scholarly journals Cellulose Triacetate (CTA) Hollow-Fiber (HF) Membranes for Sustainable Seawater Desalination: A Review

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 183
Author(s):  
Takahito Nakao ◽  
Yuki Miura ◽  
Kenji Furuichi ◽  
Masahiro Yasukawa
Keyword(s):  
Reverse Osmosis ◽  
Hollow Fiber ◽  
High Performance ◽  
Cellulose Triacetate ◽  
Optimization Strategy ◽  
Semipermeable Membranes ◽  
Additional Energy ◽  
Recent Developments ◽  
Drinking Water Production ◽  
Seawater Reverse Osmosis

Cellulose triacetate (CTA)-based hollow fiber (HF) membrane is one of the commercially successful semipermeable membranes that has had a long progress since the time the excellent semi-permeable feature of cellulose-based polymers was found in 1957. Because of the reliable and excellent performances, especially for drinking water production from seawater, CTA-HFs have been widely used as reverse osmosis (RO) membranes, especially in arid regions. In this review, recent developments and research trends on CTA-HF membranes for seawater reverse osmosis (SWRO) plants were presented. A flux analytical model, an optimization strategy for chlorine injection without losing salt rejection performance, and a module of current high performance CTA RO membranes along with its plant operation data were updated in this paper. Furthermore, a newly developed CTA-HF membrane for brine concentration (BC) application (called BC membrane) was also addressed. Finally, RO/BC hybrid operation was introduced as an effective SWRO desalination technique that enables minimizing the volume of brine disposal from the RO plant by increasing the recovery ratio and the subsequent amount of produced freshwater, without an additional energy input.

scholarly journals Forward osmosis (FO)-reverse osmosis (RO) hybrid process incorporated with hollow fiber FO

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
S.-J. Im ◽  
S. Jeong ◽  
A. Jang
Keyword(s):  
Reverse Osmosis ◽  
Hollow Fiber ◽  
Forward Osmosis ◽  
High Energy ◽  
Operating Conditions ◽  
Energy Costs ◽  
High Dilution ◽  
Volume Production ◽  
Seawater Reverse Osmosis ◽  
High Energy Consumption

AbstractCurrently, desalination is limited by high energy consumption and high operational and maintenance costs. In this study, a new concept of a hollow fiber forward osmosis (HFFO)-based infinity desalination process with minor environmental impacts (free-energy intake and no pretreatment or brine discharge) is suggested. To evaluate the concept, an element-scale HFFO was conducted in both conventional FO and pressure-assisted FO modes, simulating a submerged HFFO operation. In the HFFO test, the impacts of several operating conditions on the performance of the HFFO were investigated to select the best case. Based on these results, the energy costs were calculated and compared with those of a hybrid FO–seawater reverse osmosis (SWRO) process. The HFFO showed a high dilution rate of the draw solution (up to approximately 400%), allowing the downstream SWRO process to operate at 25 bar with the same permeate volume production (recovery rate of 60%). Consequently, the HFFO-based infinity desalination process has an annual energy revenue of 183.83 million USD, compared with a stand-alone two-stage RO process based on a 100,000 m3/day plant.

scholarly journals Preparation of Polybenzimidazole Hollow-Fiber Membranes for Reverse Osmosis and Nanofiltration by Changing the Spinning Air Gap

Membranes ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 113 ◽  
Author(s):  
Xiao Wang ◽  
Palitha Jayaweera ◽  
Radwan Alrasheed ◽  
Saad Aljlil ◽  
Yousef Alyousef ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Barrier Layer ◽  
Hollow Fiber ◽  
High Performance ◽  
Air Gap ◽  
Hollow Fiber Membranes ◽  
Barrier Layer Thickness ◽  
Fiber Membranes ◽  
Spinning Process ◽  
Surface Modified

