The Experts below are selected from a list of 336 Experts worldwide ranked by ideXlab platform

Bart Van Der Bruggen - One of the best experts on this subject based on the ideXlab platform.

  • ultra high flux alkali treated cellulose triacetate cellulose nanocrystal nanocomposite Membrane for pervaporation desalination
    Chemical Engineering Science, 2021
    Co-Authors: Indah Prihatiningtyas, Yusak Hartanto, Bart Van Der Bruggen
    Abstract:

    Abstract Cellulose triacetate/cellulose nanocrystals (CTA/CNCs) nanocomposite has recently been proposed as a promising material to synthesize pervaporation desalination Membrane. However, the water flux of such Membranes was found poor in comparison to other pervaporation desalination Membranes. In this work, time-controlled alkaline treatment is proposed to improve the water flux of CTA/CNCs nanocomposite Membrane without compromising its selectivity. An understanding how alkaline treatment changed the physicochemical properties of the Membranes was obtained through Membrane Characterization by FTIR spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), contact angle and water uptake analysis. The Membrane being treated up to 30 min results in a drastic water flux improvement to 107.5 kg m−2 h−1 with >99.8% salt rejection in comparison with the water flux obtained by the untreated Membrane, 3.6 kg m−2 h−1, when hypersaline water with 90 g/L NaCl was employed as the feed solution. The water flux decreased to 58.5 kg m−2 h−1 when 200 g/L NaCl was used as feed solution. The alkali-treated Membrane showed a stable Membrane performance for 12 h when it was evaluated for 90 g/L and 200 g/L NaCl.

Indah Prihatiningtyas - One of the best experts on this subject based on the ideXlab platform.

  • ultra high flux alkali treated cellulose triacetate cellulose nanocrystal nanocomposite Membrane for pervaporation desalination
    Chemical Engineering Science, 2021
    Co-Authors: Indah Prihatiningtyas, Yusak Hartanto, Bart Van Der Bruggen
    Abstract:

    Abstract Cellulose triacetate/cellulose nanocrystals (CTA/CNCs) nanocomposite has recently been proposed as a promising material to synthesize pervaporation desalination Membrane. However, the water flux of such Membranes was found poor in comparison to other pervaporation desalination Membranes. In this work, time-controlled alkaline treatment is proposed to improve the water flux of CTA/CNCs nanocomposite Membrane without compromising its selectivity. An understanding how alkaline treatment changed the physicochemical properties of the Membranes was obtained through Membrane Characterization by FTIR spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), contact angle and water uptake analysis. The Membrane being treated up to 30 min results in a drastic water flux improvement to 107.5 kg m−2 h−1 with >99.8% salt rejection in comparison with the water flux obtained by the untreated Membrane, 3.6 kg m−2 h−1, when hypersaline water with 90 g/L NaCl was employed as the feed solution. The water flux decreased to 58.5 kg m−2 h−1 when 200 g/L NaCl was used as feed solution. The alkali-treated Membrane showed a stable Membrane performance for 12 h when it was evaluated for 90 g/L and 200 g/L NaCl.

Takeshi Matsuura - One of the best experts on this subject based on the ideXlab platform.

  • progress in transport theory and Characterization method of reverse osmosis ro Membrane in past fifty years
    Desalination, 2017
    Co-Authors: Ahmad Fauzi Ismail, Takeshi Matsuura
    Abstract:

    Abstract In this paper an attempt is made to review the progress in Membrane Characterization and transport theory in historical perspective. Its central theme is the Membrane “pore” around which progress has been revolving, irrespective of whether the researcher is “for” or “against” the existence of pores at the top dense layer of the RO Membrane. The article starts from nineteen-fifties when the development of cellulose acetate Membrane was launched on the basis of the Preferential Sorption-Capillary Flow (PS-CF) mechanism. The Sorption-Diffusion (S-D) model, which was presented at almost the same time, regards the top surface layer dense and homogeneous. No heterogeneity is allowed and the presence of pores makes the RO Membrane imperfect, causing the leakage of salt. Thus, the PS-CF model came to direct confrontation with the S-D model. It is shown in this brief historic review how the advanced Characterization instrument has revealed the heterogeneous structure of the top surface of the RO Membrane and measured its “pore size” and “pore size distribution”. The advanced transport theory based on Molecular Dynamics (MD) simulation also resulted in the presence of the multi-modal pore size distribution.

