Water desalination and methylene blue dye removal by microalgae-based membrane: performance and mechanisms

The present work describes the preparation of a biocomposite membrane by coating of Scenedesmus sp. microalgae on the surface of stainless steel mesh. The prepared membrane was used for both water desalination and methylene blue dye removal. Some effective parameters on the bioremediation performance such as the number of mesh layers, salt and dye concentrations, and the number of desalination cycles were optimized. Under the optimum conditions, the algae-coated mesh exhibited salt rejection and dye removal of 89.4 ± 1.2% and 97.9 ± 0.6%, respectively. The results confirmed the high stability and reusability of algae-coated mesh after 20 cycles of the desalination process. The prepared membrane showed outstanding mechanical strength with corrosion resistance and tensile strength of 96.7% and 38.1 MPa, respectively. The algae-coated mesh has the ability to successfully remove salinity agent cations from well water with the yields of above 87.0%. Based on the results, the salt removal was better fitted with Temkin adsorption isotherm, while the methylene blue dye removal was compatible with the Langmuir isotherm model.