The Effect of Working Temperature on the Performance of Water Desalination Using Forward Osmosis: A CFD Study

Author(s):  
Ahmed M. Alshwairekh ◽  
Umar F. Alqsair ◽  
Anas M. Alwatban ◽  
Justin Caspar ◽  
Alparslan Oztekin

Abstract Computational fluid dynamics simulations for water desalination using forward osmosis were conducted on a flat membrane module. In the simulations, the effect of the porous support layer is assumed negligible. The simulations were performed with two values of flow rate such that the Reynolds number equals 200 and 800 in each channel. The working temperatures of both the feed and the draw solutions were varied from 20°C to 40°C. The feed solution had a concentration of 0.00355 solute mass fraction while the draw concentration was set to 0.0355 solute mass fraction. In all simulations, the laminar model was utilized. The results of the simulations suggest that the osmotic pressure is not the only factor that affects the water flux in forward osmosis when there is a temperature difference between the two sides of the membrane. The solution properties have a significant effect on the separation process. As the solution temperature increases, the viscosity decreases, which in turn increases the water permeation through the membrane. The feed temperature had a more substantial influence on the water flux compared to the draw temperature. Also, the effect of changing the flow rate did not change the results substantially.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yasamin Bide ◽  
Marzieh Arab Fashapoyeh ◽  
Soheila Shokrollahzadeh

AbstractForward osmosis (FO) process has been extensively considered as a potential technology that could minimize the problems of traditional water desalination processes. Finding an appropriate osmotic agent is an important concern in the FO process. For the first time, a nonionic surfactant-based draw solution was introduced using self-assemblies of Tween 80 and choline chloride. The addition of choline chloride to Tween 80 led to micelles formation with an average diameter of 11.03 nm. The 1H NMR spectra exhibited that all groups of Tween 80 were interacted with choline chloride by hydrogen bond and Van der Waals’ force. The influence of adding choline chloride to Tween 80 and the micellization on its osmotic activity was investigated. Despite the less activity of single components, the average water flux of 14.29 L m‒2 h‒1 was obtained using 0.15 M of Tween 80-choline chloride self-assembly as draw solution in the FO process with DI water feed solution. Moreover, various concentrations of NaCl aqueous solutions were examined as feed solution. This report proposed a possible preparation of nonionic surfactant-based draw solutions using choline chloride additive with enhanced osmotic activities that can establish an innovative field of study in water desalination by the FO process.


Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 571 ◽  
Author(s):  
Taehyung Kim ◽  
Changha Ju ◽  
Chanhyuk Park ◽  
Hyo Kang

The thermal-responsive polymers, poly(alkane-1,#-diylbis(tri-n-butylphosphonium) 4-vinylbenzenesulfonate) (PSSBP#, # = 8, 6, and 4), where # is the number of carbon atoms in the central bridge structure of the dicationic phosphonium moiety, were synthesized to examine their potential application as draw solutes in forward osmosis (FO). The polymers exhibited low critical solution temperature (LCST) characteristics in aqueous solutions, which is essential for recovering a draw solute from pure water. The LCSTs of the 20 wt% aqueous solutions of PSSBP8, PSSBP6, and PSSBP4 were confirmed to be approximately 30, 38, and 26 °C, respectively, which is advantageous in terms of energy requirements for the recovering draw solute. When the concentration of the PSSBP4 draw solution was 20 wt%, water flux and reverse solute flux were approximately 1.61 LMH and 0.91 gMH, respectively, in the active layer facing the draw solution (AL-DS) system when the feed solution was distilled water. The PSSBP# thermal-responsive draw solute has considerable potential for use as a next-generation draw solute because of its excellent osmotic performance and efficient recovery. Therefore, this study provides inspiration for novel ideas regarding structural transformations of polymers and their applicability as draw solutes.


2016 ◽  
Vol 6 (4) ◽  
pp. 533-543 ◽  
Author(s):  
W. D. Wang ◽  
M. Esparra ◽  
H. Liu ◽  
Y. F. Xie

This study evaluated the feasibility of forward osmosis (FO) in diluting and reusing the concentrate produced in a reverse osmosis (RO) plant in James City County, VA. Secondary treated wastewater (STW) was used as the feed solution. Findings indicated that pH had slight effects on the water flux of the FO membrane. As the concentration of total dissolved solids (TDS) in the concentrate was diluted from 12.5 to 1.0 g/L or the temperature in the STW decreased from 23 to 10 °C, the membrane flux decreased from 2.2 to 0.59 and 0.81 L/(m2 h), respectively. The FO membrane showed a good performance in the rejection of organic pollutants, with only a small part of the protein-like substances and disinfection byproducts permeating to the diluted concentrate. During an 89-hour continuous operation, water flux decline due to membrane fouling was not observed. Controlling the TDS in the second-stage FO effluent at 1.5 g/L, approximately 8.3% of the pump energy input could be saved. The consumption of groundwater was reduced from 22.7 × 103 to 10.6 × 103 m3/d. FO was proved to be an effective method in both diluting the discharged concentrate and reducing the energy consumption of RO.