High-performance polybenzimidazole (PBI) hollow-fiber membranes (HFMs) were fabricated through a continuous dry-jet wet spinning process at SRI International. By adjusting the spinning air gap from 4″ (10.2 cm) to 0.5″ (1.3 cm), the HFM pore sizes were enlarged dramatically without any significant change of the fiber dimensional size and barrier layer thickness. When fabricated with an air gap of 2.5″ (6.4 cm) and a surface modified by NaClO solution, the PBI HFM performance was comparable to that of a commercial reverse osmosis (RO) HFM product from Toyobo in terms of salt (NaCl) rejection and water permeability. The PBI RO HFM was positively surface charged in acidic conditions (pH < 7), which enhanced salt rejection via the Donnan effect. With an air gap of 1.5″ (3.8 cm), the PBI HFM rejected MgSO4 and Na2SO4 above 95%, a result that compares favorably with that achieved by nanofiltration. In addition, the PBI HFM has a defect-free structure with an ultra-thin barrier layer and porous sublayer. We believe PBI HFMs are ideal for water purification and can be readily commercialized.

Kristal® 2000 PVDF hollow fiber UF membrane in the pretreatment for seawater desalination

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
Zanguo Peng ◽  
Zhaoxuan Zhang ◽  
Pandurangan Mohan ◽  
Kasinathan Manimaran ◽  
Dongfei Li
Keyword(s):  
Water Quality ◽  
Pilot Study ◽  
Reverse Osmosis ◽  
Hollow Fiber ◽  
Large Scale ◽  
Operating Costs ◽  
Feed Water ◽  
Seawater Desalination ◽  
Seawater Reverse Osmosis ◽  
Uf Membranes

Membrane technology has emerged as a dominant solution to seawater desalination due to its superior advantages such as stable output water quality, lower energy consumption, ease of operation and smaller footprint. However, the design of spiral wound reverse osmosis (RO) membranes used in desalination does not allow for backwash or air scouring, thus rendering the RO membrane highly susceptible to fouling. Pretreatment for the RO system is therefore essential to ensure a long service life of the RO membranes. For waters containing suspended solids of up to 75 mg/L (such as that in the SingSpring Desalination Plant at Tuas, Singapore), conventional pretreatment methods (such as dissolved air floatation and filtration (DAFF), chemical dosing and cartridge filtration) require regular operator intervention to produce a permeate of reasonably quality. Ultrafiltration (UF) as a pretreatment for seawater desalination can offer better treated water, lower operating costs, a smaller footprint, and flexibility in dealing with poor or varying feed water quality. By improving the pretreatment permeate water quality, reducing operating costs and the footprint, capital expenses can be lowered. Greater stability is also achieved during times of poor or variable feed water conditions (such as periods of algalbloom). A pilot study was conducted at SingSpring to track the performance of Hyflux's Kristal® 2000 hollow fiber UF membranes as pretreatment for the seawater reverse osmosis (SWRO) system. The results of the pilot study will enable the design of future large-scale UF-SWRO membrane projects for seawater desalination.

scholarly journals Current Status and Future Trend of Dominant Commercial Reverse Osmosis Membranes

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 906
Author(s):  
Masaru Kurihara
Keyword(s):  
Reverse Osmosis ◽  
Hollow Fiber ◽  
Water Solution ◽  
Cellulose Triacetate ◽  
Future Trend ◽  
Global Market ◽  
Water Desalination ◽  
Current Status ◽  
Membrane Process ◽  
Spiral Wound

