Measurement of Rheologically Induced Molecular Orientation Using Attenuated Total Reflection Infrared Dichroism in Reverse Osmosis Hollow Fiber Cellulose Acetate Membranes and Influence on Separation Performance
The objective of this study is to investigate the pure influence of shear and its capacity to increase the separation performance of cellulose acetate reverse osmosis hollowfiber membranes, produced using a dry/wet spinning process with forced convection in the dry gap. In order to achieve this, the...
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Elsevier
2003
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| author | Idris, Ani Ismail, A. F. Noorhayati, M. Shilton, S. J. |
| author_facet | Idris, Ani Ismail, A. F. Noorhayati, M. Shilton, S. J. |
| author_sort | Idris, Ani |
| collection | ePrints |
| description | The objective of this study is to investigate the pure influence of shear and its capacity to increase the separation performance of cellulose acetate reverse osmosis hollowfiber membranes, produced using a dry/wet spinning process with forced convection in the dry gap. In order to achieve this, the experiments are designed to decouple the effect of extrusion shear from forced convection residence time by fixing the residence time at 0.615 s. RO hollow fibers were spun at various dope extrusion shear rates ranging from 3.0 to 4.5 ml/min corresponding to shear rates of around 13,479–20,219 s-1, respectively, at the outer spinneret wall. Fourier transform attenuated total reflection (ATR) also known as internal reflection spectroscopy was used to probe the membrane active layer so as to examine if high shear rates may induce anisotropy at the molecular level in the active layer. The rejection rates of the membranes were evaluated using salt water. Results revealed that: (i) ATR can be used to determine qualitatively and quantitatively—the degree of molecular orientation in the sheared membranes; (ii) molecular orientation is enhanced as the dope extrusion rate increases; and (iii) there exist an optimum shear rate that can induce a certain degree of molecular orientation to yield membrane morphology with optimum separation performance. |
| first_indexed | 2024-03-05T17:55:11Z |
| format | Article |
| id | utm.eprints-788 |
| institution | Universiti Teknologi Malaysia - ePrints |
| last_indexed | 2024-03-05T17:55:11Z |
| publishDate | 2003 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | utm.eprints-7882010-10-25T07:27:25Z http://eprints.utm.my/788/ Measurement of Rheologically Induced Molecular Orientation Using Attenuated Total Reflection Infrared Dichroism in Reverse Osmosis Hollow Fiber Cellulose Acetate Membranes and Influence on Separation Performance Idris, Ani Ismail, A. F. Noorhayati, M. Shilton, S. J. TP Chemical technology The objective of this study is to investigate the pure influence of shear and its capacity to increase the separation performance of cellulose acetate reverse osmosis hollowfiber membranes, produced using a dry/wet spinning process with forced convection in the dry gap. In order to achieve this, the experiments are designed to decouple the effect of extrusion shear from forced convection residence time by fixing the residence time at 0.615 s. RO hollow fibers were spun at various dope extrusion shear rates ranging from 3.0 to 4.5 ml/min corresponding to shear rates of around 13,479–20,219 s-1, respectively, at the outer spinneret wall. Fourier transform attenuated total reflection (ATR) also known as internal reflection spectroscopy was used to probe the membrane active layer so as to examine if high shear rates may induce anisotropy at the molecular level in the active layer. The rejection rates of the membranes were evaluated using salt water. Results revealed that: (i) ATR can be used to determine qualitatively and quantitatively—the degree of molecular orientation in the sheared membranes; (ii) molecular orientation is enhanced as the dope extrusion rate increases; and (iii) there exist an optimum shear rate that can induce a certain degree of molecular orientation to yield membrane morphology with optimum separation performance. Elsevier 2003-03 Article PeerReviewed Idris, Ani and Ismail, A. F. and Noorhayati, M. and Shilton, S. J. (2003) Measurement of Rheologically Induced Molecular Orientation Using Attenuated Total Reflection Infrared Dichroism in Reverse Osmosis Hollow Fiber Cellulose Acetate Membranes and Influence on Separation Performance. Journal of Membrane Science, 213 (1-2). pp. 45-54. ISSN 0376-7388 http://dx.doi.org/10.1016/S0376-7388(02)00511-2 doi:10.1016/S0376-7388(02)00511-2 |
| spellingShingle | TP Chemical technology Idris, Ani Ismail, A. F. Noorhayati, M. Shilton, S. J. Measurement of Rheologically Induced Molecular Orientation Using Attenuated Total Reflection Infrared Dichroism in Reverse Osmosis Hollow Fiber Cellulose Acetate Membranes and Influence on Separation Performance |
| title | Measurement of Rheologically Induced Molecular Orientation Using Attenuated Total Reflection Infrared Dichroism in Reverse Osmosis Hollow Fiber Cellulose Acetate Membranes and Influence on Separation Performance |
| title_full | Measurement of Rheologically Induced Molecular Orientation Using Attenuated Total Reflection Infrared Dichroism in Reverse Osmosis Hollow Fiber Cellulose Acetate Membranes and Influence on Separation Performance |
| title_fullStr | Measurement of Rheologically Induced Molecular Orientation Using Attenuated Total Reflection Infrared Dichroism in Reverse Osmosis Hollow Fiber Cellulose Acetate Membranes and Influence on Separation Performance |
| title_full_unstemmed | Measurement of Rheologically Induced Molecular Orientation Using Attenuated Total Reflection Infrared Dichroism in Reverse Osmosis Hollow Fiber Cellulose Acetate Membranes and Influence on Separation Performance |
| title_short | Measurement of Rheologically Induced Molecular Orientation Using Attenuated Total Reflection Infrared Dichroism in Reverse Osmosis Hollow Fiber Cellulose Acetate Membranes and Influence on Separation Performance |
| title_sort | measurement of rheologically induced molecular orientation using attenuated total reflection infrared dichroism in reverse osmosis hollow fiber cellulose acetate membranes and influence on separation performance |
| topic | TP Chemical technology |
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