Assessing biomimetic aquaporin membrane for forward osmosis desalination process: A dataset

This paper presents the performance of aquaporin forward osmosis membrane using chemical fertilizers as a draw solution. The comprehensive evaluation conducted for five conventional fertilizers ((CO (NH2)2, KCl, CaCl2, (NH4)2SO4) and (NH4)2HPO4) as draw solutions. The diluted fertilizer can be used directly for farming as fertigation. In this process, DSs do not need to be recovered and it is a single step desalination process. The data include the characterization of the intrinsic properties of the membrane samples and their performance under FO and PRO modes of operations. In addition, the data for various draw solution concentration under feed solution with deferent total dissolved solids (TDS) were evaluated. For example, a water flux of 17.5 L m− 2 h− 1 and 23.92 g m−2 h−1 reverse solute flux (RSF) was achieved under the FO operation mode for 3 M KCl.


Data
presents the SEM images for the top surface rejection layer and non-woven backing fabric support for Aquaporin FO membrane. The Biomimetic FO membrane top surface (rejection layer) which is formed by AQPs proteins is similar to conventional thin film composite membrane polyamide layer in terms of topology. Table 1. Presents the AQPs membrane characterization. Figs. 2 and 3 present the membrane performance in terms of water flux in the FO mode with five different fertilizers as DS different using 10 gr/ L and 20 gr/L NaCl as FS, respectively. The performance was in the following order: KCl>(NH 4 ) 2SO 4 >CaCl 2 >(NH 4 )2HPO 4 >Urea. Fig. 4 also shows the amount of wasting draw solute through phenomenon called reverse solute flux (RSF). The RSF plays a central role in the valuation of the FO process in terms of economic measure and membrane fouling tendency. Figs. 5e9 present the performance of each specific DS with five different concentration of feed solution (0e5e10e20e35 g/L NaCl) in terms of water flux in FO operation mode.
Finally, Fig. 10 shows the membrane performance in FO and PRO modes using DI water as FS at different Molar concentration for 2 selected fertilizers, KCl and (NH4) 2 SO 4 . In the PRO mode, the net gain water flux was more compared to the FO mode. This indicates the effect of ICP in the PRO mode is less than FO mode of operation. The raw data presented in the supplementary file as well.

Feed and draw solutions preparation
(NH 2 ) 2 CO, KCl, CaCl 2 , (NH 4 ) 2 SO 4 , (NH 4 ) 2 HPO 4 were used as draw solutions provided by (SAMCHUN, Korea). 0.5, 1, 2, and 3 M molar concentration levels were prepared. DI water and NaCl (5-10-20-35 g/L) were prepared as a feed solution (FS). The raw data files are provided in the supplementary file. All other data is within this article.
Value of the data FO process requires much lower energy than the existing desalination technologies. Energy requirement is even lower when the diluted draw solution (fertilizers) can be used directly for farm irrigation. This data provides valuable information and gives more insights on the newly commercialized Aquaporin FO membrane.
The key parameters in utilizing fertilizer as a draw solution applying biomimetic FO membrane were explored.

Measurement of intrinsic properties of the membrane
Intrinsic properties of the Biomimetic-FO membrane were determined by RO testing mode by utilizing the FO membrane cell and applying hydraulic pressure (0e5 bar). Water permeability (A value) was calculated based on the following equation: Water permeability was obtained by placing DI water in the FS container and adjusting hydraulic pressure of 5.0 bar. D Va is the acquired permeate water over a specific time, DP is the applied hydraulic pressure difference and Am and Dta is the membrane area.  NaCl rejection property of the Biomimetic-FO membrane was calculated by the following equation.
where C f and C p are the amount of NaCl concentrations for the feed and permeate container [1,2]. The salt permeability coefficient (B) was calculated by the following equation: where A is water permeability, R is the salt rejection, Dp is the applied pressure and Dp is the osmotic pressure difference for the Aquaporin FO membrane [3e6].

Substrate characterization
The membrane morphologies were assessed using (FE-SEM, MIRA3-LMU model, Czech Republic) a high-resolution Schottky Field Emission Scanning Electron Microscope.
Membrane porosity (ε) was calculated by weighing the wet mass (W 1 ) and the dry mass (W 2 ) of membrane samples based on the following equation:  where ri is the density of the used wetting solvent, and rm is the density of the membrane sample. The thickness of the membranes was measured by a digital micrometer (293-330 Mitutoyo, Japan).

Membrane tests under FO and PRO processes
Performance tests under the FO and PRO processes were assessed in the designed FO cell presented in Fig. 11 provides a useful area of 6.2 cm 2 with 2 cm in width, 3.1 cm in length and 0.3 cm in depth on both sides. The reverse solute flux (RSF) was assessed by observing the electrical conductivity (EC)  applying a multimeter (Lutron-CD4303, Germany) where deionized water is used as feed water [7,8] (see Fig. 12).

Application for fertigation
The desalinated water via FO process using fertilizer as a draw solution can be used directly for farming as fertigation [9,10]. In this process, draw solutions do not need recovery and directly will be used for farming [11,12]. Thus that is a single-stand desalination process [10,11].