The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Hongjun Lin - One of the best experts on this subject based on the ideXlab platform.

  • novel insights into Membrane fouling in a Membrane bioreactor elucidating interfacial interactions with real Membrane Surface
    Chemosphere, 2018
    Co-Authors: Jiaheng Teng, Liguo Shen, Bao-qiang Liao, Hongjun Lin
    Abstract:

    Abstract While governing adhesion/deposition of various foulants on Membrane Surface and Membrane fouling in Membrane bioreactors (MBRs), interfacial interactions with real Membrane Surface have not yet been fully quantified. In this study, theoretical deduction and experiments were carried out to numerically elucidate interfacial interactions in a MBR. A continuous real Membrane morphology was reconstructed based on atomic force microscopy (AFM) characterization and triangulation technique. Thereafter, a method to calculate those interactions was established by incorporating the spatial relationship between a foulant and the reconstructed morphology into Surface element integration (SEI) method. A case study of the proposed method was conducted. With Surface characterization of the foulants and Membrane, the interfacial interactions with real Membrane morphology were approximated for the first time by computer programming according to composite Simpson’s rule. The results showed that rough morphology prolonged the interfacial interactions, indicating the profound role of morphology in the interfacial interactions related with Membrane fouling. The new method would provide significant insights into Membrane fouling in MBRs.

  • A facile method for simulating randomly rough Membrane Surface associated with interface behaviors
    Applied Surface Science, 2018
    Co-Authors: Xiang Cai, Meijia Zhang, Hongjun Lin, Zhao Leihong, Bao-qiang Liao
    Abstract:

    Abstract Modeling rough Surfaces has emerged as a distinct discipline of considerable research interest in interface behaviors including Membrane fouling. In this paper, a facile method was proposed to simulate rough Membrane Surface morphology. Natural Membrane Surface was found to be randomly rough, and its height distribution obeys Gaussian distribution. A new method which combines spectrum method, Gaussian distribution and Fourier transform technique was deduced. Simulation of the rough Membrane Surface showed high similarity in terms of statistical roughness and height distribution between the simulated Surface and the real Membrane Surface, indicating feasibility of the new method. It was found that, correlation length (l) and the number of superposed ridges (N) are key parameters affecting the simulated Membrane Surface morphology. This new method has evident advantages over conventional modeling methods The proposed method for randomly rough Membrane Surface modeling could be potentially used to quantify the interfacial interactions between two rough Surfaces, giving implications for Membrane fouling mitigation.

  • Influences of fractal dimension of Membrane Surface on interfacial interactions related to Membrane fouling in a Membrane bioreactor
    Journal of colloid and interface science, 2017
    Co-Authors: Xiang Cai, Meijia Zhang, Liguo Shen, Lining Yang, Zhiwei Wang, Huachang Hong, Hongjun Lin
    Abstract:

    Influences of fractal dimension (Df) of Membrane Surface on interfacial interactions related to Membrane fouling in a Membrane bioreactor were investigated based on thermodynamic methods. It was found that Membrane Surface had significant fractal features, and its fractal dimension could be characterized by the power spectrum method. The modified Weierstrass-Mandelbrot (WM) function was found to be effective to model the fractal Membrane Surface, and higher Df corresponded to higher number of fine asperities in the modeled Surface. Moreover, the modeled Surface roughness exponentially decreased with Df. Interaction calculations according to a novel method showed that the interactions for fractal Membrane Surface were elongated and weakened as compared with smooth Membrane Surface. It was interestingly found that the absolute value of total interaction monotonically decreased with Df of Membrane Surface. As Df is a measure of substance stiffness, this result indicates that softer Surface is more susceptible to adhesion by sludge foulant. The results offered new insights into Membrane fouling mechanisms and alleviation.