Since 2000, seawater reverse osmosis method has been a dominant desalination technology against the distillation method in the global market. The large project called “Mega-SWRO” (half mega-ton per day and larger) plant in the Middle East is quite popular making full use of the combination with solar energy. Today, the price of desalinated water is affordable at as low as $0.28/m3 to $0.53/m3. Likewise, dominant commercial reverse osmosis membrane is a cross-linked fully aromatic polyamide composite membrane-spiral wound element including FT-30 (DuPont Water Solution) and UTC-80 (Toray Industries., Inc., Otsu, Shiga, Japan). The said membranes are much superior in terms of performance compared to the cellulose triacetate membranes-hollow fiber for variety of applications including seawater desalinations, brackish water desalination, wastewater reuse, ultra-pure production for semiconductor, home-use water purifier, etc. SWCC of Saudi Arabia has announced that it intends to shift from cellulose triacetate hollow fiber to spiral wound RO membranes at all of its plants. Furthermore, the state-sponsored R&D on membrane and membrane process has been put into practice in major countries, including Japan and Korea, which contributed to the progress of membrane science and membrane process, suitable for spiral-wound polyamide membranes. SWCC has announced their plans for SWRO, mainly focusing on brine mining to obtain precious materials from the brine of SWRO. New and innovative brine-mining technology has been introduced for green desalination.

Microstructure of sputter deposited Ni-Sb ohmic contacts on GaAs

1989 ◽  
Vol 47 ◽  
pp. 450-451
Author(s):  
S. Yegnasubramanian ◽  
V.C. Kannan ◽  
R. Dutto ◽  
P.J. Sakach
Keyword(s):  
High Performance ◽  
Ohmic Contacts ◽  
Surface Defects ◽  
Pure Metal ◽  
Device Fabrication ◽  
Native Oxide ◽  
Metal Thin Films ◽  
Recent Developments ◽  
Different Temperatures ◽  
Sputter Deposited

Recent developments in the fabrication of high performance GaAs devices impose crucial requirements of low resistance ohmic contacts with excellent contact properties such as, thermal stability, contact resistivity, contact depth, Schottky barrier height etc. The nature of the interface plays an important role in the stability of the contacts due to problems associated with interdiffusion and compound formation at the interface during device fabrication. Contacts of pure metal thin films on GaAs are not desirable due to the presence of the native oxide and surface defects at the interface. Nickel has been used as a contact metal on GaAs and has been found to be reactive at low temperatures. Formation Of Ni2 GaAs at 200 - 350C is reported and is found to grow epitaxially on (001) and on (111) GaAs, but is shown to be unstable at 450C. This paper reports the investigations carried out to understand the microstructure, nature of the interface and composition of sputter deposited and annealed (at different temperatures) Ni-Sb ohmic contacts on GaAs by TEM. Attempts were made to correlate the electrical properties of the films such as the sheet resistance and contact resistance, with the microstructure. The observations are corroborated by Scanning Auger Microprobe (SAM) investigations.

What Can Digitization Do For Formulated Product Innovation and Development

2020 ◽  
Author(s):  
James McDonagh ◽  
William Swope ◽  
Richard L. Anderson ◽  
Michael Johnston ◽  
David J. Bray
Keyword(s):  
High Performance ◽  
Quality Data ◽  
High Quality Data ◽  
Base Level ◽  
Hybrid Approaches ◽  
Digital Ecosystem ◽  
Recent Developments ◽  
Chemical Simulation ◽  
High Level ◽  
Physical And Chemical

Digitization offers significant opportunities for the formulated product industry to transform the way it works and develop new methods of business. R&D is one area of operation that is challenging to take advantage of these technologies due to its high level of domain specialisation and creativity but the benefits could be significant. Recent developments of base level technologies such as artificial intelligence (AI)/machine learning (ML), robotics and high performance computing (HPC), to name a few, present disruptive and transformative technologies which could offer new insights, discovery methods and enhanced chemical control when combined in a digital ecosystem of connectivity, distributive services and decentralisation. At the fundamental level, research in these technologies has shown that new physical and chemical insights can be gained, which in turn can augment experimental R&D approaches through physics-based chemical simulation, data driven models and hybrid approaches. In all of these cases, high quality data is required to build and validate models in addition to the skills and expertise to exploit such methods. In this article we give an overview of some of the digital technology demonstrators we have developed for formulated product R&D. We discuss the challenges in building and deploying these demonstrators.<br>

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