Improved membrane flux recovery by Fenton-type reactions

Fenton reactions were applied to the degradation of dissolved organic matter (OM) and fouling removal of iron oxide membranes. Humic acid (HA), bovine serum albumin (BSA) and sodium alginate (SA), were used as models of humic substances, proteins and polysaccharides respectively. The degradation reaction was performed with H2O2 1 mM at pH of 2.5 and the reactant concentration was measured over time by total organic carbon (TOC) and HPLC. Dissolved and particulate iron were efficient catalyst, achieving mineralization rates of 80%, 40% and 85% for HA, BSA and SA respectively. The H202 solution was applied as a cleaning agent on membranes previously fouled by the compounds individually, as well as their mixtures. Hydraulic cleaning of the membrane surfaces did not show significant improvement; Fenton treatment produced a flow recovery of 97% for HA, 86% for BSA and 88% for SA. Flux recovery was slightly lower for mixtures, where chemical interactions between foulants yielded a more compact, recalcitrant layer. Membrane surfaces were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), showing residual foulants after treatment, regardless of the flux recovery achieved. The results showed the cleaning ability of this reagent with a very good recovery of the initial flux. (C) 2015 Elsevier B.V. All rights reserved.