  • Fractal reconstruction of rough Membrane Surface related with Membrane fouling in a Membrane bioreactor.
    Bioresource Technology, 2016
    Co-Authors: Meijia Zhang, Jianrong Chen, Yuanjun Ma, Liguo Shen, Yiming He, Hongjun Lin
    Abstract:

    In this paper, fractal reconstruction of rough Membrane Surface with a modified Weierstrass-Mandelbrot (WM) function was conducted. The topography of rough Membrane Surface was measured by an atomic force microscopy (AFM), and the results showed that the Membrane Surface was isotropous. Accordingly, the fractal dimension and roughness of Membrane Surface were calculated by the power spectrum method. The rough Membrane Surface was reconstructed on the MATLAB platform with the parameter values acquired from raw AFM data. The reconstructed Membrane was much similar to the real Membrane morphology measured by AFM. The parameters (including average roughness and root mean square (RMS) roughness) associated with Membrane morphology for the model and real Membrane were calculated, and a good match of roughness parameters between the reconstructed Surface and real Membrane was found, indicating the feasibility of the new developed method. The reconstructed Membrane Surface can be potentially used for interaction energy evaluation.

  • Membrane fouling in a Membrane bioreactor: A novel method for Membrane Surface morphology construction and its application in interaction energy assessment
    Journal of Membrane Science, 2016
    Co-Authors: Huachang Hong, Hongjun Lin, Bao-qiang Liao, Rongwu Mei, Xiaoling Zhou, Leihong Zhao
    Abstract:

    Abstract A novel method was developed to construct Membrane Surface morphology in this study. The method was based on fractal geometry theory, and involved a modified Weierstrass-Mandelbrot (WM) function for modeling Surface topography. With MATLAB programming, Membrane Surface could be graphically modeled. It was found that the fractal dimension (Df) and cutoff frequency (Ls) were the two key parameters affecting the topography, and the Membrane Surface constructed by this method could be very close to the real situation. The method was then applied in interaction energy assessment regarding Membrane fouling in a Membrane bioreactor. The procedure which combines Membrane Surface topography construction, Surface element integration (SEI) method and the composite Simpson's rule was theoretically proposed. The Surface properties of foulant and Membrane were experimentally measured. Accordingly, a Membrane Surface was reconstructed for interaction energy assessment. With these data, quantitatively assessing interfacial interactions between foulant particles and a nearly-real rough Membrane Surface is expected to be firstly realized. This study provided a complete solution for quantitative assessment of interaction energies between a foulant particle and rough Membrane Surface.

Huachang Hong - One of the best experts on this subject based on the ideXlab platform.

  • Influences of fractal dimension of Membrane Surface on interfacial interactions related to Membrane fouling in a Membrane bioreactor
    Journal of colloid and interface science, 2017
    Co-Authors: Xiang Cai, Meijia Zhang, Liguo Shen, Lining Yang, Zhiwei Wang, Huachang Hong, Hongjun Lin
    Abstract:

    Influences of fractal dimension (Df) of Membrane Surface on interfacial interactions related to Membrane fouling in a Membrane bioreactor were investigated based on thermodynamic methods. It was found that Membrane Surface had significant fractal features, and its fractal dimension could be characterized by the power spectrum method. The modified Weierstrass-Mandelbrot (WM) function was found to be effective to model the fractal Membrane Surface, and higher Df corresponded to higher number of fine asperities in the modeled Surface. Moreover, the modeled Surface roughness exponentially decreased with Df. Interaction calculations according to a novel method showed that the interactions for fractal Membrane Surface were elongated and weakened as compared with smooth Membrane Surface. It was interestingly found that the absolute value of total interaction monotonically decreased with Df of Membrane Surface. As Df is a measure of substance stiffness, this result indicates that softer Surface is more susceptible to adhesion by sludge foulant. The results offered new insights into Membrane fouling mechanisms and alleviation.

