Forward osmosis membrane process and its mass transport mechanisms

Hybrid membrane system for desalination and wastewater treatment : Integrating forward osmosis and low pressure reverse osmosis

Comparison of flux behavior and synthetic organic compound removal by forward osmosis and reverse osmosis membranes

Enabling the use of seawater for hydrogen gas production in water electrolyzers

11 - Reverse osmosis and forward osmosis in integrated systems

정삼투막 공정을 이용한 소금 및 수크로오스 용액의 처리에서 농도분극현상이 투과유속에 미치는 영향을 검토하였다. 정삼투 공정에서 투과 유속감소는 주로 분리막 표면에서의 농도분극에 기인하며, 분리막의 지지층에서 발생한 내부농도분극에 의한 투과유속 감속이 활성층에서 발생한 외부농도분극에 의한 것 보다 더 컸다. 순수 투과유속은 삼투압이 증가함에 따라 비선형적으로 증가하였다. NaCl 용액의 활성층 배향(DS-AL)에서의 수 투과계수는 <TEX>$1.8081{\times}10^{-7}m/s{\cdot}atm$</TEX>, 지지층 배향(DS-SL)의 경우 <TEX>$1.0957{\times}10^{-7}m/s{\cdot}atm$</TEX> 이었으며, 이로부터 산출된 막저항은 각각 <TEX>$5.5306{\times}10^6s{\cdot}atm/m$</TEX>, <TEX>$9.1266{\times}10^6s{\cdot}atm/m$</TEX> 이었다. 수크로오스 용액의 경우 활성층 배향(DS-AL)에서의 투과유속이 지지층 배향(DS-SAL)에서의 투과유속보다 1.33~1.90배 크게 나타났다. 삼투압(<TEX>${\pi}$</TEX>)에 대한 투과유속(J)의 변화는 전자의 경우 <TEX>$J=-0.0177+0.4506{\pi}-0.0032{\pi}^2$</TEX>, 후자의 경우 <TEX>$J=0.0948+0.3292{\pi}-0.0037{\pi}^2$</TEX>으로 표현될 수 있었다. This study examined the effect of concentration polarization on permeate flux in forward osmosis (FO) membrane process for saline and sucrose solution. The reduction in permeate flux during the FO membrane process is largely due to the formation of concentration polarization on membrane surfaces. The flux reduction due to internal concentration polarization formed on the porous support layer was larger than that due to the external concentration polarization on the active membrane surface. Water permeate flux through the FO membrane increased nonlinearly with the increase in osmotic pressure. The water permeability coefficient was <TEX>$1.8081{\times}10^{-7}m/s{\cdot}atm$</TEX> for draw solution on active layer (DS-AL) mode and <TEX>$1.0957{\times}10^{-7}m/s{\cdot}atm$</TEX> for draw solution on support layer (DS-SL) mode in NaCl solution system. The corresponding membrane resistance was <TEX>$5.5306{\times}10^6$</TEX> and <TEX>$9.1266{\times}10^6s{\cdot}atm/m$</TEX>, respectively. With respect to the sucrose solution, the permeate flux for DS-AL mode was 1.33~1.90 times higher than that for DS-SL mode. The corresponding variation in the permeation flux (J) due to osmotic pressure (<TEX>${\pi}$</TEX>) would be expressed as <TEX>$J=-0.0177+0.4506{\pi}-0.0032{\pi}^2$</TEX> for the forward and <TEX>$J=0.0948+0.3292{\pi}-0.0037{\pi}^2$</TEX> for the latter.

Forward osmosis research trends in desalination and wastewater treatment: A review of research trends over the past decade

Fouling distribution in forward osmosis membrane process

This review addressed the fundamental principles, advantages and challenges of forward osmosis (FO) membrane processes. FO is receiving more and more research attractions because it can concurrently produce clean water with low energy input and generate hydraulic energy (pressure retarded osmosis). FO typically requires zero or low hydraulic driving pressure, therefore the fouling potential of the FO membranes is much lower than conventional pressure-driven membrane processes. However, concentration polarization (CP), especially the internal CP significantly reduces the effective osmotic pressure across the FO membrane, the major driving force for the filtration process. As a result, innovative FO membrane materials like electrospun nanofibers have been explored to make low tortuosity, high porosity, and thin FO membranes with a high rejection rate of solutes and low or zero diffusion of the draw solute. The orientation of the FO membrane with active layer-facing-feed solution has less fouling than active layer-facing-draw solution. In addition, to further decrease the fouling potential, a hydrophilic and more negatively charged membrane is preferred when filtration of natural organic matter (NOM) or alginate in the absence of multivalent cations.

