Hydrothermal carbonization coating on recycled quartz glass fiber

• Recycled quartz fiber with coating was tested for solar thermal evaporation. • Hydrothermal carbonization at 200 °C for 4 h created hydrochar on quartz wool. • Carbon coating thickness varied, enhancing solar absorption and water transport. • Carbon-coated quartz wool evaporated water 2.5 times faster than uncoated wool. Hydrothermal carbon derived from D-glucose was deposited on quartz fiber wool to enhance solar thermal evaporation. Thermogravimetric analysis (TGA) indicated 46 % weight loss for the coated wool above 500 °C. The BET surface area of the coated wool was 6.8581 m 2 /g. The carbon at the outer surface fibers of the quartz wool was thicker. The steady-state solar thermal evaporation rate of the carbon-coated quartz wool was found to be 3.1831 kg/m 2 ∙h, which is 2.5 times higher than that of the uncoated one (0.8785 kg/m 2 ∙h).