  • Membrane fouling in a Membrane bioreactor: A novel method for Membrane Surface morphology construction and its application in interaction energy assessment
    Journal of Membrane Science, 2016
    Co-Authors: Huachang Hong, Hongjun Lin, Bao-qiang Liao, Rongwu Mei, Xiaoling Zhou, Leihong Zhao
    Abstract:

    Abstract A novel method was developed to construct Membrane Surface morphology in this study. The method was based on fractal geometry theory, and involved a modified Weierstrass-Mandelbrot (WM) function for modeling Surface topography. With MATLAB programming, Membrane Surface could be graphically modeled. It was found that the fractal dimension (Df) and cutoff frequency (Ls) were the two key parameters affecting the topography, and the Membrane Surface constructed by this method could be very close to the real situation. The method was then applied in interaction energy assessment regarding Membrane fouling in a Membrane bioreactor. The procedure which combines Membrane Surface topography construction, Surface element integration (SEI) method and the composite Simpson's rule was theoretically proposed. The Surface properties of foulant and Membrane were experimentally measured. Accordingly, a Membrane Surface was reconstructed for interaction energy assessment. With these data, quantitatively assessing interfacial interactions between foulant particles and a nearly-real rough Membrane Surface is expected to be firstly realized. This study provided a complete solution for quantitative assessment of interaction energies between a foulant particle and rough Membrane Surface.

  • A new method for modeling rough Membrane Surface and calculation of interfacial interactions.
    Bioresource Technology, 2015
    Co-Authors: Leihong Zhao, Meijia Zhang, Jianrong Chen, Yiming He, Huachang Hong, Bao-qiang Liao
    Abstract:

    Membrane fouling control necessitates the establishment of an effective method to assess interfacial interactions between foulants and rough Surface Membrane. This study proposed a new method which includes a rigorous mathematical equation for modeling Membrane Surface morphology, and combination of Surface element integration (SEI) method and the composite Simpson's approach for assessment of interfacial interactions. The new method provides a complete solution to quantitatively calculate interfacial interactions between foulants and rough Surface Membrane. Application of this method in a Membrane bioreactor (MBR) showed that, high calculation accuracy could be achieved by setting high segment number, and moreover, the strength of three energy components and energy barrier was remarkably impaired by the existence of roughness on the Membrane Surface, indicating that Membrane Surface morphology exerted profound effects on Membrane fouling in the MBR. Good agreement between calculation prediction and fouling phenomena was found, suggesting the feasibility of this method.

  • Influence of Membrane Surface roughness on interfacial interactions with sludge flocs in a submerged Membrane bioreactor
    Journal of colloid and interface science, 2015
    Co-Authors: Leihong Zhao, Huachang Hong, Liguo Shen, Hongjun Lin
    Abstract:

    In this study, the interfacial interactions between sludge flocs and a rough Membrane Surface in a submerged Membrane bioreactor were investigated. Models describing these interfacial interactions were firstly proposed based on the Surface element integration (SEI) method. Surface properties of sludge flocs and Membrane were experimentally determined to simulate the models through composite Simpson’s rule. It was found that, roughness on Membrane Surface significantly decreased interaction strength, which enabled the sludge flocs to more easily attach on and detach from the rough Membrane Surface. Further analysis showed that the value of total interaction energy increased with asperity radius, while the strength of total interaction energy decreased with asperity height. Results also demonstrated that increase in floc size would significantly decrease the attractive specific total interaction with rough Membrane Surface. It was revealed that there existed a critical asperity radius above which the total interaction energy in certain separation distance coverage was continuously repulsive, facilitating Membrane fouling control in MBRs. This study demonstrated the possibility to mitigate Membrane fouling by “tailoring” Membrane Surface roughness.

