Development of Predictive Tools for Membrane Ageing

Pierre LeClech

BOOK

Development of Predictive Tools for Membrane Ageing

Pierre LeClech

(2014)

Additional Information

Book Details

ISBN: 978-1-78040-655-8
Edition: 1
Language: English
Pages: 196
Subjects: The environment
Environmental science, engineering & technology
Water supply & treatment

Abstract

This study increases our current understanding on the degradation/ageing mechanisms occurring on porous membranes used in the water and wastewater industries. Accelerated membrane degradation was obtained through both static and consecutive ageing protocols on the pilot-scale, and a range of carefully selected characterisation and analytical techniques was used to characterise the nascent changes faced by the membrane material.
The report covers four interrelated sections:

Critical assessment of characterisation techniques
Static accelerated ageing
Consecutive accelerated ageing
Consecutive ageing of industrially-aged membranes.

This final report summarises the aims, objectives, outcomes and limitations of the individual work packages, along with some recommendations for future work.
This book is co-published with Water Research Australia.

Section Title	Page	Action	Price
Cover\r	Cover
CONTENTS	v
FIGURES	v
TABLES	v
ABBREVIATIONS	vi
1. INTRODUCTION	1
2. MAIN OBJECTIVES AND OUTCOMES FROM INDIVIDUAL WORK PACKAGES	2
2.1 Critical assessment of the techniques characterising nascent changes in microporous membrane nature (work package 2 – see Appendix 1)\r	2
2.2 Static ageing for better understanding of degradation mechanisms (work package 3 – see Appendix 2)	3
2.3 Validity of accelerated ageing approach in terms of predicting membrane degradation in large-scale applications (work packages 4 & 5 – see appendices 3 and 4)\r	4
3. CONCLUSIONS AND RECOMMENDATIONS	6
4. REFERENCES	7
Appendix 1: Critical Assessment of the Techniques Characterising Nascent Changes in Microporous Membrane Nature Report No. 2\r	i
EXECUTIVE SUMMARY	ii
CONTENTS	iii
FIGURES	v
TABLES	vi
ABBREVIATIONS	vii
1. INTRODUCTION	1
2. MEMBRANE MATERIALS	2
2.1 Hydrophobic/hydrophilic interactions	4
2.2 Mechanical stability	4
2.3 Chemical tolerance	4
3. MEMBRANE FOULING AND CLEANING	6
3.1 Strategies for fouling control/removal	7
3.1.1 Physical cleaning	7
3.1.2 Chemical cleaning	8
3.2 Chemical cleaning in the WT & WWT industry	9
3.3 Cleaning agents and mechanisms	10
3.3.1 Caustics	12
3.3.2 Oxidants	12
3.3.3 Acids	12
3.3.4 Chelating Agents	12
3.3.5 Surfactants	12
3.3.6 Enzymes	12
3.4 Combined cleaning effects	13
3.5 Cleaning strategies	13
3.6 Cleaning efficiencies	14
4. POLYMERIC MEMBRANES AGEING MECHANISMS	16
4.1 Membrane degradation by cleaning agents	16
4.2 Polyvinylidene fluoride (PVDF)	17
4.3 Ageing of Polysulfone (PS) / Polyethersulfone (PES) membrane	18
4.4 Attrition of surface modifiers	19
4.5 Other parameters affecting membrane ageing	19
5. PREDICTIVE TOOLS ASSESSING MEMBRANE AGEING	21
5.1 In-place testing methods	21
5.1.1 Flux recovery and intrinsic membrane hydraulic resistance (Rm)	21
5.1.2 Permeate quality testing	23
5.2 Mechanical assessment	24
5.2.1 Surface characterisation techniques	26
Porosity test	26
Zeta potential analysis	26
Contact angle analysis	27
Electron microscopy (EM)	27
Atomic force microscopy (AFM)	28
Small Angle X-Ray Scattering (SAXS)	29
5.2.2 Chemical assessment	30
X-Ray photoelectron spectroscopy (XPS)	30
Attenuated total reflection - Fourier Transform infrared (ATR-FTIR) spectroscopy	30
Thermal analysis	31
Gel permeation chromatography (GPC)	31
6. ASSESSMENT OF RELIABILITY AND SENSITIVITY OF ANALYTICAL TECHNIQUES	34
6.1 Clean water test	35
6.1.1 Results	35
6.2 Porometry	36
6.2.1 Results	36
6.3 Contact angle	38
