Hydrogels for water filters: Characterization and regeneration

Abstract

Acrylic acid was crosslinked with N,N 0methylenebisacrylamide 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.

Natural and synthetic polymers for water treatment against dissolved pharmaceuticals

“…Moreover the swelling behavior was identified at different pH values. In addition the swelling behavior in presence of different salts with different valences such as CaCl 2 and FeCl 3 was identified in comparison with NaCl . Water retention of beads have been identified by weighing a fully saturated beads with water (starting with 1 g) at different temperatures (25, 75, and 90°C) at timed intervals; 0.5, 1, 2, 4, 6, and 8 h .…”

Novel hydrogel from functionalized glycerol and microfibrillated cellulose: towards an environmentally-friendly design

“…In this case, it can be focused on hydrogels of modified glycerol. Hydrogels are crosslinked polymers with hydrophilic functional groups that give a high capacity for absorbing water or biological fluids in the polymer matrix (Ahmed 2012;Milosavljevic ´et al 2011;Utech and Boccaccini 2016). There are several areas that hydrogels can be applied: controlled drug release, replacement of soft tissue, coverage for protection and hydration of burns, contact lenses, superabsorbent materials, hygiene products, as a water reservoir in agriculture, among others (Adnadjevic ´and Jovanovic ´2010;Ahmed 2015).…”

Reversible plasmonic biosensors based on aptamers and hydrogels

“…In the design of hydrogels, parameters like polymer chain stiffness, amount of charged groups and crosslinking density are vital to obtain high interaction between hydrogel and water for efficient swelling and larger mesh sizes for the ease of solute and water diffusion. By controlling the diffusion of different sized solutes through the hydrogel matrix, filtration and separation can be performed [86,87]. Hydrogels serving as selective filtration membrane can be prepared with the aid of other robust materials (nylon, polycarbonate and etc) as mechanical support [88].…”