Synthesis and Characterization of Pure and Ag-TiO2-Modified Diatomaceous Aluminosilicate Ceramic Membranes for Water Remediation

Mesoporous ceramic membranes were prepared from raw and modified diatomaceous earth alumi-nosilicate mineral precursors. The main modification component of the ceramic membranes was Ag-loaded TiO2 nanoparticles (STOX). Chemical and microstructural characterizations of the raw materials and the modified precursors were carried out using Fourier Transform Infrared (FTIR) Spectroscopy, Particle Induced X-ray Emission (PIXE-IBA), Energy Dispersive X-ray Spectroscopy (EDX) and Scanning Electron Microscopy (SEM). The precursors and membranes were prepared and subsequently subjected to a high temperature sintering treatment for physico-chemical modification and stability. Remediation functionalities of the ceramic membranes on water samples were studied using Atomic Absorption Spectrophotometry (AAS), Total Bacterial Count Enumeration; Total Dissolved Solids (TDS), pH, and Electroconductivity (EC). Remediation experiments showed reductions in the concentration of certain cations such as Mg2+, Mn2+, Cd2+, Ni2+ and K+ by the modified ceramic membrane samples, while increased concentrations were observed for Ca2+, Na+ and Mg2+. The antimicrobial microfiltration process showed 100% bacterial removal and 70% fungi removal in most of the samples. Membranes exhibited good flux output from 5.607 L/hr·m2 (STOX-Z) to 39.245 L/hr·m2 (ZEO-T) under a pressure of 0.0196 MPa.