  • A novel approach for quantitative evaluation of the physicochemical interactions between rough Membrane Surface and sludge foulants in a submerged Membrane bioreactor
    Bioresource technology, 2014
    Co-Authors: Hongjun Lin, Meijia Zhang, Jianrong Chen, Rongwu Mei, Huachang Hong
    Abstract:

    This study proposed a novel approach for quantitative evaluation of the physicochemical interactions between a particle and rough Surface. The approach adopts the composite Simpson’s rule to numerically calculate the double integrals in the Surface element integration of these physicochemical interactions. The calculation could be achieved by a MATLAB program based on this approach. This approach was then applied to assess the physicochemical interactions between rough Membrane Surface and sludge foulants in a submerged Membrane bioreactor (MBR). The results showed that, as compared with smooth Membrane Surface, rough Membrane Surface had a much lower strength of interactions with sludge foulants. Meanwhile, Membrane Surface morphology significantly affected the strength and properties of the interactions. This study showed that the newly developed approach was feasible, and could serve as a primary tool for investigating Membrane fouling in MBRs.

Katsumi Miyazaki - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Membrane Surface potential on the uptake and the inhibition of cationic compounds in rat intestinal brush-border Membrane vesicles and liposomes.
    Biochimica et biophysica acta, 1995
    Co-Authors: Mitsuru Sugawara, Michiya Kobayashi, Ken Iseki, Hisako Oikawa, Katsumi Miyazaki
    Abstract:

    The effect of Membrane Surface potential on the uptake of tryptamine, an organic cation, by rat intestinal brush-border Membrane vesicles was investigated. In the presence of an inside-negative K(+)-diffusion potential, the manner of initial uptake of tryptamine appeared to be pH-dependent and the uptake in the acidic medium was lower than that in the neutral medium. Changes in Surface potential of brush-border Membrane vesicles were monitored using 8-anilino-1-naphthalenesulfonic acid (ANS) and the results suggested that the Membrane Surface potential (negative charge on the Membrane Surface) decreased in the acidic medium. A good correlation was observed between the K(+)-diffusion potential-dependent uptake of tryptamine and Membrane Surface potential monitored by ANS at various pH levels. The uptake of tryptamine by liposomes (large unilamellar vesicles), which contained various amounts of dipalmitoylphosphatidylserine (DPPS), was also examined. The uptake of tryptamine decreased with a decrease of DPPS content in the liposomes, and was correlated with the Membrane Surface potential monitored by ANS. Moreover, the effect of organic cations on the uptake of tryptamine by intestinal brush-border Membrane vesicles was examined. The uptake of tryptamine was inhibited by tetracaine and imipramine. The inhibitory effect of these cations was well correlated with changes in the Membrane Surface potential in the presence of tetracaine or imipramine. These results suggest that the K(+)-diffusion potential-dependent uptake of tryptamine by intestinal brush-border Membrane vesicles is affected by Membrane Surface potential, and the inhibition of tryptamine uptake originates in changes in the Membrane Surface potential caused by the organic cations.

  • Effect of Membrane Surface potential on the uptake of anionic compounds by liposomes.
    Biochimica et biophysica acta, 1994
    Co-Authors: Mitsuru Sugawara, Akira Hashimoto, Michiya Kobayashi, Ken Iseki, Katsumi Miyazaki
    Abstract:

    The effect of Membrane Surface potential on the uptake of several anionic compounds by liposomes (large unilamellar vesicles), which contain various amounts of dipalmitoylphosphatidylserine (DPPS), was investigated. The uptake amount of four tested anionic compounds (cefixime, benzyloxyindoleacetic acid (BOIAA), ceftibuten and S-1006) decreased with an increase in the DPPS content of liposomes, and was correlated with the Membrane Surface potential monitored using a fluorescent dye, 8-anilino-1-naphthalene sulfonate (ANS). Moreover, for all of the tested anionic compounds, a good correlation was observed between the ratio of the uptake value (5 min) by each of the liposomes comprising various amounts of DPPS to the uptake value by liposomes containing 10% DPPS and a relative Membrane Surface potential monitored by ANS. On the other hand, the uptake of zwitterionic compounds (enoxacin, cephradine and benzyloxytryptophan (BOTP)) was independent of DPPS content. These results suggest that the uptake of tested anionic compounds by large unilamellar lipid vesicles is dependent on the Membrane Surface potential which originates in the Surface negative charge.

