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Process optimization of osmosis-based membrane technologies for enhancing performance and controlling fouling in sustainable development of water, energy, and food resources

  • Kim, David (김인혁, 대학원 건축사회환경공학과 환경공학전공)

초록/요약

In the face of major global issues aside from water scarcity, the water industry is currently undergoing a significant paradigm shift into water-food-energy. This work explored the potential of the osmosis membrane based technologies such as forward osmosis (FO), pressure retarded osmosis (PRO), and pressure assisted osmosis (PAO) for sustainable development of water, energy, and food resources. The PRO was integrated with reverse osmosis to simultaneously generate water and energy, executing the water-energy process. The issues to overcome have been discussed based on our results in terms of energy density and water permeation rate. The water-energy production system was also modified in this work to further improve its sustainability. Osmotic dewatering of food liquids was performed via FO as a water-food process. The impacts of operating conditions, draw solution, and feed constitution on the dewatering performance have been investigated and the system has been optimized for its feasible application. PAO also was employed as a water-food process in this study to attain better food quality with higher concentration rate. This study aimed to improve the performance and attain low fouling in the osmosis-based processes in a systematic manner.

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목차

Chapter 1. Introduction 1
1.1. Background 2
1.2. Objectives and scope of thesis 5
1.3. Structure of thesis 5
Chapter 2. Literature review 7
2.1. Forward osmosis 8
2.1.1. Working principle of RO and FO 8
2.1.2. Applications of FO 13
2.2. Pressure retarded osmosis and pressure assisted osmosis 16
2.2.1. Introduction of PRO 16
2.2.2. Fundamentals in PRO 17
2.2.3. Introduction of PAO 18
2.2.4. Fundamentals in PAO 20
2.3. Application of osmosis membrane-based technology for water-energy and water-food processes 22
2.3.1. PRO for the water-energy process 22
2.3.2. Osmotic dewatering for water-food process 26
2.4 References 27
Chapter 3. Integrating pressure retarded osmosis with reverse osmosis for simultaneous water and energy production 32
3.1. Introduction 33
3.2. Material and methods 35
3.2.1. Organic foulants 35
3.2.2. Synthetic wastewater 36
3.2.3. Synthetic seawater and brine 37
3.2.4. Osmosis membrane 38
3.2.5. PRO fouling tests 38
3.2.6. Hydrodynamic cleaning for water flux recovery 39
3.2.7. Anti-scaling pretreatment for fouling mitigation 40
3.3. Results and discussion 40
3.3.1. SEC modeling of the PRO water-energy process 40
3.3.2. Fouling propensity in PRO for water-energy process 45
3.3.3. Fouling control in PRO water-energy process 50
3.4. Conclusion 54
3.5. References 55
Chapter 4. Changing membrane orientation in PRO for sustainable water-energy generation 61
4.1. Introduction 62
4.2. Theories 65
4.2.1. Theoretical background 65
4.2.2. Determining intrinsic parameters to estimate water flux and power density 66
4.3. Materials and methods 67
4.3.1. Osmosis membrane 67
4.3.2. PRO experimental setup 68
4.3.3. Stability tests for PRO membrane 69
4.3.4. Feed and draw solution in PRO experiments 69
4.3.5. PRO fouling tests 71
4.3.6. Physical flushing for fouling reversibility tests 72
4.4 Results and discussion 72
4.4.1. Stability of PRO in AL-FS and AL-DS orientations 72
4.4.2. Estimation of power density in PRO 77
4.4.3. Fouling behavior in PRO in both orientations 80
4.4.4. SEC modeling of the PRO water-energy process 85
4.5. Conclusion 88
4.6. References 89
Chapter 5. Evaluation on suitability of forward osmosis for food processing: Osmotic dewatering for xylose concentration 95
5.1. Introduction 96
5.2. Materials and Methods 100
5.2.1. Xylose as feed solution and its characterization 100
5.2.2. FO and NF membranes 101
5.2.3. FO and NF experimental setups 101
5.2.4. Various draw solutions for osmotic dehydration using FO 103
5.3. Results and discussion 104
5.3.1. Characterization of concentrated xylose feed solution 104
5.3.2. Comparison of NF and FO processes for xylose concentration 107
5.3.3. Improvement of FO in producing concentrated xylose with high quality 111
5.4. Conclusion 119
5.5. References 120
Chapter 6. Improvement of the performance, membrane fouling, and product quality in FO for feasible water-food processing 124
6.1 Introduction 125
6.2. Materials and Methods 127
6.2.1. Osmotic membrane and grapefruit juice as feed 127
6.2.2. FO experimental setup 128
6.2.3. FO performance and fouling experiments 129
6.2.4. Sedimentation and centrifugation for fouling mitigation 129
6.2.5. Pressure assisted osmosis (PAO) system and glucose as the draw solution for improved grapefruit juice quality 130
6.2.6. Characterization of raw and concentrated grapefruit juices 130
6.3. Results and discussion 131
6.3.1. Performance evaluation of osmotic dewatering of grapefruit juice 131
6.3.2. Mitigation of fouling during grapefruit juice dehydration 136
6.3.3. Characteristics of the concentrated grapefruit juice and improvements for enhanced quality 141
6.4 Conclusions 147
6.5. References 148
Chapter 7. Concluding remarks 152

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