Dictyophora-based evaporator developed by sericin bidirectional crosslinking for photocatalytic degradation and efficient solar desalination in harsh environments

Abstract

This study introduces a novel dictyophora-based evaporator, SCNT/TiO₂@PAM-DIC, developed through a pioneering sericin bidirectional crosslinking strategy. This innovative material boasts a range of advantages, including environmental friendliness, salt resistance, antibacterial properties, acid and alkali resistance, oil repellency, and pressure resistance. By incorporating polyacrylamide (PAM) hydrogel enhanced with sericin, SCNT/TiO₂@PAM-DIC significantly improves the mechanical strength of dictyophora while offering anti-fouling, antibacterial, and high-efficiency evaporation capabilities. Unlike its predecessor DIC, SCNT/TiO₂@PAM-DIC retains a porous structure with a smoother surface, enabling multiple sunlight reflections and prolonged exposure, which enhances its solar absorption to an impressive 93 %. Photothermal conversion studies reveal that SCNT/TiO₂@PAM-DIC achieves a surface temperature of 63.5 °C within 5 min, surpassing DIC (29.1 °C) and S@PAM-DIC (30.9 °C). The evaporation rate of SCNT/TiO₂@PAM-DIC is significantly higher at 2.495 kg m⁻² h⁻¹, compared to 1.149 kg m⁻² h⁻¹ for DIC and 1.433 kg m⁻² h⁻¹ for S@PAM-DIC. Additionally, its dark evaporation rate is 1.8 times that of pure water. The material's exceptional salt rejection and self-cleaning properties are attributed to the presence of zwitterionic groups in its structure. Mechanically, SCNT/TiO₂@PAM-DIC demonstrates superior compressive performance and stability, with compressive stresses of 0.516 MPa at a 25 % compression ratio, significantly higher than DIC's 0.104 MPa. Furthermore, it achieves an 83.5 % photocatalytic degradation efficiency of methylene blue within 3 h. Its robust performance in challenging environments, such as oily wastewater, emulsified oil, organic dyes, and acidic/alkaline solutions, positions SCNT/TiO₂@PAM-DIC as a promising solution for advanced water purification technologies, offering a new avenue for sustainable water treatment.