Mohammadreza Jafari Eshlaghi

Name: 
Mohammadreza Jafari Eshlaghi
Nationality: 
Iranian
Project ID: 
ESR07
Development of novel nanofiltration (NF) membranes for selective separation between organics and inorganics
Short CV / biography: 

After my bachelor in science in chemical engineering in Iran, I finished my master in science in chemical and process engineering at the university of Bologna, Italy. I did my master thesis on ”phosphate removal of wastewater by ion exchange membrane: a numerical and experimental study” at the Delft university of technology. I am familiar with different separation processes. In my spare time, I like reading books, playing football and hanging out with friends.

Short description of my topic: 

Forward Osmosis (FO) process in water and wastewater treatment has been attracted a huge attention recently, mainly due to its low energy consumption. The distinguishing feature of FO compared to other membrane-based filtrations is the use of osmotic pressure difference as the main driving force for water permeation through a semi-permeable membrane. FO performances heavily depend on membrane (bio)fouling and scaling. Cell geometry, feed and product spacers, type of draw solute and other operation conditions could significantly affect (bio)fouling and scaling behaviour. Due to complexity of system, containing different types of fouling, a numerical model is necessary in order to recognize the quantitative effect of different parameters on the membrane performance. The aim of this project is to implement the numerical models to simulate and predict (bio)fouling behaviour and effect of different parameters on FO performance. 

My progress / state of the art : 

Status PhD

  • PhD successfully defended
  • Supervisors / promoters : Mark van Loosdrecht, Cristian Picioreanu, Arne Verliefde
  • Final title of the PhD thesis: Fouling in Membrane Processes for Water Treatment
  • Place and date of PhD defense (anticipated date if not yet defended): Delft 7-10-2021
  • PhD degree awarding institutions: TUDelft, Ghent University

Publications arising from the PhD

Link to PhD thesis

https://research.tudelft.nl/files/97913951/Dissertation_Mohammadreza_Morez_Jafari_Eshlaghi.pdf

Short abstract/summary

Membranes are widely applied in water and waste water treatment as they provide an absolute barrier against the contaminants. Membranes are offered in wide pore size range and they are applied vastly due to their versatile and cost effective operation in dealing with wide range of streams. However, membranes, like any other filtration systems, suffer from fouling. Fouling layer, accumulation of rejected materials over time on membrane surface, is often called the main bottleneck of membrane processes. Fouling formation reduces water flux, increases energy consumption and leads to the early membrane replacement.

To better control and mitigate fouling layer formation, better understanding of fouling mechanism and properties are required. Fouling properties can be categorized into hydraulic properties, mechanical properties, structural properties, chemical properties. These properties can be impacted by operational conditions, feed water quality and membrane properties. Moreover, these properties influence membrane performance parameters such as water flux, energy consumption and eventually the plant expenses. Therefore, the fouling properties, their inter-relations, their impacts on performance parameters should be further studied. We used novel modelling techniques and experimental measurements in laboratory and full-scale plants to study fouling properties and their impacts on membrane performance parameters. We also discussed the opportunities and challenges for future fouling study.

Chapter 2. To evaluate the relation between structural, hydraulic and mechanical properties of fouling layer in the membrane systems, a novel method to extract these properties was developed to extracted fouling properties in a non-destructive and in-situ technique. The performance parameters of a dead-end UF system with integrated OCT imaging (in-situ) was coupled with a fully-coupled fluid-structural interaction (FSI) model. The dead-end UF was operated under a compression-relaxation cycle to evaluate how fouling properties changes under different applied pressure. Several mechanical models were evaluated to find the most suitable mechanical model to explain the fouling layer behaviour under compression-relaxation cycle in the dead-end UF.

The results indicate that the hydraulic resistance of homogeneous biofilms under UF was much more affected by change in permeability than by the fouling layer thickness. Interestingly, we also found that even a poroelastic model (relatively simple model) can fairly good explain behaviour of the fouling layer in this study under different applied pressures. Compression of the fouling layer in UF systems can significantly increase hydraulic resistance of the membrane systems. In Chapter 2, a new technique was developed to extract fouling properties of the smooth surface biofilms. In Chapter 3 the new technique was further expanded to extract the mechanical properties of rough surface fouling layer under dead-end UF. We observed for the fouling layer which is fed with real surface water (i.e., river water), a dual-layer fouling structure with a thin and dense base layer and a thick and porous top layer could best explain the observed results. We also introduced a new fouling structure indicator, the fraction of exposed base layer, as a good indicator in the determination of water flux in UF systems. ii