Impacts of Climate Change on Seawater Temperature and Total Dissolved Solids: Challenges and Sustainable Solutions for Reverse Osmosis Desalination in the Arabian Gulf Region

This article examines the influence of seawater temperature and total dissolved solids (TDS) on reverse osmosis (RO) desalination in the Arabian Gulf region, with a focus on the impact of climate change. The study highlights the changes in seawater temperature and TDS levels over the years and discusses their effects on the efficiency and productivity of RO desalination plants. It emphasizes the importance of monitoring TDS levels and controlling seawater temperature to optimize water production. The article also suggests various solutions, including intensive pre-treatment, development of high-performance membranes, exploration of alternative water sources, and regulation of discharges into the Gulf, to ensure sustainable water supply in the face of rising TDS levels and seawater temperature. Further research and comprehensive monitoring are recommended to understand the implications of these findings and develop effective strategies for the management of marine resources in the Arabian Gulf.

Substrate matters:The influences of substrate layers on the performances of thin-film composite reverse osmosis membranes

Thin-film composite(TFC) reverse osmosis(RO) membranes are playing the dominating role in desalination.Tremendous efforts have been put in the studies on the polyamide selective layers. However, the effect of the substrate layers is far less concerned. In this review, we summarize the works that consider the impacts of the substrates, including pore sizes, surface hydrophilicity, on the processes of interfacial polymerization and consequently on the morphologies of the active layers and on final RO performances of the composite membranes. All the works indicate that the pore sizes and surface hydrophilicity of the substrate evidently influence the RO performances of the composite membranes. Unfortunately, we find that the observations and understandings on the substrate effect are frequently varied from case to case because of the lack of substrates with uniform pores and surface chemistries. We suggest using track-etched membranes or anodized alumina membranes having relatively uniform pores and functionalizable pore walls as model substrates to elucidate the substrate effect.Moreover, we argue that homoporous membranes derived from block copolymers have the potential to be used as substrates for the large-scale production of high-performances TFC RO membranes.

Investigation on removing recalcitrant toxic organic polluters in coking wastewater by forward osmosis

Investigation was made on the efficiency of two commercial membranes in removing via forward osmosis(FO)the low molecular weight organic compounds typical of coking wastewater. The membranes were supplied by Poten and HTI companies. The organics in the simulated coking water were indole and pyrridine. Under FO mode, the rejection to the organics by Poten membrane was around 50%, whereas that for HTI membrane was obviously higher, ranging from 65% to 74%. The response of the two membranes in terms of Water flux and reverse salt flux(RSF) towards changing feed/draw solution(DS) flow rates in FO mode showed similar tendency,but different degree. Generally, the flux in FO using HTI membranes was lower. For HTI membrane, FO operated with pressure retarded osmosis(PRO) mode was also performed and the overall rejection of the organics was slightly lower than that in FO mode. In the long term FO test within 15 days, both Poten and HTI membranes displayed flux reduction and rejection enhancement. But the variation with Poten membrane was much more obvious. Discussion was carried out about the reasons and the mechanisms behind the FO performance difference between two membranes and the variation in flux and rejection with operation conditions. Characterizations by SEM, FTIR, AFM, XRD and XPS were tried to support the proposed explanations.

Study of reverse osmosis membranes fouling by inorganic salts and colloidal particles during seawater desalination

Fouling phenomenon is considered among the major reasons that cause significant increase of operating cost of desalination plants equipped with reverse osmosis(RO)membranes.This phenomenon is studied in the present work in the case of RO polyamide aromatic membranes using model seawater containing inorganic salts and colloidal compounds.Different solubility conditions of CaCO3 and CaSO4 were applied to study RO performances with and without colloid presence.During experiments,the membrane permeate fluxes were continuously monitored.Moreover,studies of chemical composition,structure,and morphology of the materials deposited on the membrane surface were conducted using energy dispersive microanalysis(EDS)X-ray diffraction and scanning electronic microscopy(SEM).Results show that in conditions of calcium carbonate oversaturation there is a reduction in the permeate flow of 11.2%due to fouling of the membrane by the precipitation of this compound.While in the same conditions of calcium sulphate oversaturation the reduction of the flow is 5%,so we can conclude that in conditions of oversaturation of both salts,calcium carbonate produces a greater fouling of the membrane that in its view causes greater decrease in the flow of permeate.All this based on the results of the test with both salts in oversaturated conditions.Resulting in the formation of calcite and gypsum crystals onto the membranes as XRD analyses stated.Additional presence of colloidal silica in those conditions intensifies strongly the fouling,leading until to 24.1%of permeate flux decrease.

Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater

Tanneries reusing wastewater by combination of conventional and advanced Reverse Osmosis (RO) treatment technologies were assessed for technical and economic viabilities. Conventional treatment methods such as neutralization, clari-flocculation and biological processes are followed to clean the effluents before feeding to RO membrane modules. The characteristics of untreated composite effluents such as pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), and total chromium were in the range of 4.00-4.60, 680-3600 mg/L, 1698-7546 mg/L, 980-1480 mg/L, 4200-14500 mg/L, and 26.4-190 mg/L, respectively. Inorganic ions like Ca2+, Na+, Cl– and SO42– were found more in the wastewaters. Conventional treatments significantly removed the organic pollutants however failed to remove dissolved inorganic salts. Membrane technology removed the salts as well as remaining organic pollutants and the product water is reused in the process. The studied tanneries (5 numbers) have achieved 93-98%, 92-99% and 91-96% removal of TDS, sodium and chloride, respectively. Seventy to eighty five percentage of wastewater was recovered and recycled in the industrial processes. The rejects are subject to either solar evaporation system or Multiple Effect Evaporation (MEE) technology. The resulting salts are collected in polythene bags and disposed into scientifically managed secured land fill (SLF) site. The cost of wastewater treatment for operation and maintenances of RO including the pre-treatments (conventional methods) is INR 100-110 m-3.

Recent advances in nanofiltration,reverse osmosis membranes and their applications in biomedical separation field

In the face of human society's great requirements for health industry,and the much stricter safety and quality standards in the biomedical industry,the demand for advanced membrane separation technologies continues to rapidly grow in the world.Nanofiltration(NF)and reverse osmosis(RO)as the highefficient,low energy consumption,and environmental friendly membrane separation techniques,show great promise in the application of biomedical separation field.The chemical compositions,microstructures and surface properties of NF/RO membranes determine the separation accuracy,efficiency and operation cost in their applications.Accordingly,recent studies have focused on tuning the structures and tailoring the performance of NF/RO membranes via the design and synthesis of various advanced membrane materials,and exploring universal and convenient membrane preparation strategies,with the objective of promoting the better and faster development of NF/RO membrane separation technology in the biomedical separation field.This paper reviews the recent studies on the NF/RO membranes constructed with various materials,including the polymeric materials,different dimensional inorganic/organic nanomaterials,porous polymeric materials and metal coordination polymers,etc.Moreover,the influence of membrane chemical compositions,interior microstructures,and surface characteristics on the separation performance of NF/RO membranes,are comprehensively discussed.Subsequently,the applications of NF/RO membranes in biomedical separation field are systematically reported.Finally,the perspective for future challenges of NF/RO membrane separation techniques in this field is discussed.

An agent-based simulation with NetLogo platform to evaluate forward osmosis process(PRO Mode)

Forward osmosis(FO), as an emerging technology, is influenced by different factors such as operating conditions,module characteristics, and membrane properties. The general aim of this study was to develop a suitable(flexible,comprehensive, and convenient to use) computational tool which is able to simulate osmosis through an asymmetric membrane oriented in pressure retarded osmosis(PRO) mode in a wide variety of scenarios. For this purpose, an agent-based model was created in NetLogo platform, which is an easy-to-use application environment with graphical visualization abilities and well suited for modeling a complex system evolving over time. The simulation results were validated with empirical data obtained from literature and a great agreement was observed. The effect of various parameters on process performance was investigated in terms of temperature,cross-flow velocity, length of the module, pure water permeability coefficient, and structural parameter of the membrane. Results demonstrated that the increase in all parameters, except structural parameter of the membrane and the length of module led to the increase of average water flux. Moreover, nine different draw solutes were selected in order to assess the influence of net bulk osmotic pressure difference between the draw solution(DS) and feed solution(FS)(known as the driving force of FO process) on water flux. Based on the findings of this paper, the performance of FO process(PRO mode) can be efficiently evaluated using the NetL ogo platform.

