Composite depth filters for removal of abiotic and biotic objects

E. Sztuk, L. Gradon*, Warsaw University of Technology; J. Skowroński, Institute for Sustainable Technologies, Poland

One of the main problems in water purification process is the presence of organic compounds in the cleaned stream. Organic matter filtration is often associated with operational problems, particularly that of loss of flux and shortening of filter life. The method can be improved by optimizing the filter structure, porosity and collector diameter, and/or by performing material modifications, to obtain antibacterial or bacteriostatic properties of fibers. If the deposit contains bacteria e.g. in a growth phase, clogging of the filter results not only from the upflowing contamination but also from multiplying bacteria on the filter surface. Proper antibacterial modifications of polymer surfaces could reduce the biofouling effect, extend filter longevity and make the filtrate free of bacterial contamination. To accomplish this goal it is necessary to create an effective method of fibrous surface modifications and then analyze the performance of such modified filters. In this study a production method of antibacterial fibrous filters is proposed and the performance of standard filters made of polypropylene is compared with that of polypropylene filters modified with zinc oxide (ZnO) associated with silver (Ag) and halloysite nanoparticles. Composite fibrous filters were produced with the melt-blown technique. Filter fibers contain on their surface nanoparticles of expected surface concentration appropriate for inhibition of bacteria growth. As the bacterial environment is extremely diverse, an antibacterial and bacteriostatic test was performed on two bacterial strains, E. coli and B. subtilis as representatives of gram-negative and gram-positive bacteria respectively. The tests were carried out both under static (plate assay) and dynamic conditions, revealing the basic properties of antimicrobial activity of the filter.

Positive results of the antibacterial test of composite fibrous structures allowed us for production of regular 10” filter cartridges. Their regular filtration test with water containing defined concentration of abiotic particles and bacteria was performed. Results show the removal of particles of diameter from the range of 0,3-5 μm and bacteria with a 99,98% efficiency. Results show reduction of the pressure drop in the loaded composite filters ...

Session: L19 - Depth Filtration III
Day: 13 October 2016
Time: 13:00 - 14:15 h

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