Study of the relation between kinematic viscosity and SDI in polyethylene glycol solutions for predicting membrane fouling: preliminary test

Abstract

[EN] Nowadays, membrane technology plays an essential role in water treatment as a method of producing good-quality water. Its success is due to its ease of implementation, high efficiency and low cost. However, fouling of the active layer of the membranes is one of the main problems of this technology because it affects the operation conditions of the process, requires maintenance and limits the useful lifetime of membranes. Several parameters have been developed for the prediction of fouling being the most used Silt Density Index (SDI). However, it has some limitations that have prompted the search for alternative parameters such as Modified Fouling Index, Modified Fouling Index-UF, Mini Plugging Factor Index and Unified Membrane Fouling Index, among others. In this work, a prediction methodology of colloidal fouling is studied by means of a direct, simple and immediate measure of the combination of kinematic viscosity and SDI. To perform the tests, synthetic solutions of polyethylene glycol at a concentration ranging between 0.1 and 0.75 g/l were used. In kinematic viscosity tests, a Cannon-Fenske viscometer was used and SDI measurements were performed using a standard testing system. Results show that there is a linear relationship between the kinematic viscosity values and SDI in the concentration range studied. These preliminary results can be used to introduce a new parameter for predicting fouling potential in membranes based on the measurement of the kinematic viscosity in the feed water.