A Pilot-scale Study on Coal Gasification Wastewater Reclamation Using Pretreatment Alternatives Combined with Ultrafiltration and Reverse Osmosis

Aims to investigate the performance of the pilot-scale reclamation plant for coal gasification wastewater( CGW) using ultrafiltration and reverse osmosis with appropriate pretreatment alternatives,different pre-treatment alternatives- coagulation,adsorption,and ozonation methods were employed to treat the secondary effluent of coal gasification wastewater( SECGW) in a pilot-scale pressurized membrane system. The performance was compared to choose the most suitable pre-treatment alternative for the SECGW reclamation.Ozone reaction achieved highest COD removal efficiency( 79.6%- 91.0%),resulting in the stable normalized parameters of the subsequent ultrafiltration and reverse osmoses. In contrast,the coagulation and adsorption processes achieved only 32. 8%- 45. 7% and 53. 1%- 64. 6% decreases in COD,respectively. The residual organic pollutants in the reverse osmosis feed water led to an increase in normalized pressure drop and a decrease in normalized permeability( or membrane transference coefficient). The hydrophobic fraction was the main constituent( approx. 70% of DOC) in pretreated SECGW, and the hydrophobic-neutral fraction contributed mostly to the UV absorbance( 53%). Fluorescence excitation emission matrices revealed that ozonation removed most of the hydrophobic and aromatic proteins such as tyrosine and tryptophan which dominated in raw wastewater. The recalcitrant compounds such as phenolic compounds, heterocyclic compounds,especially long-chain hydrocarbons,which were easily attached to the membrane surface and contributed to organic fouling,could be oxidized and mineralized by ozone. Among the three pretreatments,ozonation showed highest removal efficiencies of hydrophobic and aromatic proteins,therefore resulting in highest normalized permeability.

Research Progress of Brackish Water Desalination by Reverse Osmosis

Brackish water (BW) desalination is a primary path to relieve the shortage of water. As one of the BW desalination methods, reverse osmosis (RO) technology has advantage for both technology and process procedure. The expounding of this research studied or reviewed recent years, reverse osmosis membrane, energy recovery, new energy and application technology in BW desalination of RO at home and abroad. Wind power and solar energy can be combined with energy recovery device for RO. The research also explains that BW desalination by RO is practical and feasible in some areas in China.

Performance of Nanofiltration (NF) and Low Pressure Reverse Osmosis (LPRO) Membranes in the Removal of Fluorine and Salinity from Brackish Drinking Water

Certain areas in Senegal have a serious problem of high fluoride and salinity in underground water because of soil properties. This water currently used for drink has a bad taste on consumption and caused diseases like dental fluorosis and skeletal fluorosis. A membrane filtration plant constructed by Pall Corporation was improved through nanofiltration (NF) and Low Pressure Reverse Osmosis (LPRO). Both NF and LPRO membranes were shown applicable for salinity and fluoride ions removal from brackish and high fluorinated drinking water in a remote community. The NF membrane has given a fluorine retention rate varying between 63.3% and 71% while the LPRO membrane allow to reach 97 to 98.9% for fluorine rejection. Highest salinity rejection rates expressed through conductivity measurements are around 46% and 97% for respectively NF and LPRO.

A Combined Forward Osmosis and Membrane Distillation System for Sidestream Treatment

Separate treatment of high-nutrient sidestream is an efficient and cost effective way to decrease the loading on the main plant, resulting in lower effluent nutrient concentration. This study investigated the use of a combined forward osmosis-membrane distillation (FO-MD) system for the removal of nitrogen present in high concentration in sidestream from anaerobic digestion process. The combined system was able to achieve almost 100% rejection of solids and acetic acid, and more than 98% rejection of NH3-N from the sidestream. The high rejection of NH3-N was mainly achieved by the FO process. The solids in the feed solution contributed to fouling problem in both FO and MD, resulting in significant decline in flux. However, 76% or higher flux recovery was achieved for FO membrane by cleaning with tap water. We observed that flux recovery was due to removal of solids from the membrane surface by the cleaning process. FO membrane also demonstrated excellent performance for continuous operation when cleaned for 15 min in every 24 h interval. Overall, the combined FO-MD system was found to be an effective solution for treatment of nutrient rich sidestream.

