Development of ZnO Nanoflake Type Structures Using Silk Fibres as Template for Water Pollutants Remediation

Green, Low-carbon Silk-based Materials in Water Treatment: Current State and Future Trends

The improper and inadequate treatment of industrial, agricultural, and household wastewater exerts substantial pressure on the existing ecosystem and poses a serious threat to the health of both humans and animals. To address these issues, different types of materials have been employed to eradicate detrimental pollutants from wastewater and facilitate the reuse of water resources. Nevertheless, owing to the challenges associated with the degradation of these traditional materials post-use and their incompatibility with the environment, natural biopolymers have garnered considerable interest. Silk protein, as a biomacromolecule, exhibits advantageous characteristics including environmental friendliness, low carbon emissions, biodegradability, sustainability, and biocompatibility. Considering recent research findings, this comprehensive review outlines the structure and properties of silk proteins and offers a detailed overview of the manufacturing techniques employed in the production of silk-based materials (SBMs) spanning different forms. Furthermore, it conducts an in-depth analysis of the state-of-the-art SBMs for water treatment purposes, encompassing adsorption, catalysis, water disinfection, desalination, and biosensing. The review highlights the potential of SBMs in addressing the challenges of wastewater treatment and provides valuable insights into prospective avenues for further research.

Controllable growth of Cu-Bi co-doped ZnO nanospheres on cotton fabrics and a study on their photocatalytic performance in visible light

Cu-Bi co-doped ZnO nanospheres were obtained by adopting Bi and Cu to dope ZnO to improve their photocatalytic performance in the visible region. Cu-Bi co-doped ZnO nanospheres were successfully grown on the surface of cotton fabric by a sol-gel assisted hydrothermal method with citric acid as a morphology control agent. The obtained products were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). The results showed that the size of ZnO nanospheres was about 200 nm and doping with Cu and Bi did not change their morphology. Cu-Bi co-doped ZnO nanospheres presented a hexagonal wurtzite structure with high crystallinity; meanwhile, their band gap was also obviously reduced due to doping, from 3.24 eV to 2.82 eV. Cu-Bi co-doped ZnO nanospheres endowed the cotton fabric with excellent UV (ultraviolet) resistance with a UPF (Ultraviolet Protection Factor) value of 283.54 after 40 washes. Cotton fabric with 3% Bi-5% Cu co-doped ZnO on the surface showed 98.66% degradation of methylene blue (MB) solution under visible light irradiation for 150 min, indicating remarkable photocatalytic performance.