| 1. |
- Arandia, Kenneth Gacutno, 1990, et al.
(author)
-
Fouling characteristics of microcrystalline cellulose during cross-flow microfiltration: Insights from fluid dynamic gauging and molecular dynamics simulations
- 2023
-
In: Journal of Membrane Science. - : Elsevier BV. - 1873-3123 .- 0376-7388. ; 669
-
Journal article (peer-reviewed)abstract
- The fouling behaviour of microcrystalline cellulose (MCC) particles on polyethersulfone (PES) membranes was investigated using fluid dynamic gauging (FDG) and molecular dynamics (MD) simulations. Experimental cross-flow microfiltration (MF) of a dilute MCC suspension at 400 mbar transmembrane pressure using 0.45 μm PES membranes revealed an estimated fouling layer thickness of 616 ± 5 μm for both fouled and re-fouled membranes at an applied shear stress of 37 ± 2 Pa. A decline in pure water flux was observed after each membrane cleaning and flushing procedure, indicating that highly resilient layers were formed close to the membrane surface. A possible explanation for the formation of resilient cellulose layers was obtained through MD simulations of the free energy profiles, which predicted deep energy minima at close interparticle separations of the cellulose–cellulose and cellulose–PES systems. The consequence of this energy minima is that attractive and repulsive forces are in balance at a specific distance between the particles, suggesting high binding energy at close interparticle distances. This implies that a certain force is needed to remove the layer or redisperse the cellulose particles. MD simulations also suggested that contributions made by repulsive hydration forces negatively influenced the adsorption of cellulose particles onto the PES membrane. These results highlight how experimental FDG measurements, when complemented with MD simulations, can provide insights into the fouling behaviour of an organic model material during cross-flow filtration.
|
|
| 2. |
- Arandia, Kenneth Gacutno, 1990
(author)
-
Membrane Filtration of Lignocellulosic Materials: In situ Monitoring of Membrane Fouling Using Fluid Dynamic Gauging
- 2023
-
Doctoral thesis (other academic/artistic)abstract
- The transition of process industries from utilizing fossil-based resources to bio-based ones necessitates energy-efficient and selective operations. One practical operation that can be employed for processing streams containing lignocellulosic biomass, such as forest and agricultural residues, is membrane separation. However, the persistent challenge that limits the application of membrane separation in such processes is the deposition of suspended or dissolved substances on the surface or within the pores of a membrane, a phenomenon referred to asmembrane fouling. An in-depth understanding of membrane fouling is therefore necessary to develop appropriate antifouling strategies. In this work, fluid dynamic gauging (FDG) was employed as an in situ and real-time technique for monitoring the fouling characteristics of microcrystalline cellulose (MCC), Kraft lignin, and steam explosion (STEX) liquors on flat-sheet polymeric membranes. Cross-flow microfiltration (MF) was performed for the MCC and Kraft lignin suspensions, whereas cross-flow ultrafiltration was carried out for the STEX liquors. Furthermore, physical and chemical cleaning were performed to the fouled membranes after the cross-flowMF of MCC and Kraft lignin suspensions, respectively, to restore their separation performance. The thickness and strength properties of the fouling layers formed were investigated using FDG. The FDG profiles revealed that the build-up of fouling layers was significantly influenced by the feed characteristics and operating conditions. The thickness of the cake layers varied with changes in process conditions, while the cohesive strength of fouling layers increased towards the membrane due to higher compressive pressures exerted on foulants deposited near the surface. Observations from refouling and membrane cleaning also provided significant insights into the fouling behavior, showing changes in the membrane resistance and flux recovery. These results highlight how FDG can serve as a valuable tool in gaining a better mechanistic understanding of the fouling behavior of streams containing wood components during cross-flow filtration. Such knowledge is essential, especially in developing membrane separation processes for lignocellulosic materials.
|
|
| 3. |
- Arandia, Kenneth Gacutno, 1990
(author)
-
Membrane Filtration of Wood Components − Investigation of Fouling Layer Characteristics using Fluid Dynamic Gauging
- 2022
-
Licentiate thesis (other academic/artistic)abstract
- As process industries transition from using fossil-based to bio-based resources, energy-efficient and highly selective operations will be required to process lignocellulosic biomass. Membrane separation, as a highly efficient operation, can be employed in the fractionation and dewatering of streams containing lignocellulosic biomass. The application of membrane separation in these processes has nevertheless proved to be challenging due to membrane fouling: the process by which suspended or dissolved substances are deposited on the surface or within the pores of a membrane. An in-depth mechanistic understanding of such membrane fouling behavior is therefore necessary in order to devise appropriate strategies to address fouling. In this work, the in situ monitoring technique fluid dynamic gauging (FDG), was used to investigate the fouling behavior of two feed streams containing wood components: a liquor obtained when wood was treated using steam explosion (STEX) and a microcrystalline cellulose (MCC) suspension. The cross-flow ultrafiltration (UF) of STEX liquors was performed at 200 kPa transmembrane pressure (TMP) using 10 kDa polysulfone membranes, whereas the cross-flow microfiltration (MF) of MCC suspensions was operated at 40 kPa TMP using 0.45 μm polyethersulfone membranes. Experimental results show that FDG provides valuable information regarding membrane fouling in both cross-flow MF and UF. The FDG profiles obtained during the STEX liquor fouling experiments revealed that an initial thick fouling layer of high resistance was formed rapidly. After this initial phase, the resistance increased further but only gradually, which may be due to pore blocking and/or rearrangement of the structure of the fouling layer. These results also indicate that the highest resistance of the fouling layer is close to the membrane. In the MCC fouling experiments, highly resilient layers were formed close to the membrane surface, as supported by the presence of attractive energy regions at the close interparticle separations identified via molecular dynamics (MD) simulations. These results highlight how FDG, when complemented with MD simulations, can provide a better mechanistic understanding of the fouling behavior of streams containing wood components during cross-flow filtration.
|
|
| 4. |
- Arandia, Kenneth Gacutno, 1990, et al.
(author)
-
Monitoring Membrane Fouling Using Fluid Dynamic Gauging: Influence of Feed Characteristics and Operating Conditions
- 2023
-
In: Membranes. - 2077-0375. ; 13:10
-
Journal article (peer-reviewed)abstract
- Recent studies on membrane fouling have made considerable progress in reducing its adverse effects. However, a lack of comprehensive studies focusing on the underlying fouling mechanisms remains. This work aims to address a part of this gap by investigating the influence of feed suspension chemistry and operating conditions on the fouling characteristics of microcrystalline cellulose. Fluid dynamic gauging (FDG) was employed to monitor the properties of fouling layers under varied conditions. FDG results revealed that the cohesive strength of fouling layers increased in the direction towards the membrane, which can be associated with the higher compressive pressures exerted on foulants deposited near the surface. At lower pHs and higher ionic strengths, reduced electrostatic repulsions between particles likely resulted in particle agglomeration, leading to the formation of thicker cakes. In addition, thicker cake layers were also observed at higher feed concentrations, higher operating transmembrane pressures, and longer filtration times. The cross-flow velocity influenced the resilience of fouling layers significantly, resulting in thinner yet stronger cake layers in the transition and turbulent flow regimes. These findings regarding the influence of feed characteristics and operating conditions on the fouling behavior can be beneficial in developing effective antifouling strategies in membrane separation processes.
|
|
