Faculty Publications
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Item A review: Desalination by forward osmosis(Elsevier, 2018) Gnani Peer Mohamed, S.I.; Isloor, A.M.; Yuliwati, E.Rapid population growth increases the demand for freshwater. Membrane technology is playing a dynamic role in the production of clean water from seawater and wastewater. The desalination of seawater using forward osmosis (FO) is an emerging technology to produce freshwater, as it is energy efficient than the conventional processes. In recent days, a significant amount of work has been carried out to produce high-performance FO membrane for desalination. In this chapter, usage of different types of membranes for FO desalination application and their performances enhancement by suitable modification has been discussed. © 2019 Elsevier Inc. All rights reserved.Item Carbon-based nanocomposite membranes for water and wastewater purification(Elsevier, 2018) Gnani Peer Mohamed, G.P.S.; Isloor, A.M.; Yuliwati, E.; A.F., A.F.The carbon-based nanocomposite membranes are developing core technology for water and wastewater purification. These materials are broadly used in the fabrication of ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO) and evolving forward osmosis (FO) nanocomposite membranes as an additive. In this chapter, performance enhancement of nanocomposite membranes using carbon nanotubes (CNTs) and graphene oxide (GO), especially in the field of desalination, dye removal, oil/water separation and natural organic matter removal, is discussed. © 2019 Elsevier Inc. All rights reserved..Item Fundamentals and basics of reverse osmosis(Elsevier Inc., 2019) Gnani Peer Mohamed, G.P.S.; Isloor, A.M.; Farnood, R.This chapter endows an inclusive introduction to the fundamentals and basics of the reverse osmosis (RO) process. It starts from the short history, plants, and theoretical contextual of RO. A concise summary of the recent advances in RO membranes and materials then follows. Lastly, the usage of different types of modules such as spiral wound prepared from flat sheet membranes and hollow fiber membranes used in RO desalination is discussed. © 2020 Elsevier Inc. All rights reserved.Item Reverse osmosis pretreatment techniques, fouling, and control strategies(Elsevier Inc., 2019) Gnani Peer Mohamed, G.P.S.; Isloor, A.M.; Farnood, R.In recent times, many commercial-scale seawater desalination plants have been constructed in water-stressed countries, which are expected to increase in the near future to increase the availability of potable water. In spite of many developments in the desalination technologies, seawater desalination using reverse osmosis (RO) membrane is being considered as the state-of-the-art technology. However, there are also some limitations to the RO membrane desalination such as the unavoidable membrane fouling, which increase the operating cost and transmembrane pressure. Here, we review the potential way to the RO membrane fouling control strategies, which includes the role of advanced materials, surface modification and feed water pretreatment that are emphasized based on the extensive up-to-date literature. © 2020 Elsevier Inc. All rights reserved.Item Synthesis and Characterization of PVDF/Graphene Nanocomposite Membrane for Water Treatment Applications(Trans Tech Publications Ltd, 2022) Rao, S.; Avinash, A.; As, S.; Hegde, C.; Isloor, A.M.; Vinayak, V.R.Membrane technology advancement has gained momentous consideration around the globe because of their appealing highlights, such as effectiveness, low expenses, and effective solutions for longstanding issues in alchemical industries. This study expected to incorporate graphene nanoparticles into Polyvinylidene difluoride (PVDF) to form nanofiltration (NF) layers using DMF (Dimethyl formamide) as solvent via DIPS (diffusion induced phase separation) technique. PVDF polymer membrane performances with varied percent (1 – 6% wt.) of graphene concentrations are studied with Infrared spectral, water uptake, water contact angle, and ion rejection measurements. Scanning electron microscope (SEM) analysis showed that the pore size is often regulated by incorporating graphene nanoparticles (80-90 nm) as compared to PVDF membranes. The PVDF membranes exhibited a relative increase in the contact angle from PVDF to PVDF-G6%, i.e., 50.3° to 63.46 ± .3, thus, showing a relative increase in hydrophobicity. The higher percent of graphene (> 6% by wt.) results in nano-particle accumulation that showed the performances of PVDF/graphene rejection possessing relatively the same results. The results confirmed that the prepared membranes possess an excellent ability to treat wastewater. © 2022 Trans Tech Publications Ltd, Switzerland.Item A review on RO membrane technology: Developments and challenges(Elsevier B.V., 2015) Shenvi, S.S.; Isloor, A.M.; A.F., A.F.Reverse osmosis (RO) based desalination is one of the most important and widely recognized technologies for production of fresh water from saline water. Since its conception and initiation, a significant development has been witnessed in this technology w.r.t. materials, synthesis techniques, modification and modules over the last few decades. The working of a RO plant inclusive of the pretreatment and post-treatment procedures has been briefly discussed in the article. The main objective of this review is to highlight the historical milestones achieved in RO technology in terms of membrane performance, the developments