Diatomite/polyaniline-BiOCl functionalized hierarchical composite membranes for simultaneous photothermal interface...

Interfacial solar water evaporation technology holds great promise for resource recovery and wastewater purification. In this study, diatomite/polyaniline-BiOCl functionalized hierarchical composite membranes (DpM/PANI-BiOCl) with efficient photothermal water evaporation and pollutant degradation performance were synthesized via a simple in situ hydrolysis method. The composite membrane features a three-dimensional porous polyurethane sponge filled with diatomite as the bottom water transport layer, followed by layer-by-layer loading of polyaniline (photothermal layer) and BiOCl (photocatalytic layer). This design enables the efficient synergy of water transport, photothermal conversion and photocatalytic degradation. Under one-sun irradiation, the optimized DpM/PANI-BiOCl functionalized hierarchical composite membrane achieved an evaporation rate of up to 1.11 kg/m²/h while removing 95.9 % of rhodamine B (RhB) from bulk water. After 3 cycles of stability testing, its pollutant removal rate remained above 80 %. Furthermore, the composite membrane exhibited excellent photocatalytic performance across different pollutant concentrations, with degradation rates of 90 % for methylene blue (MB) and 91.2 % for methyl orange (MO). These results highlight the importance of the functionalized hierarchical design in facilitating the photocatalytic pollutant degradation and enabling efficient, sustainable clean water extraction from wastewater.