  • changes in the permeation rate of organic anions through the intestinal brush border Membrane with Membrane Surface potential
    Biochimica et Biophysica Acta, 1994
    Co-Authors: Mitsuru Sugawara, Akira Hashimoto, Michiya Kobayashi, Ken Iseki, Takaki Toda, Masaki Takahashi, Katsumi Miyazaki
    Abstract:

    The effects of Membrane Surface potential on the uptake of anionic compounds by rat intestinal brush-border Membrane vesicles were investigated. The uptake amount of all tested anionic compounds (ceftibuten, cefixime, benzylpenicillin, s-1006 and rentiapril) in the neutral medium (pH 7.5) was lower than that in the acidic medium (pH 5.5). Changes in Surface potential of brush-border Membrane vesicles were monitored using a fluorescence dye, 8-anilino-1-naphthalenesulfonate (ANS), and the results suggested an increase of a negative charge on the Membrane Surface proportional to the increase of the pH of medium. A good correlation was observed between the initial uptake rate of all tested anionic compounds and relative Membrane Surface potential monitored by ANS. Moreover, the uptake of cefixime by artificial liposome made from PC containing various amount of DPPS was measured. The uptake value of cefixime was decreased in proportion to an increase of DPPS content. These results suggest that the permeation of anionic compounds across intestinal brush-border Membrane is dependent on Surface potential originate in the Surface negative charge.

  • EFFECT OF Membrane Surface POTENTIAL ON THE PERMEATION OF IONIC DRUGS THROUGH THE INTESTINAL BRUSH-BORDER Membrane
    Drug Metabolism and Pharmacokinetics, 1994
    Co-Authors: Mitsuru Sugawara, Michiya Kobayashi, Ken Iseki, Katsumi Miyazaki
    Abstract:

    The effect of Membrane Surface potential on the permeation of ionic compounds through the intestinal brush-border Membrane was investigated using uptake experiments by brush-border Membrane vesicles (BBMV) and large unilamellar vesicles (LUV). The uptake of anionic compounds (ceftibuten, cefixime, benzylpenicillin etc.) was decreased with increase of Membrane Surface negativity. On the other hand, the uptake of a cationic compound, tryptamine, was increased with increase of Surface negativity. The uptake of these ionic compounds was well correlated with Membrane Surface potential of BBMV and LUV monitored by ANS. These results suggest that the permeation of ionic compounds through the intestinal brush-border Membrane is dependent on the Membrane Surface potential. The mechanism of inhibitory effect on the uptake among these Ionic compounds was also examined from the viewpoint of changes in the Membrane Surface potential. The inhibitory effect of tetracaine and imipramine on the uptake of tryptamine was well correlated with changes in the Membrane Surface potential induced by these organic cations. Similar relation was observed in the inhibitory effect of flufenamic acid on the uptake of cefixime. These results suggest that changes in the Membrane Surface potential contribute to the inhibitory effect on the uptake of these Ionic compounds.

Zhongyi Jiang - One of the best experts on this subject based on the ideXlab platform.

  • Antifouling Membrane Surface construction: Chemistry plays a critical role
    Journal of Membrane Science, 2018
    Co-Authors: Xueting Zhao, Congjie Gao, Runnan Zhang, Yanan Liu, Zhongyi Jiang
    Abstract:

    Abstract Membrane technology has been broadly utilized in water purification including wastewater treatment, seawater or brackish water desalination. However, it often suffers from the severe Membrane fouling due to the nonspecific interactions between Membrane Surface and foulants. Antifouling Membrane Surface construction thus becomes an everlasting and ubiquitous issue, where chemistry plays a critical role in Membrane material design, hierarchical structure manipulation, antifouling mechanism integration and separation performance intensification. Many emerging chemistries enable the rational design and construction of state-of-the-art antifouling Membrane Surfaces. This review will highlight the recent progress in antifouling Membrane Surface construction with a focus on five promising classes of chemistries: bioinspired adhesion chemistry, supramolecular chemistry, mineralization chemistry, click chemistry and coupling chemistry. The contribution of chemistries to the physico-chemical structure, antifouling properties, separation performance and long-term durability of Membranes will be elaborated. Major challenges and perspectives on future directions of chemistries in antifouling Membrane Surface construction will also be tentatively delineated.

