Photothermal-enhanced capillary/siphon-driven self-priming pump for highly efficient recovery of various oils

Oil spills have caused devastating impacts on marine ecosystems and public health. Continuous oil-recovery system offers a cost-effective approach to achieving oil-spill cleanup. However, stable oil-water separation and efficient oil recovery remain challenging in continuous oil-recovery systems due to the influence of oil viscosity and the high cost of operating cost. In this study, an integrated self-priming pump (CSDP) with an outstanding photothermal effect was designed based on modified polyurethane sponge, which can spontaneously recover oil spills without external devices and additional power supply. A hierarchically engineered tri-layer architecture was dip-coated onto porous skeleton of CSDP, featuring a PDA-bonded hydrophobic expanded graphite supporting CuS@HKUST-1 that synergistically boost capillary action and broadband solar harvesting. Consequently, the CSDP enables autonomous and continuous oil-water separation. When processing oil spills, the CSDP achieved an oil flux of 1550.2 L·m⁻²·h⁻¹ while maintaining > 99.94% oil purity. CSDP also effectively separates nano-scale water-in-oil emulsions, yielding an oil flux of 1492.6 L·m⁻²·h⁻¹ and＞99.91% oil purity. Notably, the CSDP's excellent photothermal properties enhance oil flux by a factor of 5.4-8.8 under 1 kW·m⁻² solar irradiation relative to non-irradiated performance. Moreover, CSDP demonstrates robust stability in complex environments, which further establishes the CSDP as a highly promising platform for the practical treatment of oil spill pollution and the recovery of valuable oil.