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Poly (aspartic acid sodium salt) (PAspNa) was evaluated for its potential as a novel draw solute in forward osmosis (FO). The inherent advantages of PAspNa, such as good water solubility, high osmotic pressure, and nontoxicity, were first examined through a series of physicochemical analyses and atomic-scale molecular dynamics simulations. Then, lab-scale FO tests were performed to evaluate its suitability in practical processes. Compared to other conventional inorganic solutes, PAspNa showed comparable water flux but significantly lower reverse solute flux, demonstrating its suitability as a draw solute. Moreover, fouling experiments using synthetic wastewater as a feed solution demonstrated that PAspNa reversely flowed to the feed side reduced inorganic scaling on the membrane active layer. The recyclability of PAspNa was studied using both nanofiltration (NF) and membrane distillation (MD) processes, and the results exhibited its ease of recovery. This research reported the feasibility and applicability of FO-NF or FO-MD processes using PAspNa for wastewater reclamation and brackish water desalination. [ABSTRACT FROM AUTHOR]

Theuse of forward osmosis (FO) process for seawater desalinationhas attracted tremendous interest in recent years. Besides the manufactureof suitable membranes, the major technical challenge in the efficientdeployment of the FO technology lies in the development of a suitable“draw solute”. Owing to its inherent advantages, poly(asparticacid) has arisen to be an attractive candidate for this purpose. However,an investigation of its molecular level properties has not been studiedin detail. In this paper, the dynamics of poly(aspartic acid) andits sodium salt in the dilute concentration regime have been reported.The quantification of the polymer conformational properties, its solvationbehavior, and the counterion dynamics are studied. The neutral polymershows a preferentially coiled structure whereas the fully ionizedpolymer has an extended structure. Upon comparing with poly(acrylicacid) polymer, another polymer which has been used as a draw solute,poly(aspartic acid) forms more number of hydrogen bonds as well asfewer ion pairs. [ABSTRACT FROM AUTHOR]