Avaliação do fluxo permeado e retenção de Geosmina e 2-Metilisoborneol em membrana comercial de nanofiltração NF-90

Abstract

Degradation of water resources contributes for occurring organisms who are responsible for producing and incorporating odoriferous compounds into the environment, which are capable of changing organoleptic properties of water intended for consumption. Geosmin and 2-Methylisoborneol (2-MIB) are responsible for assigning taste and odour of dirt and mold to water. Conventional water treatment, adopted by water treatment stations, is not able to remove all this compounds completely, causing dissatisfaction from consumers. In this context, nanofiltration technology is showed as an alternative for water treatment, since it uses filter membranes whose average pore diameter is of the order of 0,68 nm, capable of containing dissolved organic compounds, such as Geosmin and 2-MIB. The membrane NF-90 used in carrying out this work is composed of thin polyamide film with a microporous polysulfone support layer, which confers it hydrophobic characteristics. Thus, constitution and morphology membranes offers resistance to water filtered flow. In this work, the influence of soaking ultrapure water and treating membranes with ethanol were evaluated as function of permeate flux and retention of Geosmin and 2-MIB in ultrapure water. Permeability tests were performed at the pressures 400, 700 and 1000 kPa with ultrapure water, and retention tests of Geosmin and 2-MIB in ultrapure water in these same pressures. The quantification of Geosmin and 2-MIB was performed by Gas Chromatography followed by Mass Spectrometry (GC-MS). High rejection levels, approaching 100%, were achieved in membranes immersed in ultrapure water and treated with ethanol both. Besides, there was a considerable increase, over four times, in permeate flow in membranes NF-90 treated with ethanol against membranes immersed in ultrapure water, indicating efficiency of the treatment proposed by this work.