2015 ◽  
Vol 15 (10) ◽  
pp. 8279-8284 ◽  
Author(s):  
Hee-Man Yang ◽  
Hye Min Choi ◽  
Sung-Chan Jang ◽  
Myeong Jin Han ◽  
Bum-Kyoung Seo ◽  
...  

Hyperbranched polyglycerol-coated magnetic nanoparticles (SHPG-MNPs) were functionalized with succinate groups to form a draw solute for use in a forward osmosis (FO). After the one-step synthesis of hyperbranched polyglycerol-coated magnetic nanoparticles (HPG-MNPs), the polyglycerol groups on the surfaces of the HPG-MNPs were functionalized with succinic anhydride moieties. The resulting SHPG-MNPs showed no change of size and magnetic property compared with HPGMNPs and displayed excellent dispersibility in water up to the concentration of 400 g/L. SHPG-MNPs solution showed higher osmotic pressure than that of HPG-MNPs solution due to the presence of surface carboxyl groups in SHPG-MNPs and could draw water from a feed solution across an FO membrane without any reverse draw solute leakage during FO process. Moreover, the water flux remained nearly constant over several SHPG-MNP darw solute regeneration cycles applied to the ultrafiltration (UF) process. The SHPG-MNPs demonstrate strong potential for use as a draw solute in FO processes.


2015 ◽  
Vol 4 (2) ◽  
pp. 319-329 ◽  
Author(s):  
Tripti Mishra ◽  
RK Srivastava

The current study aims at the selection of an appropriate draw solute for forward osmosis process. Separation and recovery of the draw solute are the major criteria for the selection of draw solute for forward osmosis process. Therefore in this investigation six inorganic fertilizers draws solute were selected. The selections of inorganic fertilizers as draw solute eliminate the need of removal and recovery of draw solute from the final product. The final product water of forward osmosis process has direct application in agricultural as nutrient rich water for irrigation. These inorganic fertilizers were tested based on their water extraction (water flux) capacity. This experimental water flux was compared with the observed water flux. It was noted that the observed water flux is much higher than the attained experimental water flux. The difference of these two fluxes was used to calculate the performance ratio of each selected fertilizer. Highest performance ratio was shown by low molecular weight compound ammonium nitrate (22.73) and potassium chloride (21.03) at 1 M concentration, whereas diammonium phosphate (DAP) which has highest molecular weight among all the selected fertilizer show the lowest performance ratio (10.02) at 2 M concentration. DOI: http://dx.doi.org/10.3126/ije.v4i2.12660 International Journal of Environment Vol.4(2) 2015: 319-329


2019 ◽  
Vol 1 (1) ◽  
pp. 18-32 ◽  
Author(s):  
Ke Zheng ◽  
Shaoqi Zhou

Abstract In this study, cyanoethyl cellulose (CEC) was used as a membrane material, and polyvinylpyrrolidone (PVP) was used as pore-forming agent to prepare the substrates for the thin-film composite (TFC) forward osmosis (FO) membrane for the first time. The experimental results demonstrate that the properties of the substrates were significantly improved after PVP was added. The scanning electron microscope (SEM) images show that a two-sublayer structure, a fringe-like top sublayer and macrovoids with sponge-like wall bottom sublayer, were formed after the addition of PVP. These improvements contributed to improved membrane performance during FO tests. Meanwhile, after adding PVP, the TFC membranes exhibited good water flux, and excellent specific reverse salt flux. For instance, the TFC-M2 exhibited 9.10/20.67 LMH water flux, 1.35/2.24 gMH reverse salt flux, and 0.15/0.11 g/L specific reverse salt flux in FO/pressure-retarded osmosis mode while using 1 M NaCl as the draw solution and deionized (DI) water as the feed solution.