  • polyaniline in situ modified halloysite nanotubes incorporated asymmetric mixed matrix Membrane for gas separation
    Separation and Purification Technology, 2014
    Co-Authors: Surya R Murali, Takeshi Matsuura, Mahesh Padaki, Mohd Sohaimi Abdullah, Ahmad Fauzi Ismail
    Abstract:

    Abstract The embodiment of polyaniline in situ modified halloysite nanotubes (PANi–HNTs) on the gas permeation properties of CO2, CH4, O2, and N2 gases in polysulfone (PSf) Membrane has been investigated. Halloysite nanotubes (HNTs) were modified by in situ polymerization of aniline. Asymmetric mixed matrix Membranes (MMMs) were synthesized by varying the PANi–HNTs concentrations of 0.5–2.5 wt.% of polymer in the PSf solutions. The MMMs were characterized by SEM, ATR-IR, DSC and XRD. Membrane Characterization reveals the structural change of the filler and interaction of PANi with PSf polymer matrix. The permeance of pure gases and the ideal selectivities were determined using an indigenously built high-pressure gas separation manifold. Increasing the PANi–HNTs incorporation in polymer enhanced the permeance of CO2 from 17.4 to 68.4 GPU, CH4 from 0.8 to 4.8 GPU, O2 from 3.9 to 18.8 GPU and N2 from 0.7 to 3.1 GPU, respectively. The use of PANi–HNTs loaded PSf Membranes provides a means for separation of CO2/CH4, CO2/N2 and O2/N2.

  • Progress in Membrane scince and technology for seawater desalination - A review
    Desalination, 2001
    Co-Authors: Takeshi Matsuura
    Abstract:

    It is imperative to review the history of the past to provide a vision for the future. It is therefore the objective of this paper to review the history of the development of Membranes and Membrane processes for water production in general and seawater desalination in particular. The review highlights some new trends observable in the following four areas; Membrane development, Membrane Characterization, Membrane transport and Membrane system design. The future prospects in the above four areas are discussed. Membrane development deals with recent progresses in the development of reverse osmosis Membranes used for desalination. There are two different approaches, both based on in-situ polycondensation technique. One is to develop Membranes for desalination of brackish water operable at ultra-low pressures, and the other is to develop Membranes operable at high pressures to achieve high pure water recovery in seawater desalination. In Membrane Characterization section, Atomic Force Microscopy (AFM) is featured as a new tool to investigate Membrane surfaces. The effects of surface roughness, which can be measured by AFM, on Membrane productivity and Membrane fouling are discussed. Electron Spin Resonance (ESR) is another method, the application of which to investigate synthetic Membranes has only begun. The potential of this method to investigate the structure of the Membrane is discussed. Recent progresses in the measurement of pore sizes as small as one nanometer are briefly described. Membrane transport deals with transport models made primarily for charged Membranes. Since most of nanofiltration Membranes are electrically charged, the development of such transport models is useful in water treatment by nanofiltration Membranes. Transport models in which pore sizes are included explicitly are particularly important since pore sizes of nanofiltration Membranes are measurable. The section in Membrane system design deals with various hybrid systems for seawater desalination in which Membrane processes are incorporated. There is a great potential to reduce desalination cost by combining Membrane processes with more conventional unit processes.

  • Characterization of synthetic Membranes by raman spectroscopy electron spin resonance and atomic force microscopy a review
    Polymer, 2000
    Co-Authors: K C Khulbe, Takeshi Matsuura
    Abstract:

    In this article an attempt is made to review critically the papers concerning novel Membrane Characterization methods. In particular, our focus on Raman spectroscopy, electron spin resonance (ESR) and atomic force microscopy. For each method the general principle is briefly outlined, followed by discussions on Characterization of polymeric materials, in general, and synthetic polymeric Membranes, in particular. After highlighting several examples, discussions are made on advantages for each method in order to identify specific area of applications. In general, Raman Spectroscopy is most adequate to obtain information on crystalline structure of the macromolecules and, change of polymeric structure in Membrane, ESR on the mobility of molecules in Membrane polymer matrixes and Membrane pores, and Atomic Force Microscope for three-dimensional display of Membrane surfaces.