  • grafting perfluoroalkyl groups onto polyacrylonitrile Membrane Surface for improved fouling release property
    Journal of Membrane Science, 2012
    Co-Authors: Xueting Zhao, Wenjuan Chen, Jinming Peng, Zhongyi Jiang
    Abstract:

    Abstract In this study, a novel kind of fluorinated polyacrylonitrile (PAN) Membrane is prepared by grafting perfluoroalkyl groups onto aminated PAN Membrane Surface through the acylation reaction. The Surface composition of the fluorinated PAN Membranes is confirmed by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The changes of Membrane Surface hydrophilicity, chemical heterogeneity and Surface free energy after fluorination treatment are evaluated by contact angle measurement. When utilized for the ultrafiltration separation of oil/water emulsion, protein aqueous solution and polysaccharide aqueous solution, the fluorinated PAN Membranes exhibit superior fouling release properties, that is, high flux recovery ratio (∼99%) and low total flux decline ratio (the minimal value is ∼13%). These results demonstrate the feasibility of grafting perfluoroalkyl groups onto the Membrane Surfaces to manipulate the physicochemical features and improve antifouling property. Moreover, the fluorinated PAN Membranes acquire distinct reversible multi-responsive properties under ionic strength and pH stimuli.

  • generation of anti biofouling ultrafiltration Membrane Surface by blending novel branched amphiphilic polymers with polyethersulfone
    Journal of Membrane Science, 2006
    Co-Authors: Zhongyi Jiang, Yanqiang Wang, Yanlei Su, Qiang Sun
    Abstract:

    Branched amphiphilic copolymers with peculiar structural and physicochemical characteristics may find promising application in generating fouling-resistant Membrane Surface. In this study, novel branched amphiphilic copolymers, P123-b-PEGs, were synthesized by reacting Pluronic P123 with PEG400 using PCl3 as a conjugation reagent, and this novel amphiphilic copolymers were blended with polyethersulfone (PES) to prepare ultrafiltration Membranes with superior protein-adsorption-resistant ability. The static water contact angle and X-ray photoelectron spectroscopy revealed the remarkable enrichment of PEO segments at blend Membrane Surface, as well as the inherent relationship between near-Surface coverage and PEO arm number in P123-b-PEG copolymers. Investigations on protein adsorption on blend Membranes showed that the protein adsorption amount was significantly decreased. The results of ultrafiltration experiments revealed that the reversible fouling resistance composed the dominated part of total fouling resistance, which endowed the blend Membranes containing P123-b-PEG copolymers with higher flux recovery ratio.

Menachem Elimelech - One of the best experts on this subject based on the ideXlab platform.

  • relating silica scaling in reverse osmosis to Membrane Surface properties
    Environmental Science & Technology, 2017
    Co-Authors: Tiezheng Tong, Song Zhao, Chanhee Boo, Sara M Hashmi, Menachem Elimelech
    Abstract:

    We investigated the relationship between Membrane Surface properties and silica scaling in reverse osmosis (RO). The effects of Membrane hydrophilicity, free energy for heterogeneous nucleation, and Surface charge on silica scaling were examined by comparing thin-film composite polyamide Membranes grafted with a variety of polymers. Results show that the rate of silica scaling was independent of both Membrane hydrophilicity and free energy for heterogeneous nucleation. In contrast, Membrane Surface charge demonstrated a strong correlation with the extent of silica scaling (R2 > 0.95, p < 0.001). Positively charged Membranes significantly facilitated silica scaling, whereas a more negative Membrane Surface charge led to reduced scaling. This observation suggests that deposition of negatively charged silica species on the Membrane Surface plays a critical role in silica scale formation. Our findings provide fundamental insights into the mechanisms governing silica scaling in reverse osmosis and highlight th...

