Self-cleaning solar water evaporation device based on polyaniline/TiO2/natural cellulose fibers for contaminant water

Wastewater accounts for a large part of the water body on the earth. Solar water evaporation is an effective way to produce fresh water from seawater or polluted water. However, the co-evaporation or deposition of contaminants may reduce the efficiency and freshwater quality during water evaporation. In this work, a self-cleaning solar water evaporator is developed based on the natural lignocellulose fibers (NCF), polyaniline (PANI), and TiO2, which shows great advantages of wide-range light absorption, super hydrophilicity, and low thermal conductivity. Nanofibrous PANI is polymerized on the surface of NCF to form a mesoporous network by adding the NCF to the polymerization solution. P25 TiO2 nanoparticles as photocatalysts are dispersed into the above reaction to form the hybrid PANI/TiO2/NCF composite disc by simply filtration. Owing to the synergistic effect between the photothermal PANI and the photocatalytic degradation of TiO2 nanoparticles in the solar water evaporator device, the water evaporation rate can reach 2.36 kg m−2 h−1 (under 1 sun irradiation), and the contaminant (100 ppm tetracycline) can be efficiently degraded. Interestingly, the solar water evaporator device still maintains a constant solar evaporation rate after working for 10 h, and no contaminant is accumulated. The bifunctional solar water evaporation device, which combines photocatalytic and photothermal effects, has great potential application in organic contaminant water with a self-cleaning effect.