  • Membrane Characterization by solute transport and atomic force microscopy
    Journal of Membrane Science, 1998
    Co-Authors: S Singh, K C Khulbe, Takeshi Matsuura, Takeshi Matsuura, P Ramamurthy
    Abstract:

    Various ultrafiltration and nanofiltration Membranes were characterized by solute transport and also by atomic force microscope (AFM). The molecular weight cut-off (MWCO) of the Membranes studied were found to be between 3500 and 98,000 Daltons. The mean pore size (μp) and the geometric standard deviation (σp) around mean ranged from 0.7 to 11.12 nm and 1.68 to 3.31, respectively, when calculated from the solute transport data. Mean pore sizes measured by AFM were about 3.5 times larger than calculated from the solute transport. Pore sizes measured by AFM were remarkably fitted to the log-normal probability distribution curve. Pore sizes of the Membranes with low MWCO (20,000 Daltons and lower) could not be measured by AFM because of indistinct pores. In most cases, the pore density ranged from 38 to 1291 pores/μm2. In general, the pore density was higher for the Membrane having lower MWCO. Surface porosity was around 0.5–1.0% as measured from the solute transport and was 9.5–12.9% as obtained from AFM images. When Membranes were coated with a thin layer of sulfonated polyphenylene oxide, mean pore sizes were reduced for all the Membranes. Surface roughness was also reduced on coating.

S S Madaeni - One of the best experts on this subject based on the ideXlab platform.

  • surface modification of heterogeneous cation exchange Membranes by simultaneous using polymerization of acrylic acid co methyl methacrylate Membrane Characterization in desalination process
    Desalination, 2014
    Co-Authors: S M Hosseini, S S Madaeni, Abdolreza Moghadassi, A R Hamidi, B Rahzani, H Asiani, A R Khodabakhshi, A Seidypoor
    Abstract:

    Abstract In the current research poly(vinyl chloride) based composite heterogeneous cation exchange Membranes were prepared by solution casting technique. Poly(acrylic acid)-co-poly(methyl methacrylate) was used as Membrane surface modifier by emulsion/graft polymerization technique to improve the Membrane electrochemical properties. Also the effect of used emulsifier content ratio in modifier emulsion on properties of Membranes was studied. The FT-IR spectrum analysis decisively proved the graft polymerization of poly(acrylic acid)-co-poly(methyl methacrylate). SOM images showed uniform particle distribution and relatively uniform surfaces for the Membranes. Results revealed that surface modification of Membrane led to increase in Membrane potential, transport number, selectivity, surface charge density, ion exchange capacity and ionic permeability in modified Membranes. Also, results showed that increase of emulsifier (SDBS) ratio in used emulsion led to increase in Membrane transport number, selectivity and ionic flux for the modified composite Membranes. Conversely, opposite trends were found for Membrane electrical resistance by AA-co-MMA polymerization.

  • influence of poly ethylene glycol as pore generator on morphology and performance of chitosan poly vinyl alcohol Membrane adsorbents
    Applied Surface Science, 2014
    Co-Authors: Ehsan Salehi, S S Madaeni
    Abstract:

    Abstract Macroporous chitosan/poly(vinyl alcohol) Membrane adsorbents were synthesized by solvent evaporation in the presence of poly(ethylene glycol) which was utilized as porogen. The Membranes were applied for Cu(II) ion adsorption from water. SEM, AFM and wettability analyses were performed for Membrane Characterization. Insertion of poly(ethylene glycol) generated macrovoids in the dense structure of CS/PVA Membranes through particulate leaching out mechanism. According to the static adsorption tests, the uptake capacity of the porous Membranes is elevated (∼26 mg/g) compared to that of the dense Membranes (∼10 mg/g). This phenomenon is attributed to the increase in the density of active sites, water affinity and surface roughness as a result of the porogen effects. The approachability of the ions to the active sites was also affected by these important parameters. Both size and density of the macrovoids increased with increasing PEG content from nil to 5 wt%. Fragility of the resultant porous structures prohibited synthesizing CS/PVA Membranes with higher porogen contents. Desorption tests showed that the porous Membranes were better regenerated in comparison to the dense Membranes using Na 2 EDTA as eluant. Generally, the results suggested that the CS/PVA Membranes, comprising PEG as pore-generator agent, are potential candidates for adsorption and elimination of Cu(II) ions from water.

