Iron oxide doped ceramic membranes for combined organic – Inorganic colloidal fouling mitigation

Abstract

Membrane fouling by the combined effect of organic – inorganic substances is a major hurdle toward the wide application of ultrafiltration processes. In this work, ceramic membranes were modified with low loading of in situ generated iron oxide nanoparticles to alleviate this fouling. Humic acid and/or silica nanoparticle dispersion were used as model foulants. The combined stream induced prompt initial flux decline and greater fouling extent to the pristine membrane, independent of silica content. On the other hand, the modified membranes displayed significantly enhanced antifouling characteristics. Compared to as-received membranes, modified membranes displayed up to 60% lower permeate flux decline at the end of fouling cycle. Moreover, still compared to as-received membranes, the irreversible fouling decreased by 22%, and the organic removal increased by up to 2 times, particularly for the larger pore size membranes. The adhesion interaction energies between the different membrane – foulant systems, based on the extended DLVO theory, successfully predicted the fouling behavior for the modified membranes in terms of reversibility. The results of this study provide an insight into organic – inorganic fouling mechanisms and suggest protocols for effective, inexpensive membrane modification techniques for fouling mitigation.