Treatment of feed water for reduction of fouling in air gap membrane distillation of seawater
Volume Title: 1
Department of chemical engineering, Amirkabir University, Tehran, Iran
The aim of this study is examining the effect of magnetic treatment of feed water on membrane fouling and performance of an air gap membrane distillation (AGMD) system for seawater desalination. A 0.22 m pore size for this purpose, flat PTFE membrane was used as the hydrophobic membrane. The experiments were carried out at temperature of 50-80 °C, feed flow rate of 60-30 ml/s, and various magnetic field intensities for 80 hours duration. According to the results, applying magnetic field caused an increase in the permeate flux during the process. In the absence of a magnetic field, during more than 80 hours operation, about 50% reduction in the permeate flux was observed, while by applying three pairs of the magnets, the flux reduction was only 30%. Moreover, a 72% decrease in TDS permeate compared to the non-applied magnetic field was observed. By increasing the magnetic field power, the size and the amount of the scale particles formed on the surface of the membrane increased. The SEM-EDAX analysis of membranes surface revealed that the fouling of the membranes were decreased upon applying the magnetic field.