2015 ◽  
Vol 72 (8) ◽  
pp. 1301-1307 ◽  
Author(s):  
Nguyen Cong Nguyen ◽  
Hau Thi Nguyen ◽  
Shiao-Shing Chen ◽  
Nhat Thien Nguyen ◽  
Chi-Wang Li

Forward osmosis (FO) is an emerging process for dewatering solid–liquid stream which has the potential to be innovative and sustainable. However, the applications have still been hindered by low water flux and membrane fouling when activated sludge is used as the feed solution due to bound water from microbial cells. Hence, a novel strategy was designed to increase sludge thickening and reduce membrane fouling in the FO process under ultrasonic condition. The results from the ultrasound/FO hybrid system showed that the sludge concentration reached up to 20,400 and 28,400 mg/L from initial sludge concentrations of 3000 and 8000 mg/L with frequency of 40 kHz after 22 hours, while the system without ultrasound had to spend 26 hours to achieve the same sludge concentration. This identifies that the presence of ultrasound strongly affected sludge structure as well as sludge thickening of the FO process. Furthermore, the ultrasound/FO hybrid system could achieve NH4+-N removal efficiency of 96%, PO43−-P of 98% and dissolved organic carbon (DOC) of 99%. The overall performance demonstrates that the proposed ultrasound/FO system using seawater as a draw solution is promising for sludge thickening application.


2011 ◽  
Vol 64 (7) ◽  
pp. 1443-1449 ◽  
Author(s):  
Kerusha Lutchmiah ◽  
Emile R. Cornelissen ◽  
Danny J. H. Harmsen ◽  
Jan W. Post ◽  
Keith Lampi ◽  
...  

This research is part of the Sewer Mining project aimed at developing a new technological concept by extracting water from sewage by means of forward osmosis (FO). FO, in combination with a reconcentration system, e.g. reverse osmosis (RO) is used to recover high-quality water. Furthermore, the subsequent concentrated sewage (containing an inherent energy content) can be converted into a renewable energy (RE) source (i.e. biogas). The effectiveness of FO membranes in the recovery of water from sewage has been evaluated. Stable FO water flux values (>4.3 LMH) were obtained with primary effluent (screened, not treated) used as the feed solution. Fouling of the membrane was also induced and further investigated. Accumulated fouling was found to be apparent, but not irreversible. Sewer Mining could lead to a more economical and sustainable treatment of wastewater, facilitating the extraction of water and energy from sewage and changing the way it is perceived: not as waste, but as a resource.


2017 ◽  
Vol 13 (1) ◽  
pp. 94-102
Author(s):  
Ahmed Faiq Al-Alalawy ◽  
Talib Rashid Abbas ◽  
Hadeer Kadhim Mohammed

The present work aims to study forward osmosis process using different kinds of draw solutions and membranes. Three types of draw solutions (sodium chloride, sodium formate, and sodium acetate) were used in forward osmosis process to evaluate their effectiveness with respect to water flux and reverse salt flux. Experiments conducted in a laboratory-scale forward osmosis (FO) unit in cross flow flat sheet membrane cell.  Three types of membranes (Thin film composite (TFC), Cellulose acetate (CA), and Cellulose triacetate (CTA)) were used to determine the water flux under osmotic pressure as a driving force. The effect of temperature, draw solution concentration, feed and draw solution flow rate, and membrane types, were studied with respect to water flux. The results showed an increase in water flux with increasing feed temperature and draw solution concentrations In addition, the flux increased with increasing feed flow rate while the flux was inversely proportional with the draw solution flow rate. The results showed that reverse osmosis membranes (TFC and CA) are not suitable for using in FO process due to the relatively obtained low water flux when compared with the flux obtained by forward osmosis membrane (CTA). NaCl draw solution gave higher water flux than other draw solutions and at the same time, revealed higher reverse salt flux.


2020 ◽  
Vol 981 ◽  
pp. 342-348 ◽  
Author(s):  
Muthia Elma ◽  
Gesit Satriaji Saputro

This work shows the performance of cobalt-silica membranes through water desalination via pervaporation process. The aim of this work is to find out the performance of the cobalt oxide as a templating agent in the silica cobalt membranes for water desalination via pervaporation process. It also aims to investigate the water flux and salt rejection of silica cobalt membranes using artificial saline water. The concentration of cobalt oxide as a template for fabricating cobalt-silica membranes were 5 – 35 wt%. The feed solution applied during pervaporation process were 0.3 – 5 wt% NaCl with operating temperatures of 25, 40 and 60 °C. The silica xerogels were characterized using Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET). From the FTIR result, it is known that the higher the concentration of cobalt in the membrane, the more silanol and siloxane groups. Based on BET analysis, Si-Co 35 wt% membrane has largest pore volume (0.129387 cm3g-1). In addition, the highest value of water flux (7.2660 kg.m-2.h-1) and salt rejection (100%) is achieved by Si-Co 5% membrane in 0.3% NaCl feed at 60 °C. The value of water flux decreases and the value of salt rejection increases with increasing feed concentration.


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