  • effect of Membrane Surface roughness on colloid Membrane dlvo interactions
    Langmuir, 2003
    Co-Authors: Eric M V Hoek, Subir Bhattacharjee, Menachem Elimelech
    Abstract:

    Recent experimental investigations suggest that interaction of colloidal particles with polymeric Membrane Surfaces is influenced by Membrane Surface morphology (roughness). To better understand the consequences of Surface roughness on colloid deposition and fouling, it is imperative that models for predicting the Derjaguin−Landau−Verwey−Overbeek (DLVO) interaction energy between colloidal particles and rough Membrane Surfaces be developed. We present a technique of reconstructing the mathematical topology of polymeric Membrane Surfaces using statistical parameters derived from atomic force microscopy roughness analyses. The Surface element integration technique is used to calculate the DLVO interactions between spherical colloidal particles and the simulated (reconstructed) Membrane Surfaces. Predictions show that the repulsive interaction energy barrier between a colloidal particle and a rough Membrane is lower than the corresponding barrier for a smooth Membrane. The reduction in the energy barrier is ...

  • Effect of Membrane Surface Roughness on Colloid−Membrane DLVO Interactions
    Langmuir, 2003
    Co-Authors: Eric M V Hoek, Subir Bhattacharjee, Menachem Elimelech
    Abstract:

    Recent experimental investigations suggest that interaction of colloidal particles with polymeric Membrane Surfaces is influenced by Membrane Surface morphology (roughness). To better understand the consequences of Surface roughness on colloid deposition and fouling, it is imperative that models for predicting the Derjaguin−Landau−Verwey−Overbeek (DLVO) interaction energy between colloidal particles and rough Membrane Surfaces be developed. We present a technique of reconstructing the mathematical topology of polymeric Membrane Surfaces using statistical parameters derived from atomic force microscopy roughness analyses. The Surface element integration technique is used to calculate the DLVO interactions between spherical colloidal particles and the simulated (reconstructed) Membrane Surfaces. Predictions show that the repulsive interaction energy barrier between a colloidal particle and a rough Membrane is lower than the corresponding barrier for a smooth Membrane. The reduction in the energy barrier is ...

  • influence of Membrane Surface properties on initial rate of colloidal fouling of reverse osmosis and nanofiltration Membranes
    Journal of Membrane Science, 2001
    Co-Authors: Eric M Vrijenhoek, Seungkwan Hong, Menachem Elimelech
    Abstract:

    Abstract Recent studies have shown that Membrane Surface morphology and structure influence permeability, rejection, and colloidal fouling behavior of reverse osmosis (RO) and nanofiltration (NF) Membranes. This investigation attempts to identify the most influential Membrane properties governing colloidal fouling rate of RO/NF Membranes. Four aromatic polyamide thin-film composite Membranes were characterized for physical Surface morphology, Surface chemical properties, Surface zeta potential, and specific Surface chemical structure. Membrane fouling data obtained in a laboratory-scale crossflow filtration unit were correlated to the measured Membrane Surface properties. Results show that colloidal fouling of RO and NF Membranes is nearly perfectly correlated with Membrane Surface roughness, regardless of physical and chemical operating conditions. It is further demonstrated that atomic force microscope (AFM) images of fouled Membranes yield valuable insights into the mechanisms governing colloidal fouling. At the initial stages of fouling, AFM images clearly show that more particles are deposited on rough Membranes than on smooth Membranes. Particles preferentially accumulate in the “valleys” of rough Membranes, resulting in “valley clogging” which causes more severe flux decline than in smooth Membranes.