热BCs在染料废水处理中的实际大规模应用成为现实，并且为废物生物质提供了一种经济高效的管理策略。