6.3.1 Results	38
6.4 Tensile test	39
6.4.1 Results	40
6.5 Thermogravimetric analysis	42
6.5.1 Results	42
7. COMPARISON OF THE MEMBRANE CHARACTERISATION TECHNIQUES	46
7.1 Ranking of the techniques	50
8. CONCLUSIONS	55
9. LIMITATIONS AND RECOMMENDATIONS	56
10. REFERENCES	58
11. ANNEXURE -1 METHODS AND MATERIALS	62
Appendix 2:\rAccelerated Membrane Ageing Study\rReport No. 3	i
EXECUTIVE SUMMARY	ii
CONTENTS	iii
FIGURES	v
TABLES	vi
ABBREVIATIONS	vii
1. INTRODUCTION	1
2. MATERIALS AND METHODS	3
2.1 Membranes	3
2.2 Cleaning solutions	3
2.3 Accelerated membrane ageing experimental conditions	3
2.4 Membrane characterisation	4
2.4.1 Clean water test	4
2.4.2 Bubble point test	4
2.4.3 Contact angle	5
2.4.4 Tensile test	5
2.4.5 Thermogravimetric analysis (TGA)	5
2.4.6 Fourier transform infrared spectroscopy (FTIR)	5
3. RESULTS AND DISCUSSIONS	7
3.1 Effect of membrane rinsing	7
3.2 Accelerated ageing tests	8
3.3 Ranking of membrane stability	11
3.3.1 Presentation of raw data	11
3.3.2 Interim conclusions	13
3.4 Membrane degradation mechanisms during accelerated chemical cleaning	14
3.4.1 Assessment of membrane degradation by NaOCl	14
3.4.1.1 PVDF-HF	14
3.4.1.2 PVDF-HPI	16
3.4.1.3 PVDF-HPO	17
3.4.1.4 PP	17
3.4.1.5 PES	19
3.4.2 Assessment of membrane degradation by SDS	20
3.4.2.1 PVDF-HF	20
3.4.2.2 PVDF-HPI	20
3.4.2.3 PVDF-HPO	21
3.4.2.4 PP	21
3.4.2.5 PES	22
3.4.3 Assessment of membrane degradation by HCl	23
3.4.3.1 PVDF-HF	23
3.4.3.2 PVDF-HPI	24
3.4.3.3 PVDF-HPO	25
3.4.3.4 PP	25
3.4.3.5 PES	26
3.4.4 Assessment of membrane degradation by NaOH	27
3.4.4.1 PVDF_HF	27
3.4.4.2 PVDF-HPI	28
3.4.4.3 PVDF-HPO	28
3.4.4.4 PP	29
3.4.4.5 PES	30
4. CONCLUSIONS	32
5. REFERENCES	34
6. APPENDICES	36
Appendix A: FTIR analysis of NaOCl-aged membrane	36
Appendix B: FTIR analysis of SDS-aged membrane	39
Appendix C: FTIR analysis of HCl-aged membrane	42
Appendix D: FTIR analysis of NaOH-aged membrane	45
Appendix 3: Membrane Ageing During Consecutive Fouling/Cleaning Cyclical Tests\rReport No 4	i
EXECUTIVE SUMMARY	ii
CONTENTS	iii
FIGURES	iv
TABLES	iv
ABBREVIATIONS	v
1. INTRODUCTION	1
2. MATERIALS AND METHODS	2
2.1 Membranes	2
2.1.1 Module preparation	2
2.2 Chemicals	2
2.3 Filtration set up and automatic operational phases	2
2.4 Membrane characterisation	4
2.4.1 Membrane resistance and TMP behaviour	4
2.4.2 Tensile test	5
2.4.3 Thermogravimetric analysis (TGA)	5
2.4.4 Fourier transform infrared spectroscopy (FTIR)	5
2.4.5 Bubble point test	6
2.4.6 Contact angle	6
3. RESULTS AND DISCUSSION	7
3.1 Physicochemical properties of membranes during wetting and rinsing	7
3.2 Initial testing for ageing optimisation	9
3.3 PVDF membrane ageing	11
3.3.1 TMP behaviour	11
3.3.2 Contact angle	13
3.3.3 TGA	14
3.3.4 FTIR	15
3.3.5 Other tests	16
3.4 PP membrane ageing	17
3.4.1 TMP behaviour	17
3.4.2 TGA	19
3.4.3 FTIR	19
3.4.4 Tensile test	20
4. CONCLUSIONS	21
REFERENCES	22
Appendix 4: Fouling/Cleaning Consecutive Testing on Industrially-Aged Membranes\rReport No 5	i
EXECUTIVE SUMMARY	ii
CONTENTS	iii
FIGURES	iv
TABLES	iv
ABBREVIATIONS	v
1. INTRODUCTION	1
2. MATERIALS AND METHODS	2
2.1 Membranes	2
2.2 Module preparation	2
2.3 Chemicals	3
2.4 Filtration set up and automatic operational phases	3
2.5 Membrane characterisation	4
2.5.1 Membrane resistance and TMP behaviour	4
2.5.2 Tensile test	5
2.5.3 Thermogravimetric analysis (TGA)	5
2.5.4 Fourier transform infrared spectroscopy (FTIR)	6
2.5.5 Bubble point test	6
3. RESULTS AND DISCUSSIONS	7
3.1 Membrane ageing	7
3.1.1 TMP Temporal changes during cyclical testing in industrially-aged membranes	7
3.1.2 TGA	8
3.1.3 FTIR	10
3.1.4 Other tests	11
4. CONCLUSIONS	12
REFERENCES	14

Development of Predictive Tools for Membrane Ageing

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