STUDIES ON REVERSE OSMOSIS SEPARATION OF AQUEOUS ORGANIC SOLUTIONS BY PAA/PSF COMPOSITE MEMBRANE

The reverse osmosis (RO) separation of aqueous organic solutions, such as alcohols, amines, aldehydes, acids, ketones, and esters etc., by PAA (polyacrylic acid)/PSF (polysulfone) composite membrane has been studied. It was found that the separation results for aliphatic alcohols, amines and aldehydes are satisfactory, the solute rejection (R-a) and the volume fluxes of solutions (J(V)) for 1000 ppm ethanol, ethylamine and ethyl aldehyde are 66.2%, 61.0%, 84.0% and 0.90 x 10(-6), 0.35 x 10(-6), 0.40 X 10(-6) m(3)/m(2) . s, respectively, at 5.0 MPa and 30 degrees C. R-a increased with increasing molecular weights of alcohols, amines and aldehydes, and the R-a for n-amyl alcohol, n-butylamine and n-butyl aldehyde reached 94.3%, 88.6% and 96.0%, respectively. Satisfactory separation results (R-a > 70%) for ketones, esters, phenols and polyols have been obtained with the PAA/PSF composite membrane. The effect of operating pressure on the properties of reverse osmosis has also been investigated. Analysis of experimental data with Spiegler-Kedem's transport model has been carried out and the membrane constants such as reflection coefficient sigma, solute and hydraulic permeabilities omega and L-p for several organic solutes have been obtained.

Performance of Nanofiltration and Reverse Osmosis Membranes in Metal Effluent Treatment

不同 nanofiltration (NF ) 和反渗透(RO ) 的表演膜在对待有毒的金属自河从被学习冶金工业。包括废水流动，盐拒绝和离子拒绝对操作压力的过程的特征和过滤行为被评估。当时， RO 膜的废水流动与用传质模型的理论计算相比，并且好一致性被观察。它被发现地席超过95%金属离子和低化学需氧量(货到付款) 10 mg-L 珍视在的高拒绝率渗入能用 RO 复合膜被完成，当盐的 NF 拒绝能直到78.9%，在permeate 的货到付款价值是 35 mg ·L ~时(-1)。结果证明由 NF 和 RO 脱盐的产品水满足了州的利用资格，而是 NF 将对大规模工业实践更合适，它出现了更高显著地渗入在低操作压力的流动。

Potential use of nanofiltration like-forward osmosis membranes for copper ion removal

The discharge of industrial effluent containing heavy metal ions would cause water pollution if such effluent is not properly treated.In this work,the performance of emerging nanofiltration(NF)like-forward osmosis(FO)membrane was evaluated for its efficiency to remove copper ion from water.Conventionally,copper ion is removed from aqueous solution via adsorption and/or ion-exchange method.The engineered osmosis method as proposed in this work considered four commercial NF membranes(i.e.,NF90,DK,NDX and PFO)where their separation performances were accessed using synthetic water sample containing 100 mg·L-1 copper ion under FO and pressure retarded osmosis(PRO)orientation.The findings indicated that all membranes could achieve almost complete removal of copper regardless of membrane orientation without applying external driving force.The high removal rates were in good agreement with the outcomes of the membranes tested under pressuredriven mode at 1 MPa.The use of appropriate salts as draw solutes enabled the NF membranes to be employed in engineered osmosis process,achieving a relatively low reverse solute flux.The findings showed that the best performing membrane is PFO membrane in which it achieved N 99.4%copper rejection with very minimum reverse solute flux of<1 g·m-2·h-1.

Development and Extension of Seawater Desalination by Reverse Osmosis

Seawater desalination has been peoples fond dream since ancient times, the dream is now becoming a reality. This paper presents a brief development history of reverse osmosis. Much attention was paid to innovative development in membranes, modules, equipments and applied technology, including asymmetric and composite membranes, spiral-wound element and hollow fiber module, energy recovery equipments and different technological processes. The extension of reverse osmosis, such as desalination, pre-concentration, integrated processes and nanofiltration, is also briefly mentioned.

Inhibition of CaCO_3 Scaling in Reverse Osmosis System by Zinc Ion

Scaling of reverse osmosis (RO) membrane surface is one of the main problems in desalination proc- esses. To mitigate scales, organic anti-scalants are often used. If the dosages of anti-scalants are reduced, by using other much cheaper scale inhibitors, RO running cost will decrease greatly. The present paper investigated the inhi- bition of CaCO3 precipitation by zinc ions in RO system. The results show that the zinc ion concentration of 2mg?L-1 was able to exert a marked suppression effect on both bulk precipitation of CaCO3 and on membrane scaling on waters of moderate hardness.

