A Novel Approach for the Desalination of Seawater by Means of Reusable Poly(acrylic acid) Hydrogels and Mechanical Force

Höpfner, Johannes; Klein, Christine A.; Wilhelm, Manfred

doi:10.1002/marc.201000058

Cited by 61 publications

(55 citation statements)

References 13 publications

(14 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of nonfreezable water can be estimated by following a standard procedure described by Mansor and Malcolm. 40 The amount of unbound water was calculated with the assumption that the heat of fusion of unbound water in the hydrogel was the same as that for ice applying the following equation (10) where W c , W b , W f , and W fb are the equilibrium water content (%) (EWC), the amount of nonfreezable bound water (%), the amount of freezable free water (%), and the amount of freezable bound water (%), respectively, whereas Q endo is defined as the heat of fusion of freezable water (freezable free water and freezable bound water) within the hydrogels and Q pure is the heat of fusion of ice (340.1 J/g). The influence of the cross-linking degree of gel 4 on nonfreezable water content was investigated as shown in Figure 8b.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Design of Thermally Responsive Polymeric Hydrogels for Brackish Water Desalination: Effect of Architecture on Swelling, Deswelling, and Salt Rejection

Ali

Gebert

Hennecke

et al. 2015

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

In this work, we explore the ability of utilizing hydrogels synthesized from a temperature-sensitive polymer and a polyelectrolyte to desalinate salt water by means of reversible thermally induced absorption and desorption. Thus, the influence of the macromolecular architecture on the swelling/deswelling behavior for such hydrogels was investigated by tailor-made network structures. To this end, a series of chemically cross-linked polymeric hydrogels were synthesized via free radical-initiated copolymerization of sodium acrylate (SA) with the thermoresponsive comonomer N-isopropylacrylamide (NIPAAm) by realizing different structural types. In particular, two different polyNIPAAm macromonomers, either with one acrylate function at the chain end or with additional acrylate functions as side groups were synthesized by controlled polymerization and subsequent polymer-analogous reaction and then used as building blocks. The rheological behaviors of hydrogels and their estimated mesh sizes are discussed. The performance of the hydrogels in terms of swelling and deswelling in both deionized water (DI) and brackish water (2 g/L NaCl) was measured as a function of cross-linking degree and particle size. The salt content could be reduced by 23% in one cycle by using the best performing material.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Design of Thermally Responsive Polymeric Hydrogels for Brackish Water Desalination: Effect of Architecture on Swelling, Deswelling, and Salt Rejection

Ali

Gebert

Hennecke

et al. 2015

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

show abstract

“…As a result, water with a lower salt content is obtained. This new process opened up the possibility to desalinate saltwater via polymeric hydrogels …”

Section: Introductionmentioning

confidence: 99%

Osmotic Engine: Translating Osmotic Pressure into Macroscopic Mechanical Force via Poly(Acrylic Acid) Based Hydrogels

et al. 2017

Self Cite

View full text Add to dashboard Cite

Poly(acrylic acid)‐based hydrogels can swell up to 100–1000 times their own weight in desalinated water due to osmotic forces. As the swelling is about a factor of 2–12 lower in seawater‐like saline solutions (4.3 wt% NaCl) than in deionized water, cyclic swelling, and shrinking can potentially be used to move a piston in an osmotic motor. Consequently, chemical energy is translated into mechanical energy. This conversion is driven by differences in chemical potential and by changes in entropy. This is special, as most thermodynamic engines rely instead on the conversion of heat into mechanical energy. To optimize the efficiency of this process, the degree of neutralization, the degree of crosslinking, and the particle size of the hydrogels are varied. Additionally, different osmotic engine prototypes are constructed. The maximum mean power of 0.23 W kg−1 dry hydrogel is found by using an external load of 6 kPa, a polymer with 1.7 mol% crosslinking, a degree of neutralization of 10 mol%, and a particle size of 370–670 µm. As this is achieved only in the first round of optimization, higher values of the maximum power average over one cycle seem realistic.

show abstract

“…In 2010, Höpfner et al presented a new technique for the desalination of salt water using charged polylectrolyte hydrogels as both the drawing and separation agent simultaneously . A similar approach was also introduced by Ali et al who used thermally responsive polyelectrolyte hydrogels based on copolymers made of N ‐isopropylacrylamide and acrylic acid .…”

Section: Introductionmentioning

confidence: 99%

“…The drawing agents usually consist of thermally removable salts, but more recent examples use hydrogels, which are afterward deswollen by pressure or temperature . Yet, in contrast to the technique employed in the here presented work, these examples still use a semipermeable membrane for the separation instead of the hydrogel itself …”

Section: Introductionmentioning

confidence: 99%

Energy Consumption for the Desalination of Salt Water Using Polyelectrolyte Hydrogels as the Separation Agent

Arens

Albrecht

Höpfner

et al. 2017

Macro Chemistry & Physics

Self Cite

View full text Add to dashboard Cite

The energy consumption for a novel desalination approach using charged hydrogels under externally applied pressure is experimentally measured and calculated. The salt separation is based on a partial rejection of mobile salt ions caused by the fixed charges inside the polyelectrolyte network. Self‐synthesized and commercial poly(acrylic acid) hydrogels are used to study the desalination performance in reference to sodium chloride solutions within the concentration range of 0.1–35 g L−1. The influence of various synthetic parameters, such as the degree of crosslinking (DC) and the size and shape of the particles, is investigated. Furthermore, the effect of process parameters including the amount of the feed solution, the applied pressure profile, and the swelling time of the hydrogel is discussed. The best energy estimation found so far, is 8.9 kWh m−3 fresh water if a poly(acrylic acid) with a DC of 5 mol% is used in an infinite large salt bath.

show abstract

A Novel Approach for the Desalination of Seawater by Means of Reusable Poly(acrylic acid) Hydrogels and Mechanical Force

Cited by 61 publications

References 13 publications

Design of Thermally Responsive Polymeric Hydrogels for Brackish Water Desalination: Effect of Architecture on Swelling, Deswelling, and Salt Rejection

Design of Thermally Responsive Polymeric Hydrogels for Brackish Water Desalination: Effect of Architecture on Swelling, Deswelling, and Salt Rejection

Osmotic Engine: Translating Osmotic Pressure into Macroscopic Mechanical Force via Poly(Acrylic Acid) Based Hydrogels

Energy Consumption for the Desalination of Salt Water Using Polyelectrolyte Hydrogels as the Separation Agent

Contact Info

Product

Resources

About