  • fabrication of polyvinyl chloride cellulose acetate electrodialysis heterogeneous cation exchange Membrane Characterization and performance in desalination process
    Desalination, 2012
    Co-Authors: Sayed Mohsen Hosseini, S S Madaeni, A Gholami, Abdolreza Moghadassi, A R Hamidi
    Abstract:

    In this research, polyvinylchloride (PVC)/cellulose acetate (CA) blend heterogeneous cation exchange Membranes were prepared by solution casting technique using tetrahydrofuran as solvent and cation exchange resin powder as functional groups agent. CA was employed in Membrane fabrication to improve the hydrophilicity of Membranes. The effect of blend ratio of polymers binder (PVC to CA) on physico-chemical characteristics of home-made Membranes was studied. Scanning optical microscopy (SOM) images showed uniform particles distribution and relatively uniform surfaces for the Membranes. Membrane water content and surface hydrophilicity were enhanced with increase of CA blend ratio in casting solution. Membrane ion exchange capacity was also improved slightly with increase of CA ratio in prepared Membranes. Membrane fixed ion concentration, Membrane potential, charge density, permselectivity, transport number and areal electrical resistance all showed decreasing trends by the increase in CA blend ratio in casting solution. Results revealed that ionic permeability and flux were initially enhanced by the increase of CA concentration up to 20%wt in casting solution and then showed decreasing trend by more CA loading from 20 to 50%wt. These parameters were enhanced again by more increase in CA ratio from 50 to 100%wt in prepared Membranes.

  • tio2 embedded mixed matrix pes nanocomposite Membranes influence of different sizes and types of nanoparticles on antifouling and performance
    Desalination, 2012
    Co-Authors: Vahid Vatanpour, Ehsan Salehi, S S Madaeni, Alireza Khataee, Sirus Zinadini, Hossein Ahmadi Monfared
    Abstract:

    Abstract Three different types of titanium dioxide (TiO 2 ) nanoparticles (P25, PC105 and PC500) with various sizes were applied for the preparation of mixed matrix polyethersulfone nanofiltration Membranes. This work investigates the effect of types and sizes of TiO 2 on the morphology, performance and fouling control of nanofillers embedded Membranes. The Membrane Characterization was carried out by FTIR, XRD, EDX, contact angle, surface and cross-section SEM images and pure water flux measurements. The surface hydrophilicity of the TiO 2 blended Membranes was improved due to water affinity improvement of the Membrane surface. The high content of PC105 and PC500 TiO 2 nanoparticles in the casting solution diminished Membrane performance due to the agglomeration of these nanoparticles in polymer matrix. However, the P25 nanofillers showed better dispersibility. The antibiofouling performance of the Membranes fouled by whey solution was investigated by measuring fouling resistance parameters. The nanofiltration Membranes made from the nano-sized TiO 2 particles elevated the pure water flux and antifouling properties. Flux recovery percentage of the nascent PES Membrane was increased from 56 to 91% by blending 4 wt.% P25 nanoparticles. At low concentration of TiO 2 , the nanoparticles with small size caused more biofouling reduction due to this fact that the aggregation of the nanoparticles was not prominent at low amount.

  • fabrication of cellulose acetate sodium dodecyl sulfate nanofiltration Membrane Characterization and performance in rejection of pesticides
    Desalination, 2012
    Co-Authors: Negin Ghaemi, Vahid Vatanpour, S S Madaeni, Abdolhamid Alizadeh, Parisa Daraei, Monir Falsafi
    Abstract:

    Abstract The effect of addition of sodium dodecyl sulfate (SDS) anionic surfactant on the characteristics and performance (i.e. flux and rejection) of cellulose acetate (CA) nanofiltration Membrane was investigated at this study. Nitrophenols (p-nitrophenol (PNP) and 3,5-dinitrosalicylic acid (DNSA)) were selected as the subject-matter of this study since they are listed as two of the harmful pesticides in drinking water by US Environmental Protection Agency. The prepared Membranes were characterized by several techniques including SEM, AFM, FTIR-ATR, water contact angle, and zeta potential measurements. The process of addition of SDS resulted in Membranes with higher pure water flux, superior rejection, and flux in comparison to CA Membrane. Also, it was found that the rejection of PNP and DNSA depend on a series of factors including the solution pH, structural properties of the solutes, and characteristics of the Membranes.

Nidal Hilal - One of the best experts on this subject based on the ideXlab platform.

