Hydrogels for Water Filters: Characterization and Regeneration

Acrylic acid was crosslinked with N,N'-methylenebisacrylamide followed by a reaction with hexamethylenetetramine (HMTA) to form a new hydrogel, Gel (2). Water absorbance rate and retention of Gel (2) were characterized. At the same time, factors affecting absorbance rate such as pH, temperature, and ions concentration were studied. The rate decreased with decreasing pH and increasing ions concentration, whereas increased with raising temperature. The effect of the hydrogel on bacterial (Staphylococcus aureus and Escherichia coli) viability and growth rate was determined. Gel (2) has achieved a 5 log reduction on both E. coli and S. aureus in 2 h while no cells were detected after 3 h in case of S. aureus and 4 h in case of E. coli. Lifetime and regeneration of Gel (2) using both stirred flask and column (a model for a water filter) methods were determined. Identifying the lifetime using columns showed that the gel stays active up to 5 and 7 runs for both E. coli and S. aureus respectively. In addition, it was recycled successfully up to 10 times, using column and stirred flask methods, against both types of bacteria. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1889-1895, 2012