Efficient 3D Solar Evaporator for water-cleaning/seawater-desalination made with Loofah coated with graphite recycled from alkaline/spent batteries

Solar steam generation (SSG) devices are a promising alternative for producing fresh water from seawater and polluted matrices. This study evaluates graphite recycled from spent lithium (CLB) and alkaline carbon-zinc batteries (CZB) for their application as photothermal materials in evaporation processes. A 3D loofah sponge served as the structural support for the fabricated steam evaporators, which were coated with graphite recycled from alkaline/lithium batteries. The evaporator coated with CZB achieved an evaporation rate of 2.22 kg/m 2 h, while the evaporator coated CLB reached the higher evaporation rate of 2.4 kg/m 2 h under natural sunlight exposition. The most efficient solar evaporators were successfully tested for the purification of tap water contaminated with the recalcitrant pollutants (20 ppm) ambroxol (ABX) and glyphosate (GYL). Absorbance analysis of the evaporated water confirmed the complete purification of tap water, that is, the complete elimination of ABX and GYL from the water. The superior performance of solar evaporator made with CLB over that made with CZB is attributed to three main factors: i) enhanced optical absorbance in the visible region, ii) higher hydrophilicity and iii) higher content of defect, which facilitates the heat localization and minimizes the thermal loss. Overall, this study confirms that utilizing recycled graphite from batteries for SSG applications is a feasible strategy for developing high-performance devices capable of water desalination/cleaning. • Solar evaporators were made by coating loofah with graphite recycled from spent batteries. • Solar evaporators made with graphite recycled from LIBs produced an evaporation rate of 2.4 kg/m 2 h. • Solar evaporators made with graphite recycled from alkaline batteries had evaporation rate of 2.22 kg/m 2 h. • Solar evaporators also eliminated ambroxol and glyphosate (20 ppm) from tap water. • Intrinsic Mn, Zn, Li, Fe ions and defects in recovered graphite enhanced the evaporation efficiency by 6.6 %.