Usuwanie substancji organicznych z roztworów wodnych z wykorzystaniem ceramicznych membran ultrafiltracyjnych

Procesy membranowe są obecnie szeroko stosowane w wielu gałęziach przemysłu oraz w szeroko pojętej ochronie środowiska do usuwania różnorodnych zanieczyszczeń zarówno o charakterze organicznym jak i nieorganicznym. W eksploatowanych na całym świecie instalacjach membranowych najczęściej stosowane są membrany wytwarzane z materiałów organicznych, np. polisulfonu, polietersulfonu, poliamidu lub materiałów celulozowych. Powszechność stosowania membran polimerowych wynika przede wszystkim z bardzo dużej dostępności membran o różnorodnych możliwościach separacyjnych. W związku z tym, iż polimery wykorzystywane do produkcji membran nie są odporne na działanie czynników chemicznych, termicznych i biologicznych, od dłuższego czasu trwają prace nad wytwarzaniem membran o znacznie większej wytrzymałości na działanie niekorzystnych czynników. Wymogi te spełniają membrany nieorganiczne wytwarzane z materiałów ceramicznych.

Membrane processes are now widely used in many industries and in the widely understood environment protection to remove the various pollutants of both organic and inorganic character. In the operated worldwide membrane installations membranes made from organic materials such as polysulphone, polietersulphone, polyamide or cellulosic materials are most commonly used. The universality of application of polymer membranes is primarily attributed to very high availability of membranes with various separational characteristics. In view of the fact that the polymers used for production of membranes are not resistant to chemical, thermal and biological factors, works in order to produce membranes with a much higher resistance to the action of unfavourable factors have been carried out for a long time. These requirements meets the inorganic membrane made from ceramic materials. The advantages of ceramic membranes, deciding about their their advantage over organic membranes, include primarily their high thermal, chemical, mechanical and biological resistance. Not without significance is the fact that they can be sterilized with steam and cleaned using strong acids or bases, which allows long-term operation of such membranes. The usability of the ultrafiltration ceramic membrane in removal of natural and synthetic organic pollutants from aqueous solutions has been evaluated. The ultrafdtration experiments have been carried out towards Odra river water, model solution containing NOM and model solutions of organic dyes (methyl orange, indigo carmine, hellion blue, direct black). The ultrafiltration ceramic membrane (cut-off 50kDa) made by Tami Industries and laboratory installation ProFlux Ml2 Millipore were applied in the tests. This installation allows to run separation tests in flow system using a filtration modules of any configuration. Installation enables circulation of the solution between the supply tank with a capacity of 3 dm3 and a filter module.The influence of the transmembrane pressure (0.03,0.06, and 0.09 MPa) on the process efficiency was determined. It was stated that the increase of the applied pressure caused the increase of permeate flux. In the course of ultrafiltration of solutions containing organic substances the determined membrane permeability was much lower (by 10-40%) than observed for water. The separation properties were influenced by the composition of the treated solution and the nature of the organic pollutants. The organic dyes of the molecular weight higher than 900 Da were retained in more than 95%. The reduction of color for solutions containing NOM amounted to 46-65%.