Brushing a superhydrophilic cross-linked coating on the metal mesh for dye separation

Abstract

The rapid growth of the dye industry and the worsening water resource crisis have drawn significant focus to the treatment of dye wastewater. Membrane separation technology is increasingly being utilized in addressing this issue. However, traditional separation membranes face challenges such as susceptibility to contamination and significant decline in subsequent separation permeance. This work utilizes a straightforward brushing technique to effectively apply a coating comprising titanium dioxide (TiO₂) nanoparticles and attapulgite (APT) onto a stainless steel mesh (SSM), equipping it with the capability for dye adsorption and separation. Studies show that coatings with different ratios yield varying degrees of coverage on the SSM. A higher concentration of TiO₂/attapulgite results in improved coverage on the SSM, creating a denser coating on the mesh surface and the degree of cross-linking of the coating was as high as 92.22%. The coated meshes exhibited superhydrophilicity uniformly and excellent negatively charged properties. Separation experiments of the meshes with different TiO₂/attapulgite ratios were conducted by separating simulated dye wastewater with methylene blue (MB) and safranine T (SaT). The results indicate that the prepared meshes achieved a maximum rejection of over 98.0% for MB and over 96.5% for SaT. In addition, the prepared meshes maintained high dye rejection efficiencies (>96%) even after 10 consecutive separation cycles. The above results indicate that the prepared meshes are promising for application in industrial dye wastewater treatment.