Gravity-driven membrane based on solid waste for water purification: Manufacturing, XDLVO theory and algae removal evaluation

Abstract

To mitigate the environmental pressures associated with waste management, it is crucial to adopt scientific and rational approaches to solid waste treatment. This study introduces a novel gravity-driven membrane (GDM) that utilizes industrial solid waste as its structural framework, significantly enhancing algae removal efficiency. The industrial solid wastes examined include bayer red mud (BRM), sintered red mud (SRM), fly ash (FA), and gangue (GA). Notably, the adsorption energy (E_ads) of modified iron atoms on BRM was found to be −0.532 eV, indicating robust interaction forces. The adsorption efficiency of the GDM is primarily governed by the Lewis acid-base interactions ($\Delta U_{\mathrm{fwm}}^{\mathrm{AB}}$). Further analysis combining interaction energy with fluorescence characteristics demonstrates the effectiveness of the Fe–O network in BRM at extracting tryptophan protein-like substances from the membrane pores. The algae removal efficiency of the GDM incorporating BRM reached 66.71 %, suggesting a promising application for filtering algal-rich waters at the molecular level within ceramic matrices.