Multi-functional forward osmosis draw solutes for seawater desalination

Forward osmosis(FO), as one of the emerging desalination technologies, has the potential to produce fresh water from a variety of water sources by utilizing the osmotic pressure gradient across a semi-permeable membrane.Draw solution, as an essential component of any FO process, can extract water molecules from seawater or wastewater. An ideal draw solution should meet three essential requirements, namely high osmotic pressure, low reverse flux, and facile regeneration mechanism. The selection of proper draw solutes is especially critical for an energy-efficient FO process since the energy consumption mostly arises from the separation or regeneration of the draw solution. Recently, we developed a few multi-functional FO draw solutes, mainly aiming to enhance the FO water flux and to explore facile re-concentration methods. This review summarizes these draw solutes,including Na^+_- functionalized carbon quantum dots, thermoresponsive copolymers, hydrophilic magnetic nanoparticles, and thermoresponsive magnetic nanoparticles.

Energy Recovery Device with a Fluid Switcher for Seawater Reverse Osmosis System

精力恢复设备(ERD ) 是海水反渗透(SWRO ) 的重要部分脱盐系统。主要有二种 ERD，离心的类型和积极排水量(PD ) 类型。PD 类型具有广泛的担心并且在大规模工厂被比较喜欢。在这篇文章，创新液体 switcher 被介绍，有实验室规模液体 switcher 的一个二柱体的水力的精力恢复单位被建立。自来水在 SWRO 脱盐工厂被用作工作媒介而不是实际海水和盐水。在稳态操作条件下面，试验性的结果在压力和流量的变化上被获得到恢复联合起来并且从精力。水力的恢复效率(啊) 有液体的精力恢复单位， switcher 到达了多达 76.83% 。

Layer by Layer Assembly of Poly(Allylamine Hydrochloride)/Phosphate Ions and Poly(Sodium 4-Styrene Sulfonate) Membrane for Forward Osmosis Application

Based on the layer by layer(Lb L)assembly technology,the nano-scale composite membrane with excellent structure can be prepared by changing the polyelectrolyte and controlling the deposition conditions.Polyamines and phosphate ions(Pi)can be self-organized to form supramolecular systems which could be exploited to stabilize the interfacial architecture.The LbL membrane was made of the positively charged poly(allylamine hydrochloride)(PAH)self-organized with Pi and the negatively charged poly(sodium 4-styrene sulfonate)(PSS)alternatively on top of a poly(acrylonitrile)(PAN)substrate.Compared to the membrane without Pi,the membrane assembled by PAH/Pi improved forward of flux and reduced flux of salt.The concentration of PAH and PSS,deposition time,pH and number of layers showed significant influences on the performance of the membrane.In this experiment,we systematically investigated the preparation conditions and under the optimized conditions the prepared membrane exhibited high water fluxes of 13.5 L m^-2 h^-1 with corresponding salt to water flux,Js/Jv,ratio of 0.07 g L^-1 tested by forward osmosis when DI water as feed solution and 2 mol L^-1 MgCl2 as draw solution.

Correlations between silt density index,turbidity and oxidation-reduction potential parameters in seawater reverse osmosis desalination

The reverse osmosis method is one of the most widely used methods of seawater desalination at present.Hydrophilic and desalting membranes in reverse osmosis systems are highly susceptible to the input pollutants.Various contaminants,including suspended organic and inorganic matter,result in membrane fouling and membrane degradation.Fundamental parameters such as the turbidity,the amount of chlorine injection,and silt density index (SDI) are the most predominant parameters of fouling control in the membranes.In this study,the operation system included a water intake unit,a pretreatment system,and an RO system.The pretreatment system encompassed a clarifier,a gravity sand filter,pressurized sand filters,and a cartridge filter.The correlation between the amount of chlorine injection in terms of the oxidation-reduction potential (ORP) and the SDI value of the input water was investigated at a specified site next to the Persian Gulf.The results showed that,at certain intervals of inlet turbidity,injection of a certain amount of chlorine into the raw water has a distinct effect on the decrease of SDI.