Machine learning models for predicting the rejection of organic pollutants by forward osmosis and reverse osmosis membranes and unveiling the rejection mechanisms

Toward a combined system of forward osmosis and reverse osmosis for seawater desalination

Comparison between Forward Osmosis-Reverse Osmosis and Reverse Osmosis processes for seawater desalination

In order to ensure long-term sustainability of the reservoir, the gas industry in Qatar is faced with the challenge of reducing the volume of produced and process water (PPW) sent to disposal wells by 50% [1-3]. Recently, Qatargas initiated a project to recycle process water and thus, reduce disposal volumes using commercial advanced water treatment technologies [4]. One emerging technology, “osmotic concentration” (OC) has been identified that offers a low-energy alternative to conventional thermal or membrane volume reduction methods. Osmotic concentration is a membrane filtration process that mimics first step in a forward osmosis (FO) system. It requires a high salinity draw solution (DS) which passes on one side of a semi-permeable FO membrane while the feed passes on the other side. Water from the feed is drawn through the membrane, via natural osmosis, reducing the feed volume and increasing the volume of the draw solution. This paper summarizes the results of bench-scale volume reduction tests wit...

Concentration of ammonium diuranate effluent by reverse osmosis and forward osmosis membrane processes

Desalination is probably the only means for fresh water supply to countries in decertified climate. The majority of GCC counties rely on desalinated water for fresh water supply to major cities. Over 70% of the desalinated water in the GCC comes from thermal desalination plants including Multi Stage Flash (MSF) and Multi Effect Distillation (MED). The new trend in the desalination plant in the GCC is 30% Reverse Osmosis (RO) and 70% thermal. However, these percentages vary from one to another country depending on feed water quality and expertise. For example, Oman Sea has lower salinity than the Gulf water and hence Oman uses more RO for desalination than MED and MSF. This decision is also driven by economy as RO process less energy intensive and hence the produced water is less expensive as compared to thermal plants. On the contrary, Qatar and Kuwait use more MSF followed by MED due to the high salinity and low quality feed water. This is also because trials of RO in both Qatar and Kuwait were not successful because of the problems of membrane fouling and restrict pre-treatment requirements due to the quality of the water intake.The advantages of RO over thermal technologies are well known in terms of lower energy consumption and the cost of produced water; but are not yet taken advantage of in the GCC zone. One of the reasons is blamed on high feed water salinity and bad water quality; other reasons such as lack of experience, red tides and reliability are contributed to the dominance of thermal plants. However, field experience showed that good pretreatment and optimized RO design may overcome the problems of high feed salinity and bad water quality. Several RO plants, such as Fujairah in UAE, are good examples of a working RO technology in the harsh water environment. Good RO design includes design and optimization of both pretreatment and post-treatment. Field experience showed that most of RO plants failure was due to inefficient pretreatment which resulted in providing low quality water to the RO membrane that caused fouling. Fouling, including biological and scaling, can be handled once an efficient pretreatment process is available. Recent advances in pre-treatment techniques include the combination of Forward Osmosis (FO) with RO among other methods. Recent studies by the authors including commercial implantations have shown that the combination of FO with RO addresses the most technical challenge of RO process and that is fouling, which results in lower energy consumption and less chemical additives. Experience showed fouling in FO process in reversible, i.e. can be removed by backlashing while fouling in conventional RO process is irreversible.In this study, the feasibility of integrating FO with RO process for the desalting of the Gulf water in Qatar is presented. The results are expressed in terms of specific energy consumption, process recovery, produced water quality, chemical additives and overall process cost.The implementation of RO for desalination is not only reducing the cost of desalination but also the environmental impact. More R&amp;D should be done to provide useful data about RO application and suitability for the Gulf water. The R&amp;D should be focused on laboratory to market development of RO technology using rigorous lab scale and pilot plant testing program.

Two-stage FO-BWRO/NF treatment of saline waters