Ceramic membrane filtration of organic compounds: Effect of concentration, pH, and mixtures interactions on fouling

A comparative assessment of iron oxide ceramic ultrafiltration membranes fouling by model organic compounds was performed. To characterize this fouling phenomenon, humic acid (HA), bovine serum albumin (BSA) and sodium alginate (SA) were used as models of humic substances, proteins and polysaccharides respectively. Clean and fouled iron oxide membranes surfaces were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The influence of concentration, foulant mixtures and pH on the fouling mechanism was investigated. Fouling was observed to depend first on foulant-membrane interactions, followed by a second step where membrane material plays a less important role. Membrane surface chemistry and solution pH were significant factors affecting irreversibility of the fouling layer. A strong dependence was observed in foulant concentration and solution pH. Foulant mixtures showed synergetic results, determined by foulant-foulant interactions.