seen over the last few years and the challenges perceived. The material properties of the membrane dominate the performance of a RO process. The emergence of nano-technology and biomimetic RO membranes as the futuristic tools is capable of revolutionizing the entire RO process. Hence the development of nano-structured membranes involving thin film nano-composite membranes, carbon-nanotube membranes and aquaporin-based membranes has been focussed in detail. The problems associated with a RO process such as scaling, brine disposal and boron removal are briefed and the measures adopted to address the same have been discussed. © 2014 Elsevier B.V.Item Carbon nanotube- and graphene-based advanced membrane materials for desalination(Springer Verlag, 2017) Hebbar, R.S.; Isloor, A.M.; Siddique, I.; Asiri, A.M.The development of membrane-based desalination and water purification technologies offers new alternatives to meet the global freshwater demand. Rapid advancement in carbon nanotube-based and graphene-based nanomaterials has drawn the attention of scientific investigators on various desalination technologies. These nanomaterials indeed offer advantageous structure, size, shape, porosity and mass transport behavior for membrane separation process. This article reviews theoretical and experimental investigations of carbon nanotube- and graphene-based composite materials for desalination. Special attention is given to the simulation of molecular transport through these materials. Further, recent advances in the application of functionalization of carbon nanotube- and graphene-based materials for salt rejection and hydraulic permeation properties are discussed. © 2017, Springer International Publishing AG.Item Synthesis and desalination performance of Ar+-N+ irradiated polysulfone based new NF membrane(2011) Hegde, C.; Isloor, A.M.; Padaki, M.; Wanichapichart, P.; Liangdeng, Y.In the last few years, membrane technology has gained more attention from polymer chemists throughout the globe. Nowadays, surface modification of membrane is very useful in biotechnology and food science. In the present investigation, we have synthesized polysulfone based composite nanofiltration (NF) membranes, and characterized these membranes by FT-IR, SEM and membrane performance studies. Surface plasma treatment was carried out by irradiation with argon and nitrogen beams in suitable conditions. It was observed that nitrogen beam caused surface roughness that was more severe than the Ar beam. After irradiation, water contact angle was slightly increased. For pure water permeability, flux increased linearly with the operating pressure. However, for the salt solution, the flux was decreased marginally and salt rejection increased after irradiation due to surface modification. The modification effect was characterized in terms of contact angle, AFM employed roughness measurement and dielectric property. It revealed that irradiated NF membranes showed higher salt rejection and lower flux as compared to the nonmodified membranes. Accordingly, the roughness of the membrane surface intensively affected the performance of RO membrane. © 2010 Elsevier B.V.Item Conversion of microfiltration membrane into nanofiltration membrane by vapour phase deposition of aluminium for desalination application(2011) Padaki, M.; Isloor, A.M.; Nagaraja, K.K.; Nagaraja, H.S.; Pattabi, M.Preparation and modification of NF membrane are challenging aspects in research. In the present work, we have synthesised Polysulfone (PSf) microfiltration membrane and reduced the pore size to nano level by physical vapour deposition (PVD) of aluminium metal. Membrane pore size was reduced from micro pore to nano pore, which rejected 42.22% of NaCl from the solution with 164L/m2h. And also water permeation decreases from 1.10324-10-10 to the 9.141-10-12. The SEM and AFM pictures showed the surface modification and metal deposition in the pores. The performance of the membrane was studied by dead end flow cell using 3.5% of NaCl solution, in which PVD membrane showed 42.22% of rejection with 16.4L/m2h flux. Thermal analysis from DSC showed Tg of 265°C. Contact angle measurement, and water uptake were also reported. © 2011 Elsevier B.V.Item New polypropylene supported chitosan NF-membrane for desalination application(2011) Padaki, M.; Isloor, A.M.; Fernandes, J.; Prabhu, K.N.In the present study, a new NF membrane was prepared by coating chitosan on polypropylene fiber support, by the dissolution of chitosan in 2% acetic acid solution. The resulting membrane was characterized by thermo gravimetric analysis, water absorption, contact angle measurement and scanning electron microscopy. Prepared membrane showed two Tg peaks, one at ~90 °C that was due to chitosan and the other peak at ~170 °C that was corresponding to the supporting polypropylene membrane. The membrane showed a low swelling ratio at pH 7, 9, and 11 as compared with pH 5. The performance of the membrane was assessed out using dead end cell. Water flux was studied at different pressures. The salt rejection study was done using NaCl solution and the effect of pH on performance of the membrane was also examined. Newly prepared membrane showed improved water flux, and % of rejection is highest in acidic pH and lowest in basic pH. Hydrulic permeability coefficient and the dielectric constant confirms that the prepared membrane is nanofiltration membrane. © 2011 Elsevier B.V.
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