  • reverse osmosis desalination a state of the art review
    Desalination, 2019
    Co-Authors: Muhammad Qasim, Nidal Hilal, Mohamed Badrelzaman, Noora Darwish, Naif A Darwish
    Abstract:

    Abstract Water scarcity is a grand challenge that has always stimulated research interests in finding effective means for pure water production. In this context, reverse osmosis (RO) is considered the leading and the most optimized Membrane-based desalination process that is currently dominating the desalination market. In this review, various aspects of RO desalination are reviewed. Theories and models related to concentration polarization and Membrane transport, as well as merits and drawbacks of these models in predicting polarization effects, are discussed. An updated review of studies related to Membrane modules (plate and frame, tubular, spiral wound, and hollow fiber) and Membrane Characterization are provided. The review also discusses Membrane cleaning and different pre-treatment technologies in place for RO desalination, such as feed-water pre-treatment and biocides. RO pre-treatment technologies, which include conventional (e.g., coagulation-flocculation, media filtration, disinfection, scale inhibition) and non-conventional (e.g., MF, UF, and NF) are reviewed and their relative attributes are compared. As per the available literature, UF, MF and coagulation-flocculation are considered the most widely used pre-treatment technologies. In addition, this review discusses Membrane fouling, which represents a serious challenge in RO processes due to its significant contribution to energy requirements and process economy (e.g., flux decline, permeate quality, Membrane lifespan, increased feed pressure, increased pre-treatment and Membrane maintenance cost). Different Membrane fouling types, such as colloidal, organic, inorganic, and biological fouling, are addressed in this review. Principles of RO process design and the embedded economic and energy considerations are discussed. In general, cost of water desalination has dropped to values that made it a viable option, comparable even to conventional water treatment methods. Finally, an overview of hybrid RO desalination processes and the current challenges faced by RO desalination processes are presented and discussed.

  • laser doppler electrophoresis and electro osmotic flow mapping a novel methodology for the determination of Membrane surface zeta potential
    Journal of Membrane Science, 2017
    Co-Authors: Tony E Thomas, Saif Al Aani, Darren L Oatleyradcliffe, Paul M Williams, Nidal Hilal
    Abstract:

    Abstract A novel technique employing an Uzigirs dip cell arrangement is used in conjunction with Laser Doppler Electrophoresis for the determination of the surface zeta potential for a UF, NF, and RO Membrane. To the authors best knowledge this is the first study employing Laser Doppler Electrophoresis and Electro-osmotic Flow Mapping for Membrane surface charge determination. High correlation of the regression fit (R 2 >0.95) for a carboxylated polystyrene latex particle electrophoretic mobility was achieved at low electrolyte concentrations (1 mM and 10 mM NaCl), but the reliability and accuracy of the extrapolated zeta potential values were problematic at higher concentration due to high measurement uncertainty (>10% in some cases). Changes in the applied electric field increased the phase resolution of 50 mM NaCl electrolyte solutions between 0.5–2.0 V. However, the effects of Joule heating at higher voltages compromised 50 mM NaCl sample integrity. When compared with the established Tangential Streaming Potential method, Laser Doppler Electrophoresis measurements provided similar zeta potential values and trends indicating that this new methodology can indeed be employed for Membrane Characterization purposes; however, further research needs to be conducted in order to optimize this new technique and set appropriate operating limits.

  • a comprehensive review of nanofiltration Membranes treatment pretreatment modelling and atomic force microscopy
    Desalination, 2004
    Co-Authors: Nidal Hilal, Naif A Darwish, H Alzoubi, A W Mohamma, Abu M Arabi
    Abstract:

    Nanofiltration Membranes (NF) have applications in several areas. One of the main applications has been in water treatment for drinking water production as well as wastewater treatment. NF can either be used to treat all kinds of water including ground, surface, and wastewater or used as a pretreatment for desalination. The introduction of NF as a pretreatment is considered a breakthrough for the desalination process. NF Membranes have been shown to be able to remove turbidity, microorganisms and hardness, as well as a fraction of the dissolved salts. This results in a significantly lower operating pressure and thus provides a much more energy-efficient process. Similar to other Membrane processes, a major problem in NF Membrane applications is fouling. Several studies have investigated the mechanisms of fouling in NF Membranes and suggested methods to minimize and control the fouling of NF Membranes. For NF Membrane Characterizations and process prediction, modeling of NF processes and the use of atomic force microscopy (AFM) are very important. The ability to predict the performance of NF processes will lead to a lower number of experiments, saving of time and money, and help to understand the separation mechanisms during NF. A comprehensive review of NF in water treatments is presented including a review of the applications of NF in treating water as well as in the pretreatment process for desalination; the mechanism as well as minimization of NF Membrane fouling problems; and theories for modelling and transport of salt, charged and noncharged organic compounds in NF Membranes. The review will also address the application of AFM in studying the morphology of Membrane surfaces as part of the NF Membrane Characterization.