Recovered Energy from Salinity Gradients Utilizing Various Poly(Acrylic Acid)-Based Hydrogels.

Hydrogels can be utilized to extract energy from salinity gradients when river water mixes with seawater. Saline-sensitive hydrogels exhibit a reversible swelling/shrinking process when they are, alternately, exposed to fresh and saline water. We present a comparison of several poly(acrylic acid)-based hydrogels, including poly(acrylic acid) (PAA), poly(acrylic acid--vinylsulfonic acid) (PAA/PVSA), and poly(4-styrenessulfonic acid--maleic acid) interpenetrated in a poly(acrylic acid) network (PAA/PSSA-MA).

Salinity Gradient Energy from Expansion and Contraction of Poly(allylamine hydrochloride) Hydrogels.

Salinity gradients exhibit a great potential for production of renewable energy. Several techniques such as pressure-retarded osmosis and reverse electrodialysis have been employed to extract this energy. Unfortunately, these techniques are restricted by the high costs of membranes and problems with membrane fouling.