MFI Zeolite Membranes as Potential Devices for Water Treatment

Nowadays, the absence of sufficient available water resources has already affected every continent and thus represents a significant global problem. Exploitation of natural fresh water resources combined with higher water demand has led to an increased requirement for alternative water resources. Membrane technology has emerged, in the last years, as the main contributor to solve water shortage problems. Intense research efforts are being made for the use of membranes, in particular combined with distillation process, in applications related to the water treatment, such as desalination of seawater or brackish water and drinking water purification (Zhu et al.,. 2013). Considering these aspects, zeolite membranes, due to their crystalline structure and to their pore diameters close to molecular size of different species, have gained a growing importance. In this area wide attention was focused on the MFI (silicalite, ZSM-5) membranes, having a pore size lower (around 5.5 Å) than the major kinetic diameters of hydrated ions. In the present work tubular supported silicalite membranes with a length of 30 cm were synthesized using the secondary growth method coupled with the cross flow seeding procedure (Garofalo et al., 2014). Afterwards, the prepared membranes were tested by means of single gas permeation and then applied in desalination process by vacuum membrane distillation (VMD) to investigate their performance. Deionized water and NaCl solutions at different concentrations were used as feed