Spatial and temporal evolution of fouling phenomena in membrane systems

The use of membranes in the treatment of wastewater is very limited in part because of the fouling phenomena. This thesis presents a parametric study of the efficiency of nanofiltration flat sheet membrane and the fouling behavior on the membrane surface. Experiments were performed by using copper nanofluid and iron salt (FeCl3) diluted solution as wastewater. The solute concentrations in the wastewater were varied from 10 to 370 ppm to gain understanding of the impact of concentration on foulant deposition rate. Different types of flat sheet membranes were tested to understand the fouling phenomena on the membrane surface with time and along the length of the membrane. It was observed that the behavior of permeate flux was a function of cross flow velocity, feed flow rate, feed concentration and transmembrane pressure. Experimental evidence showed fouling rate was a function of solute concentration and time of the experiment. The progression of foulants and particle deposition rate was correlated with feed concentration and permeate flux. Results indicate non-uniformity in the spatial development of fouling on the membrane surface. The tendency of starting fouling was observed in the retentate side of the membrane surface and it increased with time on the feed side. Fouling was strongly dependent on the crossflow velocity inside the crossflow cell and membrane properties. The shape of formation of fouling on the membrane surface was independent of the parameters tested