Forward Osmosis as a Pre-Treatment Step for Seawater Dilution and Wastewater Reclamation

Motsa, Machawe M.; Mamba, Bhekie B.

doi:10.5772/intechopen.72289

Cited by 1 publication

(4 citation statements)

References 94 publications

(133 reference statements)

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“…Figure 3 demonstrates the osmotic water flux as a function of the draw solute concentration, with DI water on the feed side, for the Porifera membrane. Our values match those obtained by Motsa and Bamba [ 62 ]. Variations in measured water flux even at similar draw concentrations support the high error of approximately ±20%, similar to those given by [ 40 ].…”

Section: Resultssupporting

confidence: 91%

“…This may be caused partly by the compact character of the support layer and partly by the non-woven fabric layer, which can hinder the transport of the water molecules. This conclusion is in harmony with [ 62 ]. On the one hand, the FO system serves somewhat higher values of water flux at larger draw solute concentration.…”

Section: Resultssupporting

confidence: 91%

“…The water flux data are approximately one-order of magnitude lower than those of the cellulose triacetate membrane from [ 40 ] (see Section 4.4.2 , it discussed later) and the Porifera membrane in PRO mode ( Figure 3 ). This low water flux, despite the NanoH 2 O membrane’s permeability, may be caused by the fabric layer as well as the rather dense support layer hindering water transfer, thereby reducing the effect of osmotic pressure relative to the hydraulic pressure difference ([ 62 ] reached a similar conclusion). The salt fluxes of the NanoH 2 O membrane in both operating modes are shown in Figure 2 b.…”

Section: Resultsmentioning

confidence: 97%

“…Experimentally, two sets of commercially available membranes were investigated, namely, a thin-film nanocomposite membrane (NanoH 2 O), with inorganic nanoparticles incorporated in the selective layer [ 60 ], and the asymmetric Porifera membrane [ 61 , 62 ]. The main objective of these experiments was twofold.…”

Section: Introductionmentioning

confidence: 99%

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The Need for Accurate Osmotic Pressure and Mass Transfer Resistances in Modeling Osmotically Driven Membrane Processes

et al. 2021

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The widely used van ’t Hoff linear relation for predicting the osmotic pressure of NaCl solutions may result in errors in the evaluation of key system parameters, which depend on osmotic pressure, in pressure-retarded osmosis and forward osmosis. In this paper, the linear van ’t Hoff approach is compared to the solutions using OLI Stream Analyzer, which gives the real osmotic pressure values. Various dilutions of NaCl solutions, including the lower solute concentrations typical of river water, are considered. Our results indicate that the disparity in the predicted osmotic pressure of the two considered methods can reach 30%, depending on the solute concentration, while that in the predicted power density can exceed over 50%. New experimental results are obtained for NanoH2O and Porifera membranes, and theoretical equations are also developed. Results show that discrepancies arise when using the van ’t Hoff equation, compared to the OLI method. At higher NaCl concentrations (C > 1.5 M), the deviation between the linear approach and the real values increases gradually, likely indicative of a larger error in van ’t Hoff predictions. The difference in structural parameter values predicted by the two evaluation methods is also significant; it can exceed the typical 50–70% range, depending on the operating conditions. We find that the external mass transfer coefficients should be considered in the evaluation of the structural parameter in order to avoid overestimating its value. Consequently, measured water flux and predicted structural parameter values from our own and literature measurements are recalculated with the OLI software to account for external mass transfer coefficients.

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Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 91%